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TRANSCRIPT
T a i n a Maria Tuominen
B.SC, (Honours), Simon f r a s e r University, 1972
THESIS SUBMITTED IN PARTIAL FULFILLMENT Of
THE REQUIREifEWTS FOR THE DEGRBE Of
MASTER OF SCIENCE
in the D e p a r t m n t
of
B ioloqical Sciences
@ Taina Maria Tuominen 1980
S I P I O N FRASER UWIVERSITY
December 10, 1980
A l l r i g h t s reserved. T h i s thesis say not be r e p r o a u c e d i n whole or i n part , b y photocopy
or other Beans, without permission of the a u t h o r ,
APPROVAL
Name: Taina M. Tuominen
Degree : Master of Science
T i t l e of Thesis : Seasonal changes in t h e d i e 1 p r o d u c t i v i t y of Macrocyst is
i n t e g r i f o l i a Bory under near - in s i t u cond i t i ons
Examining Committee
Chairman : D r . Robert C. Brooke
/ - , / c .
gr. L. D. ~ r u e h l ; s e n i o r supe rv i so r
D r . L. M. S r i v a s t a v a
- R A - P P
,. , -- ' ~r ."fir E. Vidaver , %of e s s o r , Bio log ica l Sc i ences , Simon Fraser Univer s l ~ y
Publ ic Examiner
Date approved
PARTIAL COPYRIGHT LICENSE
I hereby g r a n t t o Simon Fraser U n i v e r s i t y t h e r i g h t t o lend
my t h e s i s , p r o j e c t o r extended essay ( t h e t i t l e o f which i s shown below)
t o users o f t h e Simon Fraser U n i v e r s i t y L i b r a r y , and t o make p a r t i a l o r
s*ng l e cop ies o n l y f o r such users o r i n response t o a req l tes t f rom t h e
l i b r a r y o f any o t h e r u n i v e r s i t y , o r o t h e r educa t iona l i n s t i t u t i o n , on
i t s own beha l f o r f o r one o f i t s users . I f u r t h e r agree t h a t permiss ion
f o r m u l t i p l e copy ing o f t h i s work f o r s c h o l a r l y purposes may be g ran ted
by me o r t h e Dean o f Graduate S tud ies . I t i s understood t h a t copy ing
o r p u b l i c a t i o n o f t h i s work f o r f i n a n c i a l g a i n s h a l l n o t be a l lowed
w i t h o u t my w r i t t e n permiss ion.
T i t l e o f Thes i s /Pro ject /Extended Essay
Seasonal changes i n t h e . d i e 1 p r o d u c t i v i t y of i n t e g r i f o l i a
Bory under near- i n s i t u cond i t i ons
Author: - -- - -
( s i g n a t u r e )
Taina M. Tuominen
(name
ABSTB ACT b
Near-in situ e x p e r i m e n t s on e n c l o s e d e n t i r e specimens o f
Flac&ggystis i n t e u r i f o l i a of B a r k l e y Sound, 3, C. shoved - s e a s o n a l i t y i n t h e k e l p ' s n e t d i e 1 l i q h t - d e p e n d e n t c a r b o n
f i x a t i o n rates -- s p r i n g r a t e s were t h e qreatest, summer r a t e s
sere intermediate and fa11 r a t e s Mere lowest, Lor f a l l r a t e s
c o i n c i d e d w i t h low t e m p e r a t u r e s a n d low i r r a d i a n c e s . The c a u s e s
o f the o b s e r v e d summer d e c l i n e a r e unknown, b u t n u t r i e n t
d e p l e t i o n i s s u s p e c t e d . No s e a s o n a i i t y was a p p a r e n t i n the
l i q h t - i n d e p e n d e n t c a r b o n f i x a e i o n r a t e s which r a n q e d from 3.2 X
t o 11,1 X of l i q h t - d e p e n d e n t c a r b o n f i x a t i o n r a t e s , t h e ranqe
p a r a l l e l i n g t h e r a n q e of l i q h t - d e p e n d e n t f i x a t i o n r a t e s .
R e s u l t s from t h e determination of e x u d a t i o n l e v e l s
i n d i c a t e d 2.0% dissolved o r q a n i c c a fbon (DOC) e x u d a t i o n . Hinimum
e x u d a t i o n , a s raeasured by r a d i o c a r b o n tracer t e c h n i q u e s , was
q e n e r a l l y less t h a n 1 X and ranqed up t o 3.9 X of t h e p l a n t ' s
c a r b o n a s s i m i l a t i o n a n d a p p e a r e d t o b e d i r e c t l y r e l a t e d t o
i r r a d i a n c e and c a r b o n f i x a t i o n levels. Total e x u d a t i o n
measurements, d e t e r m i n e d b y a n a l y s i s of t h e w a t e r for t o t a l DOC
f i n c l u d i a q l a b e l l e d and u n l a b e l l e d DOC) , q e n e r a l l y d i d n o t
e x c e e d t h e Sechnigue*~ minimum l e v e l of d e t e c t i o n , Based on
c u r r e n t theories of c a u s e s of m a c r o a l q a l e x u d a t i o n , the q r e a t
b u l k of e x u d a t i o n s h o u l d be d e t e c t e d b y r a d i o c a r b o n
tsacer methodoloqy and consequent ly , a y minimum e x u d a t i o n l e v e l s
are proba hl 7 close to rea l i s t i c total ex#dat ion values.
I am q r e a t l y indebted t o L o u i s Druehl, m y s e n i o r
s u p e r v i s o r , f o r t h e s u q q e s t i o n of t h e r e s e a r c h t o p i c , a d v i c e a n d
e n c o u r a q e m e n t t h r o u q h o u t all aspects of t h e s t u d y , and t h e u s e
of h i s b o a t f l o a t fo r experiments, I aa a l s o q r a t e f u l t o
G e o f f r e y sister and Z a l i t S r i v a s t a o a , the r e m a i n i n q aer r tbers of
my supervisory comutittee, f o r t h e i r s u g q e s t i o n s and c o m m e n t s on
t h e s t u d y a n d t h e s i s ,
I an t h a n k f u l to the f o l l o w i n q f o r t h e i r a s s i s t a n c e d u r i n q
t h i s s t u d y : David 8 o r l e y a n d Mickie Yanq f o r t h e i s i n v a l a a b l e
a d v i c e a n d a s s i s t a n c e i n t h e d e v e l o p m e n t of new t e c h n i q u e s ;
David f l o r l e y f o x h i s assistance i n t h e d e s i q n of c o r n p u t o r
proqrarr ts ; H i c k i e Yanq f o r h i s n u s e r o u s c a r b o n a n d n i t r o q e n
a n a l y s e s ; ~ o b i n B o a l , Lana F i t z p a t r i c k , K i t t y L l o y d a n d M i c h a e l
Stanhope f o r t h e i r excellent t e c h n i c a l a s s i s t a n c e d u r i n q t e d i o u s
e x p e r i m e n t s a n d a n a l y s e s ; J o h n Born f o r the d e s i q n a n d
c o n s t r u c t i o n of t h e c y l i n d e r s u p p o r t s y s t e m ; P r a n k V i c k and the
o t h e r aeabers of t h e S,F.U. H a c h i n e Shop for t h e i r c o n s t r u c t i o n
a n d d e s i q n of e q u i p m e n t ; t h e S,F,U, e l e c t r o n i c s S h o p wentbers f o r
t h e i r a i d i n electrical p r o b l e m s ; Ron Loag f o r h i s p h o t o q r a p h i c
a s s i s t a n c e ; Huqh B a r c l a y for h i s s t a t i s t i ca l c o n s u l t a t i o n ; the
t e c h n i c a l s t a f f o f t h e B a n i f i e l d B a r i n e S t a t i o n f o r t h e i r a i d
w i t h e q u i p m e n t r e p a i r s ; T a r j a T u o n i n e n f o r typing. tables; a n d
~ u u l a T u o m i n e n for t h e k e l p i l l u s t r a t i o t , 1 am a l s o q r a t e f u l t o
- C h a r l e s scrivener of the P a c i f i c Bioloqical Station, Nanaiao,
3. C, for k i n d l y prov id inq pyreheliometer d a t a and t o John Case
for obtaining the two larqe p l a s t i c cylinders from t h e Ceper
Project a t Saanich, 0. C.
TaBLE OF C O l T E 8 9 S
. . Approval ................................e.....e...e...........~~ . . . ....................................................... abstract
Acknonledqements ............................................... . . .
L i s t of Tables ............................................. V L I I
L i s t of F i q u r e s ...............................................~ A . Introttuctirsn.... ............................................ 1
B. Nakeria3.s and Bethods ...........~..e.....................m.. 5
Exper imenta l and collection sites ................... ,.5 E x ~ e r i m s n t a l a p p a r a t u s ................................ 7
E x p e r i ~ e n t a l procedure ....e.........m......l......... 13
DOC in n a t u r a l k e l p beds ............................. 30
S t a t i s t i c s ........................................... 30
C* Result~..~~.~...+..~.~ ~ * t m m m m e m t m m e m * * m * * m e m m m m e m * a m s m m e e m m 3 I
Environmental c o n d i t i o n s ........................~.... 3 1
Carbon fixation r e s u l k s .............................. 34
Exudation of o r q a n i c carbon .......................... 46
....... Carbon and n i t r a q s n c o n t e n t o f t h e &acz:oc~s$&$ 58
Dm D i s c a s s i o n ................................................. 61
~ r p e r i @ e n t a l Approach ..................we........-.... 61
................................. Expet iaen%al Results 6Y
............................................. L i t e r a t u r e C i t e d 70
Appwidi .~ m.mmae.~.m..ma.m..mm..~~.~......~...m.....*.*. m . * m a * * 8 7
vii
LIST OF TABLES
Tab le
E n v i r o n m e n t a l c o n d i t i o n s p r e s e n t d u r i z g . 24 h and 48 h
e xp er i r a en t s,
E n v i r o n m e n t a l c o n a i t i o n s p r e s e n t d u r i n g 'dark *
e x p e r i a e n t s ,
Ca rbon f i x a t i o n results e x p r e s s e d a s mqC qdw-1 for 2Q h
p e r i o d and a s mql: gdw-a h l i q h t - 1 .
a p p l i c a t i o n o f t h e ' A p p r o x i i t ~ a t e T e s t of E q u a l i t y of
Beans when V a r i a n c e s are H e t e r o q e n e o u s v t o s e a s o n a l
means of c a r b o n fixation r e s u l t s .
Net c h a n q e s i n t h e t o t a l i n o r q a n i c c a r b o n content o f the
e x p e r i m e n t a l cylinder's water d u r i n g 2 4 h a n d 48 h
e x p e r i m e n t s ,
Compar i son o f l i q h t - d e p e n d e n t a n d l i q h t - i n d e p e n d e n t n e t
c a r b o n f i x a t i o n rates,
Levels of DOC, as e s t i ~ a t e d by the l a b e l l e d DOC ( D O t T +
POD 4C) data, i n t h e i n c u b a t i o n water a t d u s k a n d a t dawn
when compared t o i n i t i a l and c o n t r o l l e v e l s ,
Levels of DOC, as e s e i m a t e d by t h e t o t a l DOC {TDOC * TPOCf data, i n the i n c u b a t i o n water a t d u s k and a t d a m
when c o n p a r e d t o i n i t i a l and c o n t r o l l e v e l s .
T a b l e Paqe
Levels of p a r t i c u l a t e c a r b o n a t d u s k and a t dawn as
e s t i m a t e d by TPBC, P O C V and ATP r e s u l t s ,
DOC and POC l e v e l s a t Kirby P t , Cove and S . Dodqer
Channel kelp b e d s a t v a r i o u s tilaes of the year. 57
Dry weights, c a r b o n and n i t r s q e n levels and C/N r a t i o s
of plants u s e d for 24 h , 40 h and dark experinrents. 59
a , R e s u l t s of I -nay Analyses of V a r i a n c e for carboc
c o n t e n t , nitrogen c o n t e n t and C/H ratios of Macroc~stis
& ~ g q ~ j , f o l i a w i t h respect to season,
b, Results of ~ u l t i p l e c o m p a r i s o n s of s e a s o n a l C, N and
C/N coatents o f 4. inteqgf$g&ia usinq t h e
student-Neuaari-Xeuls test.
LIST OF FIGURES
F i q u r e Paqe
1. Map of san tp l inq a n d e x p e r i m e a t a l sites i n Bark lev S o u n d ,
0, Cw 5
2. Drawinq of the c y l i n d e r - c a r b o y systern. 8
3. '&Q. P h o t o q r a p h of t h e empty cylinders a f loa t ,
Bo t , t~&. Pho tog raph of t h e c y l i n d e r s h a l f f u l l of s e a w a t e r , 3
2 9 . P h o t o g r a p h of a c y l i n d e r f u l l of seawater w i t h the
l i d a n d Zcubinq a t t a c h e d ,
Bo t toa . Pho tog raph o f the two c a r b o y s f e x p e r i mental. and
c o n t r o l ) which are c o n n e c t e d by t u b i n q t o t h e two
c y l i n d e r s , 10
4, T h e t o t a l DOC a n a l y s e r , 2 1
5, Tee. Pho tog raph of t h e k e l p q r i n d e r b e i n g ro l l ed on t h e
floor.
f!oJ&p~, P h o t o q r a p h of o v e n - d r i e d k e l p b e i a q p l a c e d i n t o
the kelp q r i n d e s ,
6, H i s toq rams of n e t c a r b o n f i x e d , t o t a l n e t c a r b o n fixed
and n e t qrowth i n s p r i n q , s u m m r and fall 24 h and 48 h
e x p e r i ~ e n t s, His toq rams of total d a i l y i r r a d i a a c e f o r
each e x p e r iaen-t are a lso p r e s e n t e d , 35
Paqe
S c a t t e r q r a l g of h o u r l y t o t a l n& c a r b o n fixation r a t e s
p l o t t e d a q a i n s t h o u r l y quantum i r r a d i a n c e l e v e l s ,
Histograms of h o u r l y n e t f i q h t - i n d e p e n d e n t carbon
f i x a t i o n rates i n s p r i a q , s u a a e r a n d f a l l , 4 4
W i s t o q r a a s of DOC l e v e l s i n t h e i n c u b a t i o n water, a s
e s t i n s a t e d by t h e l a b e l l e d DOC iDOg*C * Pot W) r e s u l t s ,
a t d u s k and at davn when compared t o i n i t i a l a n d c o n k r o l
l e v e l s . 47
S c a t t e r q r a a t of dusk DOC (h l i q h t ) -1 r e l e a s e d , a s
e s t i m a t e d by t h e l a b e l l e d D O L W * PO%% r e s u l t s , p f o t t e d
a q a i n s t a v e r a g e h o u r l y q u a n t u a i r r a d i a n c e s i n d i e 1
experiments, 48
S c a t t e r q r a a t of dusk DOC {h l i q h t ) - a r e l e a s e d , as
e s t i m a t e d by t h e l a b e l l e d D O S V * POI% results, p l o t t e d
a q a i n s t average hourly t o t a l n e t carbon f i x e d in d i e 1
e x p e r i ~ e n t s . 50
H i s t o q r a m s of DOC l e v e l s i n t h e incubation water, a s
esti laated by the t o t a l DOC ITDOC + TPOC) r e s u l t s , a t
d u s k and a t dawn whea compared t o i n i t i a l and controi
l e v e l s , 5 2
(Appendix) A s t a n d a r d c u r v e f o r t h e t o t a l DOC a n a l y s i s . 88
8. Introduct ion
The p u r p o s e o f t h i s study was t o d e t e r a a i n e d i e 1
p r o d u c t i v i t y of the lesser q i a n t k e l p , Hacrocystis &&garifof ia
Bor y (Order L a m i n a r i a P e s ) u n d e r near-An_ &$_u c o n d i t i o n s dur i n q
d i f f e r e n t t imes of t h e yea r , I t was n e c e s s a r y t o modify soma
existins a n a l y t i c a l , t e c h n i q u e s t o a c h i e v e a h i g h e r level o f
p r e c i s i o n t h a n was p r e v i o u s l y p o s s i b f e,
The p r i m a r y p r o d u c t i v i t y of g, i ~ t e q h i f o l i a has b e e n the
f o c u s of f e u q u a n t i t a t i v e s t u d i e s . P r e v i o u s s t u d i e s c a n be
divided i n t o t u o c a t e q o r i e s -- t h e f i e l d a p p r o a c h and the
l a b o r a t o r y approach . F i e l d s t u d i e s have p r o v i d e d i n f o m a t i o n o n
wet weiqh t qaia for p l a n t s t r a n s p l a n t e d t o a non-ke lp bed
locat ion IDruehl , m?), stipe e l o n y a k i o n rates (Scaqel, 3948;
Sharp , 1975; Lobban, 1976, 1378) a n d b l a d e e l o n q a t i o n rates
(Sharp , 3 975) . The l a b o r a t o r y a p p r o a c h i n v o l v e d o b s e r v a t i o n s on
c a r b a n f i x a t i o n r a t e s by e x c i s e d b l a d e d i s c s under l a b o r a t o r y
c o n d i t i o n s ( # i l l e n b r i n k 8% a_., 1979) .
The q i a a t r e l a t i v e of 4, jaggqg&f_o_.&, 4. ~xa&ga_ /L.) C.
