Corals, Climate, and Sea Level Changes

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Corals, Climate, and Sea Level Changes

• Lida Teneva, LDEO
• February 9, 2008
• Earth 2 Class

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What is a coral reef?

• 1/3rd of all marine species
• shallow, warm tropical waters between 30 S and
  30 N
• around volcanic islands, or as isolated atolls

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What is a coral?

• Colonial, immobile animals
• various sizes, shapes, colors
• secrete a calcium carbonate skeleton
• Symbiotic relationship with algae

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Why are coral reefs important?

• Ecosystem services
• Fish habitat
• Source of food and medicine
• protection the coast from erosion

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The coral-climate connection

• Look at skeletal chemistry carbon, oxygen,
  nitrogen isotopes trace amounts of certain
  elements
• Get information about past temperature change,
  sea level change, ocean environmental changes,
  ocean circulation, air-sea interactions, CO2
  changes, etc.

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What we do in our lab

• Focus on
• Sea-surface temperatures (SSTs) since the last
  glacial period (estimates 5 C cooler than today)
• Sea level change since the last glacial period
  (estimates global sea level was 120m 400
  feet lower than today)

Fairbanks, 1989
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Effects of global warming on coral reefs
Coral bleaching due to temperature increase,
often leading to coral death
With increased CO2 in the atmosphere, the
carbonate balance in the ocean changes and the
ability of the corals to make their skeletons is
negatively affected.
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Take home points

• Corals are colonial, immobile animals, existing
  in symbiosis with algae, and recording ambient
  chemical information within their skeletons
• Corals are very sensitive to environmental
  changes
• We can gain a lot of insight by studying ancient
  corals
• We need to conserve and monitor reefs carefully
  in light of future climate changes and other
  anthropogenic threats
• There is a lot we still need to learn about
  corals and coral reefs, but it is certain they
  need our protection -- for the sake of
  biodiversiry, preservation of climate
  information, coastal protection, etc.

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Thank you!