element fluxes and cycling in marine particles during vertigo 2004: preliminary results near station...
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Element Fluxes and Cycling in Marine Particles During VERTIGO 2004: Preliminary Results
Element Fluxes and Cycling in Marine Particles During VERTIGO 2004: Preliminary Results
near Station ALOHA
Thanks to: Captain and crew of R/V Kilo Moana, Science Party of KM0414, Lary Ball, Suilou Huang, Mak Saito, Matt Charrette, Meagan Gonneea, Brian Guest, NSF-OCE, WHOI Post-doctoral Scholar Program (esp. John Farrington, Janet Fields and Christine Charrette), Penzance Endowed Discretionary Fund.
Thanks to: Captain and crew of R/V Kilo Moana, Science Party of KM0414, Lary Ball, Suilou Huang, Mak Saito, Matt Charrette, Meagan Gonneea, Brian Guest, NSF-OCE, WHOI Post-doctoral Scholar Program (esp. John Farrington, Janet Fields and Christine Charrette), Penzance Endowed Discretionary Fund.
Carl Lamborg, Ken Buesseler, Jim Valdes, Tom Trull, Jim Bishop, Karen Casciotti, Steve Pike, John Andrews, Steve Manganini, Chanda Bertrand and Dave Schneider
Carl Lamborg, Ken Buesseler, Jim Valdes, Tom Trull, Jim Bishop, Karen Casciotti, Steve Pike, John Andrews, Steve Manganini, Chanda Bertrand and Dave Schneider
WHOI ICPMS Facility
•Introduction to VERTIGO
•Our Interests in Element Fluxes and Cycling
•VERTIGO 2004 (North Central Pacific Ocean)
•Methods
•Fluxes
•How Accurate? Solubilization of Poisoned Trap Materials
•Remineralization. Unpoisoned Incubations
•Remineralization Time and Space Length Scales…Factors Affecting Flux Attenuation
•Summary/Implications
At the heart of VERTIGO is the question:What controls the efficiency of particle transport between the
surface and deep ocean?
•There is an obvious mismatch between spatial patterns in primary production and the export of carbon to the deep ocean that indicates a complex suite of transformations must occur in the “twilight zone”, the region below the surface euphotic zone and the deep ocean.
C flux to seafloor -benthic O2 demand. Jahnke,
1996
C uptake in surface ocean-SeaWiFS global primary production. Behrenfeld & Falkowski, 1997
Sinking Marine Particles –detritus from the euphotic zone and lithogenic material
Swimmers
Conventionally studied using shallow “sediment” traps, at the base of euphotic zone (100-150 m)
The VERTIGO P.I.’s have identified two general mechanistic possibilities:
1.particle source characteristics are the dominant control on the efficiency of particle transport.
2.mid-water processing, either by zooplankton or bacteria, controls transport efficiency.
and/or
The Twilight Zone is Undersampled!
A compilation of all particle flux vs. depth data available from the last decade of JGOFS studies (redrawn from Berelson, 2001; not all shallow data plotted). Solid line is Martin curve for POC with b=-0.858.
This is likely to be where a lot of the action is…but few data.
Our Interests in Element Fluxes and Cycling•Fluxes for many elements other than C, N and P are not well known…especially in the top 500m.
e.g., Fe flux data lacking…fundamental information for understanding micronutrient cycling, and efficacy of Fe fertilization…
•Multi-element determinations may provide multiple tracers to constraining rates of particle remineralization, variable sinking rates (particle dispersion), and sources.
biomineral and crustal elements in particular, in conjunction with other fluxes…
•Additional tests on Th-derived approach to calculating POC fluxes.
•e.g., will (Fe/234Th)part when combined with 234Th deficits match collections in sediment traps?