Bq, h a s been t h e subject of s e v e r a l p r o d u c t i v i t y s t u d i e s . Its
p r o d u c t i v i t y h a s been e s t i i n a t e d b y c h a n q e s i n s t a n d i n g cfop
(Alee@, 1 9 5 & ) , c h a n q e s i a the d i s s o l v e d oxyqen content o f t h e
kelp bed waters f @ c F a r l a n d a n d P s e s c o t t , 1959) , s t i p e e l o n q a t i o n
rates f C r i b b , 3954; Horth, 3361; Neushul and Haxo, 7963), uptake
of z a d i o c a r bun by i n d i ~ i d u a l attached blades { T o w l e and Pearse,
3973) and b y sxyqen p r o d u c t i o n by e x c i s e d s e c t i o n s of b l a d e s
e n c l o s e d i n b o t t l e s IS a r q e n t a n d L a n t r i p , 1952; Clendenn i n q ,
1964; L i t t l e r aad Hurray, 197Ua,b),
AT1 of the p r e c e d i n q s t u d i e s f a 1 9 short o f a c c u r a t e l y
d e t e r a i n i n q the n e t p r i r a a ry p r o d u c t i v i t y of a n e n t i r e
Ilas25;9sgis plant, Chanqes i n s t a n d i n g c r o p p r o v i d e i n f o r m a t i o n - oa har v e s t a b l e b i o m a s s b u t , b e c a u s e o f unmeasured loss of
biornass d u e t o s l o u q h i n q a n d qrazinq, f a i l t o a c c u f a t e l y measu re
t h e p r i m a r y p r o d u c t i v i t y ( P o s e m y , 196'1). The McFar lana and
P f e s c o t t (1959) study on c h a n q e s i n d i s s o l v e d oxyqen c o n t e n t of
kelp bed waters f a i l e d t o a c c o u n t for m e t a b o l i s m b y o t h e r
o r g a n i s n t s i n the coreimrunity and c h a n q e s ia oxyqen levels clue ' to
diffusion a n d c u r r e n t s , The s e i p e e l o n q a t i o n rates d o not
t r ans l a t e d i r e c t l y i n t o b i o n a s s increases d u e t o t h e changinq
l e n q t h s of i n t e r n o d e s a lms the s t i p e (Lobban, 1978)
Extrapolatioas o f whole p l a n t p r o d u c t i v i t y from
p r o d u c t i v i t y measu remen t s made on excised p o r t i o n s o f t h e k e l p
are d i f f i c u l t because of t h e k e l p " spatial p h y s i o l o q i c a l
d i v e r s i t y , fur exaaple , t raasloca t i o n o f a s s i ~ i l a t e s f r o a n a t u r e
b l a d e s t o young blades and f r o n d s h a s been d e n o n s t r a t e d (Parker,
1963, 1965; Lobban, 1977, l W 8 ) , Yaryinq l e v e l s o f
p h o t o s y n t h e s i s a l o n q a b l a d e (Clendenning, 1964; Towle and
P e a r s e , 1973) and w i t h r e s p e c t t o the age a n d p o s i t i o n of t h e
b l a d e {Sarqenk and L a n t r i p , 1952; T o w l e and P e a r s e , 1973) have
been measu red i n &, sy r i f f egq , F u r t h e r u m r e , e s t i ~ a t e s o f an
i n t a c t p l a n t ' s p r o d u c t i v i t y f rom t i s s u e s e q a e n t s h a v e been
de~onstrated t o q i ~ e u n r e a l i s t i c r e s u I % s . H a t c h e r ' s (1977)
corn parisonas of p h o t o s y n t h e s i s and r e s p i r a t i o n rates o f t i s s u e
s e q a e n t s v e r s u s whole t h a l f i of & g j g i n a s h demonstrated t h a t the
h i q h i n i t i a l r e s p i r a t o r y r a t e of t h e t i s s u e seqenent required 10
h o u r s t o r e t u r n t o t h e lower respira tory rate o f the whole
u n i n j u r e d t f ia l lus a n d t h e t i s s u e seqraen t showed q s e a t e r
v a r i a b i l i t y i n p h o t o s y n t h e s i s and r e s p i r a t i o n r a t e s ,
I n a11 of the a b o v e s t u d i e s , a n a s s e s s m e n t o f t h e p l a n t a s
released d i s s o l v e d o r g a n i c c a r b o n (DOC] was either i m p o s s i b l e
due t o t h e naethods used or i t was n o t c o n s i d e r e d , T h e r e is s o w
controversy on t h e i a p o r t a n c e or e x i s t e n c e of e x t r a c e l l u l a r
release o f DOC with respect t o t h e p r i m a r y p r o d u c t i o n o f taarine
a a c r o p f i y t e s , Some s t u d i e s i n d i c a t e c o n s i d e r a b l e r e l e a s e (Foqq
and Boalch , 3958; C r a i g i e and McLachlan, 1964; Kha i lov and
Bur l akova , 1969; S i e b u r t h , 1969; S i e b u r t h and J e n s e n , 1369;
Kroes, 1930) w h e r e a s o t h e r s t u d i e s report the r e l e a s e of
organics t o be low o r n o n - e x i s t e n t (Ma jak gg a&. , 1'966; Hoebus
and Johnson, 1974; H a r l i n and Craiqie, 1975; B r y l i n s k y , 1977;
Fankboner and deBurqh, 1977; P e n h a l e and S ~ i t h , 1977; Raqan and
Jensen, 1973) ,
An accurate a s s e s s m e n t of a a a c r o p h y t e B s c a r b o n u p t a k e and
release r e q u i r e s some forta of c o n t a i n m e n t . Fo r a e a s u r e m e n t of
the. c a r b o n flux of an e n t i r e plant a n d t h u s , t h e i n f l u e n c e o f
t h e mac rophy te on its s u r r o u n d i n q envi ron inen t , enclosure of t h e
e n t i r e p l a n t and monitorinq of t h e w a t e r w i t h i n t h e enclosure
would seem a realistic approach. G u t e r s t a m 41977) and Hatcher
( 1 977) h a v e measured the primary p r o d u c t i v i t y of the
m a c r o p b y t e s , Fucus and Lminqrig respectively & situ, b y
desiqniaq larqe a b o t t l e s a t o e n c l o s e the entire p l a n t ,
Similarly, in this s t u d y , 1 h a v e u s e d an e v e n lasqer ' b o t t l e * t o
e n c l o s e a n entire B. i n t e u r i f o l & p l a n t , This larqe * b o t t l e s was
p l a c e d i n t h e water column and p r o d u c t i v i t y was a e a s u r e d by
carbon tracer t e c h n i q u e s ,
Seasonality i n t h e qrouth rates and p h o t o s y n t h e s i s of
rsarine aacrophytes has been d e m o n s t r a t e d by v a r i o u s reseasc hers
{Parke, 1948; 3,,;ning, 1971; Yokohama, 1971; Zavodnik, 1973;
Buqqela , 1974; B a t h i e s o n and N o r a l l , 1975; Kinq and Schramm,
1976; B r i n k h u i s , 1977a , b,c; Chapman and ~ r a i q i e , 1977; Hatcher t
& &, 1977; Lobban, 197%: Niernect and B a t h i e s o n , 1978; Chock
and Hathieson, 1979; Littler _e& sf*, 1679) and was a l s o
i n v e s t i g a t e d i n this study,
EL !laterials and Bethods
Ex~e;cirne_nta, gg&gction _s&tg_s
The e x p e r i n t e n t s Mere conducted a t Port ~ & h r e / , G r a p p l e r
I n l e t , i n B a r k l e y Sound, B, C , , Canada (Fig, 1) d u r i n q s p r i n q
( A p r i l 26 t o May 26), summer ( J u l y 79 t o Ruqust 8 ) and fall
(October 31 to December 6 ) in the years 1977 and 1978,
The p l a n t for experiraent 1 was collected a t Mud Cove; t h e
p l a n t s for a l l o t h e r e x p e r i m e n t s were c o l l e c t e d a t Kirby P t .
Cove (Pig, I ) , Kirby Pt, Cove was chosen b e c a u s e of its
a c c e s s i b i l i t y durinq most w e a t h e r c o n d i t i o n s and t h e p a u c i t y of
e p i p h y t e s o n g, &&errrifolQ a t t h a t site, Small. @(commonly < 2m
i n l e n q t h ) plants with at l e a s t one a p i c a l sciloi-tar (qrowinq
t i p ) v e r e c o l l e c t e d usinq SCUBA, After c o l l e c t i o n , t h e fronds
were wrapped i n s e a w a t e r - s o a k e d paper t o w e l l i n q , placed i n t o a
plastic bucket and transported to Port Idsire/ where t h e y vere
a t t a c h e d onto b r i c k s and suspended i n - t h e water from the boat
f l o a t a w a i t i n q e x p e r i m e n t . The time o u t of water n e v e r e x c e e d e d
1.5 he
Pigure 1, Rap of sampliag and experitaental sites in Barkley
Sound, 8, C,
Two s u b r ~ e r s i b l e clear a c r y l i c plastic cylinders c o n n e c t e d
by a s y s t e m of t u b i n q t o a s e p a r a t e carboy l o c a t e d a b o v e the
w a t e r were used f o r t h e e x p e r i m e n t a l i n c u b a t i o n s f F i q . 2 ; Fiq,
31, An entire , i n t e ? r i f o l & _ a p l a n t was p l a c e d i n t o o n e cylinder
I e x p e r i m e n t a l c y l i n d e r ) ; t h e s e c o n d c o n t r o l c y l i n d e r c o n t a i n e a
no p l a n t . T h e c y l i n d e r s were 102 c~ d i a m e t e r x 214 cm h e i q h t x
1,9 ern t h i c k n e s s with a c a p a c i t y 5 5 1750 1, The c y l i n d e r s Yere
supported in the water by lines a t t a c h e d t o a wooden boom a t a
d i s t a n c e of 1,3 m from the f l o a t .
A 53 cm d i a m e t e r hole located a t t h e t o p of e a c h c y l i n d e r
was covered by a D,64 cm thick clear p l e x i q l a s s l i d b o l t e d t o
the c y l i n d e r a n d s e a l e d by a neop rene r u b b e r 0 - r i n q coated w i t h
si l icone s t o p c o c k qrease. Each l i d was e q u i p p e d w i t h one n i p p l e
f o r a v a l v e c o n n e c t i o n ( f o r b l e e d i n s a i r d u r i n q f i l l i a q ) (Pig
3 . , BY), two nipples for tubinq c o n n e c t i o n s and +-wo h o l e s for
the e l ae rqence of t w o electrical wires t o two s u b m e ~ s i b l e pulnps
(Fiq . 3, PU) located within each c y l i n d e r . R 1 1 n i p p l e
a t t a c h a e n t s were w a t e r - t i q h t a n d t h e h o l e s for t h e electrical.
wires were s e a l e d w i t h 0 - r i n q s . T h e t u b i n q (1,27 cm I.D.
nylon-re inf o r c e d p o l y v i n y l c h l o r i d e fPVC) h o s e and t y q o n t u f i i n q
( N a r t o n * ~ RGD L a b o r a t o r i e s , Akron, Ohio) ) c o n n e c t e d t h e c y l i n d e r :
f i q u r e 2, ~ r a w i n q of the c y l i n d e r - c a r b o y system.
K e y t o symbo2s,
b l e e d v a l v e
carboy
c o a r s e c o t t o n ba t t en f i l t e r
qlass f i b r e filter d i s c
s u b m r s i b f e pump
re se r voi r c a r b o y
se,rum stopper
sampling p o r t
va l v e
CONTROL I I I I
CYLINDER U U
F i g u r e 3, '1
Tog. Photograph of the empty c y l i n d e r s afloat, --
Bottom, Photoqraph of the c y l i n a e r s half full of ----- seawater .
F i g u r e 3 Icont.)
222. Photograph of a c y l i n d e r full of seawater with t h e l i d
and t u b i n q a t t a c h e d .
Bottom, Photoqraph of t h e two carboys (experimental and ------ control) which are c o n n e c t e d b y t u b i n q t o the two c y l i n d e r s ,
to a 38.9 1 nalqene (Sybron Corp , . R o c h e s t e r , W. Y e )
p o l y e t h y l e n e carboy { F i q . 3, CA) located on t h e float, One set
of tubinq t r a n s p o r t e d water f rom the c y l i n d e r t o t h e c a r b o y ' s
inlet located near the lid of the carboy and t h e other set of
t u b i n q t r a n s p o r t e d water f rom the c a s b o y t s o u t l e t # l o c a t e d near
the bottom of the c a r b o g ) b a c k t o the cylinder, A spiqot on t h e
carboy was used as a samplinq p o r t (Fiq. 3, SP). Each carboy was
sealed w i t h an O-ring p l a c e d u n d e r the l i d .
T h e t u b i n q t r a n s p o r t i n q water f rom the carboy t o t h e
cylinder was i n t e r r u p t e d , j u s t beyond +,he c a r b o y o u t l e t , b y a
nylon 'T* comection which a l l o w e d f o r the i a s e r t i o n of a r u b b e r
serum s t o p p e r {Piq, 3, SS) , R a d i o c a r b o n - c a r b o n a t e was i n t r o d u c e d
t h r o u g h t h i s serum s t o p p e r , The t o t a l volume o f the
c y l i n d e z - c a r b o y - t u b i n q c l o s e d systea was 1770 1. . Circulation within each c y l i n d e r - c a r b o y c l o s e d s y s t e m was
p r o v i a e d by one subaersible pump (Hodel LC-2C-AC March
Epoxy-clad purapI R a r ~ h EIfq, Co., G l e n v i e v , I l l i n o i s ) , Further
circulation within the cylinder was p r o v i d e d by t h e second March
submers ible pump, To prevent eanta n q l e n e n t of t h e experilaentaf.
p l a ~ t w i t h the pumps, both pumps were e n c l o s e d i n a perforated
p l a s t i c bucket . The e x a c t r a t e of c i rculat ion was unknown;
however, when f l u o r e s c e i n dye was injected i n t o the s y s t e m at
t h e serunr s t o p p e r , it t o o k 3 nin f o r the d y e t o c i r c u l a t e back
to t h e seruw s t o p p e r ,
S e a w a t e r for t h e two c y f i n d e r s y s t e m s was provided b y a
common seawater f i l t e r i n q c o s p l e x c o n a e c t e d t o e a c h s y s t e m by a
separa te v a l v e {P ig , 3, V), The f i l t e r i n g complex c o n s i s t e d of a
s u b m e r s i b l e pump w h i c h pumped seawater f r o % a depth of 1.5 tn t o
a series of f o u r c o t t o n batten filters, supported by p e r f o r a t e d
p l a s t i c buckets {Fiq . 3, C 3 3 . The Buckets were s u s p e n d e d , i n a
series, a b o v e a 190 3, p l a s t i c bucke t . A s u b a e r s i b l e pump w i t h i n
t h e 190 1 bucke-t d r o v e t h i s * c o a r s e l y q f i l t e r e d water, t h r o u q h a
39 d i a m e t e r p o s i t i v e p r e s s u r e filter d i s c s u p p o r t i n q a
Whatman (Bhatman f n c . , C l i f t o n , N, J, f GF/D qlass f i b r e f i l ter
(retention d i a m e t e r = 2.7JCcm) f F i q , 3, GFF) to a 51 1 n a f s e n e
p o l y e t h y l e n e r e s e r v o i r * c a r b o y ( P i q , 3, BC) . The s p i q o t a t the
bottoln of t h e r e s e r v o i r c a r b o y was c o n n e c % e d to kubinq which l e d
t o a n y l o n q Y * c o n n e c t o r which d i v i d e d the rater for the
enperintental. and c o n t r o l c y l i n d e r s , C l o s i n q t h e c o n n e c t i n q
v a l v e s i s o l a t e d e a c h c y l i n d e r s y s t e m f rom the r e s e r v o i r c a r b o y
a n d t h e o t h e r c y l i n d e r sy s t em. Eight h o u r s were r e q u i r e d f o r
f i l l i n q both c y l i n d e r s y s t e ~ s ,
The a b o v e a r r a n g e m e n t a s s u r e d t h a t backq round p a r t i c u l a t e
matter l a r q e r t h a n 2,7/Lcm diameter was f i l t e r e d from t h e water
and t h a t b o t h c y l i n d e r s y s t e m s r e c e i v e d s i n i l a s water.
J o h n s t o n (1969) r e c o m a e n d s a q dry w e i q h t o f s e a v e e d / l
volume of i n c u b a t i o n laedia r a t i o of 0 ,1 t o 0,3 t o p r e v e n t
n u t , r i e n t or carbon d i o x i d e d e f i c i e n c i e s i n 2 4 h i n c u b a t i o n s , The
p l a n t i n e x p e r i ~ e n t 2, with a dry weiqh t / vo lume r a t i o of 0.52
e x c e e d e d t h e s e lilpits; a l l o t h e r 24 h or 48 h e x p e r i m e n t s
[ r a t i o s r a n q i n q from 0,03 t o 0.22) were w i t h i n t h e recolamefided
l i m i t s ,
Pre-exper heat preparation
Each e x p e r i i i i e n t a l p l a n t was hosed with filtered s e a w a t e r
and v i s i b l e e p i p h y t e s were removed before t h e plant was p l a c e d
ia t h e c y l i n d e r , The p l a n t s v e r e a l l o w e d t o a c c l i m a t i z e t o t h e
cylinder cond3.tions for a t least 12 h for 2 @ h a n d 48 h
e x p e r i m e n t s a n d a p p r o x i m a t e l y 24 h for d a r k e x p e r i m e n t s , Dur inq
t h i s period filtered water was f l u s h e d throuqh the cylinders,
Before dawn t h e next a o r n i n q (for 24 h or 4 8 h e x p e r i m e n t s )
or a t d u s k the n e x t d a y (for d a r k e x p e r i m e n t s ) , t h e c y l i n d e r s
vere s e a l e d , c o n v e r k i n q t h e open f low- throuqh system into a
closed c i r c u l a t i o n systea, 811 l i n e s , f i t t i n q s , a n d containers
were i n s p e c t e d f o r t r a p p e d a i r which was always removed, The
cylinders were then lowered s o that t h e i r t o p s were 0 . 3 m below
t h e water's s u r f a c e ,
E x g e r imenit
T o s t a r t an e x p e r i a e n t a a*C c a r b o n a t e s o l u t i o n was
i n j e c t e d w i t h a syriaqe t h r o u q h t h e se rum stopper, The Na*4CQ3
s o l u t i o n (Atomic Enerqy of Canada I t d , , c h a l k R i v e r , Ont.) was
13
d i l a t e d p r i o r t o t h e e x p e r i m e n t t o a c o n c e n t r a t i o a of 1 mCi iitl-1
with d i s t i l l e d water, a t pH 10. The a c t i v i t y added t o e a c h
c y l i n d e r was a s •’of lows: 90 m C i f o r e x p e r i m e n t s I throuqh 3 04
and ?,5 mCi f o r e x p e r i m e n t s 105 t h r o u q h 125.
A f t e r t h e a d d i t i o n of t h e r a d i o i s o t o p e , 7 min was a l l o w e d
for its c i r c u l a t i o n i n the sys tem. T h e n t h e c i r c u l a t i o n p u t a ~ s
were s h u t off a n d 2 3. of water was wi thd rawn v i a the c a r b o y ' s
s a m p l i n g p o r t i n t o a n e r l e n ~ y e r f l a s k a n d p l a c e d i m a e d i a t e l v
i n t o a n i c e - c h e s t t o await f u r t h e r p r u c e s s i n q , T h e carboy was
t h e n * t o p p e d u p r with f i l t e r e d water and the pumps were s t a r t e d .
The * t a p p i n g u p 1 p r o c e s s f o l l o w i n q e a c h s ae tp l i nq , r e s u l t e d i n a
~ax i r aum t o t a l d i l u t i o n of 0.8 ?k.
F o r a l l e x p e r i m e n t s , 2 1 water s a m p l e s were taken a t d a m
a n d a t dusk .
A t the t e rmina - t i on of t h e e x p e r i n m a t , t h e e x p e r i ~ e n t a l .
c y l i a d e r * ~ l i d was opened , t h e p l a n t was removed and , t o
minimize a d h e r i n q non-f i x e d ' r a d i o c a r b o n , r i n s e d i n t h e
s u r r o u a d i n q seawater. T h e p l a n t was then p l a c e d i n t o a p l a s t i c
q a r b a g e can and t r a n s p o r t e d to the l a b o r a t o r y for dryinq. T h e
time of t r a n s p o r t was a p p r o x i m a t e l y 10 min.
