the effects of ocean acidification on the physiology of dominant antarctic algal species

8/2/2019 The Effects of Ocean Acidification on the Physiology of Dominant Antarctic Algal Species

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The Effects of Ocean

Acidification on the Physiologyof Dominant Antarctic Algal

SpeciesAmelia SnowDr. Oscar Schofield and Dr. Grace Saba


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The CO2 Problem

Since 1800s 40% increase Preindustrial= 280 ppm Current= 385ppm 0.5% increase per year


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Carbonate chemistry controls pH of seawater atmCO2 = CO32- andpH Decrease by 0.12 pH units and 28% increase in ocean acidity

CO2 projected to double by 2100


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Warming in the West AntarcticPeninsula

Fastest warming location on Earth (winter)Increase of 6oC in past 50 years (>5x the global average)

Increase in ocean heat content87% of laciers in retreat


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Changes in West AntarcticPeninsula Phytoplankton

Changes in climate=changes in phytoplanktonWarming =chl a by 12%Shift from large to small cells

Montes-Hugo et al. 2009

1970s-1980s

1995-2005


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Phytoplankton Ocean Acidification

Tortell etal. 2008

Few studies in Ross Sea, AntarcticaCO2= relative growth rate and primary productivity

Low CO2-small pennate diatoms


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Diatoms v. Cryptophytes

http://tolweb.org

http://www.jgi.doe.gov http://www.biol.tsukuba.ac.jp

Fragilariopsis cylindrus Chaetoceros atlanticus Geminigera cyrophila

15-270 mSingle-celledChain-formingCell wall made of silicaResponsible for 20% of globalphotosynthesis

Responsible for most carbon sequestrationMost trophic carbon transfer


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Objectives and Hypothesis

Objectives:Compare cell growth and photosynthetic performance of threespecies of dominant Antarctic algae

Cryptophyte-Geminigera cryophila Pennate diatom-Fragilariopsis cylindrus Chain-forming diatom-Chaetoceros atlanticus


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Objectives and Hypothesis

Objectives:Compare cell growth and photosynthetic performance of threespecies of dominant Antarctic algae

Cryptophyte-Geminigera cryophila Pennate diatom-Fragilariopsis cylindrus Chain-forming diatom-Chaetoceros atlanticus

Hypothesis:pH will decrease as CO2 increases

Diatom abundance and photosynthetic efficiency will increase asCO2 increasesCryptophyte abundance and photosynthetic efficiency will decreaseas CO2 increases


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SignificancePhytoplankton are

link between lowerand higher trophiclevels in food web

Drastic changes in

phytoplankton resultin extreme changesin higher trophiclevels

Ultimately couldaffect carbon cycle


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Experimental DesignCO2 bubbling setup

27 1L bottles 3 replicates of each species

3 treatments180 ppm385 ppm

750 ppmDilution 180 ppm 385 ppm 750 ppm

Geminigera cryophila

Fragilariopsiscylindrus

Chaetoceros atlanticus


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Experimental DesignMeasurements

pH (pH probe)Cell count (coulter counter)fv/fm (FIRe)


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Results-pH

pH

Geminigera cryophila Fragilariopsis cylindrus Chaetoceros atlanticus

G h C G


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Growth Curve-Geminigeracryophila

Cells/mL

Time (Days)


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Growth Curves-Fragilariopsis cylindrus

Cells/mL

Time (Days)


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Growth Curves -Chaetoceros atlanticus

Cells/mL

Time (Days)


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Results-Growth Rates

k

180 385 750


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Results-Photosynthetic Efficiency

fv/fm

180 750385


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Conclusions Geminigerabest under ambient conditions and

did not survive 750 ppm

Fragilariopsis does not vary between pCO2

Chaetoceros more successful under higher CO2 Community structure unknown future


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Further Investigation

1000 ppm

Fe Limitation

Low vs. High Light Time


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Acknowledgements Dr. Oscar Schofield

Dr. Grace Saba

Emily Pirl

Dr. Josh Kohut

Dr. Scott Glenn Dr. John Reinfelder

George H. Cook Honors Program

Rutgers Coastal Ocean Observation Lab

Institute of Marine and Coastal Sciences


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the effects of ocean acidification on the physiology of dominant antarctic algal species

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