determining the effects of co2 ocean … oceanica marine ecology - ocean acidification • can form...

MARINE ECOLOGY - OCEAN ACIDIFICATION

Biological Consequences of Ocean Acidification

Jon. Havenhand

Dept. Marine Ecology - Tjärnö

[email protected]


review: why is this an issue?review: why is this an issue?

CO2 + H20 H2CO3 HCO3- + H+ CO3

2- + 2H+

CO32- + Ca2+ CaCO3

CO2

CO2 in seawater:pHcarbonate saturationcalcification

air – sea exchange

1% 91% 8%

atmospheric CO2 and the marine carbonate systematmospheric CO2 and the marine carbonate system


review: why is this an issue?review: why is this an issue?

Fabry et al. 2008 ICES J. Mar. Sci.

units = µmol.kg-1


calcification in marine organisms

• aragonite is twice as soluble as calcite

Raven et al. 2005 Royal Society


calcite & aragonitecalcite & aragonite

http://webmineral.com/data/Aragonite.shtml

http://webmineral.com/data/Calcite.shtml

http://webmineral.com/data/Aragonite.shtml

http://webmineral.com/data/Calcite.shtml


Orr et al. 2005 Nature

A1F1

changes in aragonite saturationchanges in aragonite saturation


changes in aragonite saturation: Atlanticchanges in aragonite saturation: Atlantic

Orr et al. 2005 Nature

• aragonite saturation horizon will rise closer to surface

- depth varies with model and scenario

• Ωaragonite of 1 ≈ pH 7.7


spatial variation in ocean pH

GLODAP / Royal Society 2005


spatial variation in ocean pH

Kleypas, J. et al. (2006) NSF, NOAA, USGS

MARINE ECOLOGY - OCEAN ACIDIFICATIONFeely, R. et al. (2008) Science

seasonally low pH

- June 2007

- much lower than previously known


pH variation in the BalticpH variation in the Baltic

• greater seasonal variation at lower salinities

• seasonal variation exceeds predicted changes due to CO2-induced acidification

7.1 - 8.5

8.0 - 8.4

7.9 - 8.4

7.9 - 8.6

seasonal pH variation, 10-20mseasonal pH variation, 10-20m

http://produkter.smhi.se/pshark/datamap_nationell.php?language=e

http://produkter.smhi.se/pshark/datamap_nationell.php?language=e


pH variation at one site:

Gotland Deep

pH variation at one site:

Gotland Deep

• interannual trends in pH vary with depth

y = 0.0043x - 0.2992 R2 =

7.5

8

8.5

9

1992 1994 1996 1998 2000 2002 2004 2006 2008

Surface

y = -0.002x + 12.281

7.5

8

8.5

9

1992 1994 1996 1998 2000 2002 2004 2006 2008

pH

20 m

y = -0.010x + 27.986

7.5

8

8.5

9

1992 1994 1996 1998 2000 2002 2004 2006 2008

pH

50 m

y = -0.010x + 27.751

7

7.5

8

8.5

1992 1994 1996 1998 2000 2002 2004 2006 2008

pH

100 m


temporal variation in the Baltictemporal variation in the Baltic

• models predict pattern of surface water pH

• pH is declining throughout the deeper waters of the Baltic

• rate of decline is greater than that due to CO2-induced acidification

Omstedt, A. et al. (2009) Coast. Shelf Sci.

Andersson, P. et al. (2008) SMHI Oceanogr. Rep. 92

Dore, J. et al. (2009) PNAS2000 20061994


temporal variation in Pacifictemporal variation in Pacific

• data for open ocean off Hawaii

rate = - 0.0019.yr-1rate = - 0.0019.yr-1


temporal variation on small timescalestemporal variation on small timescales

• intertidal zone, US Pacific coast

• clear decadal changes (B)- 0.045 pH units.yr-1

• seasonal pH change ≤ 0.9 units (A)

• diurnal pH excursions ≤ 0.5 units (A)

• similar magnitude in western Sweden

Wootton T. et al 2008 PNAS

pH algal belt, Ursholmen, 2009-06-29

7.5

7.9

8.3

8.7

9.1

16

;42

19

;02

21

;42

23

;42

01

;02

07

;12

08

;32

10

;02

11

;22

12

;52

15

;02

pH algal belt, Ursholmen, 2009-06-29

7.5

7.9

8.3

8.7

9.1

16

;42

19

;02

21

;42

23

;42

01

;02

07

;12

08

;32

10

;02

11

;22

12

;52

15

;02

range of pH variation inopen water 2009-06-30


what impacts will this have?