The f o l l o w i n g e n v i r o n m e n t a l c o n d i t i o n s were m o a i t o r e d
d u r i n q e x p e r i m e n t s : water t e a p e r a t u r e , s a l i n i t y , a n d s e c c h i
d e p t h , I n s o l a t i o n v a l u e s were o b t a i n e d f rom p y r e h e l i o m e t e r d a t a
[ c o u r t e s y o f C . S c r i v e n e r , P a c i f i c B i o l o q i c a l S t a t i o n , Nana imo,
B. C.) recorded at C a r n a t i o n Creek, arkl ley Sound, 8 km from
/ Port ilkire. Cos tpar i son of B a ~ r E i e l d p y r a n o m e t e r c h a r t s with
C a r n a t i o n C r e e k pgreheliolaeter c h a r t s conf iraed that t h e
i n s o l a t i o n levels were sirttilar a t these two locationsl
Saa p l e p r o c e s s i n q
T o t a l carbon d i o x i d e , n i t r a t e , n i t r i t e , ammonia a n d
p h o s p h o r u s c o n t e n t s of the water were e s t i ~ a t e d by t h e
techniques d e s c r i b e d i n S t r i c k l a n d and Parsoras { 1 972) . T o t a l particulate o r q a a i c carbon (POC) content was sampled
by f i l t r a t i o n of 100 o r 200 ~l of water throuqh pre-cornbusted
4450 C, 4 h ) hatm man'^^/^ q l a s s f i b r e f i l t e r s [ r e t e n t i o n
d i a m t e r = 0 . 7 1 ~ ~ ) a t a vacuum of 0.25 atm, and f o l l o w e d by a 5
sec e x p o s u r e of the f i l t e r t o c o n c e n t r a t e d HC1 fumes to r i d t h e
fileer of inorqanic carbon. The f i l t e r s Mere d r i e d i n a n oven a t
65 C and r e f r i q e r a t e d u n t i l a n a l y s i s w i t h a Perkin-Elnes: Model
240 Elementa l . A n a l y z e r [Coleman I n s t r , Co rps , Haywood, Ill. )
The r e l a t i v e precision (2 x ( s t a n d a r d e r ro r l ' l aean) x 100) o f t h i s
technique was 13,2 %, as calculated from 143 a n a l y s e s ,
L a b e l l e d POC ( P O I r C ) c o n t e n t was s amp led by filtration, a s
d e s c r i b e d a b o v e , The HC1-fumed f i l t e r was p l a c e d i n a qlass
scintillation v i a l , 2 m l of Protosol tissue and g e l s o l u b i l i z e r
[ N e w Enq land N u c l e a r , Lachine, Que,) was added , and t h e v i a l was
r e f r i g e r a t e d u n t i l p r o c e s s i n q . Processinq i n v o l v e d incubation of
t h e v i a l s a t 60 C (to ensure s o l u b i l i z a t i o n of a l l o r q a n i c
Ra t t e r ) , the a d d i t i o n of two d r o p s of g l ac i a l acetic acid {to
n e u t r a l i z e t h e basic P r o t o s o l ) a n d t h e a d d i t i o r ! 9.f 15 n t l of
r e q u l a r toluene c o c k t a i l (42 L F q u i f l u o r (New E n q l a n a N u c l e a r )
per 1 t o l u e n e ) . The s a m p l e s were t h e n c o u n t e d on a Beckman 1.5
8000 S c i n t i l l a t i o n C o u n t e r [Beckman I n s t r , , P u l l e r t o c , C a l i f . )
for 30 mia o r 1 % c o u n t i n q e f f i c i e n c y u s i n g t h e ex te rna l
s t a n d a r d ~ e t h o d for quench c o r r e c t i o n , T h e r e l a t i v e precision of
t h i s t e c h n i q u e was 21), 8 1 as ca l cu la ted from 1 3 3 a n a l y s e s .
The l abe l led d i s s o l v e d orqanic carbon (901 4C) c o n t e n t of
t h e water gas e s t i a a k e d by a concentration p r o c e d u r e d e weloped
for t h i s study, F i f t y sf of Whatwan G F l P f i l t e r e d water was
dispensed with a g l a s s syrinqe i n t o each of three 272 m l qhass
b o t t l e s , Three drops of c o n c e n t r a t e d HC1 g a s added to each
battle t o b r i n q the pH<2. The s a n p l e s were bubbled w i t h a i r fo r
3 h t o rid t h e water o f i n o r g a n i c l a b e l l e d c a r b o n a n d t h e n they
were refriqerated u n t i l a n a l y s i s , I n p r e p a r a t i o n for aria l y s i s ,
t h e sautples rere e v a p o r a t e d a t Q5 C i n a f l a s h e v a p o r a t o r down
%:0 a vrzfur~nte of 1,5 t o 3,0 m l , 'This s a l t *brines was p o u r e d i n t o
a s c i n t i l l a t i o n v i a l c o n t a i n i n q 35 m l of A q u a s o l c o c k t a i l [ N e w
Enqland Nuclear), T h e e v a p o r a t i o n flask was then r i n s e d and
s o n i c a t e d w i t h t w o or t h r e e snaall volurnes of distilled w a t e r ,
which ia t u r n were poured i n t o t h e s c i n t i l l a t i o n vial. T h e total.
voluute of salt brine + r i n s e water added t o t h e s c i n t i l l a t i o n
v i a l was 5 &I., The v i a l was then r e f r i q e r a t e d a n d shaken u n t i l
t h e c o n t e n t s foraed i n t o a homoqeneaus qel. T h e v i a l s were
c o u n t e d i n a r e f s i q e r a t e d P a c k a r d Model 83003 T r i - G a r b L i q u i d
S c i n t i l l a t i o n Spec t roane t e r [Packard Instr, Co. , Downers, Ill,)
n s i n q t h e c h a n n e l s ra t io method f o r quench c o r r e c t i o n ,
The a b o v e c o n c e n t r a t i o n p r o c e d u r e was n e c e s s a r y d u e t o t h e
q f e a t d i l u t i o n of t h e DO%% i n t h e larqe volume w i t h i n t h e
c y l i n d e r s . T e s t s w i t h 1 % - q l y c i n e showed a mean r e c o v e r y o f
100.8 515 ( s t a n d a r d error (s/fn) = 1,17, n = 6) f o l l o w i n q the
a c i d i f i c a t i o n a n d bubbling s t e p a n d a Rean r e c o v e r y of 97.3 X
[ s t a n d a r d error = 1,23, n = 5) f o l l o w i n q the e v a p o r a t i o n s t e p .
The m i n i m a d e t e c t i o n l e v e l o f t h e t e c h n i q u e , a s c a l c u l a t e d froin
the p r e c i s i o n 1 2 ~ 1 ~ ) 05 6 4 a n a l y s e s , was 0 . 3 9 DPH a l - % o r 19.5
DPPI ( 5 0 ~ 1 ) - a , T h e r e l a t i v e s t a n d a r d error of t h i s t e c h n i q u e was
10.13 94 a s c a l c u l a t e d froa 127 a n a l y s e s ,
T o t a l DOC ITDOC) was a n a l y z e d by a t e c h n i q u e i n v o f v i n q d r y
c o m b u s t i o n in a n oxygen stream f o l l o w e d by c a r b o n d e t e c t i o n v i t h
an i n f r a r e d qas a n a l y s e r { I B G A ) , T h i s t e c h n i q u e was a d a p t e d froa
the methods o f Gordon and S u t c l i f f e (79731, who used 3 dry
c o a b u s t i o n t e c h n i q u e but with the less s e n s i t i v e p e r k i n - E h e r
E l e a e n t a l A n a l y z e r fo r c a r b o n d e t e c t i o n , and the inethods of Van
Wall g& 81963) and Sharp f 1 9 7 3 ) , who developed e l a b o r a t e
l i q u i d colxlbustors w i t h t h e IRGA f o r c a r b o n d e t e c t i o n , T h e
t echn ique used i n this s t u d y was:
I , Sainple p r e p a r a t i o n .
F i f t y a1 of filtered w a t e r was d i s p e n s e d i n t o 136 ~f
. q l a s s b o t t l e s ; a l u e i n u a f o i l was p l a c e d between t h e
b o t t l e - c a p and t h e b o t t l e , T h e b o t t l e s vere d a r k e n e d and
r e f r i g e r a t e d u n t i l f ceezinq (1/2 h to 1 f: later), Prior t o
f r e e z e - d r y i n g , t h e s a m p l e s were thawed and 10 ml. s u b - s a m p l e s
f rola each b o t t l e were d i s p e n s e d i n t o ve iqhed 50 m l . erlenmyer
f l a s k s . To r i d %he sample of i n o r q a n i c carbon, t h e water n a s
a c i d i f i e d w i t h t n o d r o p s of 85 X p h o l ~ p h o r i c a c i d a a d bubbled
for 5 ain with n i t r o q e n gas , The flasks were ther, c o v e r e d
w i t h p e r f o r a t e d aluminum f o i l c a p s a n d f r e e z e - d r i e d .
F r e e z e - a r i d s a e p l e s were s t o r e d i n a d e s s i c a t o r until
analysis, The w e i q h t of t h e s a a p l e ' s s e a s a f t s was the
d i f f e r e n c e in t h e flask's weiqht before t h e i n t r o d u c t i o n of
t h e s a m p l e and after the freeze-drying. T h e a i t r o q e n
hubblinq a n d freeze-dryins steps p r o b a b l y purqed t h e water
of v o l a t i l e o r g a n i c co i~pounds ; this is a coamon shor t co rn ins
of most DOC a n a l y t i c a l t e c h n i q u e s (Wanqersky, 1978;
AacKinnon, I W g ) , PlacKinnon f 1979) h a s developed a technique
for: t h e aeasuremexlt of v o l a t i l e o r q a n i c c a r b o n and h i s
results show t h a t the v o l a t i l e s compose 1.5 t o 6 % of t h e
t o t a l d i s s o l v e d o r q a n i c c a r b o n con tent i n ocean waters. '
A p p a r e n t l y , e v e n h i s t e c h n i q u e f a i l s to d e t e c t t h e very
volatile compounds {HacRinnon, 1379) .
C a l i b r a t i o n was accompl i shed w i t h a standard
salt /qlucose solution which c o n s i s t e d of f r e e z e - d r i e d s a l t
co-subl i t .aated u i t h a defined quantity of q l u c o s e , A 1 qC l-%
. s t o c k qlwose solution was p r e p a r e d by dissalvinq 1.25 CI
q l u c o s e i n 500 m3. d i s t i l l e d water, The s t a n d a r d s a l t
s o l u t i o n was made by a d d i n u 7.5 q of ~aC.1, which had b e e n
p r e v i o u s l y combus ted f o r 1 2 h a t 6 5 0 C, a n d 2.5 at1 of the
s k o c k q l u c o s e s o l u t i o n inko a 250 ltll ~ o l u m e t r i c f l a s k . T h e
volume was b r o u g h t t o 250 m l w i t h c a r b o n - f r e e - w a t e r ,
p r e p a r e d a s d e s c r i b e d i~ t h e DOC a n a l y t i c a l technique i n
S t r i c k l a n d and P a r s o n s (1972) . This r e s u l t e d i n a 10 myC 1 - I
s o l u t i o n w i t h a s a l i n i t y of 30 $ 0 . T h i s s t a n d a r d s o l u t i o n
t h e n was p r a c e s s e d as %he s e a w a t e r s amp le s ,
To p r e v e n t c o n t a m i n a t i o n of s a m p l e s and s t a n d a r d s ,
p r i o r t o u s e a l l g l a s s w a r e a n d metalware were combus ted a t
500 C f o r 4 h a n d pipettes were washed w i t h
c a r b o n - f r e e - w a t e r , T o e n s u r e homoqenie ty of t h e o r g a n i c
s u b s t a n c e s w i t h i n t h e f r e e z e - d r i e d salts i a the f l a s k s , the
s a l t s were qround t o a fine powder with a mortar ar,d pestle.
To p r e v e n t c r o s s - c o n t a m i n a t i o n of s a m p l e s , mortar a n d p e s t l e
were c o a b u s t e d i n t e r m i t t e n t l y a n d c l e a n e d between samples by
q r i n d i n q w i t h ca rbon - f ree-salt,
2, Equipment d e s c r i p t i o n
The corabustor was constructed by t h e S.P.I1, a a c h i n e ,
E l e c t r o n i c s and G l a s s - b l o v i n q Shops and was b a s e d on t h e
P e r k i n - E l m r nodal 2Y0 E l e m e n t a l A n a l y s e r $ s c o m b u s t o r
d e s i q n , A d i f f e r e n c e is t h a t my combustor r e q u i r e d manua l
o p e r a t i o r i of t h e q a s v a l v e s , A Beckmaa i n f r a r e d gas ana'fyser
, was u s e d f o r t h e c a r b o n d e t e c t i o n .
E s s e n t i a l l y , t h e corabastor ccmsisted of a 53 cm l o a g
h o l l o w q u a r t z t u b e sealed at e i t h e r end w i t h an 0 - r i n q and
knurled bolt (Piq, 4 , El. The first 30 CB o f t h i s t u b e was
for sample i n s e r t i o n , f o l l o w e d by a 15 cra l e n q t h e n c a s e d i n
a furnace (Piq, 4, I?) which, i n t u r n , was f o l l o w e d b y an
18 em c h e m i c a l t rap , T h e coinbastion t u b e a n d c h e m i c a l t r a p
were i d e n t i c a l t o those o f the P e r k i n - E l m e r E l e m e n t a l
Analyser, Each end of the t u b e was c o n n e c t e d , via a s o l e n o i d
v a l v e , to a g a s l i n e ; oxyqen entered via the v a l v e at t h e
s a l a p l e i n s e r t i o n e n d o f ' t h e t u b e { f i q , 4 , G ) and e x i t e d
throuqh the v a l v e a t the c h e a i c a l t r a p end o f the tube
(Fiq. 4, H). T h e e x i t i a q gas t h e n f l o w e d t o w a r d the I R G A
u n i t , I n s e r t e d i n the q a s L i n e , be tween t h e co l abus to r unit
and the IRCA, u a s a Bg (ClC3y)2 water t r a p tfiq. 4, 1) a n d a
* c r u m p l e d up r Kimwipe particle t r a p (Fiq, 4, M ) , The f l o u
ra te was measured on a Gasmt f lomete r (Fiq. 4, N) a f t e r
the oxyqen lef t t h e IRGA, The IRGA p e a k s were recorded on a
Riken-Densh i X-Y r e c o r d e r {Riken Denshi Co, , Tokyo,
J a b ) j F i q , 4, 01 . The sample was i n t r o d u c e d into the c o m b u s t i o n tube b y
means o f a quartz ladle e q u i p p e d with a magnet in the
h a n d l e ,
F i q u r e 4. T h e t o t a l DOC a n a l y s e r ,
0 recorder
Key to c o a p o n e n t s ,
combus'zor
i n f r a - r e d gas a n a l y s e r fIRGA)
oxyqen s u p p l y to r e f e r e n c e I R G A cell
oxyqen s u p p l y t o corabustor
q u a r t z combust ion tube
f u r n a c e
s o l e n o i d valve c o n t r a f l i n q oxygen flow i n t o
corabustor
solenoid v a l v e c o n t r o l l i n g oxyqen flow e x i t i n q from
combustor
combust ion t u b e F r e s s u r e qauqe
furnace t e m p e r a t u r e c o n t r o l
qas line from cambustor to XRGA
HqfC10q)2 wakez t r a p
Kimwipe particle trap
flowmetel:
A n a l y s i s
T h e f u r n a c e was set t o a t e m p e r a t u r e o f 750 C a n d the
oxyqen flow ra te t h r o u q h the c o m b u s t i o n t u b e was set t o 250
m l min-1, The IBGB was s t a n d a r d i z e d w i t h oxyqen qas for '0'
s e t t i n q a n d 350 ppm s t a n d a r d c a r b o n d i o x i d e qas* Us inq a
Cahn e l e c t s o b a l a n c e { f len t son Corp, , Cerrilss, C a l i f , ) 10 t o
20 ~ag of ground seasa l t s were weiqhed o n t o a p r e v i o u s l y
c o n b u s t e d l a d l e , a n d i n s e r t e d i n t o the c o m b u s t i o n t u b e , T h e
c soabus t i on tube was seaXed a n d a l l o w e d t o p u r q e f o r 30 sec
t o r e a o v e i n t r o d u c e d c a r b o n d i o x i d e f r o a t h e a i r . Then the
e x i t v a l s e was c l o s e d ; t h e oxyqen e n t r a n c e v a l v e r e m a i n e d
open u n t i l a p r e s s u r e of 0 * & kq ca-2 a n d t h e n was c l o s e d *
The saap le was a l l o w e d t o bu rn 45 see, Tests showed t h a t
b u r a i n q times s f 3 0 sec t o 3 glie y i e l d e d identical carboa
v a l u e s ,
when the conbus i t i on tube was o p e n e d and e x p o s e d to t h e
a t m o s p h e r e , the e x i t v a l v e was c l o s e d a n d t h e e n t r a n c e v a l v e
opened t o create a p o s i t i v e i n t e r n a l pressure to prevent the
e n t r a n c e of a t n o s p h e s i c a i r ,
C a l c u l a t i o n
Calibration was a c h i e v e d b y c o a t b u s t i n q d i f f e r e n t
w e i g h t s of t h e s t a n d a r d q f u c o s e - s a l t s a n d c o m p u t i n q a
r e q r e s s i o n of t h e I R G B peak h e i g h t s a q a i n s t t h e a m u n t o f
c a r b o n p r e s e n t as d e t e r m i n e d by t h e u e i q h t of t h e cornbusted
s t a n d a r d s a l t s , P r e v i o u s l y coa tbus t ed l ac1 c rys t a l s were
a n a l y z e d t o d e t e r m i n e the backqr sund 90' carbon l e v e l , For
the q u a n t i t i e s of c a r b o n t e s t e d (0 ~9 t o 5 k q ) t h i s r e s u l t e d
i n a s t r a i q h t line f u n c t i o n , A s t a n d a r d curve frora one set
of a n a l y s e s is presented i n t h e Appendix (P iq , A l l . Tests
showed t h a t peak h e i q h t s and peak a r e a s produced s i r a i l a r
r e s u l t s , The amount of c a r b o n p r e s e n t i n a s a ~ p l e was t h e n
c a l c u l a t e d by c o w p a r i s o n o f t h e peak heiqht t o the
c o r r e s p o n d i n q c a r b o n c o n t e n t , The r e l a t i v e s t a n d a r d error of
this t e c h n i q u e , b a s e d o n 1 10 a n a l y s e s , was 7,6 X,
Adenos ine t r i p h o s p h a t e (ATPI c o n t e n t of t h e water was
e s t i m a t e d by t h e extraction a n d a n a l y t i c a l technique of
Holla-fiansen a n d Booth ( t966) , a s moilif i e d by Ifamtnersted t f 1 973)
and usinq T o b i n 3% ass (1978) r e c u m e n d e d pHas for t h e s t a n d a r d
s o l u t i o n s , The ATP c o n t e n t was c o n v e r t e d t o a n a p p r o x i m a t e
c a r b o n v a l u e b y t h e BTP, c a r b o n , and t o t a l cell. w e i q h t
i n t e r r e l a t i o n s h i p s calculated by Iiofn-Hansen and Booth 4 1966) . g e t c a r b o n a s s i m i l a t e d b y t h e p l a n t n a s e s t i m a t e d by the
q u a n t i t y of r a d i o c a r b q n r e t a i n e d by the p l a n t , After b e i n q hunq
t o d r y i n a uarat room f o r 2 h , the p l a n t uas p l a c e d into ar, oven
a t 55 C for t h r e e d a y s t o c o m p l e t e t h e d r y i n q process. After
d r y i n q , t h e plant was p u l v e r i z e d w i t h t h e * k e l p q r i c d e r ' . The ' k e l p q r i n d e r ' (Fiq, 5) c o n s i s t e d o f a cast i r o n h o l l o u
c y l i n d e r , 44.5 cm i n l e n q t h a n d 27 cm i n d i a m e t e r , i n t o which
was; p l a c e d a s d i d iron c y l i n d e r (27 cm l o n q , 10 cm d i a m e t e r ] . The d r i e d p l a n t was p l a c e d i n t o t h e c y l i n d e r w i t h the r o l l e r .