Site Lat/LonChl avg (mg m-3)
Shallow POC Flux (g m-2 y-1)
f-ratioDeep POC
flux (g m-2 y-1)bSi/Cinorg deep
trap (mole)Dust Flux(g m-2 y-1)
ALOHA22.75º N158º W
0.1 17-22 0.15 0.51 <1 (est.) ~0.5
K247º N160º E
0.5 86 0.42 0.82 4.2 ~10
Time Series sites provide context, data.
Gadgets!
CLAP Trap-BuesselerCLAP Trap-Buesseler
NBST-ValdesNBST-ValdesMULVFS-BishopMULVFS-Bishop
SplitterSplitter
MOCNESS-UNOLS/SteinbergMOCNESS-UNOLS/SteinbergIRS Trap-TrullIRS Trap-Trull
2 tubes poisoned w/ HgCl2
2 tubes preserved w/formalin
1 tube covered
blank
1 tube preserved w/formalin
biological i.d. work
“Clap” Trapssurface tethered, drogued arrays
screen, combine
, split, filter
filters dried, stored frozen
1 Ag (d#1) or 1 nucl. (d#2)
filtrate
Consists of 10 tubes on each drifting array.Deployed at 3 depths: 150, 300 and 500m
2 tube Trull’s Gels
screen, combine
, split, filter
filters dried, stored frozen
1 Ag (d#1) or 1 nucl. (d#2)
filtrate
screen, combine
, split, filter
filters dried, stored frozen
1 Ag (d#1) or 1 nucl. (d#2)
filtrate
2 tubes aging expts. 1st HgCl2;
2nd formalin
NBSTs3 deployed @ 150 m, 2 @ 300 m and 2 @ 500m.Consists of 5 tubes on each array.
Time
0.0 0.5 1.0 1.5 2.0
Mas
s in
Sed
. T
rap
0.0
0.2
0.4
0.6
0.8
1.0
)1(' kte
kt
F
F
From incubation experiments, one acquires the value of k, the remineralization rate constant
Accuracy Issue: Solubilization of material in the sediment traps lowers estimate of flux.•some also believe “interstitial fluids” are an important component of flux…becoming enriched during sinking. squeezed out during processing (e.g., Avan Antia).
slope=F
slope=F’
VERTIGO Poisoned Particulate Solubilization Experiments
1. brine/particle mixture collected from 2 combined sediment tubes designated for incubation experiments. experiments conducted with samples from 150, 300 and 500m. poisons change with deployment.
2. mixture split 8 ways on splitter, into 500 mL bottles.
4. at pre-determined times, incubation bottle filtered on 0.2 µm PC, with liquid subsamples for ICPMS and DOC. half PC filter washed onto Ag filter for PC/PN/PP/bSi. filters dried and frozen.
t = 3d 5d 30d1d
3. splits combined. samples incubated at in-situ temperature
Ca/Al
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
mas
s ra
tio
0
10
20
30
40
50
150m
300m
500m
1st Dep. - Hg 2nd Dep. - Formalin
Fe/Al
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
mas
s ra
tio
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
150m
300m 500m
1st Dep. - Hg 2nd Dep. - Formalin
P/Al
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
mas
s ra
tio
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
150m
300m
500m
1st Dep. - Hg 2nd Dep. - Formalin
DOC in overlying brine
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
1 day
3 days
5 days
DO
C (
µM
)
0
50
100
150
200
150m
300m
500m
1st Dep. - Hg 2nd Dep. - Formalin
Incubations of Poisoned Trap Material (and DOC from brine)
Remineralization k (d-1)
-0.2 0.0 0.2 0.4 0.6
Co
rrec
tio
n F
acto
r
0.0
0.5
1.0
1.5
2.0
2.5
3.0
3.5
3 days (150m)4 days (300m)5 days (500)
k = 0.1 d-1 suggests correction of 15-27%.In general, modest corrections needed from in-trap remineralization.
