Impacts of Global Warming on the Ocean and Coral Reefs - PowerPoint PPT Presentation

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Impacts of Global Warming on the Ocean and Coral Reefs

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Title: Impacts of Global Warming on the Ocean and Coral Reefs


1
Impacts of Global Warming on the Ocean and Coral
Reefs
  • Emily Underriner
  • ChE 359
  • November 24, 2008

2
Agenda
  • Global Warming and Climate Change
  • The Ocean and Coral Reefs
  • Impacts
  • Temperature
  • Acidity
  • The Future Challenges

3
Global Warming
  • Prior to industrial revolution 280 ppm
  • Current day 387 ppm
  • Greenhouse effect
  • By 2100, CO2 levels to double pre-industrial
    revolution
  • Loss of environmental biodiversity, disrupt
    ecosystem processes, and reduce ecological goods
    and services

4
Importance of the Ocean
  • Yearly global economic value of 21 trillion
  • The largest sink/reservoir of atmospheric CO2
    emissions
  • Contains 50 times the amount of carbon in the
    atmosphere and 10 times more carbon than is held
    by soil and plants
  • CO2 uptake has not been without negative
    consequences

5
Coral Reefs
  • Coral reefs corals, coralline algae, fish,
    others
  • Corals small animals
  • Begin as larva, attach to hard surface
  • Build coral skeleton via reaction of Ca and CO2
    to make CaCO3, or limestone
  • Symbiotic relationship with yellow-brown algae,
    zooxanthellae
  • Provide coral with nutrients
  • Coral provides protection and
    access to light

http//oceanworld.tamu.edu/students/coral/coral5.h
tm
6
Coral Reefs
Source wwf.org
Source myclimatechange.net
7
Importance of Coral Reefs
  • Among the most diverse and productive ecosystems
    on earth (tropical rainforests of the sea)
  • Support 25 of all known aquatic wildlife
    species, over 4,000 species of fish, 700 species
    of coral, and thousands of others
  • Provide food, supply economic income via fishing
    and tourism, shoreline protection, integral ocean
    sink for atmospheric carbon dioxide
  • Supply 375 billion in ecosystem goods and
    services to the global economy each year

8
Impacts on the Ocean
  • Temperature Rise
  • Air has higher thermal heat capacity than water
  • Since the 1950s, average temperature increase of
    0.31 C in top 300 meters of water
  • Acidification
  • Since the 1900s, 30 increase in H in ocean

9
Temperature Impact on Coral Reefs
  • Coral reefs very sensitive to changes in the
    oceans temperature
  • Generally require T between 25C and 29C
  • T change of only a few degrees above the
    long-term average can cause coral to die
  • Bleaching loss of zooxanthellae
  • Over 60 of the earths coral reefs will be lost
    by the next 25 years

10
Coral Reef Bleaching
  • Between 1979 and 1990, out of 105 mass coral
    moralities, 60 coral reef bleaching events were
    reported, compared with only three bleaching
    events among 63 mass coral moralities for the
    preceding 103 years

Source http//www.marinebiology.org/coralbleachin
g.htm
Source Texas AM University, Coral Reefs
11
Acidification
  • Increasing ocean CO2 concentration
  • Historically pH of 8.2
  • Since early 1900s, pH drop by 0.1 units, estimate
    a drop in seawater pH by 0.5 units by 2100
  • CO2 reacts with water to form carbonic acid
    (H2CO3)
  • Increases carbonate (HCO3-) and H in the ocean
    surface water (reducing pH), decreases
    bicarbonate (CO32-)
  • Coral reef organisms rely on the concentration of
    bicarbonate to form hard skeletons
  • Predict threshold to be met around 2050

12
The Future
  • More research on coral reef impacts
  • Increasing carbon concentration is dangerous
  • GHG and carbon mitigation
  • Reduce emissions
  • Sequestration
  • Impacts on entire ocean ecosystem difficult to
    predict

13
Thank you!
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