Ocean AcidificationOcean AcidificationEffects on Marine OrganismsEffects on Marine Organisms

Submitted by Roy ArezzoSubmitted by Roy Arezzo

pH ScalepH Scale

Composition of Dissolved Salts in Water

chloride55.4%

sodium30.8%

sulfate7.0%

magnesium3.7%

calcium1.2%

other0.7%

potassium1.1%

chloridesodiumsulfatemagnesiumcalciumpotassiumother

ClNa

SMg

Ca 1.2% K

pH challengepH challenge

If ocean water has a pH between 8 If ocean water has a pH between 8 & 8.5, what does a change of pH to & 8.5, what does a change of pH to 7 represent in the marine 7 represent in the marine environment?environment?

A)A)NeutralNeutral

B)B)Acidification Acidification

C)C)Alkalinity Alkalinity

What is Ocean Acidification?What is Ocean Acidification?

Ocean acidification is the name given to Ocean acidification is the name given to the ongoing decrease of the pH of the the ongoing decrease of the pH of the Earth’s oceans.Earth’s oceans.

Ocean acidification is caused by the Ocean acidification is caused by the ocean’s uptake of excess carbon dioxide ocean’s uptake of excess carbon dioxide from the atmospherefrom the atmosphere

Ocean acidification is decreasing the Ocean acidification is decreasing the ability of many marine organisms to build ability of many marine organisms to build their shells and skeletal structures.their shells and skeletal structures.

What is Ocean Acidification?What is Ocean Acidification?Ocean acidification is different than climate Ocean acidification is different than climate

change:change: When COWhen CO2 2 dissolves in seawater, carbonic acid is dissolves in seawater, carbonic acid is

formed. It is this chemical reaction that leads to ocean formed. It is this chemical reaction that leads to ocean acidification. It is independent of the climate processes.acidification. It is independent of the climate processes.

Reduction of global temperatures and the concentration Reduction of global temperatures and the concentration of other greenhouse gases will not reduce the ocean of other greenhouse gases will not reduce the ocean acidificationacidification

Both climate change and ocean acidification are caused Both climate change and ocean acidification are caused by the release of anthropogenic COby the release of anthropogenic CO22

8

Carbon dioxide dissolves in the ocean, where it causes a potentially more serious problem ocean acidification.

Hoegh-Gulderg et al. 2007

9

CO2 + H2O

CO2 + CO32- + H2O

carbonate ions

Carbonic acid reduces

ocean pH.

The concentration of carbonate

ions decreases.

H2CO3

carbonic acid

2HCO3 –

bicarbonate ions

• The reduction in pH reduces the availability of The reduction in pH reduces the availability of carbonate ionscarbonate ions

• Carbonate ions play an important role in shell formation Carbonate ions play an important role in shell formation for marine organisms (shells are made of calcium for marine organisms (shells are made of calcium carbonate – our bones are made of calcium)carbonate – our bones are made of calcium)

• COCO22 is corrosive to the shells and skeletons of marine is corrosive to the shells and skeletons of marine organismsorganisms

• Some of the organisms affected: Some of the organisms affected: – Corals, sea urchins, Corals, sea urchins, – some marine plankton, some marine plankton, – marine snails, crabs, mollusksmarine snails, crabs, mollusks

11

Ocean acidification poses a threat to shell-forming organisms like corals and calcifying plankton.

www.greendiary.comhttp://elrid.cult.bg

Meroplankton:Meroplankton: Young organisms are more Young organisms are more

vulnerable to pH changesvulnerable to pH changes

Corals decrease the production of their Corals decrease the production of their reef-building skeletonreef-building skeleton

Reduction in ability of marine algae and Reduction in ability of marine algae and zooplankton to maintain protective shellszooplankton to maintain protective shells

Reduction in survival of certain larvaeReduction in survival of certain larvae

What are some obvious What are some obvious concerns if meroplankton concerns if meroplankton

populations drop?populations drop?

• Coral reefs are less resilient to bleaching, Coral reefs are less resilient to bleaching, disease, and deathdisease, and death

• The rate of reef building is decreasedThe rate of reef building is decreased• The base of the food web (algae and The base of the food web (algae and

zooplankton) is reduced creating a ripple zooplankton) is reduced creating a ripple effect along the food webeffect along the food web

• The economy will be negatively affectedThe economy will be negatively affected– Fisheries (i.e. shellfish, sea urchins) may declineFisheries (i.e. shellfish, sea urchins) may decline– Food Security and Job SecurityFood Security and Job Security– Tourism may declineTourism may decline– Affect on bio-tech and pharmaceuticalsAffect on bio-tech and pharmaceuticals