Poisoned Solubilization Rates
PC 1st Deployment
Flux (mg m-2 d-1)
0 10 20 30
De
pth
(m
)
0
100
200
300
400
500
600
PC 2nd Deployment
Flux (mg m-2 d-1)
0 5 10 15 20 25 30 35D
ep
th (
m)
0
100
200
300
400
500
600
PN 1st Deployment
Flux (mg m-2 d-1)
0 1 2 3 4 5
De
pth
(m
)
0
100
200
300
400
500
600
PN 2nd Deployment
Flux (mg m-2 d-1)
0 1 2 3 4 5
De
pth
(m
)
0
100
200
300
400
500
600
HOTS Primary ProductionJune ’04: 531 mg C m-2 d-1
August ’04: 539 mg C m-2 d-1
f-ratio: 0.04
Deep Trap Limit(Karl, unpublished)
Though there’s variability in the absolute magnitude in the traps…the particles do not appear to be sorting very much…they index pretty well. The organic matter is decaying as one would expect. Makes up about 60% of attenuating mass.
The zero OM endmember is 4 g m-2 y-1…average dust flux is 0.5 g m-2 y-1.
red=150mgreen=300mblue=500mopen=NBSTclosed=CLAP
average dust Al flux
red=CLAPblue=NBST
Vertigo '04 - All Traps, All Depths
Ca/Al (mass/mass)
0 20 40 60 80 100 120
Ba
/Al (
ma
ss
/ma
ss)
0.00
0.05
0.10
0.15
0.20
0.25
0.30
0.35
Filled - STDAOpen - NBSTRed - 150 mGreen - 300 mBlue - 500 m
Vertigo '04 - All Traps, All Depths
Ca/Al (mass/mass)
0 20 40 60 80 100 120
Sr/
Al (
ma
ss
/ma
ss
)
0
1
2
3
4
5
6
red=150mgreen=300mblue=500mopen=NBSTclosed=CLAP
Vertical Flux Behavior Elements
Decreasing with DepthSr, P, Ca, Mg, Total Mass, Ni, Th, PC, PN
Constant with Depth Al, Sc, Fe, Cu
Increasing with Depth Ba, Mn
Hard to Tell Ti, V, Co, Zn, Cd, Pb
Summary of Flux Measurements
No statistically significant difference between poisons.Little difference between CLAP and NBST for most elements...suggests
little hydrodynamic particle sorting and/or systematic under/oversampling.
The Martin CurveParaphrasing Tom Trull from the VERTIGO website…it’s the Law, but is it a good Idea?
Does it fit the data any better than other functional forms, for instance that
proposed by Lutz et al. (2002):
If flux attenuation is completely due to in-situ remineralization, then degradation rates of unpoisoned material can be used to estimate sinking rates through comparison of remineralization length (time/space) scales…
define remineralization length scale as e-folding scale (time or depth over which flux changes by 1/e):
refrac
zW
D
labilez FeFF
b
z
zFF
100100
1
1
1
100
1001
1
0
112
1
2
1
2
1100
2100
bMartin
time
ktt
bdepth
b
b
b
b
ekzS
kL
eFF
ezzzL
ez
z
z
z
zF
zF
e
Martin
Martin
D
kW
t
zS
zW
Dkt
FeFFeF
Lutz
refrac
zW
D
labilerefrackt
labile
The Martin Attenuation Curve is matched with exponential decay to zero, while Lutz Attenuation Curve is matched with exponential decay to a constant.
Lutz Curve matches the data better (esp. if you include deep trap data)…but Martin Curve appears to require increasing bulk sinking rates, which is consistent with increasing importance of ballasting biomineral phases.
Is Reality somewhere in between?
sinking rate accelerates with depth!
sinking rate is constant in relation to remineralization
t = 0 1d 2d
VERTIGO Unpoisoned Particulate Degradation Experiments
1. quarter filter washed into incubation bottle using 0.2 µm filtered 500m water
2. water/particle mixture occasionally agitated, incubated at depth appropriate temperature in dark.150m: 25 ºC; 300m: 15 ºC; 500m: 4 ºC
3. at particular times, incubation bottle agitated and aliquot removed by clean syringe. mixture is filtered on 0.2 µm PC, with liquid subsamples going for nitrification experiments (15NH4
+), ICPMS and DOC. filters rinsed and dried for ICPMS. half PC filter washed onto Ag filter for POC.
