This action funds an NSF Minority Postdoctoral Research Fellowship for FY 2010. The fellowship supports a research and training plan in a host laboratory for the Fellow who also presents a plan to broaden participation in biology. The title of the research and training plan for this fellowship to Camille Paxton is "Characterizing the cellular and molecular mechanisms of coral bleaching." The host institution for this research is Oregon State University and the sponsoring scientist is Dr. Virginia Weis.
Coral bleaching leads to decreased coral productivity, growth, and reproduction, and dramatically increased coral mortality. Ultimately, bleaching causes reef degradation and the breakdown of the entire coral reef ecosystem. Coral bleaching is caused by the breakdown of the cnidarian/dinoflagellate symbiosis and the loss of the dinoflagellates from the coral's tissues as a result of environmental changes such as increased sea surface temperature or change in pH. There is evidence that the loss of the dinoflagellates can occur via different mechanisms. This project is characterizing two of these identified mechanisms: apoptosis and autophagy. The research examines mechanisms of both pathways and how the pathways may interact in the sea anemone Aiptasia pallida, a model organism for coral research. The knowledge gained from this model system is then transferred to scleractinian corals, to establish the potential role that these mechanisms play in coral bleaching in nature.
The training objectives are to further develop expertise in cellular and molecular biology, acquire a thorough knowledge of marine biology, and obtain the skills needed for field research. The broader impact is to provide insight into the nature of the processes of coral bleaching and provide information needed to determine the likely fate of coral reefs and their capacity to survive global climate change; this, in turn, can inform management and conservation measures. Additionally, the Fellow increases the participation of underrepresented groups by mentoring graduate and undergraduate students and outreach to the general public.
Coral reefs are one of the most important ecosystems on the planet. They are home to a large array of sea life that in turn provides sources of food and income for many people. Coral reefs are threatened by global warming. When the seawater surrounding coral reefs increases in temperature, corals, normally brown in color, turn a bright white, a process called coral bleaching. The brown color of corals comes from single-celled algae that live inside of the corals cells. During the bleaching process, the algae are lost from the corals. how they are lost is still a topic of active research. I am examining how the algae are lost from the coral by studying two processed that are thought to cause bleaching. The first is apoptosis, a process where a cell launches a programmed that results in cell suicide. The second is autophagy, a process where the cell is able to degrade its internal components. I have found that when the coral cells undergoes apoptosis, this lead to the death of the algae. This indicates that the coral may have an active role in the apoptotic process. In addition, I was able to show that coral host cells can use autophagy to degrade the algae. This is also important because it shows a method of bleaching that does not involve death of the host cell.