The cylinder was s e a l e d and rol led on t h e f loor u n t i l the plant
was pulverized,
Radiocarbon d e t e c t i o n of sample s of t h e fine ponder #as
a c h i e v e d by c o a b u s t i o n , Plants from experiments 1 to 1 1 4 were
c o n b u s t e d i n a Searle Combustor Bodel 6550 { S e a r l e Analytic
Inc,, Des Plaines, Ill,) and p l a n t s from e x p e r i m e n t s 1 2 1 to 125
were coinbusted i n a Packasd flodel B306 Tri-Carb Sample D x i d i a e r .
The released carbon d i o x i d e was a b s o r b e d i n Oxisorb-COs ( N e w
Enqlaad l u c l e a r ) w i t h ACS (Amersham Corp, Oakvilf e , Omt. f a s t h e
s c i n t i l l a t i o n c o c k t a i l , The s c i n t i l l a t i o n v i a l s were c o u n t e d on
a B e c k ~ a n LS 8000 S c i n t i l l a t i o n Counter for 10 min or 1 96
efficiency u s i n q t h e ex terna l s t a n d a r d method for quench
c o r r e c t i o n , The r e l a t i v e standard error of t h i s t e c h n i q u e * as
based on 26 analyses, was 2.4 X ,
T o t a l carbon and n i t r o q e n content af t h e p l a n t powder was
d e t e r m i n e d with a Perkin-Elmer Model 240 Elemental Analyzer,
F i q u r e 5.
Tog. P h o t o q r a p h of t h e k e l p qr inder beinq ro l led on t h e -- f loor ,
Bottom, Photograph of o v e n - d r i e d k e l p b e i n q p l a c e d i n t o the ------ k e l p qrinder.
T h e l i q h t a v a i l a b l e t o the p l a n t a t +he mean i n c u b a t i o n
d e p t h was e s t i m a t e d b y a L a m b e r t 8 s Lav form o f r e l a t i o n s h i p a s
d e s c r i b e d i n S t r i c h l a n d (1958). The i r r a d i a n c e i n the
p h o t o s y n t h e t i c a l l y a c t i v e r a d i a t i o n r e q i o n (PAR = 400 nm t o
700 nm w a w e l e n q t h r a n g e ) was c a l c u l a t e d b y m u l t i p l v i n q s p i n s
a n d summer p y r e h e l i o m e t e r v a l u e s by 0.48 a n d f a l l v a l u e s b y 0.45
( S z e i c z , 1974) , Trans& i s s i o n t h r o u q h the a i r / n a t e t i n t e r f a c e was
e s t i a a t e d a s 85 5 ( P a r s o n s a n d T a k a h a s h i , 1973) .
The u a t e r 9 s a t t e n u a t i o n c o e f f i c i e n t , k , was d e t e r a i n e d b y
t h e f o l l o w i n q r e l a t i o n s h i p :
k = f a c t o r / D ( S t r i c k f a r i d , 1358)
= 2,13/D
D = secchi d e p t h i n RI
2, "1 = • ’ a c t o r d s t e r a i n e d by reqression a n a l y s i s of
i s r a d i a n c e r e a d i n q s 05 0, 1, 2, 3, 4 a n d 5 m d e p t h s
m e a s u r e d v i t h t h e L i - C o r quantum r a d i o m e t e r (Lambda
1 n s t r u a e n . t ; ~ ~ L i n c o l n , N e b r a s k a ) week ly a t raidday for
a period from Pllarch to J u l y i n t h e Barnf ie ld a r e a
{data, courtesy of L. D. D r u e h l ) ,
L i q h t a t t e n u a t i o n t h r o u g h t h e a c r y l i c c y l i n d e r s , i n the PAR
r e q i o n was m e a s u r e d a s 8 %, All v a l u e s were c o n v e r t e d td
E i a s t e i n s in-2 h-1 'by t h e f o l l o w i n q rela t i o n s h i p :
1 l a n q l e y t i -1 (q ca3. cm-* h-a) = 0,131 E m - 2 h-1,
C a l c u l a t i o n s
Carbon assimilated by t h e p l a n t , a s determined b y
radiocarbon uptake , was c a l c u l a t e d a s S o U ~ v s :
mqC gdw-l plant {where qdv = q dry weiqht]
= 1QLantDP# - bkuPf4f x w t . o f - C i n wats&gC_z x 3.05
a c t i v i t y added to water (DPfl) x qdw p l a n t
DPM = d i s i n t e g r a t i o n s @in-%,
bkq = backq-round count. .
w t , of C i n w a t e r = t u t a l a m u n t of inorqan ic carbon
i n t h e e n t i r e c y l i n d e r system's water a t the beqinuincr
of t h e experiment .
1.05 = c o r r e c t i o n f a c t o r t o a c c o u n t for t h e different
b e h a v i o u s of As colapared to {Slcr ickland and Parsons,
3 972) . En this s t u d y t h e DOC c o n t e n t of the water was defined a s
f D O C + POC), The reasons for t h i s definition are presented i n
t h e Discussion,
1. T o t a l DOC + POC gas ca l cu la t ed as f o l l o w s :
2 , Por t h e e s t i m a t i o n of t h e DOC c o n t e n t o f t h e water f rom t h e
l a b e l l e d DOC ( D W W + PDs*C) r e s u l t s , t h e DPM v a l u e s were
c o n v e r t e d t o mqC qdw-1 v a l u e using t h e s a n e e q u a t i o n as f o r
c a Z c u l a t J n g c a r b o n a s s i ~ i l a t i o n by t h e p l a n t , above,
i n c l u d i n q t h e v o l u a e c o r r e c t i o n f r o m aqC 1-1 t o
R ~ C c y l i n d e r 1 ,
The DOC and POC v a l u e s were c o r r e c t e d for backq round
l e v e l s measured a t t h e b e q i n n i n q of the e x p e r i m e n t a n d for
l e v e l s i n t h e c o n t r o l c y l i n d e r b y s u b t r a c t i n q the initial
a n d c o n t r o l v a l u e s f rom the f i n a l e x p e r i m e n t a l c y l i n d e r
v a l u e .
T h e DOC c o n t e n t (DOC + POC), a s e s t i a a t e d fro% t h e
labelled DOC r e s u l t s , r e p r e s e n t e d e x u d a t e t h a t had been
o r q a n i c a l l y fixed d u r i n q t h e e x p e a i n e n t a l p e r i o d . T o t a l DOC
( r e f e r r e d to a s TDOC *. TPOC t o d i s t i n q u i s h i t froin DOC
v a l u e s o b t a i n e d from t h e l a b e l l e d DOC d a t a ) r e p r e s e n t e d a l l
t h e osqanic c a r b o n released d u r i n g t h e e x p e r i m e n t -- i n c l u d i n q t h e u n l a b e l l e d c a r b o n which was i n c o r p o r a t e d by
t h e plant prior t o t h e e x p e r i m e n t and t h e l a b e l l e d a n d
u n l a b e l l e d arb on which was i n c o r p o r a t e d by t h e p l a n t d u r i n q
t h e e x p e r i m e n t .
T h e p l a n t ' s r a d i o c a r b o n u p t a k e was c o n s i d e r e d a n estimate
of n e t c a r b o n f i x a t i o n , P h y t o p l a n k t o n p r o d u c t i v i t y s t u d i e s ha we
shown t h a t r a d i o c a r b o n u p t a k e , e s p e c i a l 1 y i n e x p e r i m e n t s of
qreater t h a n 6 h d u r a t i o n a r e e q u a l t o n e t p a r t i c u l a t e c a r b o n
i n c r e a s e s ( A n t i a gt &A,, 1953; R y t h e r a n d Henzel, 1965; Eppley
and S h a r p , 1975) ,
The p l a n t e s c a r b o n f i x a t i o n was e x p r e s s e d i n t h e f o l l o w i n s
3 forms:
1, && c a r b o n f i x e d = carbon a s s i a t i l a t e d and r e t a i n e d by t h e
p l a n t a t t h e e n d o f t h e e x p e r i m e n t a s d e t e s a i n e d b y s a m p l i n q
t h e p l a n t %issue f o r l a b e l l e d c a r b o n .
2 , P*aX net c a r b ~ fixed = * n e t c a r b o n f i x e d t (as d e f i n e d
above) plus the c a r b o n a s s i n t i l a t e d d u r i n g t h e e x p e r i m e n t ,
but r e l e a s e d a s exudate a s d e t e r r a i n e d b y a n a l y s i s of the
i n c u b a t i o n water for l a b e l l e d d i s s o l v e d o r q a n i c s .
3, && arowth = ' n e t carbon f i x e d 3 minus or p l u s +he ' o l d *
d i s s o l v e d o r q a n i c c a r b o n r e l e a s e d o x t a k e n up , r e s p e c t i v e l y ,
The * o l d 9 DOC i n t h e v a t e r r e p r e s e n t e d o r q a n i c c a r b o n which
had been f i x e d by t h e p l a n t p r i o r t o t h e e x p e r i m e n t ,
Twenty-four h l i g h t - i n d e p e n d e n t c a r b o n f i x a t i o n ( d a r k
c a r b o n f i x a t i o n ) was s u b t r a c t e d fro^ the above t h r e e
a e a s u r e r a e n t s of c a r b o n f i x a t i o n , Kretner ( 1379) a n d W i l l e n b r i n k
et a&, f3979) r e p o r t e d t h a t l i q h t e x p e r i m e n t s w i t h brown alqae,
i n c l u d i n q 4, &n-teqgifp&aI r e s u l t e d i n c a r b o x y l a t i o n p r o d u c t s of
l i q h t - i n d e p e n d e n t c a r b o n f i x a t i o n i n a d d i t i o n t o p r o d u c t s of
liq h t - d e p e n d e n t ca rboa f i x a t i o n ,
DOC & m u r a l &&E beds -- DOC e x u d a t i o n bg M a i n t e q r j f g & b was s t u d i e d indirectly b y
DOC a n d POC s a m p l i n q i n two B a r k l e y Sound n a t u r a l k e l p b e d s a t
Kirby P t , Cove and s o u t h Dodqer C h a n n e l (Fiq, 1 ) . Out-of-kelp
bed water s a a p l e a were taken a t a d i s t a n c e o f 100 XI s e a w a r d of
these k e l p beds, The v a t e r samples were c o l l e c t e d froin jus t
be low t h e water s u r f a c e i n 3 , 8 1 q l a s s jars, DOC a n d POC c o n t e n t
were a n a l y s e d b y the t e c h n i q u e s described a b o v e , S a n l p l i n q s *ere
made a t s l a c k t i d e , t o ensure m i n i m a l o f f s h o r e t o inshore l o r
v i c e v e r s a ) water aovement , on F e b r u a r y 24, Ray I , flay 23,
July 27, a n d December 15,1978,
5 ta ti s t A a
Each e x p e r i ~ e n t had a s a m p l e s ize o f one p l a n t ; a n a l y t i c a l
precisian was estimated by i n t r a - plant a n d in t ra- water sample
r e p l i c a t i o n , For b e t u e e n s e a s o n c o m p a r i s o n s , the p l a n t s w i t h i n
one s e a s o n were t r e a t e d as s e a s o n a l replkcates; t h e seasonal
B e a n s were calculated a c c o r d i n q t o t h e q u i d e l i n e s described i n
B l i s s (1967). T h e statistical. tests a r e i d e n t i f i e d a s +,hey are
nsed, A l l are referenced t o Sokoh and Rohlf ( 1969) , T h e overaf l
l e v e l of significance f o r m u l t i p l e tests was set a t I?_( 0.30.
J3nvirongaenta1 sg&i&&gs
T h e dates a n d e n v i r o n m e n t a l c o n d i t i o n s f o r each 2 4 h and
4 8 h e x p e r i m e n t are t a b u l a t e d i n Table I and for t h e dark
e x p e r i m e n * ~ in T a b l e 2, Summer t e m p e r a t u r e s r a n q e d f rom 94.5 t o
18,2 C, s p r i n g t e a p e r a t u s e s r a n q e d from 31,5 t o 15.0 C and f a l l
t e m p e r a t u r e s sanqed from 7.5 t o 11.2 C, Salinities r a n q e d f rum
22 .0 t o 32.8% in fall, 30.0 to 3 1 . 8 % ~ i n s p r i n q and 32.0 t o
33.4% i n sumaer, I n o r q a n i c c a r b o n levels d i d n o t d e m o n s t r a t e
marked s e a s o n a l t r e n d s ; the l e v e l s r a n q e d f r o a 16.8 mqC 1-1
( e x p e r i m n t 5 i n fall) t o 24.0 BJC 1-"experinteat 121 in fall).
The mean i n o r q a n i c c a r b o n level per s e a s o n was between 21.2 a n d
22,2 reqi: 1-1, N u t r i e n t l e v e l s were appsox i r ea t e lg a n order of
maqni tude higher i n f a l l t h a n i n s p r i n q and summer. T h e r e was
i n s u f f i c i e n t d a t a for a d e t a i l e d c o a p a r i s o n of summer and spriaq
n u t r i e n t levels,
The hours of s u n l i q h t {from dawn t o dusk ) v a r i e d f r o @ 15.0
t o 37,2 h i n sulamer, 1U.5 t o 16,8 h i n s p r i n q , a n d 9.3 tb 10.0 h
i n f a l l , S e c c h i d e p t h r e a d i n q s i n d i c a t e d greatest iiqht
p e n e t r a t i o n i n fall, with s e c c h i r e a d i n g s r a n q i n q fro& 4.8 t o
10,8 m; the lowest r e a d i n q s were i n summer, r a n q i n q from 3 , 0 t o
3.4 w, The t o t a l quantum i r r a d i a n c e r e c e i v e d a t t h e wean
Tab
le 1
. E
S1v
iron
men
tal
con
dit
ion
s p
rese
nt
du
rin
g 2
4 h
and
4$
h ex
per
imen
ts.
Fk
per
imen
ts 1
08
and
10
9 w
ere
48 h
ex
per
imen
ts.
- d
eno
tes
an
aly
sis
no
t pe
rfor
med
. L
* d
eno
tes
tha
t N
H~
+ co
nte
nt
is
no
t in
clu
ded
in
val
ue.
**
d
eno
tes
tha
t se
cc
hi
dep
th w
as n
ot
tak
en o
n th
at
da
te b
ut
was
ex
trap
ola
ted
fro
m
oth
er
sum
mer
rea
din
gs.
Ran
ge in
T
ota
l Q
uant
um
Sec
chi
Init
ial
Ino
rgan
ic
Init
ial
Ini
ial
Wat
er
Sa
lin
ity
Ir
rad
ian
ce
De
th
Hou
rs
of
Car
bon
eve1
NO
3- +
NO2
+ iW
4+
R)$
le
ve
l S
easo
n E
xpt.
D
ate
Tem
p.
(c)
($
0)
(E
m-2
day
-I)
(m
y li
gh
t (m
g~
I")
Lev
el
(kg
-at
L-I)
(Ag
-at
L-1
)
Sp
rin
g
10
1
Ap
r.2
6-
11.5
-12.
0 31
.2
6.9
7.5
1
4.5
23
.2
--
--
27,
19
78
lo
3
May
2-
11.5
-13.
0 30
.6
28.4
8
.1
15
.5
21.4
--
--
3
, 1
97
8
(48
h)
10
8
May
20
- 13
.0-1
5.0
31.8
23
.2
+ 1
9.4
= 42
.6
4.2
3
2.
0
22.9
22
, 19
78
3.5
(4
8 h
) 1
09
h
y 2
4-
13.4
-14.
8 31
.1
26.5
+
8.0
=
34
.5
4.5
33.5
2
.4
W
ro 26
, 1
97
8
4.7
Sum
mer
1
10
Ju
ly 1
9-
20,
1978
Ju
ly 2
2-
27,
1978
Ju
ly 2
5-
26,
19
78
A
ug.
7-
8,
1978
1. $
9"
--
0. L
O*
-
Fa
ll
2
Oct
. 31
- N
ov.
1,
19
78
N
ov.
6-
7,
1978
N
O^.
19-
20,
1978
N
ov.
29-
30,
19
78
D
ec.
2-
3,
19
78
D
ec.
5-
6,
19
78
o o o m o . m m m m m 4 4 4 4 4
i n c u b a t i o n d e p t h was a f u n c t i o n o f t h e d a y l e n q t h , t h e sunas
e l e v a t i o n i n t h e sky, a n d t h e c l a r i t y of the s k y and water, P a l l
d a i l y quan tum i r r a d i a n c e l e v e l s were the l o w e s t , ranqinq from
0 . 6 to 4.8 E en-* day-a , sumDaer v a l u e s ranqed front 1 5 , l t o 19.7
E m - 2 day-1, a n d the h i q h e s t l e v e l s were r e c e i v e d i n s p r i n q ,
r a n q i n q f ro i a 5.9 t o 28.4 E ea-2 day-%. W i t h i n a s e a s o n , low
i r r a d i a n c e l e v e l s c o r r e s p o n d e d t o d u l l d a y s a n d h i q h i r r a d i a n c e
l e v e l s c o r r e s p o n d e d t o b f i q k t , stannny days . A l thouqh summer
e x p e r i m e n t s 110, 1 1 1 a n d 112 had l o n q e r d a y l e n g t h s t h a n the
s p r inq e x p e r i m e n t s , total quantum i r r a d i a n c e v a l u e s were lower
i n sueamer b e c a u s e o f summer sea foq a n d qreater liqht
a t t e n u a t i o n i n the water co lumn a s i n d i c a t e d b y the s e c c h i depth
s e a d i n q s .
L i q h t carbon f i x a t i o n r e s u l t s
P i q u r e 6 d i s p l a y s h i s t o q r a m s of the c a r b o n f i x a t i o n
r e s u l t s e x p r e s s e d a s net c a r b o n f i x e d , t o t a l . net c a r b o n fixed
a n d net q r o u t h f o r t h e e n t i r e i n c u b a t i o n period fo r e a c h 24 h
a n d 48 h e x p e r i m e n t , Each e x w r i m e n t r e p r e s e n t e d o n e plant, A l s o
p r e s e n t e d are h i s t o q r a ms of t o t a l d a i l y quantum i r r a d i a n c e
r e c e i v e d a t t h e mean i n c u b a t i o n dep th .