calcificationcalcification primary production

ecosystem effects physiology© Greenpeace


1765 280 ppm

Aragonite saturation state

© R. Feely, A. Dickson


2008 385 ppm




2050 560 ppm




2100 788 ppm




• unicellular algae, bearing calcite plates (“coccoliths”)

• globally abundant- ~50% of all Carbon exported to deep ocean is dead coccoliths

• carbonate “ooze” forms from coccoliths & foraminiferans- covers half of the deep ocean floor ≤ 600 m thick

effects on phytoplankton - coccolithophores

Emiliania huxleyiGephyrocapsa oceanica


• can form massive blooms- > 100,000 km2

- dominant sp. ( > 90% of algal cells)


Emiliania huxleyi


• acidification causes decreases in:- specific growth rate - cell size, coccolith size- calcification per cell

(Riebesell 2004, Engel et al. 2005)

Riebesell, U. (2004) J. Oceanogr.


Engel, A. et al. (2005) Limnol. Oceanogr.

Riebesell, U. (2004) J. Oceanogr.

Iglesias-Rodriguez, D. et al. (2008) Science





Langer, G. et al. (2009) Biogeosciences Disc.

• effects of acidification differ between strains

- no consistent trend in effects of pCO2 on growth, PIC, POC, or production

Langer et al. 2009 Biogeosci. Disc.


effects on phytoplankton - Baltic coccolithophores

effects on phytoplankton - Baltic coccolithophores

• largely absent- none found in 2006 survey (Tyrell et al 2008)

- due to low Ωaragonite ?

- present in SMHI data (rarely: 1998-2007)


• macroalgae

• foraminifera

• tropical corals

• cold-water corals

• bryozoans

• molluscs

• echinoderms

• crustaceans

effects on other calcifying marine organisms

Kleypas, J. et al. 2006 NSF, NOAA, USGS


• macroalgae

• foraminifera

• tropical corals

• cold-water corals

• bryozoans

• molluscs

• echinoderms

• crustaceans

Baltic, Kattegatt, Skagerrak

Kattegatt, Skagerrak only

effects on other calcifying marine organisms

Kleypas, J. et al. 2006 NSF, NOAA, USGS


bivalve calcification ratesbivalve calcification ratesca

lcifi

catio

n ra

te

Gazeau et al. 2007 Geophys. Res. Lett.


bivalve growth ratesbivalve growth rates

• shell growth of Mytilus edulis only affected at very low pH- pH 7.4 ≈ 2000 ppm CO2

Berge et al. 2006 JEMBE

• does “no difference” mean “no effect” ? ?

Berge, J.A. et al. 2006 J. Exp. Mar. Biol. Ecol.


assumptions of statistical tests: α and βassumptions of statistical tests: α and β

• α = probability of concluding an effect when no effect is present- we determine this (usually α = 0.05)

• β = probability of concluding no effect when an effect is present- we usually don’t control this- ?? free to vary - often very high !

• Power = 1 - β- depends on:

- effect size- variance- sample size

Power (1 - β) effect size x α x √nvariance


Power AnalysisPower Analysis

G*power


importance of Power Analysis in climate change research

importance of Power Analysis in climate change research

• we need to know when climate change / acidification will have an effect and when it will not have an effect

• cannot conclude absence of effect from absence of significance in (eg) t-test, ANOVA

• need:- tests of similarity between treatment groups- Power Analysis of results

- pilot studies to ensure sufficient power in main study


larval bivalve growth rateslarval bivalve growth rates

• embryos & larvae of marine organisms are typically the most sensitive life-stages- Mytilus galloprovincialis

- 20% reduced growth at 2000 ppm CO2 (pH 7.4)

- Crassostrea gigas- 30% reduced growth at

2000 ppm CO2

- only 6% of larvae survived to D-stage in high CO2 (68% in controls)

- Mercenaria mercenaria- high mortality in

juveniles settling in low

Kurihara, H. et al. 2009 Aq. Biol.