22

www.travel-vancouver-island.com

www.bigmoviezone.com

www.noaanews.noaa.gov

http://elrid.cult.bg

www.nceas.ucsb.edu

23

http://www.noaanews.noaa.gov

If trends continue:If trends continue: Atmospheric COAtmospheric CO22 levels could reach 500ppm, levels could reach 500ppm,

possibly 800ppm by the end of the centurypossibly 800ppm by the end of the century That would decrease surface water pH by .3 That would decrease surface water pH by .3

units by 2100 units by 2100 The pH scale is logarithmic so a change in 1 The pH scale is logarithmic so a change in 1

pH unit equals a 10-fold change in acidity, so pH unit equals a 10-fold change in acidity, so while .3 units sounds small it is really a large while .3 units sounds small it is really a large changechange

Plankton: The base of the food chain; Plankton: The base of the food chain; Phytoplankton also produces majority Phytoplankton also produces majority (~70%) of the oxygen(~70%) of the oxygen

Sea Urchins: Important local fisherySea Urchins: Important local fishery Crabs: fisheryCrabs: fishery Lobster: fisheryLobster: fishery Coral reefs: provide habitat that increases Coral reefs: provide habitat that increases

biodiversitybiodiversity

s

TransportationTransportation Use public Use public

transportationtransportation Ride your bikeRide your bike WalkWalk

EnergyEnergy Use lessUse less Turn out LightsTurn out Lights Use less hot waterUse less hot water Use “clean” energyUse “clean” energy

Goods (fossil fuels Goods (fossil fuels are used to produce are used to produce goods)goods) Consume lessConsume less Buy in bulk (less Buy in bulk (less

packaging)packaging) Buy locallyBuy locally

Smart Food ChoicesSmart Food Choices Eat less meatEat less meat Buy local foodsBuy local foods

Choose a material to testChoose a material to test Create a hypothesis about what you think Create a hypothesis about what you think

will happen to your materialwill happen to your material Record Initial MassRecord Initial Mass Place material in both sea water (or tap) Place material in both sea water (or tap)

and vinegar and/or carbonated waterand vinegar and/or carbonated water Record observations and Final Mass after Record observations and Final Mass after

2 hours2 hours

Sample pH Initial Mass

FinalMass

% change Comments

YourResult

3

AVG Oyster

3

AVGClam

3

AVGCoral

3

Control 1Oyster

8

Control 2Clam

8

Control 3Coral

8

Ocean acidification: the ongoing Ocean acidification: the ongoing decrease of the pH of the oceandecrease of the pH of the ocean

Corrosive: Harmful, destructive, Corrosive: Harmful, destructive, eating away ateating away at

Dissolve: to break up, to liquefy, Dissolve: to break up, to liquefy, to disintegrateto disintegrate

Argonite: a more unstable Argonite: a more unstable calcium carbonate mineral used calcium carbonate mineral used to form coral skeletons and to form coral skeletons and bivalvesbivalves

Calcite: calcium carbonate Calcite: calcium carbonate mineral used to form mineral used to form coccolithophores, and coccolithophores, and foraminiferansforaminiferans

Foraminifera: marine protozoan Foraminifera: marine protozoan having a concentric shellhaving a concentric shell

CoccolithophoreCoccolithophore Calcareous: containing calcium Calcareous: containing calcium

carbonatecarbonate Pteropod: small molluscPteropod: small mollusc Mollusc: snailsMollusc: snails Echinoderm: phylum of marine Echinoderm: phylum of marine

organisms with radiating organisms with radiating sections and a calcareous sections and a calcareous skeletonskeleton

Socio-economic: pertaining to Socio-economic: pertaining to the interaction of social and the interaction of social and economic factorseconomic factors

• NOAANOAA– http://www.pmel.noaa.gov/co2/OA/ http://www.pmel.noaa.gov/co2/OA/

• Ocean Acidification NetworkOcean Acidification Network• http://ioc3.unesco.org/oanet/index.html http://ioc3.unesco.org/oanet/index.html

• National Resources Defense CouncilNational Resources Defense Council– http://www.nrdc.org/oceans/acidification/default.asp http://www.nrdc.org/oceans/acidification/default.asp

• Channel Islands National Marine SanctuaryChannel Islands National Marine Sanctuary– http://channelislands.noaa.gov/sac/pdf/CWG_OAR_final.pdf http://channelislands.noaa.gov/sac/pdf/CWG_OAR_final.pdf

• Farallones National Marine SanctuaryFarallones National Marine Sanctuary– http://farallones.noaa.gov/pdfs/manage/http://farallones.noaa.gov/pdfs/manage/

OceanAcidification_021209.pdf OceanAcidification_021209.pdf