Coral Growth in Response to Increased Atmospheric CO2

Jim Billingsley

Biology 881

University of Nebraska, Kearney

Introduction

• Overview

• Coral Structure

• Seawater Chemistry

• Affects of CO2 on Seawater

• Conclusions

Overview

– CO2 emissions

– Physiology of marine organisms.CO2

CO32-

Overview

Photosynthesis and calcification problems

• Sealevel rise

• Faster growing algae

• Boring organisms and storm damage

Trends in Atmospheric CO2

Mauna Loa, Hawaii and Law Dome, Antarctica

(Etheridge et al, 1998); (Keeling and Whorf, 2001)

Vostok, Antarctica Ice Core Atmospheric CO2 Record

(Petit, et al, 1999)

100

200

300

400

0100000200000300000

Years before present

CO

2, p

pm

100

200

300

400

1000 1200 1400 1600 1800 2000

Year

Ice coreKeeling

Global Emission of CO2

0

50

100

150

200

250

300

1700 1750 1800 1850 1900 1950 2000 2050

Year

Gt

C

280

300

320

340

360

380

CO

2, p

pm

EmissionsCO2

(Marland, Boden and Andres 2001)

Coral Structure

• Polyps• Colony• Nematocysts

Coral Structure

• Animal• Calcium carbonate

skeleton• Symbiotic plant

Zooxanthellae

• Dinoflaggellate

• Photosynthetic

• Pigments

Seawater Chemistry

H2O + CO2 (aq) H2CO3 HCO3- + H+

Dissolution of calcium carbonate

• Temperature, pressure and partial pressure of carbon dioxide

• CaCO3 + H20 + CO2 Ca2+ + 2HCO3-

• Higher pressures and cooler temperatures

• Corrosive

CO2 Emissions and Calcification in the Oceans

• Rising atmospheric CO2

• Carbonate equilibrium • Decrease in alkalinity

• Reduces the CaCO3 saturation

• Harder for coral reefs to grow

1880

Present

Future – Double CO2

Calculated changes seawater carbonate chemistry(assuming S=35, TA=3.5 meq/L)

1

2

3

4

5

1800 1850 1900 1950 2000 2050 2100 2150

Year

War

ag

5

10

15

20

CO

2 aq

, mm

ol k

g-1

-0.011 y-1

Warag

CO2 aq

Observations at the Hawaii Ocean Times Series Station

3

4

5

1990 1992 1994 1996 1998 2000

Year

War

ag

slope = -0.022±0.08 (95% CI) y-1

Chemical treatments

nweeks

pCO2

matm

HCO3-

mmol kg-1

CO32-

mmol kg-1

pH sws

29 22529

154670

31028 8.230.04

47 37155

169676 22625 8.050.06

43 74199

195445 14918 7.810.06

Effect of CO2 on community calcification

y = 62373.77x-1.24

R2 = 0.61

0

40

80

120

0 200 400 600 800

pCO2, matm

Cal

cifi

cati

on

mm

ol C

aCO

3 m

-2 d

-1

Coral Response

(Marubini et al., 2001)

200 matm

700 matm

Porites compressa

Effect of a doubling in CO2 (350-700) on calcification, (% decrease)

Calcareous macroalgaeAmphiroa foliacea -36 Borowitzka, 1981Porolithon gardineri -16 Agegian, 1985Corallina pilulifera -44 Gao et al., 1993

CoralsStylophora pistillata -3 Gattuso et al., 1998Porites porites -16 Marubini & Thake, 1999Porites compressa -27 Marubini et al., 2001Acropora sp. -37 Schneider & Erez, 2000Porites/Montipora -50 Langdon &

Atkinson, in prep.

CoccolithophoridsEmiliania huxleyi -10 Riebesell et al.,

2000

Gephyrocapsa oceanica -29 “ “

Natural pop. (N. Pac.) -38 “ “

Emiliania huxleyi -17 Zondervan et al., 2001

Gephyrocapsa oceanica –29 “ “

CommunityBiosphere 2 -40 Langdon et al., 2000

Monaco mesocosm -21 Leclercq et al., 2000

Bahama Bank -30 Broecker & Takahashi, 1966

Future pH Changes• Burn all known stocks of fossil fuels

– Atmospheric CO2 would exceed 1,900 parts per million around the year 2300

• pH reduction at the ocean surface– Calcium carbonate skeletons

• Unabated CO2 emissions – Changes in ocean pH

Conclusions

CO2 Calcification

• for 200 to 280 matm pCO2 Calcif. 34%

• for 350 to 700 matm pCO2 Calcif. 58%

Conclusions

• Saturation state (W) controls calcification

• Consequences of reduced calcification

– Space and light

– Sealevel rise

– Erosion and damage

• Decomposition of Calcium Carbonate

Literature Cited• Barker, S., Higgins, J.A., and Elderfield, H. 2003. The future of the carbon cycle: review,calcification response,

ballast and feedback on atmospheric CO2. Philosophical Transaction of the Royal Society, 361, 1977–1999.

• Caldeira, K. and Wickett, M.E. 2003 Oceanography: anthropogenic carbon and ocean pH. Nature, 425, 365.

• Etheridge, D.M., ,Steele, L.P., R.L. Langenfelds, Francey, R.J., Barnola, J.M., and Morgan, V.I.. 1998. Historical CO2

records from the Law Dome DE08, DE08-2, and DSS ice cores. In Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

• Gattuso, J.-P., Allemand, D., and Frankigoulle, M. 1999. Photosynthesis and Calcification at Cellular, Organismal and Community Levels in Coral Reefs: A Review on Interactions and Control by Carbonate Chemistry. American Zoological Society, 39, 160-183.

• Gerin, F. & Edmunds, B. 2001. Mechanisms of interaction between macroalgae and scleractinians on a coral reef in Jamaica. Journal of Experimental Marine Biology and Ecology, 261, 159–172.

Literature Cited

• Keeling, C.D. and Whorf, T.P. 2005. Atmospheric CO2 records from sites in the SIO air sampling network. In Trends:

A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

• Langdon, C. 2001. Overview of experimental evidence for effects of CO2 on calcification of reef builders. Proceedings of the 9th International Coral Reef Symposium, Oct 23.27, 2000, Bali Indonesia.

• Marland, G., Boden, T.A., and Andres, R.J. 2006. Global, Regional, and National Fossil Fuel CO2 Emissions. In

Trends: A Compendium of Data on Global Change. Carbon Dioxide Information Analysis Center, Oak Ridge National Laboratory, U.S. Department of Energy, Oak Ridge, Tenn., U.S.A.

• Marubini, H., Barnett, C., Langdon, M., and Atkinson, M.J. 2001. Dependence of calcification on light and carbonate ion concentration for the hermatypic coralPorites compressa. Marine Ecology Progress Series, 220, 153–162.

• Marubini, F., Ferrier-Pages, C., and Cuif, J.-P. 2003. Suppression of skeletal growth in scleractinian corals by decreasing ambient carbonate-ion concentration: a cross-family comparison. Proceedings of the Royal Society of London B, 270, 179–184.

• Petit, R., Jouzel, J., and Raynaud, D. 1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399, 429-436.