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The Effects of Ocean Acidification on Coral A Comparison between the Alkalinity Anomaly and Buoyant Weight Methods of Measurement PowerPoint PPT Presentation


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The Effects of Ocean Acidification on Coral A Comparison between the Alkalinity Anomaly and Buoyant Weight Methods of Measurement. Aaron Cevallos Advisor: Andreas Andersson , Ph.D. Summer 2010. What is ocean acidification? What is causing it?.

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The Effects of Ocean Acidification on Coral A Comparison between the Alkalinity Anomaly and Buoyant Weight Methods of Measurement

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The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

The Effects of Ocean Acidification on CoralA Comparison between the Alkalinity Anomaly and Buoyant Weight Methods of Measurement

Aaron Cevallos

Advisor: Andreas Andersson, Ph.D.

Summer 2010


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

What is ocean acidification? What is causing it?

  • The ocean absorbs approximately 1/3rd of the CO2 emitted to the atmosphere from the burning of fossil fuels.

  • As CO2 dissolves in seawater, the pH of the water decreases. Since the beginning of the industrial revolution, ocean pH has dropped globally by approximately 0.1 pH units.

  • By the end of this century, we may expect to see changes in pH that are the greatest in 21 million years.

  • http://ioc3.unesco.org/oanet/FAQacidity.html


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

Evidence of ocean acidification at BATS

N. Bates


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

Bermuda coral reef: the canary in a coal mine?

Buddemeier et al. 2004, based on Veron 1995

[CO32-] across coral reef platform

-Marginal reef

-Lower [CO32-]

-Healthy reef

-No major industries or pollution

-Natural gradient in [CO32-]

Alex Venn

Mid-platform

Inshore

Outer rim


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

What can we expect in the future ?

Changes in atmospheric CO2 under the "business as usual" scenario to the year 2100 and associated changes in ocean pH and carbon chemistry. Adapted from Wolf-gladrow et al., 1999

  • The IPCC expects:

  • a drop in ocean pH of about 0.4 pH units by the end of this century

  • a 60% decrease in the concentration of calcium carbonate

http://ioc3.unesco.org/oanet/FAQacidity.html


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

Why is ocean acidification a problem?

  • Seawater acid-base balance important in regulating biological and chemical processes, e.g.:

    • Function of enzyme and proteins

    • Chemical reaction rates

    • Availability of nutrients and trace metals

  • CO32- is an essential building block for marine calcifiers depositing skeletons or shells made of CaCO3†

    • Less building material equals slower growth, weaker structures (similar to osteoporosis in humans) and increased vulnerability to environmental stress in general

†Ca2+ is the other building block, but there are plenty of calcium in seawater


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

Ca2+

CO32-

CaCO3

The Alkalinity Anomaly Method

  • The alkalinity anomaly method relies on the principle that when a calcifying organism produces a mole of calcium carbonate, total alkalinity is decreased by two moles.

  • I will be able to know the exact degree to which synthesis or dissolution is taking place using this method.


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

Average Daytime vs. Nighttime Calcification Rates


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

The Buoyant Weighing Method

Calcification (or dissolution) of a coral sample is inferred from changes in the sample’s mass. The weight can be determined in water using the formula: Wa= Ww / [1-(pw/ps)]

http://www.aagaines.com/man/graphics/scale.jpg


The effects of ocean acidification on coral a comparison between the alkalinity anomaly and buoyant weight methods of m

AA Predicted Weight Change vs. BW Actual Weight Change


Thank you

Thank You!


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