Greater c a r b o n f i x a t i o n v a l u e s c o r r e s p o n d e d t o h i q h e r daily
Fiqurce 6 , Histoqsams of n e t carbon f i x e d , total n e t c a r b o n
fixed and n e t growth i n s p r i n q , sumaer and f a l l 2U h
a n d ri8 h f+ f e x p e r i m e n t s , The h i s t o q r a i a s r e p r e s e n t the
t o t a l carbon fixed d u r i n q the entire e x p e r i m e n t .
H i s t o q r a m s of total d a i l y i r s a d i a n c e for each
e x p e r i m e n t are a l s o presented,
Vertical bars a t t o p o f h i s t o q f a r s denote i n t r a - p l a n t
, p r e c i s i o n (2s/+; n = intra-plant r e p l i c a t i o n = 8 - 12),
'5' d e n o t e s t h a t a t l e a s t one of the three carbon
f i x a t i o n values is s i q n i f i c a n t l y d i f ferent from the
o t h e r two v a l u e s LPIO. 1)
i r r a d i a n c e l eveb . S p r i n q h a d a w i d e r a n q e o f l i q h t c o n d i t i o n s
a n d a c o r r e s p o n d i n q l y wide r a n q e i n the p l a n t ' s r e s p o n s e , Summer
c a r b o n f i x a t i o n l e v e l s were i n t e r m e d i a t e be tween s p r i n q and
f a l l ; summer carbon f i x a t i o n v a l u e s were lower t h a n sprinq
v a l u e s a t c o m p a r a b l e i r r a d i a n c e l e v e l s (for e x a m p l e , summer
e x p e r i m e n t s 110, 1 1 1, a n d 1 12 v e r s u s sprinq e x p e r i n r e n t 1051
Carbon f i x a t i o n was l o w e s t i n f a l l , a s were t h e i r r a d i a n c e
l e v e l s ,
Some n e t qrowth v a l u e s appeared t o v a r y from t h e other t w o
f i x a t i o n v a l u e s { n e t c a r b o n f i x e d a n d t o t a l net c a r b o n f i x e d ) .
However, when t e s t e d with r e s p e c t t o t h e p r e c i s i o n of the values
t u s i n q the in tra-p lant Roans a n d v a r i a n c e s ) , ossly e x p e r i m e n t s
10 1, 110, 122 and 123 s h o v e d t h e n e t q r o w t h v a l u e t o b e
s i q n i f i c a n t l y different iPsD,1) from the o t h e r two c a r b o n
fixation v a l u e s (Table 31,
C o m p a r i s o n of c a r b o n f dxat ion and i r r a d i a n c e l e v e l s be tween
s e a s o n s i s q i v e n i n Fiq, 7, where mean h o u r l y t o t a l n e t carbon
f i x a t i o n valses uere q r a p h e d a q a i n s t the h o u r l y quantum
i r r a d i a n c e l e v e l s , In q e n e r a l , s p r i n q hourly f i x a t i o n Levels
were h i q h e r t h a n summer o r f a l l l e v e l s a t s imi la r i r r a d i a n c e s ,
T h e o n e e x c e p t i o n b e i n q the s p r i n q 48 h e x p e r i ~ e n t , 109, which
d i s p l a y e d a n h o u r l y c a r b o n f i x a t i o n r a t e s imilar t o t h e suamer
rates,
. S e a s o n a l d i f f e r e n c e s i n t h e e f f i c i e n c y o f g.&geq?cifol . ia i n
f i x i n q c a r b o n a r e i n d i c a t e d i n Fiq, 7 a n d Table 3, S p r i n q
Tab
le 3
. C
arbo
n fi
xa
tio
n r
es
ult
s e
xp
ress
ed a
s m
gC
gdw
41
for
24 h
per
iod
(*
= 4
8 h
pe
rio
d)
and
as
mgC
gd
w-l
.h
lig
ht
-I.
Exp
erim
ent
1 (
sum
mer
1
97
7)
was
ex
clu
ded
fro
m
the
sum
mer
se
aso
nal
mea
n.
+ 2
S/~
n; n
=
intr
a-p
lan
t re
pli
ca
tio
n f
or
ind
ivid
ua
l ex
per
imen
ts;
n =
nu
mbe
r o
f ex
per
imen
ts
in s
easo
n f
or
seas
on
al m
eans
.
The
'T
est
of
Eq
ual
ity
of
Mea
ns W
hen
Var
ian
ces
Are
H
eter
og
eneo
us'
w
as
use
d
to t
es
t if
th
e t
hre
e c
arb
on
fix
ati
on
val
ues
wit
hin
an
ex
per
imen
t w
ere
sig
nif
ica
ntl
y d
iffe
ren
t (s
) o
r n
ot
dif
fere
nt
(Ns)
. (P
9.1
0).
Sea
son
Sp
rin
g
19
78
Sum
mer
1
97
8
Sum
mer
1
97
7
Fa
ll
19
78
Exp
t . N
et
C F
ixed
in
24
h
To
tal
Net
C
Fix
ed in
2
4 h
N
et
Gro
wth
in
24
h
3.5
5 1
.90
16
.42
3.5
1
11
.92
0.8
0
34
.22
1.
16*
21
.15
3.8
5*
14
.35
3.2
6
6.1
5 3
.64
10
.62
8.6
1
5-8
2 1
.77
1.9
2 1
.69
0.5
2
0.39
8-3
2 k
.33
9.9
5
5-9
2
-6.0
5 1
.98
-26
.65
0.2
3
Net
C
Fix
ed
Sea
sona
l.
pe
r h
Mea
n T
ota
l N
et
C S
easo
nal
F
ixed
per
h
Mea
n
0.79
4
.21
2
- 0.59
4
.02
7
- 0.1
6
to. 1
03
- 0
.18
to.
013
-
Net
G
row
th
Sea
son
al
per
h
Mea
n
Re
sult
s of
S
ign
ific
ance
T
est
P i q u r e 7, Scattergraa of h o u r l y total net carbon f i x a t i o n
rates p l o t t e d aqainst h o u r l y quantum irradiance levels,
The number adjacent to each p o i n t on t h e scatterqraa
refers to t h e experiment n u ~ b e r .
(I) e
d e i a o n s t r a t e d the q s e a t e s t c a r b o n f i x a t i o n ra tes , summez rates
were i n t e r ~ e d i a t e , and f a l l ra*s %ere t h e l o w e s t ,
T h e seasonal r a n q e s in t h e t o t a l net c a r b o n fixed were t h e
s p r i n q
suifttaer
6,1 to 30,4 mgC qdw-a d a r t or 0.41 t o 0,62 rnqC qdv-1 h f i q h t - t
f a l l
0,9 t o 2,6 mqC qdv-1 day-% or 0.09 t o 0.26 mqC qdw-1 h l i q h t - a .
To e x a m i n e s e a s o n a l d i f f e r e n c e s i n carbon fixation rates of
t h e Kirby Pt, Cove & inteq&&Ai,a p o p u l a t i o n , the v a r i a n c e s o f
hourly r a t e s w i t h i n a season were compared to t h e v a r i a n c e of
h o u r l y rates between seasons, The seasonal rates indicated B.
i s tegr i foA_l ,_a*s c a r b o n fixation response to full. s e a s o n a l r a n q e s
i n l i q f n t conditions -- from o v e r c a s t days t o s u n n y d a y s , T h e o n e
excep'cion b e i n g suaaes, where a l l e x p e r i m e n t s were conduc%ed i n
a t l e a s t partially sunny c o n d i t i o n s ,
The m a n s for e a c h season of e a c h year a r e p r e s e n t e d i n
Table 3. Sumaes e x p e r i m e n t 1 was exc luded f r o n these c o ~ p a r i s o n s
b e c a u s e the p l a n t was n o t c o l l e c t e d f r o @ t h e Kirby Pt. Cbve
site, Table 4 p r e s e n t s the r e s u l t s o f t h e tests of s i q n i f i c a c c e ,
Pall, 1977 { e x p e r i m e n t s 2, 3, 4) a n d f a l l . 1978 [ e x p e r i m e n t s 121,
122, 123) v a l u e s were pooled b e c a u s e t h e Approximate S t u d e n t ' s
T - t e s t showed that they were not s i q n i f i c a n t l y different
Ta
ble
4
. A
pp
lic
ati
on
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(P<O. 05) . Comparison of mean h o u r l y fixation r a t e s v i t h i n a
s e a s o n [Table Ya) showed t h a t there was no s i q n i f i c a n t
d i f f e r e n c e between n e t c a r b o n f i x e d , t o t a l n e t c a r b o n fixed, and
n e t qrou-th in e i t h e r s p r i n g , snmtaer, o r f a l l . T a b l e 4b shows
t h a t t h e hourly n e t c a r b o n f i x e d and h o u r l y t o t a l n e t c a r b o n
fixed b e v e l s of spring an3 sumRer were s i q n i f i c a n t l y q r e a t e r
(P=O, 1) t h a n f a l l l e v e f s , but were n o t d i f f e r e n t front each
o-ther,
Due to the qreat v a r i a n c e of the net qrowth l e v e l s within
and between s e a s o n s , t h e *Approxi@ate T e s t of Equality o f Means
when V a r i a n c e s are Heteroqeneous* i n d i c a t e d no s i q n i f i c a n t
seasonal d i f f e r e n c e in n e t q rowth rates. The i n c l u s i o n of t h e
TDOC + TPOC v a l u e s w i t h their hiqh variances [low levels of
p r e c i s i o n ) , e s p e c i a l l y i n f a l l e x p e r i m e n t s , i n t h e c a l c u l a t ion
of net qrowth masked a n y seasonal t r e n d s and c o n s e q u e n t l y
decreased the s i q a i f i c a n c e of .$-,he n e t q r o v t h r e s u l t s . T h i s
effect c a n be v i s u a l i z e d by o b s e r v a t i o n o f t h e h i s t o q r a m i n
Piq. 6 ,
T h e n e t change in t h e t o t a l i n o r q a n i c c a r b o n content o f t h e
experimental cylinder's water is tabulated i n Table 5.
U n f o r t u n a t e l y , the pH t e c h n i q u e u s e d f o r the a n a l y s i s o f
i n o r q a n i c carbon l a c k e d the precision of t h e r a d i o c a r b o n
~ e t h o d o l o g y f o r p r e c i s e detection of t h e s i t ta l l c a r b o n c h a n q e s
occ .u r r inq i n many e x p e r i i w n t s , e s p e c i a l l y the f a l l e x p e r i rnents ,
C o a p a r i s o n o f t h e c h a n q e s i n inorqanic c a r b o n expressed a s
T a b l e 5 . N e t c h a n g e s i n t h e t o t a l i n o r g a n i c c a r b o n c o n t e n t of t h e e x p e r i m e n t a l c y l i n d e r ' s w a t e r d u r i n g 2 4 h a n d 48 h ( e x p e r i m e n t s . 1 0 8 a n d 1 0 9 ) e x p e r i m e n t s . T h e n e t c h a n g e s a r e e x p r e s s e d a s mgC 1-1 a n d a s mgC gdw- l p l a n t . N e g a t i v e v a l u e s d e n o t e a d e c r e a s e i n t h e w a t e r ' s i n o r g a n i c c a r b o n c o n t e n t o r n e t u p t a k e o f c a r b o n b y , t h e p l a n t . P o s i t i v e v a l u e s d e n o t e a n i n c r e a s e i n t h e w a t e r ' s i n o r g a n i c c a r b o n c o n t e n t , o r a n e t r e l e a s e of c a r b o n b y t h e p l a n t . +2s/$n; n = i n t r a - s a m p l e r e p l i c a t i o n = '2 . -
S e a s on E x p t . N e t C h a n g e i n I n o r g a n i c C a r b o n a s m g ~ 1-1 a s m g ~ g d w - l
S p r i n g
1 0 8 - 2 - 4 2 0 . 6 1 - 3 4 . 8 2 8 . 8 8
1 0 9 - 1 . 0 2 0 . 1 7 - 1 2 . 8 2 2 . 2 6
Summer 1 1 0 - 1 . 7 2 0 . 1 7 - 1 1 . 4 2 1 . 1 5
11 1 - 1 - 3 2 0 . 4 7 - 1 2 . 0 2 4 . 4 2
F a l l
mqc qdn-1 p l a n t i n T a b l e 5 with the t o t a l n e t c a r b o n f i x a t i o n
results i n Table 3, r e v e a l s t h a t t h e r a d i o c a r b o n r e s u l t s were,
q e n e r a l l y close to a n d u s u a l l y s l i q h t l y less t h a n t h e Bean n e t
i n o r q a n i c c a r b o n chanqe, T h i s c o & p a r i s o n i n d i c a t e s t h a t the
r a d i o c a r b o n u p t a k e t e c h n i q u e was ~ e a s u r i a q v a l u e s that c l o s e 1 y
a p p r o x i m a t e d n e t p r o d u c t i v i t y .
L i q h t - i n d e p e n d e n t carbon fixation r e s u l t s
His l toqra~ l l s o f h o u r l y n e t l i q h t - i n d e p e n d e n t c a r b o n
f i x a t i o n , a s e v a l u a t e d b y e x p e r i i i l e n t s c o n d u c t e d d u s i n q t h e n i q h t
{from af tes d u s k t o b e f o r e dawn t h e next morn inq ) , a r e p r e s e n t e d
in Fiq , 8, The a u r a t i o n of e a c h e x p e r i m e n t is r e c o r d e d i n Table
2 , T h e mean s e a s o n a l h o u r l y rates were as f o l l o w s : 0 .013
mqC qdw- h-1 i n s p r i n q , 0,014 mqC qdn-f h-"n summer, and
0,010 mqC qdu-1 h - t i n f a l l , T h e r e Mas n o s i q n i f i c a n t seasonal
d i f f e r e n c e i n t h e s e h o u r l y r a t e s when t e s t e d b y t h e *Test of
E q u a l i t y o f Means when V a r i a n c e s are Heter=qeneousq dP:O* 1)
Table 6 presents t h e net l i q h t - i n d e p e n d e n t c a r b n f i x a t i o n
r e s u l t s a s hour ly rates and a s p e r c e n t o f n e t l i q h t - d e p e n d e n t
carbon f i x a t i o n rates, T h e s e p e r c e n t a q e s Mere 1.2 to 2,4%
( s p r i n q f , 2,3 t o 3 , 4 X (summer) and 3.8 t o 1 1, 1 % ( f a l l ) a n d
were a direct function of t h e v a r i a t i o n s in l i q h t - d e p e c d e n t
fixation rates.
Fiqure 8, H i s t o q r a m s of h o u r l y net f i q h t - i n d e p e n d e n t carbon
fixation rates in s p r i n q , sumer and fall,
Vertical l i n e s a t top of histoqrarns denote p r e c i s i o n
(2s/+; n = i n t r a - p l a n t replication = 8 - 12) .
DOC e x u d a t i o n b a s e d on l a b e l l e d DOC results
F i q u r e 9 p r e s e n t s the l e v e l s of DOC * POC i n t h e water, a s
c a l c u l a t e d f r o a t h e l a b e l l e d DOC {DOI*C + P O I % ) r e s u l t s a n d
e x p r e s s e d a s mqC qdw-2, P r e s e n t e d are t h e l e v e l s a t d u s k arid
dawn i n the e x p e r i m e n t a l cylinder when the i n i t i a l a n d c o n t r o l
l e v e l s h a v e been s u b t r a c t e d from t h e e x p e r i ~ e n t a l l e v e l s , Dusk
and dawn l e v e l s were s imi la r when o b s e r v e d w i t h r e s p e c t to the
i n t r a - e x p e r i a e n t p r e c i s i o n of the v a l u e s . VAen f i q , 9 is
compared t o P i q , 6 , similar t r e n d s i n 'ups* a n d 'downs* i n
i r r a d i a n c e , c a r b o n f i x a t i o n a n d DOC + PDC l e v e l s are apparent,
The r e l a t i o n s h i p between DOC e x u d a t i o n a n d i r r a d i a n c e
l e v e l s was i n v e s t i q a t e d h t h e s c a t t e r q r a m , Fiq, 10, w h e r e t h e
DOC + PUG r e l e a s e d per hour l i g h t , a s c a l c u l a t e d from t h e d u s k
DOC + POC v a l u e s , was g r a p h e d a q a i n s t t h e a v e r a q e h o u r l y
i s r a d i a n c e l e v e l i n e a c h e x p e r i m e n t . Surtlaser e x p e r i m e n t 3 was
e x c l u d e d f rom t h i s s c a t t e r q s a ~ a n d t h e f ollow3.nq s c a t t e r q r a l n
[F iq , 111 b e c a u s e of r e a s o n s s t a t e d earl ier ; t h e dusk DOC + POC
v a l u e f o r d a y 2, o n l y , was i n c l u d e d f o r 48 h e x p e r i m e n t s 108 a n d
109 i n t h e s c a t t e r q r a r e s , F i q , 10 a n d 11, S e a s o n a l differences i n
da ; l eng ths were c a n c e l l e d b y u s i n q hourly v a l u e s . R positive
F i q u r e 9, Histogrants o f DOC le~srels i n t h e incubation water*
as estimated b y the l a b e l l e d DOC {DOI*C * PDs*C)
results, a t d u s k and dawn s a a p l b n q s when colspared to
initial. and control levels.
Vertical l i n e s at t o p of histoqrams denote precision
(2s/-fh; a = intra-sample repl icat ion = 2-31.
' N D 1 denotes t h a t no data is a v a i l a b l e for the
experim&nt.
* * denotes that value includes only DO&*C data,
P i q u r e 10, Scattergram of dusk DOC (h l i q h t ) - 1 released, as
e s t i a a t e d b y t h e labelled DO%% * PO$% r e s u l t s ,
plotted aqainst averaqe hourly quanta& i r s a d i a n c e s i n
d i d experiments.
r e l a t i o n s h i p bekneen t h e DOC + POC a n d irradiance levels was
j i n d i c a t e d ; a n i n c r e a s e i n DOC e x u d a t i o n c o r r e s p o n d e d t o an
increase in i r r a d i a n c e ,
A s i m i l a r r e l a t i o n s h i p was i n d i c a t e d between DOC e x u d a t i o n
a n d t o t a l n e t carbon fixed h l i g h t * - 1 i n t h e s c a t t e r q r a m , ~ i q ,
3 1 ,
T a b l e 7 t a b u l a t e s t h e dusk and dawn DOC + POC levels b a s e d
on the l a b e l l e d o r q a n i c c a r b o n r e s u l t s . T h e f i n a l (dawn)
e x u d a t i o n v a l u e s r a n g e d from < 0,Ol mgC qdw-1 ( e x p e r i m e n t 4,
f a l l ) t o 0,554 mqC gdw-1 ( e x p e r i m e n t 103, s p r i n g ) r e p r e s e n t i n q
a p p r o x i ~ a t e l y 0 % t o 3.3 % of t h e p l a n t ' s total n e t c a r b o n
f i x e d ,
A n e t DOC u p t a k e was i n d i c a t e d i n some experiments, but the
l e v e l s were below the l e v e l of precision and t h e r e f o r e n o t
aif f e r i n q siqnificantl y fro@ z e r o ,
DOC e x u d a t i o n based on t o t a l DOC (TDOC + TPOC) results
H i s t o q r a m s of TDOC + TPOC e x p r e s s e d as mqC qdw-A are
p r e s e n t e d in Fig, 12; T a b l e 8 t a b u l a t e s t h e s e l e v e l s , Detection
o f s i g n i f i c a n t c h a n g e s i n fDOC * TPOC l e v e l s i n t h e c y l i n d e r was
limited by the p r e c i s i o n of t h e analytical t e c h n i q u e s , i n
p a r t i c u l a r t h e DOC technique, The ~ i n i r t t u m amount of c h a n g e t h a t
c o u l d b e detected i n the e x p e r i m e n t a l c y l i n d e r ' s DOC 3 POC level
was 0-53 mqC 1 - a t T h i s level t r a n s l a t e d i n t o 1,0 t o 17,3
mqC qdw-a d e p e n d i n q on t h e b i o a a s s of t h e p l a n t b e i a q i n c u b a t e d ,
P i q u r e 11, Scatterqrara of dusk DOC (h 1iqh-t) - $ r e l e a s e d , a s
estimated by ?he l a b e l l e d D O t * C + POa*C results,
plotted against a v e r a q e h o u r l y t o t a l n e t carbon f i x e d
i n d i e 1 e x p e r i n e n t s.