380 ppm CO2 2000 ppm CO2 2000 ppm CO2380 ppm CO2

Kurihara, H. et al. 2007 Aq. Biol.

pH 8,1 pH 7,7

pH 8,1 pH 7,9 pH 7,7

pH 7,7

larval brittle-star growth rateslarval brittle-star growth rates


effects on fertilizationeffects on fertilization

predicted fertilization

no effect

no effect

- 52 %

- 26 %

observed fertilization

- 25 %

early development

no effect

no effect

no effect

no effect

no effect

( + 61 % )

Strongylocentrotus droebachiensis

( - 6 % )

no effectAsterias rubens

no effect

( 0 - 88 % )

effects of acidification by 0.4 pH units in comparison to controls

• different impacts on different life stages of the same species

• different impacts on closely related species

larval growth& development

fertilization


marine invertebrate life-cyclemarine invertebrate life-cycle

adultspawning

settlement & metamorphosis

juvenile


1765 280 ppm

Aragonite saturation state(from corals’ point of view)

Extremely low Optimal



2008 385 ppm





2050 560 ppm





2100 788 ppm





• growth rates of Porites on GBR are 21% lower - than pre-1990 (Hoegh-Guldberg at al, Science 2007)

• predicted 40% reduction in calcification of corals within 40 years- Biosphere project, tropical corals (Kleypas & Langdon, Coast. Est.

Stud. 2006)

• reduced density increases breakage loss of habitat integrity

loss of refugia

fewer niches

reduced resilience (Mumby et al, Nature 2007)

effects on corals


effects on corals

• data for the past 420,000 years

• ocean pH varied by ± 0.1 pH units

Hoegh-Guldberg et al. Science 2007

reef growth ceases ( Ω aragonite ≈ 3.3)


effects on corals

Source: Hoegh-Guldberg et al. Science 2007

2007 ≤ 21002050


• “community-level” investigation of pCO2

- mixed populations in experimental mesocosms- pCO2 = 350 ppm, 700 ppm, 1,050 ppm

• increasing pCO2 had positive effect on diatoms - no effect on coccoliths

- no effects on dinoflagellates

• positive effects on C uptake

effects on phytoplankton communities

diatoms

coccoliths

(dino)flagellates

Riebesell et al, Nature 2007


effects on seagrasseseffects on seagrasses

• Hall-Spencer et al, 2008 Nature

• natural CO2 seeps in Italy- local acidification



Hall-Spencer et al (2008) Nature

QuickTime™ and a decompressor

are needed to see this picture.



• increased seagrass growth rate at low pH- increased shoot density

- no increase in photosynthetic rate

- strong -ve correlation between calcareous epiphytes and shoot density

• increased growth rate due to decreased competition

• indirect effect


mechanisms of physiological stressmechanisms of physiological stress

• effects of increasing pCO2

depend on duration of exposure - acute extreme effects:

- respiratory stress- behavioural changes

- chronic intermediate effects:- hormonal changes

- reproduction / growth

• more pronounced in “lower”invertebrates- fewer compensation mechanisms

- eg cuttlefish respiration, calcification unaffected by 4000 ppm CO2 (Gutowska et al. 2009)

Pörtner H. 2008 Mar. Ecol.Prog.Ser.


mechanisms of physiological stressmechanisms of physiological stress

• in “lower” organisms, ambient pH affects internal pH regulation

• eg acorn worm Sipunculus - metabolic rate is lower when

internal pH is low

- but only when external pH is low

- causes reduced aerobic capacity

• acid-base regulation can be expensive- ≤ 50% of energy budget

- limits “scope for growth”

Pörtner et al, 2004 J.Oceanogr.

oxyg

en c

onsu

mpt

ion

(% o

f co

ntro

l)

controlelevated CO2

Metzger et al, 2007 J. Therm. Biol.

oxyg

en c

onte

nt o

f blo

od (k

Pa)


synergies create additional stresssynergies create additional stress

• pCO2 acts in synergy with other stressors- eg Cancer pagurus

- pCO2 in “control” blood depends on T°:

- normal ≤ 16°C (“Tp”)- minimal ≥ 20°C (“Tc”)

- at high external pCO2

- Tp drops to ~11°C- Tc drops to ~16°C

• increased pCO2 reduces thermal tolerance


synergistic effects on physiological stresssynergistic effects on physiological stress

T° / pH

T° / pH

SpawnersGrowing Adults

Juveniles

Eggs, early larvae

Pörtner 2008 Nature

• generalised pattern of thermal tolerance

• increased pCO2 reduces thermal tolerances


ecosystem effectsecosystem effects

• hard to assess:

• closely related species respond differently to similar pCO2 / pH changes

• very few species studied to date- especially at environmentally relevant pCO2 / pH levels ( ≤ 1000 ppm, ≥ 7.7)

• negative data hard to interpret without Power Analysis- was there really no effect, or were there too few replicates / too much

variability to detect one ?

