marine ecology coral reefs. global distribution of coral reefs

Download Marine Ecology Coral reefs. Global distribution of coral reefs

Post on 19-Dec-2015

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  • Slide 1
  • Marine Ecology Coral reefs
  • Slide 2
  • Global distribution of coral reefs
  • Slide 3
  • Productivity and diversity
  • Slide 4
  • Structure of coral
  • Slide 5
  • Coral anatomy
  • Slide 6
  • Zooxanthellae are within the gastrodermal layer lining the gastrovascular cavity.
  • Slide 7
  • What does the coral animal provide to the zooxanthellae? Nutrients, especially nitrogen and phosphorus-containing compounds Carbon dioxide Location in the photic zone Protection
  • Slide 8
  • What do the zooxanthellae provide to the coral? Organic molecules (carbohydrates, proteins, other organic molecules) End products of photosynthesis Radiolabelled C-14 experiments verify this transfer of organic molecules 98% of a corals nutrition comes from the zooxanthellae Oxygen Aids in calcification
  • Slide 9
  • Calcification Active transport of calcium from seawater into epidermal cells of coral occurs. At peak of calcium deposition, a cell must transport 50-100 times its own volume. Calcium carbonate deposition is 14X greater in light than in dark, so role of zooxanthellae proposed to be important Highest deposition on sunny days at noon. Mechanism of coupling not well-understood.
  • Slide 10
  • Calcified coral skeleton
  • Slide 11
  • Other coral basics Feeding Shape vs. depth
  • Slide 12
  • Role of coral in food web Primary producers Primary consumers Secondary consumers, and up Detritovores?
  • Slide 13
  • Factors affecting reef growth Temperature Depth Salinity Sediment Wave action Nutrients
  • Slide 14
  • Paradox: low nutrients, high productivity Hypotheses Efficient coupling between coral and its symbionts High flow rate of water over reef; integrated amount that flows over the reef is relatively high Nitrogen fixation by cyanobacteria creates a source of nitrate Nutrients in particulates are relatively high, and are efficiently sequestered by reef organisms.
  • Slide 15
  • Reef structure Reef building Reef breakdown
  • Slide 16
  • Types of coral reefs Fringing Barrier Atoll (Darwins other theory)
  • Slide 17
  • Pacific vs. Atlantic reefs Differences in diversity Differences in species composition Hypotheses to explain these differences
  • Slide 18
  • Key threats to coral reefs The scope of the problem Major threats (explained in some detail) Coral bleaching Overfishing Sewage and other pollutants Storms Implications of reef loss