Linking Global Climate Change to Oceanic Ecosystem Functioning

Ocean Acidification

Uta Passow

Marine Science Institute UC Santa Barbara

Understanding Ocean Acidification: WorkshopChannel Islands National Marine Sanctuary, 10/2010

The Problem:Fossil Fuel EmissionResulting Increase in CO2

Discussion:What if peopled do not believe this?The basics: plants and animals and oil

www.globalwarmingart.com

http://carboncycle.aos.wisc.edu/index.php?page=global-carbon-cycle

Global C-Cycle

Fate of Anthropogenic CO2 Emissions (2000-2008)

Le Quéré et al. 2009, Nature Geoscience; Canadell et al. 2007, PNAS, updated

1.4 PgC y-1

+7.7 PgC y-1

3.0 PgC y-1

29%

4.1 PgC y-1

45%

26%2.3 PgC y-1

What can we do?• Reduce your CO2 foot print

• Reduce gasoline / energy usage• Use CO2 neutral energy• plant trees

• Lobby for Reduction of CO2 foot print• Public transportation• Development of “alternative technology”

2000 2050

390

Measurements from ice coresdirect Measurements

2010: 387 ppmV

Atmospheric CO2 concentration

Redrawn after www.globalwarmingart.com

We can already measure the anthropogenic CO2 in the ocean in the upper 1000 m.

Feely 2004

Ocean acidification

Doney, Scientific American 2006

Dissolved Inorganic Carbon in Seawater

DIC = CO2 +HCO3- + CO3

2-

pHAs pH decreases• DIC increases• Composition of DIC shifts (Impact cells as it matters what type of ion they have available)

As atm. CO2 increases•DIC in seawater increases• pH decreases• Saturation state for calcium carbonate decreases

Feely, Doney, Oceanography 22, 2009

A shift of 1 pH unit e.g. 8.2 to 7.2 is a factor of 10 difference in H+ Ions

How does the ocean work – in 3 slides!&

Biological Impacts of Ocean Acidification – Lots of Examples!

Not much question that ocean acidification is happening!The question is how the marine ecosystems react to this.

• Stress• Acclimatization• Adaptation

Phytoplankton

Diatoms:

Coccolithophores

Dinoflagellates

Phaeocystis

Cyanobacteria

http://rohlenscience.pbworks.com/Energy%20Notes

How does the ocean work?

Burd & Passow, unpubl.

Eelgrass

Primary production increases

Photosynthesis increases!

Not for all organisms!

MEPS 2007

Phytoplankton

Species composition shifts!

Feng et al MEPS 2009

Calcification

Calcite Aragonite Mg-CalciteCoccolithophorids Pteropods Coraline AlgaeForaminifera Corals cold water Coralssome Bivalves most MollusksSpongesEcinoderms

SHELLED ORGANISMS and crystal structure of CaCO3

Aragonite saturationHorizon

MODERNPAST

Calcite Saturation Horizon

SaturationHorizonsare shallowing

Oceanography 22, 2009

Waters that are naturally acidic

Coccolithophorids

Calcification decreasesAt least in many organisms

Phytoplankton

Coccolithophores

CaCO3-plates

May use organic nitrogen or phosphorus.

Blooms visible from space

N-Fixation

Nitrogen fixation: Biological process by which nitrogen (N2) is converted into ammonia. This process is essential for life (amino acids, proteins) contain N.

Some bacteria, especially cyano-bacteria can fix nitrogen. Some plants have a symbionticrelationship with such bacteria (lupines, peanuts).

Cyanobacteria common in surface ocean.

Hutchins, Oceanography 22, 2009

N-fixation by Trichodesmium sp.