• most studies done over short timescales- almost no multi-generational data

- capacity for adaptation ?


will species be able to adapt ?will species be able to adapt ?

• adaptive capacity depends on:- generation time- heritable variation- gene-flow

• average generation time for key taxa:

- microalgae 1 d - 2 weeks- copepods ≈ 3 weeks- barnacles ≈ 1 year- macroalgae, echinoderms 1 - 5 years- large crustaceans 2 - 20 years- bivalves 1 - 50 years- deep water corals ?


ecosystem effects - potential losers?ecosystem effects - potential losers?

• natural CO2 seeps, Ischia, Italy

• fewer calcifying species in low pH

• few differences in non-calcifying species

• representative ?

Hall-Spencer et al (2008) Nature


ecosystem effects - potential winners?ecosystem effects - potential winners?

Richardson et al 2009 TREEMARINE ECOLOGY - OCEAN ACIDIFICATION

effects of acidification on jellyfisheffects of acidification on jellyfish

overfishing

eutrophication

warming

acidification ?


effects of acidification on jellyfisheffects of acidification on jellyfish

Attrill M. et al 2007 Limnol. Oceanogr.

Richardson & Gibbons 2008 Limnol. Oceanogr.

survey area


• distribution & abundance of species will change

• more affected:- calcifyers, spp. from more environmentally stable areas, long generation times

• which species are candidate indicators ?- ecological engineers: mussels ?

- keystone spp: phytoplankton, fish

• reducing other stressors will increase resilience

• probable extreme socio-economic impacts- marine ecosystem services globally valued at ≈ $27 trillion




• species composition in functional groups will change

• interactions withinfunctional groups will change

• interactions betweenfunctional groups maychange . . .- and be replaced by?

Simplified Baltic Food Web - from Österblom et al. 2007 Ecosystems


one last thing . . .


Collaborators - and many thanks (!) to:Collaborators - and many thanks (!) to:

• Sam Dupont, Elin Renborg, Peter Schlegel (Marine Ecology, University of Gothenburg)

• Mike Thorndyke (Royal Swedish Academy of Sciences, Kristineberg)

• Jane Williamson, Steph Mifsud, Fenina Buttler (Macquarie University, Australia)

• Gerry Quinn (Deakin University, Australia)

• Jessica Marks (University of Oslo, Norway)

• Pia Andersson, Ann-Turi Skjevik (SMHI)

• Ove Hoegh-Guldberg (University of Queensland, Australia)

• Martin Wahl, Andrea Frommel (IFM-GEOMAR, Kiel, Germany)

• Andrew Dickson (Scripps Institute, USA)

• Jim Barry (Monterey Bay Aquarium Res. Inst., USA)


Skagerrak 0-50 m -0.0028 P = 0.136

> 75 m -0.0026 P = 0.156

Kattegat 0-25 m -0.0044 P < 0.0001

> 30 m -0.0079 P < 0.0001

S. Baltic 0-20 m -0.0041 P = 0.094

30-60 m -0.0142 P < 0.0001

> 70 m -0.0156 P < 0.0001

Central & N. Baltic 0-20 m +0.0024 P = 0.347

30-60 m -0.0102 P < 0.0001

> 70 m -0.0063 P < 0.0001

• annual Δ pH (1993 - 2007):

pH variability in Sweden

Source: Lars Andersson, SMHI

• current pH (Anholt, 30 m) = 8.1

• at 0.0025 units.yr-1 , 2050 pH = 7.96, 2100 pH = 7.83

• at 0.0051 units.yr-1 , 2050 pH = 7.78, 2100 pH = 7.53

determining the effects of co2 ocean … oceanica marine ecology - ocean acidification • can form...

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