3d 5d
Ca/Al
T0
150
T1
150
T2
150
T3
150
T5
150
T0
300
T1
300
T2
300
T3
300
T5
300
T0
500
T1
500
T2
500
T3
500
T5
500
ratio
0
5
10
15
20
25
Ba/AlT
0 15
0
T1
150
T2
150
T3
150
T5
150
T0
300
T1
300
T2
300
T3
300
T5
300
T0
500
T1
500
T2
500
T3
500
T5
500
ratio
0.0
0.1
0.2
0.3
0.4
P/AlT
0 15
0
T1
150
T2
150
T3
150
T5
150
T0
300
T1
300
T2
300
T3
300
T5
300
T0
500
T1
500
T2
500
T3
500
T5
500
ratio
0.0
0.2
0.4
0.6
0.8
1.0
Unpoisoned Remineralization Rates
More elements showed remineralization in these experiments than in the poisoned experiment, but not all…
Fe/Al
T0
150
T1
150
T2
150
T3
150
T5
150
T0
300
T1
300
T2
300
T3
300
T5
300
T0
500
T1
500
T2
500
T3
500
T5
500
ratio
0.0
0.1
0.2
0.3
0.4
0.5
0.6
Remineralization of Unpoisoned MULVFS material
Ba
150
Ba
300
Ba
500
Mg
150
Mg
300
Mg
500
P15
0P
300
P50
0
Ca
150
Ca
300
Ca
500
Sc
150
Sc
300
Sc
500
V15
0V
300
V50
0
Mn
150
Mn
300
Mn
500
Fe
150
Fe
300
Fe
500
Co
150
Co
300
Co
500
Sr
150
Sr
300
Sr
500
Rem
iner
aliz
atio
n k
(d-1
)
0.0
0.5
1.0
1.5
2.0
2.5
3.0
ElementApparent sinking
Rate (m d-1)
Ba 114 - 233
Mg slow - 294
Al undefined
P 14 - 43
Ca 51- fast
Sc fast
Mn slow
Fe fast
Co Slow - 107
Ni undefined - slow
Sr 77 - 219
Sinking Rates for Comparison of Remineralization Rates and Attenuation Lengths (deployment 1)
For elements where attenuation and remineralization both seen, the analysis suggests sinking rates comparable to those observed directly…remineralization can explain the vertical profiles!
For the others, analysis suggests constrained fast or slow rates…either approach is breaking down or perhaps other factor important (particle type, grazing)
slow=attenuation in flux profile seen, but little remineralization on 5 day timescale.
fast=vertical profile doesn’t show much attenuation, but some remineralization seen.
Martin, Lutz give comparable results.
Summary/Implications
Sediment traps were successfully used for trace level work for many elements.In the quiet conditions of the N. Pacific Gyre, NBSTs and tethered traps mostly compared well. Some differences, with tethered often higher.In-trap solubilization of most elements, as indicated by poisoned incubations, did not significantly alter flux estimates.
shallow traps, deployed for short times, generally not as affected as deep traps as suggested by Antia and others.
Though there appears to be something of a biological imprint on Fe cycling, Fe “remineralization length scales” are longer for Fe than C.
no catalytic effect can be expected for Fe additions in removing CO2.
Sinking rates suggested by matching unpoisoned remineralization rates and vertical flux attenuation are, for many particle constituents, consistent with direct sinking rate measurements.
this suggests that much of the control on the flux of this material was through mid-water remineralization processes. microbial and physical/chemical processes likely dominant. particle source/type and grazing less important.
