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John Dawson
Math/Science Assistant Professor
| Over the last decade there has been increasing concern about the impact
of global warming and pollution on zooxanthellate (primarily reef-building)
corals. As a result, the ecology, systematics, biogeography, and evolutionary
history of zooxanthellate corals have been extensively studied. Azooxanthellate
corals, in contrast, have been less well studied. Unlike their zooxanthellate
relatives, azooxanthellate corals lack symbiotic algae and are broadly
distributed in both shallow and deep waters (up to 6,000 meters). In addition
to being found in the tropics, azooxanthellate corals can be found in polar,
cold temperate, and warm temperate regions.
My dissertation research has two major themes: 1) biogeography and diversity of azooxanthellate corals from the Neogene to the Recent in the Caribbean and surrounding areas and 2) the morphology and evolution of the azooxanthellate coral genera Anomocora and Asterosmilia and their relationships to the closure of the Central American Isthmus and the onset of northern hemisphere glaciation. I have used multivariate statistics, traditional and geometric morphometrics, and cladistics in order to resolve the patterns in the biogeographic, diversity, and morphologic data sets. In the future, I want to continue with the two themes in my research. For diversity and biogeography patterns, I will expand the database to include all of the Cenozoic azooxanthellate corals, since the evolutionary patterns and processes in this group of corals are heavily influenced by their ecological and environmental requirements. In order to accomplish this, the database will be initially compiled from data published in the biologic and paleontologic literature. In addition, I will compliment and augment the global database by making collections of azooxanthellate corals from classic localities in the Atlantic Coastal Plain, the Gulf Coast and West Coast of the United States, Poland, Dominican Republic, Jamaica, and Carriacou. For the morphologic patterns, I plan to look at the coral Septastrea marylandica. This azooxanthellate coral had a very broad geographic range as well as a long geologic history that ranged from 15 million years to two millions years ago. The central question of this research is why did this geographically widespread as well as geologically long lasting coral species go extinct around two million years ago, since widespread species are supposed to be less susceptible to extinctions than restricted species. |
Selected Meeting Abstracts:
Additional Information:
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E-mail: john.dawson@kirkwood.edu
Last updated: August 13, 2004
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Community College, Iowa City
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