T a b l e 7 L e v e l s o f D O C a s e s t i m a t e d b y t h e l a b e l l e d D O C (DO-1 4C + PO-14C) d a t a i n t h e i n c u b a t i o n
w a t e r a t d u s k a n d a t d a w n w h e n c o m p a r e d t o i n i t i a l a n d c o n t r o l 1 e v e 1 s . N e g a t i v e v a l u e s d e n o t e a p p a r e n t u p t a k e o f o r g a n i c s . ** = i n c l u d e s d i s s o l v e d v a l u e o n l y . N D = no d a t a a v a i l a b l e . + 2 s / J n ; n = i n t r a - s a m p l e r e p l i c a t i o n = 2 t o 3 . -
Sea s o n E x p t D O C + POC l e v e l F i n a l l e v e l e x p r e s s e d a s m g ~ gdw-I a s % o f t o t a l n e t C
a t d u s k a t d a w n f i x e d
S p r i n g 1 0 1 0 . 0 2 2 0 . 0 1 2
1 0 3 0 . 4 9 _ + 0 . 1 8 9
1 0 5 0 . 1 2 + 0 . 0 8 9 -
( 4 8 h ) 1 0 8 0 . 4 3 A 0 . 1 4 7 0 . 5 5 f O - 1 8 1
( 4 8 h ) 1 0 9 0 . 0 8 2 0 . 0 9 6 - 0 . 0 4 + 0 . 0 8 9
Summer 1 1 0 0 . 3 0 + 0 . 0 6 5 -
111 0 .03_+0 .086
1 1 2 0 . 1 6 + 0 . 0 6 1 -
1 - 0 . 1 0 + 0 . @ 1 5 -
F a l l 2 0 . O l t O . 0 1 0
3 ND
4 - 0 . 0 5 + 0 . 0 6 6 -
- 0 . 0 1 + 0 . 0 4 3 - - 0 . 1
0 . 5 9 + 0 . 1 2 3 - 3 .9
0 . 1 3 1 0 . 0 8 3 1 . O
0 . 3 2 k O . 1 5 4 ( d a y l ) 0 . 5 9 _ f O . 2 1 3 ( d a y 2 ) 1 . 7
0 . 0 1 _ + 0 . 0 7 5 ( d a y l ) - 0 . 0 3 + 0 . 0 9 6 - (da y 2 ) -0 .1
0 . 2 0 + 0 . 0 6 2 - 1 - 9
0 0 3 2 0 . 0 9 4 0 . 3
0 . . 0 4 + 0 . 1 3 1 - 0 . 3
- 0 . 0 2 + 0 - 1 0 7 - 0 . 3
0 . 0 1 + 0 . @ 0 7 - 0 . 3
N D N D
O . O O + O . 0 3 0 0 . 0
P i q u r e 12, ffistoqrams of DOC levels i n the i n c u b a t i o n
water, as estimated by the t o t a l DOC ITDOC * TPOC) results, a t dusk and a t dawn when coiupared to i n i t i a l
and control levels,
vertical fines a t t o p of histoqsams denote precision
(2s /&; n = intra-sample precision = 2-9).
* d e n o t e s that v a l u e i n c l u d e s o n l y POC data,
* * d e n o t e s that v a l u e i n c l u d e s only DOC data.
Table 8 .Leve l s of DOC a s e s t i m a t e d by t h e t o t a l DOC (TDOC+TPOC) d a t a i n t h e i n c u b a t i o n w a t e r a t dusk and a t dawn when compared t o i n i t i a l and c o n t r o l l e v e l s . Minimum l e v e l of s i g n i f i c a n t d e t e c t i o n was de te rmined by t h e p r e c i s i o n (2s/<n) of t h e t e c h n i q u e s . S i g n i f i c a n c e t e s t =
S t u d e n t ' s T - t e s t ; only l e v e l s e x c e e d i n g minimum d e t e c t i o n l e v e l were t e s t e d . The o v e r a l l l e v e l of s i g n i f i c a n c e P , =0 .1 -
S = l e v e l s i g n i f i c a n t l y d i f f e r e n t f r a n 0. NS = l e v e l n o t "
I, 11 I 1
, , - d e n o t e s u p t a k e of o r g a n i c s . * i n c l u d e s only d i s s o l v e d v a l u e . ** i n c l u d e s on ly p a r t i c u l a t e v a l u e . +2s/<n; n = i n t r a - p l a n t r e p l i c a t i o n . -
Season Expt . TDOC+TPOC l e v e l s Dawn l e v e l Minimum l e v e l of d e t e c t i o n a s mgC gdw-' a s % of t o t a l a s a s % of t o t a l
a t dusk a t dawn n e t C f i x e d mgC gdw-' n e t C f i x e d
S p r i n g 101 6 - 5 2 1 - 4 9 S 4.42 2 -31 S 53 - 6 2.5 31
Summer 110 -0.42 4.50 - 3 - 9 2 4.41 NS
1978 111 8 .12 4.52**NS 3 .72 4.14**
112 4.3210.28 -0.6214-28
1977 1 2.32 2.99 0 - 3 2 3.07
F a l l 2 0 .82 1.14 0 - 7 2 2 -62 23.8 1 - 0 35
1977 3 - 0 - 9 5 0-58* 0.32 0-92* 3 1 - 1 2 - 4 216
4 -0.92 4.67 - 7 - 0 5 6 - 1 3 NS -455.1 2.7 174
1978 121 -6 .12 7.67 -e.0+ 6.84 -379.1 10.6 499
F
T h i s f u r t h e r t r a n s l a t e d i n t o 2 1 % to 972 R of the p l a n t " k o 2 a l
n e t c a r b o n f i x e d , a q a i n dependinq on t h e p l a n t q s b iomass i n
a d d i t i o n to t h e p l a n t ' s carbon f i x a t i o n r a t e (refer t o T a b l e 8
fa r the minimum detection l e v e l of each experiment),
T h e r e were no o b v i o u s t r e n d s o r c o r r e l a t i o n s with
i r s a d i a n c e o r c a r b o n f i x a t i o n l e v e l s i n t h e s e r e s u l t s . The
f e v e r s uere f rom two tirmes to one o r tau oaaqni tudes greater t h a n
t h e DOC levels c a l c u l a t e d f r o m the l a b e l l e d o r g a n i c c a r b o n
results. However, only experiments 101 and and 103 i n d i c a t e d
e x u d a t i o n s s i g n i f i c a n t l y above t h e d e t e c t i o n l i ~ i t a t i o n s and
e x p e r i m e n t 103 d i d so only d u r i a q t h e day. Experiment 103's low
DOC l e v e l the f o l l o u i n q dawn i n d i c a t e d n i q h t - t i m e u p t a k e of t h e
DOC r e l e a s e d during t h e day, These r e s u l t s i n d i c a t e d no
e x c e s s i v e e x u d a t i o n of DOC by M I &g$_eqrifol&p, i n e p r i n q or
suaaes, F a l l e x u d a t i o n would have been u n d e t e c t a b l e by these
t e c h n i q u e s ,
ATP r e s u l t s
An a n a l y s i s o f ATP l e v e l s i n t h e c y l i n d e r s t waters
p r o v i d e d a n e s t i ~ a t e o n t h e q u a n t i t y o f suspended microscopic
p a r t i c u l a t e o r q a n i c cafbon that was l i v i n g ~ a t t e r , T a b l e - 9
p r e s e n t s a cogparison of the e x p e r i m e n t a l c y l i n d e r ' s n e t POC
l e v e l s b a s e d on t o t a l , l a b e l l e d and l i v i n q f= ATP) p a r t i c u l a t e
c a r b o n r e s u l t s , T h e p a r t i c u l a t e c a r b o n l e v e l s based on the
l i v i n g a n d t h e l a b e l f e d POC r e s u l t s were wery low o r below
0) 3
l-l
6 % (d a,
k W
a a, U u a k U P 3 m
a, k
$ m d a,
t rl
rl 0 k U
E 0
a 9 rl (d 7-1 U d c d
a, C I3 . m C, rl 3 m 0) k
PI
2 a 3
p r e c i s i o n l i m i t a t i o n s . The p a r t i c u l a t e carbon l e v e l s based on
the t o t k l POC results were up t o two m a q n i t u d e s Wester t h a n t h e
l i v i n q p a r t i c u l a t e c a r b o n levels.
DOC a n d POC levels i n k e l p b e d s
The e x u d a t i o n o f o r g a n i c s b y 4, intearifo1i.a was
i n v e s t i q a t e d i n d i r e c t l y b y e x a n k n a t i o n of DOC c o n t e n t i n n a t u r a l
k e l p bed waters f roat t h e K i r b y P-t. Cove and S, Dodqer C h a n n e l ,
B a s e l i n e DOC a n a l y s e s were made on w a t e r s 100 m seaward from the
k e l p beds , T h e r e s u l t s of t h e s e analyses are p r e s e n t e d i n T a b l e
10, The l e v e l s of DOC ?in* and * o u t * of t h e kelp bed f o l l o w e d
t h e same s e a s o n a l t r e n d ; l e v e l s were h i q b e s t i n mid- sumtaer,
f a l l , and e a r l y s p r i n g , a t 4 t o 5 wqC 1 - 8 and lowest i n
mid-sprinq a t 1 t o 2 mqC I - a , However, t h e 'in' k e l p bed v a l u e s
vere e i t h e r q r e a t e r t h a n o r equal t o t h e ' o u t * o f kelp bed
v a l u e s , T h e * i n y k e l p bed levels were s i q n i f i c a n t l y ( P = D . O 3 f
q r e a t e r %hen t e s t e d by t h e Bann-Hhitney U-test,
POC uas also a n a l y s e d and *he r e s u l t s a re presented i n
T a b l e 10, T h e B a n n - Y h i t ~ e y a- test showed t h a t POC was
s i q n i f i c a n t l y (P=0,008) q s e a t e r J i n * t h e kelp bed t h a n ' o u t * of
t h e k e l p bed,
0 03 m " O N
0 0 0
+ I ($1 + I cn N
m e *
ma 2.~~,09e_n ~ p n s s t t,b ~aczo~ystrs
The s e a s o n a l chanqe i n t h e p l a n t ' s nutritive state was
i n v e s t i q a t e d by measure~eants o f i n t e r n a l . carbon and n i t r o q e n
levels (Table 11). A o n e - g a y Analysis of Variance indicated
sisnif i c a n t seasonal d i f f e r e n c e s (P(O, Q 1) i n levels of carbon,
n i t rogen , and C/N rat ios of the p l a n t s , T h e p l a n t from
e x p e r i n e n t 1 was n o t i n c l u d e d in t h e s e s t a t i s t i c a l . corn pa r i s o n s
for reasons s t a t e d e a r l i e r . The carbon c o n t e n t was f i i q h e s t i n -
sumaer, X = 20.32 % dry w t , i n t e r m e d i a t e i n fall, ? = 25,55 %I -
dry wt, and lowest i n s p s i n q , X = 24.26 $ d r y w t . Conversefy, -
t h e p l a n t * s n i t roqen content was qreatest i n f a l l , X = 3.93 % -
dry w t , intermediate i n spring, X = 1.60 % dry vt, and iowes? i n
suatner, = 1.33 96 dry w t . These r e s u l t e d i n a h i g h summen: C/H -
r a t i o , X = 25.0, and l o n e r s g r i n q , X = 18.4, and fall, ==3*6
C/H r a t i o s , A m u l t i p l e coraparison test ['Table 12) indicated that
s p r i n q and fall r a t i o s sere n o t siqnificantly d i f f e r e n t due t o
c o n f l i c t i n g s e a s o n a l t r e n d s i n carbon a n d nitroqen levels for
t h e s e two s e a s o n s ,
Ta
ble
1
1.
Dry
. w
eig
hts
, c
ar
bo
n
an
d
ni
tr
og
en
l
ev
el
s a
nd
C/M
ra
ti
os
of
p
la
nt
s
use
d
fo
r
24
h
,
48
h
an
d
da
rk
e
xp
er
ime
nts
. (+
S.E
.)
-
* P
lan
t fr
om
e
xp
t.
1 w
as
n
ot
inc
lud
ed
i
n
se
as
on
al
me
an
o
r s
ea
so
na
l c
om
pa
ris
on
s.
** F
all
19
77
an
d
19
78
we
re
c
om
bin
ed
w
he
n
Stu
de
nt'
s
T-
tes
t in
dic
ate
d
the
y w
er
e
no
t s
ig
ni
fi
ca
nt
ly
di
ff
er
en
t (P
c 0
.01
).
Se
a s
on
E
xp
t.
Pla
nt
C c
on
ten
t M
ean
N
co
nte
nt
Mea
n
C (m
o 1
es
)
Mea
n
C/N
d
ry
wt
.
as
%d
ry
s
ea
so
na
l a
s %
dr
y
se
as
on
al
N(m
o1
es
) r
at
io
(!
3 w
t.
C c
on
ten
t w
t.
N
co
nte
nt
Sp
rin
g
10
1
19
78
1
02
1
03
1
04
1
05
1
06
1
07
1
08
1
09
Su
mm
er
11
0
2 6
1
29
.40
2
8.3
2
1 .0
7
1 *
33
3
2.1
2
5.0
22
.03
1
97
8
11
1
18
6
27
.80
-
+0
.54
1
1.3
2
+0
.09
4
-
24
.6
11
2
11
4
29
.70
1
.42
2
4.4
1
13
1
49
2
7.9
0
1.3
4
24
.3
11
4
18
5
26
.80
1
.61
1
9.4
I
Table 12a. Resu l t s of 1-way Analyses of Variance f o r carbon content , n i t rogen content and C / N r a t i o s of Macrocyst is i n t e g r i f o l i a w i t h r e s p e c t t o season. F a l l 1977 and f a l l 1978 v a l u e s were pooled when t h e Student 's T- tes t showed them n o t t o be s i g n i f i c a n t l y d i f f e r e n t (P=0.01). Summer 1977 (expt . 1 ) was not included i n t h e comparisons.
C content
N content
C / N r a t i o
Table 12b.
C content
N content
C / N r a t i o
Fac tor df F P
season 2 28.541 0.000
Resu l t s of mu l t ip l e comparisons of seasonal C , N , and C / N conten ts of M. - i n t e g r i f o l i a us ing t h e Student-Newman-Keuls test. Common unde r l ine between means denotes no s i g n i f i c a n t d i f f e r e n c e between t h e means. Values expressed a s % of dry w t .
Season P
summer> f a l l > s p r i n g - - - 0.01 X=28.32 X=26.55 X=24.26 (n=5) ( n = l l ) h = 9 )
-
f a l l > s p r i n g > summer - - - 0.01 X=1.99 - X=1.60 X=1.33
summer > s p r i n g > f a l l - - - 0.05 X=25 .O X=18.4 X=15.6
D, Discussion
The i n v e s t i q a t i o n of die1 p r o d u c t i v i t y of a n entire 4 ,
JakesrifolLp p l a n t was realized w i t h the developaent o f a system
o f s u f f i c i e n t d i a e n s i o n s to a l l o w f o r t h e e n c l o s u r e of a n e n t i r e
p l a n t u n d e r c o n d i t i o n s of low biomass,fvolnme of rates. The
incubation cylinder's suspension i n the water column a t a
near-& s&gg l o c a t i o n d u p l i c a t e d many of t h e e n v i r o n m e n t a l
coadi t ions n o r m a l l y e x p e r i e n c e d b y t h e p l a n t , A 1 t housh g b
intesrifol&q does n o t qrou n a t u r a l l y a t P o r t ~e'sire':
t r a n s p l a n t e d p l a n t s have s u r v i v e d t h e r e (Druehl, 1978). D r u e h l
sugqests t h a t the p e r s i s t e n c e of 4. & q & g ~ i f o l i g at P o r t ~e'sire/
is p r e v e n t e d by s e d i a e n t c o l l e c t i n q o n the qame tophy t e
qeaeration, Jackson (1'377) a a i n t a i n s t h a t , d u e t o c h a n q e s i n
e n v i r o n m e n t a l factors with d e p t h , s i r a n l a t i o n of a qiant kelp's
natural c o n d i + , i o n s is i n t p o s s i b l e , J a c k s o n , however , is referrinq
t o the ~ a l i f o r n i a q iant kelp, 2, ~ y r i f e r a , which s p a n s a much
q a e a t e r d e p t h t h a n Br U s r i f 01&g* Further, t h e s e v a r i a n c e s i n
c o n d i t i o n s were p r o b a b l y n o t a s p ronounced i n m y experimental
p l a n t s : n a t n r a l e n v i r o n l a e n t because my p3.ant.s were smal l , a b o u t
2 B. i n lenqth,
T h e s i r a u l t a n e o u s m o n i t o r i n q o f t h e control a n d e x p e r i m e n t a l
c y l i n d e r s f a c i l i t a t e d e v a l u a t i o n of backg round a i c r o b i o t i c
a c t i v i t y , C o n t i n u o u s s t i r r i n q p r o v i d e d b y t w o s u b m e r s i b l e pumps,
presualably restricted t h e f o r l a a t i o n of l a r a e l l a r botm d a r i e s + & a r o u n d t h e p l a n t , ~ i t t l e r " / ( 1 9 7 3 ) a n d Buesa (1977) d m o n s t r a t e d
t h a t t h e a b s e n c e of c o n t i n u o u s s t i r r i n q r e d u c e d p h o t o s y n t h e t i c
rates up t o 73 $ a n d 34 X, r e s p e c t i v e l y ,
The low b i o t t i a s s / v o l u ~ e r a t i o i n these d i e 1 e x p e r i m e n t s
n e c e s s i t a t e d the deve lopmen t of DOC c o n c e n t r a t i o n p roced ares and
i m p r o v e m e n t s on e x i s t i n q a n a l y t i c a l t e c h n i q u e s i n o r d e r t o
d e t e c t o r g a n i c s released b y t h e p l a n t . The f l a s h e v a p o r a t i o n
t e c h n i q u e f o r a n a l y s i s of labelled DOC e n a b l e d d e t e c t i o n o f DOC
lewels down t o 1 0 F q C 1-1 P h i s i s a p p r o x i s a t d y 70 times Bore
s e n s i t i t r e t h a n would h a v e been p o s s i b l e ! u s i n q t h e c o n v e n t i o n a l
me thods tcf,, Anderson and Z e u t s c h e l , '1970; B r y l i n s k y , 1977;
Fankboner a n d deBurgh, 1977; P e n h a l e and Smi th , 1977) .