Oceanography 22, 2009

N-Fixation:Percent increase in N-fixation of 7 different strains of Trichodesmiumspp. under at future (750 ppmV) vs. current CO2 levels.Calculted increase in global N-fixation, minimum (red) or maximum (blue). Green atm. pCO2

Oceanography 22, 2009

Oyster

Lifecycle

Calcification/ Reproduction

3 weeks planktonic

Precipitation of oyster shell after settlement (benthic)

970 ppmVVs 380

Shell precipitated

16% less

Size @ settelment

7% less

Size after 4-5 days

42% less

Exp 1

After Hettinger ASLO 2010

Larvae 380 970 380 970juvenile 380 970 970 380

Hypothesis

ResultsCarry -over

H L H L * (35%)

* Even if then put in normal environment 40 days later still 28% smaller: larvae effect persists After Hettinger ASLO 2010

Calcification, Reproduction: decrease with higher CO2, Photosynthesis, N fixation increase, or remain constant Oceanography 22, 2009

DIC-drawdown (ΔDIC)

pH decrease

Net community carbon consumption(photosynthesis, C:N, TEP)

Loss of OC = ΔDIC-(Δ POC+ Δ DOC)

Past Future

OA will lead to an increase in sedimentation

Budget in the “black box”

Carbon flux: CO2 perturbation in mesocosms

The Future Riebesell, Nature 2007

http://oceanservice.noaa.gov/education/kits/corals/coral01_intro.htmlhttp://animals.nationalgeographic.com/animals/invertebrates/coral.html

Coral polyps are tiny, soft-bodied organisms related to sea anemones and jellyfish. At their base is a hard, protective limestone skeleton called a calicle, which forms the structure of coral reefs. Reefs begin when a polyp attaches itself to a rock on the sea floor, then divides, or buds, into thousands of clones. The polyp calicles connect to one another, creating a colony that acts as a single organism. As colonies grow over hundreds and thousands of years, they join with other colonies and become reefs. Some of the coral reefs on the planet today began growing over 50 million years ago.

Corals

Almost all corals are colonial organisms. This means that they are composed of hundreds to hundreds of thousands of individual animals, called polyps. Each polyp has a stomach that opens at only one end. This opening, called the mouth, is surrounded by a circle of tentacles.

Corals

Corals live in tropical waters throughout the world, generally close to the surface where the sun's rays can reach the algae.

While corals get most of their nutrients from the byproducts of the algae's photosynthesis, they also have barbed, venomous tentacles they can stick out, usually at night, to grab zooplankton and even small fish.

Most reef-building corals contain photosynthetic algae, called zooxanthellae, that live in their tissues.

The corals and algae have a mutualisticrelationship. The coral provides

a protected environment compounds for photosynthesis

The algae produceoxygenhelp to remove wastesglucose, glycerol, amino acids,

The relationship between the algae and coral polyp facilitates a tight recycling of nutrients in nutrient-poor tropical waters.

Corals

Zooxanthellae cells provide corals with pigmentation. On the left is a healthy stony coral. On the right is a stony coral that has lost its zooxanthellae cells and bleached.

http://www.osdpd.noaa.gov/ml/ocean/cb/hotspots.htmlMap with hot spots

Zooxanthellae are responsible for the unique and beautiful colors of many stony corals.

Corals: Bleaching, a temperature effect

Corals

Cohen, Oceanography 22, 2009

Cohen

Ambient 780-1200 ppmV pCO2

3 x NO3

7 x NO3

Enough food can compensate stress by high CO2, as proton pumping costs energyInternal pH is different from external (Ω internal: 3.7 if external 0.2

or internal 3 if external 20)

% ambient calcification

80%

25%

Interaction of several processes

Corals

Oceanography 22, 2009

Kleypas, Oceanography 22, 2009

Coral reef: many calcifying organisms

Oceanography 22, 2009

Corals

Kleypas, Oceanography 22, 2009

Oceanography 22, 2009

No skeleton, polyps healthy. Survived Permian extinction?

Oceanography 22, 2009

Fossil fuel

Ocean uptake

http://carboncycle.aos.wisc.edu/index.php?page=carbon-budget-tool

Land use

Ocean acidification at the organism level tends to lead to• increase in photosynthesis – but temperature effects

change this• increase in N-fixation – but iron availability important• decrease in calcification – some species survive without shell• decreased reproduction: benthic calcifiers (larvae vulnerable)

Variability is highgenetic variationmany interdependent processes

Biological Reactions to OA

pCO2

today

370

Year 2100

~750 µatm

irradiance

pH ~8.1 ~7.8

mixing

• Growth conditions- [CO2]aq / pH / Ω …

- light regimes

- nutrient availability

nutrientinput

Temperature & Stratification

- Temperature increase

Overall photosynthesis decrease observed. That could be a real problem as phytoplankton make up almost 50% of global photosynthesis.

Questions?

THANK YOU!