Coral Reefs and Their Problems

1. Coral Reefs and Their Problems

2. Introduction to Coral Reefs • Dynamic geomorphological and biological systems • Can be more than one type of environment • Best developed in the Indian Ocean and on the western margin of the Atlantic and Pacific Oceans – excluded from the upwelling of cold water on the eastern margins • Seawater temps rarely below 17-18° C or above 33-34° C • Prefer average salinities for seawater – hypersalinity limits them • Excess sedimentation is also a limitation – “smothers” the corals • High inputs of terrigenous sediment will limit their occurrence • For example, individual reefs along the Great Barrier Reef are not well developed with mainland rainfalls are high • At their latitudinal limits, biodiversity drops • In the Atlantic Ocean, the northern most reefs off Bermuda occur due to the Gulf Stream

3. Reef Morphology

4. Coral Reef Zonation

5. Physical and Biological Processes in Time and Space

6. African Dust • coincidental with the decline of Caribbean coral reefs over the past 25 years there has been a sharp increase in the transport of African dust to the western Atlantic. • can serve as a substrate for numerous species of viable spores, especially the soil fungus … Aspergillus sydowii, the cause of an ongoing Caribbean-wide seafan disease. • his fungus has been cultured from air samples taken during dustfalls in the Virgin Islands, but that spores of the fungus are absent when the air is clear