The total DOC t e c h n i q u e i n v o l v i n q f r e e z e - d r yinq f o l l o w e d b y
t o t a l c o ~ b u s t i o n w a s r e l a t i v e l y precise and q u i c k t o perforra
when compared to the s t a n d a r d lgenzel and Vacarro (3964) wet
o x i d a t i o n t e c h n i q u e , b u t n o t s u f f i c i e n t l y s e n s i t i v e f o r
d e t e c t i o n of low l e v e l s of e x u d a t i o n , T o t a l DOC t e c h n i q u e s a re
c o n t i n u o u s l y b e i n g m o d i f i e d a n d i a p r o v e d ; S a l o n e n l s (1 3 7 9 )
t e c h n i q u e m e a s u r e s DOC levels down t o 0.5 lnqC 1-1 and
MacKinnonss ( I 378) t e c h n i q u e i s r e p u t e d l y t e n tiilles more
s e n s i t i v e ,
An a d v a n t a q e of the whole p l a n t approach for the a s t i n a t i o n
of n e t daily p r o d u c t i v i t y b y a m a c r o p h y t e is t h a t a n y
i n t r a - p l a n t p h o t o s y n t h e t i c d i f f e r e n c e s , a s h a v e Been
d e a o n s t s a t e d i n 4, ~ u g r p [Sarqent a a d L a n t r i p , 1952; T ~ w l e
a n d P e a r s e , 3973) , can b e c isc lamvented.
T h e n e t d a i l y c a r b o n f i x a t i o n was u s u a l l y e s t i m a t e d b y t h e
uptake of r a d i o c a r b o n d u r i n q a 24 h i n c u b a t i o n . A s h o r t c o m i n q o f
the r a d i o c a r b o n p r o d u c t i v i t y t e c h n i q u e is t h e a m b i q u i t y of t h e
a e a s u r e d u p t a k e -- is it g r o s s or n e t p r o d n c t i v i t y ? i s t r i c k l a n d ,
1960). N e t p r o d u c t i v i t y c o u l d be a e a s u r e d fn 24 h r a d i o c a r b o n
u p t a k e e x p e r i ~ e n t s i f newly s p a t h e s i z e d l a b e l l e d s u b s t r a t e s are
p r e f e r e n t i a l l y m e t a b o l i s e d or r e s p i r a t i o n rates a r e min ima l
[Hobson et a,, 1976). T h e s i m i l a r i t y be tween m y r a d i o c a r b o n
uptake r e s u l t s and the n e t change in i n o r g a n i c c a r b o n c o n t e n t of
the e x p e r i m e n t a l c y l i n d e r s u g q e s t s t h a k aty radiocarbon up-take
r e s u l t s e s t i m a t e d n e t carbon f i x a t i o n . Q u i t e o f t e n , t h e
r a d i o c a r b o n u p t a k e r e s u l t s were less t h a n the n e t inorqaaic
c a r b o n chanqe i n t h e c y l i n d e r , This d i s c r e p a n c y may h a v e been
c a u s e d b y some a * C l o s s e s due t o r e s p i r a t i o n by the p l a n t d u r i n q
t h e i n i t i a l stages of t h e plant d r y i n q p r o c e s s followinq the
e x p e r i m e n t ,
Experiments of a few h o u r s d u r a t i o n , a s o p p o s e d t o 24 h
e x p e r i m e n t s , Bay e r r o n e o u s l y p r e d i c t d a i l y p s o d u c t i v i t y b e c a u s e
o f . p o s s i b l e d i e 1 r h y t h m s i n p h o t o s y n t h e t i c a c t i v i t y . D i e 1
r hy thms i n a t a c r c a l g a l p r o d u c t i v i t y have b e e n studied i n f e u
species; &gp&iyhg [Oohusa, 1980) a n d S p a t o q l p s s u g (Kaqeyama
et 2&. , 1979; H a ~ a d a g& &., 1979) have b e e n demons t r aked t o - possess s u c h rhy thms ; whe rea s B l i n k s a n d Givan 11961) f a i l e d t o
f i n d d i u r n a l r h y t h a s i n t h e r e d , qseen, and brown alqae t h a t
t h e y t e s t e d ,
Exveg&,mentaJ Resurtg
These r e s u l t s are d i s c u s s e d i n r e f e r e n c e t o 8,
iatearifoA&q, houeve r , b e c a u s e t h e e x c l u s i o n of i t s e p i p b y t e s
was i m p a s s i b l e , the r e s u l t s were a c t u a l l y due t o t h e 14.
h t e s r i f o l i g - e p i p h y te sys-tea, Because r e l a t i v e l y e p i p h y t e - f r e e
plants were u s e d for a11 e x p e r i n e n t s , the e p i p h y t e s t
c o n t r i b u t i o n t o t h e r e s u l t s were p r o b a b l y small.
Carbon f i x a t i o n r e s u l t s
S e a s o n a l i t y i n the r a n q e of carbon f i x a t i o n rates o f 4.
in%.e@&&_a u n d e r n e a r - 9 s i t u c o n d i t i o n s has b e e n
d e n o n s t r a t e d , The g r e a t e s t t d a l n e t c a r b o n f i x a t i o n r a t e s were
measu red i n s p r i n g , r a n q i n g f rom 0.55 t o 1,09 mqC q d r * h-t ;
sufamer rates r a n q e d from 0.41 to 0.62 mqC qdw-g h - * ; f a l l rates
were the lowest a t 0 - 0 3 t o 0.25 raqC qdw-a h-a ,
The e x p e r i m e a t a l a p p r o a c h u s e d here d i d n o t l e n d i t s e l f t o
S h e d e t e r m i n a t i o n of p h o t o s y n t h e s i s v e r s u s liqht i n t e n s i t y
c u r v e s . E xper imenlrs were p e r f o r m e d at natural. i r r a d i a n c e
c o n d i t i o n s . Durinq eac h season solae e x p e r i m e n t s were c o n d u c t e d
on clear briqht days r e p r e s e n t i n q a s briqht a n i s r a d i a n c e a s t h e
p l a n t would n o r m l l y e x p e r i e n c e in t h e season , T h e r e f o r e , t h e
h i q h e s t c a r b o n f i x a t i o n r a t e s i n any season probab ly
a p p r o x i a a t e d t h e p l a n t % ma x i iRua c a r b o n f i x a t i o n per formance ,
&@*
ag~gocvst& 5 n t e u f : i f g l i a ' s p h o t o s y n t h e t i c r a t e s uere
d e t e r m i n e d b y wi l l enbr ink gg 52;& f3973) a s 1 , 2 8 mqC qdn-a h-a
for old blades and 3.06 mqC qdu-a h-1 fo r younq b l a d e s u n d e r
satwatin q liqht i n September . T h e i r ex periiuerats, however, were
per formed o n b l a d e d i s c s w i t h no c o n s i d e r a t i o n f o r less
p h o t o s y n t h e t i c a l l y a c t i v e t i s s u e , Lobban (1976) summarized
year ly q r o w t h rates i n I, jn teqr&f~3.&2~ w i t h respect t o stipe
e l o n g a t i o n , a s Hay/June r a t e s b e i n q two times the rates o f
Auqus t /Sep te@ber and f o u r tinres t h e rates of October/November,
Cobban l s r e l a t i v e s e a s o n a l rates a q r e e with my relative carbon
f i x a t i o n rates,
V a r i o u s f a c t o r s may c o n t r i b u t e t o t h i s s e a s o n a l i t y ,
I r r a d i a n c e levels showed a s e a s o n a l i t y s i m i l a r t o t h a t o f t h e
c a r b o n a s s i l a i f a t i o n rakes. F a l l i r r a d i a n c e s , even on briqht,
sunny days, were c o n s i d e r a b l y 'Lower than irradiances of the
o t h e r two seasons, Likewise, fall tetrtpera-tures were 5 to 7 C
lower than s p r i n g t e m p e r a t u r e s a n d 7 t o 10 C lower t h a n sunmer
t e a p e r a t u r e s , O t h e r studies on m a c r o a l q a l s e a s o n a l p r o d u c t i v i t y
h a a e shown q r e a t e r p h o t o s y n t h e t i c rates t o be c o i n c i d e n t with
s e a s o n s k a v i n q l o n q e r d a y l e n q t h s (= qreater c u l a u l a t i v e
i r r a d i a n c e s ) and h i g h e r t e m p e r a t u r e s {Zavodnik, 1973; Dsinthuis,
1977a,b,c; L i t t l e r 2% &., 19791 . W i n t e r and f a l l
liqht-saturates l e v e l s of p h o t o s y n t h e s i s Mere l o w e r t h a n summer
1966; Chock a n d R a t h i e s o n , 1979) a n d in h a a n a r i a m z h g g g Jr
, (Zuninq, 1971). These p r o v i d e p o s s i b l e e x p l a n a t i o n s for -the
l o w e r f a l l f i x a t i o n l e v e l s , b u t d o n o t e x p l a i n t h e l o v e r sugtmer
levels w i t h respect t o s p r i n q f i x a t i o n l e v e l s .
The w a t e r s o n u t r i e n t c o n t e n t was h i q h e s t i n f a l l and a n
o r d e r of maqni tude loner i n s p r i n q and suatmer, Exairt ination o f
t h e p l a n t ' s n i t r o q e n content f u r t h e s reflects this t r e a d . The
h i q h e s t p l a n t n i t r o q e a c o n t e n t was i n f a l l , f o l l o w e d b y s p r i n q
and t h e n surtliues w i t h the lowest content, Afthouqln sprinq carbon
f i x a t i o n rates were shown n o t t o be s i q n i f i c a n t l y different f rom
sunmel: ra.f;es ( p a r t i a l l y a c o n s e q u e n c e of t h e small s a m p l e
sizes), visual i n s p e c t i o n of Fiq, 7 i n d i c a t e s the s p r i n q rates,
with t h e e x c e p t i o n of e x p e r i n e n t 189, were q r e a t e r than suxamrtr
r a t e s a t e q u i v a l e n t i r r a d i a a c e s a n d w i t h the summer temperatures
equal or qreater t h a n s p r i n q t e a p e r a t u r e s , P o s s i b l y n u t r i e n t
r e s e r v e s a c c u m u l a t e d d u r i n q f a l l were b e i n g d e p l e t e d b y s n ~ l m e r
a n d , thereby, d e p r e s s i n g t h e plant s summer c a r b o n f i x a t i o n
rates, T r a n s l o c a t i o n of n i t r o g e n o u s compotlnds h a s been
dem.ons t ra ted i n 4. g y r i f e r a (Jackson, 1977) i n which the
t t a n s l o c a t e d fluid had a l o v e s c/% r a t i o (C/N = 9 ) than the
canopy b l a d e s (C/N = 45) . J a c k s o n hypothesized t h e t r a n s l o c a t i o n ,'
of a i t r o q e n compounds t a k e n u p b y lower b l a d e s o c c u p y i n q tie
d e e p e r , hiqher n u t r i e n t w a t e r s and n i t r o q e n o u s storase p r o d u c t s
t o t h e canopy b l a d e s uccupyiraq n u t s i a n - t - d e f i c i e n t surface
waters, Al thouqh & ~ y g & f s g g s p a n s a g r e a t e r d e p t h r a n q e a n d
probably a qxeater n u t r i e n t d i f f e r e n t i a l t h a n 4, j.nteqg&&&., a
s i s i l a r process miqht be o c c u r r i n ~ i n 4, ing&e~rif&La_ d u r i n q 4
p e r i o d s of s p r i n q aad sulamer n u t r i e n t d e p r e s s i o n s u n t i l t h e
n i t r o q e n r e s e r v e s are d i ~ i n i s h e d i n summer, F u r t h e r e v i d e n c e on
t r a n s l o c a t i o n of n i t r o q e n o u s coapounds was p r o v i d e d b y
t r a n s l o c a t i o n s t u d i e s on g, i ~ t e p g j . f @ g b y S c h ~ i t s and
S r i v a s t a v a ( 1979) which showed 44 &ate~rifolia*s ' t r ans l o c a t e t o
have a h i q h e r aniino a c i d c o n t e n t t h a n t h e p h o t o s y n t h a t e o f t h e
blades and some o f t h e t r a n s l o c a t e laovement was a c r o p e t a l t o w a r d
the younq t i s s u e ,
Similarljt, s t u d i e s b y Chaplgan and C r a i q i e 11977) oa
Laainqdg & o n ~ i c r u g & off Cianadaqs E a s t Coast shoved t h e p l a n t
t o have a l a t e f a l l a n d w i n t e r n i t r o q e n r e s e r v e a c c u r a u l a t i o n
which appeaadd to be e x h a u s t e d by summer and was c o n c u r r e n t t o a
susmer q r o w t h d r a t e d e p r e s s i o n . Suraaer n i t r a t e f e r t i l i z a t i o n o f
the I_. 1 ~ n a i c = & bea r e s u l t e d i n s u a s e r q r o u t h rates s i a i l a c
t o the h i q h e r s p r i n q qrowth sates. i n d i c a t i n q n i t r a t e depletion
as t h e c a u s e of t h e q r o w t h d e p r e s s i o n ,
. By g, i n t e q a f o l i a c a r b o n f i x a k i o n v a l u e s represented tbtj
sutrtaed a c t i v i t y of t h e whole t h a l l u s . Bay s e a s o n a l c b a n q e i n t h e
s t r u c t u r e o f a p l a n t would a l t e r t h e f i n a l c a r b o n fixation
s u m a a t i o n , Fall s t o r m s c a n reao;e many of t h e c a n o p y blades and
therefore r e d u c e their c c n t r i b u t i o n t o t h e t o t a l c a r b o n
f i x a t i o n . T h i s could r e s u l t i n s i q n i f i c a n t l y r e d u c e d c a r b o n
f i x a t i o n b e c a u s e t h e younq ~ a t u r e c a n o p y b l a d e s h a v e b e e n shown
t o h a v e h i q h e r rates of p h o t o s y n t h e s i s t h a n most other p l a n t
r e g i o n s i n a, ~ y g f f s p I C l e a d e n n i n q , 1964; T o u l e and P e a r s e ,
1973) . This a i q h t c o n t r i b u t e t o s e a s o n a l i t y i n c a r b o n f i x a t i o n
r e s u l t s ,
S e a s o n a l c h a n q e s i n m a c r o a l q a l r e s p i r a t o r y rates ha v e n o t
f o l l o w e d t h e e x p e c t e d Q , ~ f L e h n i n q e r , 1975) r e l a t i o n s h i p t o
t e m p e r a t u r e i n c r e a s e s i n s u a m e r , r e s u l t i n q i n q r e a t e r suinmer n e t
prodvctivit y [Kanvisher, 1966; ~ G n i n ~ , 1971; a a n n and Chapman,
3375) . Irrcseases i n c h i o r o p h y l l content duriaq v i a t e r h a v e b e e n
shown t o i n c r e a s e w i n t e r p h o t o s y n t h e s i s rates, t h e r e b y
d e c r e a s i n g s e a s o n a l d i f f e r e n c e s i n net p r o d u c t i v i t y (Zavodnik,
1973; B r i n k h u i s , t 9 7 7 b f . Such s e a s o n a l p h y s i o l o g i c a l c f i a n q e s
h a v e not b e e n i n v e s t i g a t e d i n 8, inteclrif01ia b u t r a iqh t b e
i a p o r t a n t a e c h a n i s a s i n r e q u l a t i n q s e a s o n a l q r o w t h p a t t e r n s i n
t h e k e l p ,
G i q h t - i n d e p e n d e n t c a r b o n f i x a t i o n r e s u l t s d i d not show
s i g n i f i c a n t s e a s o n a l d i f f e r e n c e s . The mean rate was 0,0 1
mqC qdv-1 h-' w i t h rates r a n q i n q from 0 , 0 0 8 t o 0 ,016
laqC qdu-a h-2 . When e x p r e s s e d as p e r c e n t of l i q h t - d e p e n d e n t
c a r b o n fixation, t h e rates r a n g e d f roin 1.2 $ t o 1'1.1 X,
reflect i n q v a r iat ions i n l i g h t fixation rates, R i l l l e n b r i n k
et & ( 1 979) o b s e r v e d q e e a t e r levels o f 1 l q b t - i n d e p e n d e n t -- c a r b o n f i x a t i o n a n d c o r r e s p o n d i n q l y o f t h e d a r k c a r b o x y f a t i o n
e n z y m e p h o s p h e n o l p y r u v a t e carboxykinase (PEP-CK), i n youns
blades as opposed t o o l d e r b l a d e s , They s u q q e s t e d that h i q h
l i q h t - i n d e p e n d e n t carbon f i x a t i o n a c t i v i t i e s aiqht be i m p o r % a n t
i n t h e late w i n t e r and ,early s p r i n q p e r i o d s of low i r r a d i a n c e s
for growth o f younq f r o n d s , fly Apri l /May spr i r sq e x p e r i m e n t s were
too l a t e i n s p r i n q t o iaeasure t h i s e a r l y sprinq qrowth a n d ,
f u r t h e r , t h e whole p l a n t a p p r o a c h would n o t d e t e c t t h e h i q h e r
dark f i xa t i ozn r a t e s i n the younq blades, T h i s area o f r e s e a r c h
benefits f r o m studies o n i s o l a t e d b l a d e s .
Exuda t ion Results
E x u d a t i o n of orqanic c a r b o n was d e f i n e d as an i n c r e a s e i n
the dissolved plus p a r t i c u l a t e o r q a n i c c a r b o n levels of the
w a t e r i n the e x p e r i l a e n t a l c y l i n d e r when t h e initial a n d c o n t r o l
c y l i n d e r s s l e v e l s were s u b t r a c t e d f rum t h e e x p e r i ~ e n ta l
c y l i n d e r ' s level. A d e c r e a s e in t h e d i s s o l v e d + p a r t i c u l a t e
level was i n t e r p r e t e d as an u p t a k e of o r q a n i c c a r b o n b y t h e 4,
i n t e u r i f o l i ~ system, T h e seawater i n the e x p e r i m e n t a l a n d - c o n t r o l c y l i n d e r s was t h e salge a t t h e s t a r t of t h e e x p e r i m e n t ;
t h e o n l y d i f f e r e n c e i n t h e s e two systems k i n q t h e p r e s e n c e of
t h e p l a n t i n t h e e x p e r i a a e n t a l cyl iader , E x u d a t i o n sf DOC by t h e
m i c r o f l o r a of t h e w a t e r s h o u l d b e s i a i l a r i n both cylinders.
T h e r e f o r e , a n e t increase i n t h e DOC l e v e l i n t h e e x p e r i m e n t a l
c y f i n d e r , r e p r e s e n t e d DOC/exudation b y t h e e x p e r i m e n t a l p l a n t "
systera, P r i m a r y f i x a t i o n of i n o r q a n i c c a r b o n i n t o o r q a h i c c a r b o n
by t h e water's m i c r o f l o r a s h o u l d also b e similar i n t h e two
c y l i n d e r s . T h e r e f o r e , a n y c h a n q e s i n t h e n e t POC v a l u e s o f t h e
e x p e r i m e n t a l c y l i n d e r , when c o r r e c t e d f o r c o n t r o l v a l u e s , ~ u s t
b e due t o t h e presence, o f a. &&;,egrifolia i n the c y l i n d e r a n d
t h r o u q h r o u t e s o t h e r t h a n t h e d i r e c t p r i m a r y f i x a t i o n of
i n o r g a n i c c a r b o n i n t o p a r t i c u l a t e o r q a n i c c a r b o n by t h e water s
wicrof b r a , The o t h e r possible r o u t e s i n c l u d e b i o l o q i c a 1
h e t e s o t s o p h i c uptake of DOC by %he n t i c r o f l o r a (Nalewajko et a l . ,
3975; Williams and Yenitsch, 1976), p h y s i c a l a d s o r p t i o n o f DOC
upon the p r e - e x i s t i n g p a r t i c u l a t e s $ C h a w a n d Suess , 1967;
R i l e y , 1970) a n d molecular a q q r e q r a t e f a s r a a t i o n of Poi3 f r o & DOC
(R i l ey , 1963; Wanqerskg, 1972, 1'378), T h e s o u r c e o f DOC for a l l
these p r o c e s s e s would b e the p l a n t sys te ia , The low net AZP
values i n t h e e x p e r i a e n t a l c y l i n d e r , s u q q e s t e d v e r y l i t t l e
d i f f e r e n c e i n t h e l i v i n q a i c r o s c o p i c p a r t i c u l a t e c a r b o n levels
between the e n p e r i n i e n t a l a n d c o n t r o l c y l i n d e r s . T h i s , i n t u r n ,
i n d i c a t e d that rainimal m i c r o b i a l h e t e r o t r o p h i c uptake o f t h e
k e l p s y s t e ~ v k z e l e a s e d DOC was o c c u r r i n q ,
The above arquoaent a s s u a e s that d e t r i t a l p a r t i c l e s are n o t
beinq produced by the p l a n t , O b s e r v a t i o n of t h e i n c u b a t i o n w a t e r
d u r i n q an e x p e r i m e n t c o n f i r m e d t h e absence of v i s i b l e p l a n t
p a r t i c l e s , Due t o t h e s e i n t i m a t e DOC/POC r e l a t i o n s h i p s , i t was
70
deem& art if icial to set t h e arbitrary filter p o f e - s i z e
(0.7A m) as a b o u n d a r y be tween PDC a n d DOC; a n d instead they I'
were c o m b i n e d a s o n e measure ,
The m e a s u r e m e n t o f d i s s o l v e d o r g a n i c c a r b o n P o s e s
d i f f i c u l t i e s i n i n t e r p r e t a t i o n a n d t e c h n i q u e . F i r s t , the a o s t
s e n s i t i v e t e c h n i q u e , a n d t h e r e f o r e , the t e c h n i q u e most commonly
u s e d i n e x u d a t i o n s t u d i e s is the r a d i o c a r b o n tracer t e c h n i q u e , .. When t h e water's l a b e l l e d D O r V c o n t e n t i s m e a s u r e d a n d compared
to t h e p l a n t *s c a r b o n f i x a t i o n rates, t h e common a s s u ~ l l p t i o n i s
t h a t t h e e x u d a t e o r i g i n a t e d from a n i n t r a c e l l u l a r pool o f
interaediate metabolites a t i s o t o p i c e g u i l i b r i u a v i t h t h e
i n o r q a a i c c a r b o n of t h e i n c u b a t i o n media@, The v a l i d i t y of t h i s
a s s u m p t i o n h a s n o t been f u l l y tested and consequently i s o t o p i c
m e a s u r e m e n t s of DOC e x u d a t i o n p e r h a p s s h o u l d be i n tetpreted a s
minimum m e a s u r e a e n t s -- t h e r e is t h e p o s s i b i l i t y of releases o f
compounds fro& a n l a b e l l e d c e l l u l a r s o u r c e s n o t a t isotopic
e q u i l i b r i u m lie,, c o a p o u n d s t h a t were s y n t h e s i z e d p r i o r t o the
tracer e x p e r i m e n t ) . The e x u d a t i o n of o r q a n i c s f i x & p r i o r t o the e x p e r i n w i t was
i n v e s t i q a t e d b y ~ a r l i n and Craiqie (1975) . T h e y P a b e l l e d
t i s s u e into u n l a h l l e d seawater, a n d m e a s u r e d a t o t a l e x o d a % i o n
of 1.5 X of t h e i n i t i a l l y f i x e d r a d i o c a r b o n o v e r a p e r i o d of 1
weak, T h i s s u q q e s t s a min imal e x u d a t i o n o f p r e v i o u s l y f i xed
o r q a n i c s ,
A s o l u t i o n t o the a m b i q u i t y i n the i n t e r p r e t a t i o n of
r a d i o c a r b o n DOC rueasurements, is the measurement of the t o t a l
DOC c o n t e n t of t h e v a t e r by n o n - r a d i o i s o t o p e tracer techniques.
U n f o r t u n a t e l y , these n o n - r a d i o i s o t o p e t r a c e r t e c h n i q u e s l a ck t h e
s e n s i t i v i t y for t h e d e t e c t i o n of the a p p a r e n t Pow l e v e l s of
orqanic e x u d a t i o n , a
It has been s u q g e s t e d t h a t i n c u b a t i o n s unde r n o n a x e n i c
c u n d i t i o n s u a d e r e s t i m a t e e x u d a t i o n s b e c a u s e of h e t e r o t r o p h i c
u t i l i z a t i o n of t h e e x u d a t e s b y t h e u a t e r *s r n i c r o f l o r a (Nalewajko
&., 1976; Yilliaius and Yentsch , 1976; Sharp, 137 7) . T h i s
s h o u l d n o t have b e e n a problem i n my e x p e r i p l e n i s because , a s
l aen t ioned earlier, P included p a r t i c u l a t e c a r b o n t c o r r e e t e d f o r
primary p a r t i c u l a t e carboa p r o d u c t i o n i n t h e c o n t r o l c y l i n d e r )
i n my 3 d i s s o l v e d 3 organic c a r b o n measurements . H e t e r o t r o p h i c
a c t i v i t y by b e n t h i c r s i c robes a d h e r i n q t o the p l a n t was a
p o s s i b l e interfering factor.
I n this s t u d y , I i n v e s t i q a t e d t h e exudation of o rqan ic s b y
3, hteur$&Aia by u t i l i z i n q b o t h of +,he above a p p r o a c h e s ; t h e
radiocarbon tracer t e c h n i q u e allowed f o r s e a s u r e m e n t of minimum
e x u d a t i o n a n d the TDOC t e c h n i q u e a l l o w e d for measurement o f
exudations e k e e d i n q t h e TDOC t e c h n i q u e ' s d e t e c t i o n l i ~ i i a t i o n s .
Due t o t h e l e n g t h of the e x p e r i m e n t s , some c y c l i n q of e x u d a t e
s u c h a s t h e u p t a k e of p r e v i o u s l y r e l e a s e d e x u d a t e could have
o c c u r r e d and was o n l y d e t e c t e d i f i t o c c u r r e d d u r i n q t h e n i q h t
(between t h e dask a n d dawn s a a p l i n q s ) .
T h e d a i l y exudation l e v e l s a s d e t e r m i ~ e d b y t h e r a d i o c a r b o n
tracer r e s u l t s r a n q e d from 0 t o 0.59 myC qdw-a h-1 or 0 % t o
3.9 X of t h e t o t a l ne.3: c a r b o n f i x e d , T h i s e x u d a t i o n a p p e a r e d t o
be d i r e c t l y r e l a t e d to the l e v e l of i r r a d i a n c e a n d t h e r a t e of
c a r b o n f i x a t i o n , T h e r e d i d n o t a p p e a r t o b e a n y s e a s o n a l
e x u d a t i o n p a t t e r n s t h a t c o u l d n o t be e x p l a i n e d b y r e l a t i o n s h i p s
t o i r r a d i a n c e l e v e l s o r c a r b o n f i x a t i o n rates, P e n h a l e and S m i t h . (1977) a l s o r e p o r t e d a direct r e l a t i o n s h i p b e t v e e n e x u d a t i o n and
carbon f i x a t i o n by t h e s e a q r a s s , &ptera t~taxina.
The TDOC l e v e l s , i n q e n e r a l , d i d n o t r e a c h the TDOC
t e c h n i q u e * s d e t e c t i o n l i m i t a t i o n s , On1 y one s p r i n g e x p e r h e a t
(1 0 1) s i q n i f i c a n t l p e x c e e d e d t h e TDOC d e t e c t i o n l i m i t a t i o n wi th
a 24 h e x u d a t i o n of 53,6 % of t h e to ta l rset c a r b o n f i x a t i o n , b u t
t h i s was n o t shown i n other e x p e r i m e n t s and t h e r e f o r e i t would
seem t o b e t h e e x c e p t i o n r a t h e r t h a n the nor@, E x c e s s i v e
e x u d a t i o n d i d n o t occur i n sprinq a a d sumreer; and f a l l
e x u d a t i o n s would h a v e been u n d e t e c t a b l e b y the TDOC t e c h n i q u e ,
S p e c u l a Z i o n on the c a u s e of e x u d a t i o n h a s i n c l u d e d the
release of a n t i b a c t e r i a l and a n t i a l q a l s u b s t a n c e s and releases
of a s s i a i l a t g r y s u r p l u s e s d u r i n q p e r i o d s when e n v i r o n m e n t a l
c o n d i t i o n s p r e v e n t e d ce l l nnu l t i p l i ca - t i on b u t not: carkaoxl f i x a t i o n
[see Hell e b u s t , 1974; Wanqersky, 1978) , # i t b i n t h e y e a r l y c a r b o n
budqe t of J&&&g& & s g q i c r u g L s and a c c o u n t i n q f o r qrowth a n d
s t o r a g e , H a t c h e t g$ &. 11377) c a l c u l a t e d , f rom t h e i r
p h o t o s y n t h e t i c ra te e x p e r i m e n t s z r e s u l t s , a s p r i n q and suntaer:
35 % s u r p l u s i n c a r b o n a s s i m i l a t i o n a n d s u q q e s t e d exudation a s
t h e f a t e o f t h i s a s s i a i f a t o r y s u r p l u s , They a l s o s u q g e s t e d t h a t
hiqh sumner i r r a d i a n c e s would e n c o u r a q e p h o t o s y n t h e s i s b u t \,
n u t r i e n t d e p l e t i o n s would i n h i b i t c e l l d i v i s i o n and growth.
J a c k s o n ( 3 377) h y p o t h e s i z e d e x u d a t i o n of a s s i r e i l a t e d c a r b o n b Y
PI, g ~ r i f e z a of C a l i f o r n i a waters d u r i n g n i t r a t e d e p l e t i o n i n the
water, SolPowing d e p l e t i o n of s t o r e d n i t r o q e n reserves.
The release of a n t i b a c t e r i a l and a n t i a l q a l s u b s t a n c e s ,
e s p e c i a l l y i n younq t i s s u e , would n o t b e s u a p r i s i n q b e c a u s e of
t h e p a u c i t y of e p i p h y t e s on younq q r o v i n q b l a d e s of 4.
i n t e q r i f o l & _ a (Roland, 1980) . F u r t h e r , a n t i b a c t e r i a l s u b s t a n c e s - have been i s o l a t e d from a p i c a l s c i a i t a r s o f t h i s a l q a iA, Quek,
pers, comaa,) . Houeves, the release of such s u b s t a n c e s p r o b a b l y
would b e i n small q u a n t i t i e s and u n d e t e c t a b l e ,
I f assimilatory s u r p l u s e s were b e i n q r e l e a s e d d u f i n q
p e r i o d s o f h i g h i s r a d i a n c e s a n d n u t r i e n t d e p l e t i o n t h e e x u d a t e
s h o u l d be c o ~ p r i s e d rnainly of t h e newly a s s i m i l a t e d 4 s u r p l u s *
o r q a n i c s and, c o n s e q u e n t l y , d u r i n g a r a d i o c a r b o n e x p e r i l a e n t
should be close t o i s o t o p i c e q u i f i b r i u r a and d e t e c t a b l e b y t h e
s e n s i t i v e r a d i o c a r b o n tnethodoloq y, fly r a d i o c a r b o n e x u d a t i o n
r e s u l t s f o r g* a t e r r r i f o u d i d not e x c e e d 3,9 X and, q e n e r a l l p
were less than 1 % of the carbon fixed, F u r t h e r , d u r i n s summer,
when t h e C/N r a t i o s were h i q h e s t (C/M i n summer = 25; C/N i n
fa21 = l 5 , 6 ) , no qreater e x u d a t i o n was detected, P e r h a p s t h e
n u t f i e a t r i a i t a t i o n is n o t a s s e v e r e i n t h e 4, L g t e a r i f o l i a
e n v i r o n m e n t or t h e plant has d e v e l o p e d a mare conservative
r e s p o n s e t o n u t r i e n t d e p l e t i o n .
Host a t h e r marine macrophyke e x u d a t i o n s t u d i e s t h a t attempt
t o employ q e n t le and 'close t o n a t u r a l 8 experimental c o n d i t i o n s
report e x u d a t i o n s from less t h a n 1 % t o 4 R of t h e plant as
carbon f i x a t i o n f f loebns and Johnson , 1374; HarZin and Craiq ie ,
1975; Fankbane r and deBurqh, 1377; P e n h a l e and Smi th , 1977;
Raqan and Jensen , 1 9 7 9 ) . Greater r e l e a s e s , up t o 40 % of t h e
plant *s a s s i ~ i l a t i o n , h a v e been r e p o r t e d , q e n e r a l l y , under
stressful c o n d i t i o n s s u c h as d e s s i c a t i o n f s i e b n r t h , 1369; Kroes,
1970; Moebus g& &, 1974). These s t u d i e s i n d i c a t e t h e
possibility of q r e a t e r e x u d a t i o n by a, inteur&f,o&& u n d e r
stress, s u c h .as d e s s i c a t i o n d u r i n q extrelae3.y low t i d e s . Hy
r e s u l t s indicate l i t t l e release 05 o r q a n i c compounds u n d e r
near -normal , submerged c o n d i t i o n s .
Uptake of p r e v i o u s l ~ r e l e a s e d DOC was i n d i c a t e d i n
exper imenl t 103, D r e w (1963) reported that many brown a l q a e have
s l o w a i e c h a n i s a s for u p t a k e of e x o g e n o u s l y s u p p l i e d s u q a r s a n d
are unable t o convert t h e s e s u q a r s i n t o t h e i r u s u a l s o l u b l e
c a r b o h y d r a t e s , However, the exact chemical f o r m s o f macroalqal ,
exudates are n o t known [cf,, H e l l e b u s t , 1374) and map i n c l u d e
c h e ~ i c a l forms that are r e a d i l y a s s i m i l a t e d by the i a ac roa lqae ,
P o s s i b l y the a p p a r e n t u p t a k e i n e x p e r i m e n t 103 can be a t t r i b u t e d
t o p a s s i v e a d s o r p t i o n o r uptake b y t h e plant combined w i t h
epiphytic h e t e r o t r o p h i c microbial u p t a k e ,
75
An i n d i r e c t a p p r o a c h t o the i n v e s t i q a t i o n o f e x u d a t i o n by
,A 4, i n t e u r i f o h a was t h e s a ~ p l i n q o f n a t u r a l . PJ, i . n t e u r & f o a i a bed
waters, w i t h r e s p e c t X;o- w a t e r s 100 n d i s t a n t from t h e k e l p bed
f o r DOC c o n t e n t , T h e DOC c o n t e n t 05 t h e w a t e r d e m o n s t r a t e d
s e a s o n a l i t y a t a l l s a m p l i a q sites, S e a s o n a l i n c r e a s e s i n the DOC
c o n t e n t of n e a r b s h o r e waters h a v e b e e n a t t r i b u t e d t o
a u t o c h t h o n o u s s o u r c e s s u c h as release of DOC b y p h y t o p l a n k t o n
durinq p h y t o p l a n k t o n b l o o ~ s ( P a r s o n s a n d T a k a h a s h i , 1373) a n d
a l l o c h t h o n o u s s o u r c e s such a s r i v e r f r e s h e t s fNaiman a n d
Siebert, 1979) , Possibly the summer (July 27) DOC peak was d u e
t o p h y t o p l a n k t o n e x u d a t i o n ; w i t h t h e s u m m r POC peak
r e p r e s e n t i n q i n c r e a s e d p h y t o p l a n k t o n numbers , The f a l l DOC peak
p o s s i b l y r e s u l t e d from tesrestial run-of f d u r i n q heavy fall
r a i n s ,
O f spec ia l i n t e r e s t , h o w e v e r , were the d i f f e r e n c e s between
kelp bed and n o n - k e l p bed DOC l e v e l s n e s t e d w i t h i n t h e larqer
u n i v e r s a l s e g s o n a l DOC l e v e l s , When d i f f e r i n q frolit t h e n o n - k e l p
bed DOC l e v e l s , t h e k e l p bed DOC levels were q r e a t e r , T h e s e
r e s u l t s suqqested t h a t f ac tors c o i n c i d e n t t o k e l p bed l o c a t i o n s
were r e s p o n s i b l e for i n c r e a s i n q t h e b a s e l i n e DOC c o n t e n t o f t h e - waters, M a c r o c y s t i s Inlteai.fq&ig was c e r t a i n l y t h e most
c o n s p i c u o u s b i o t i c tneraber of these l o c a t i o n s a n d the
e x p e r i a e n t a l r e s u l t s showed t h e o c c u r r e n c e of some e x u d a t i o n b y
t h e s e p l a n t s . O t h e r f ac tors c o i n c i d e n t t o kelp bed l o c a t i o n s
i n c l u d e d o t h e r s u b t i d a l and i n t e r t i d a l m a c r o p h y t e s a n d
t e r r e s t i a l shoreline i n p u t , If terrest ia l organic input was a n I
inportant source of the water's b a s e l i n e DOC content, t h e f ower
n o n ~ k e l p bed ( o f f s h o r e ) fX>C levels might m e r e l y be a r e f l e c t i o n
of a seaward DOC dilution, The p a r t i c u l a t e c o n t e n t a l s o :,was
qreater in t h e kelp bed. Perhaps, k e l p fragraentation and
subsequent DOC l e a c h i n q was one source of the POC and DOC i n
t h e s e nearshore waters,
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Appendix ,"
P i q u r e 81, B standard c u r v e for t h e total DOC a n a l y s i s
(IRGA peak fneiqht vs / i q ~ of s tandard glucose-salt
p o n d e r ) , This curve was computed for the June 20, 1978 ..
DOC analyses,
