International Research Fellowship Program: The Effects of Increased Temperature and pCO2 on the Molecular Physiology of the Reef-Building Coral Seriatopora Hystrix

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0852960MayfieldThis award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The International Research Fellowship Program enables U.S. scientists and engineers to conduct nine to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.This award will support a twenty-four month research fellowship by Dr. Anderson B. Mayfield to work with Dr. Chii-Shiarng Chen at the National Museum of Marine Biology and Aquarium in Taiwan, and with Dr. Gretchen Hofmann at the University of California, Santa Barbara in the U.S.The most significant threat to coral reef ecosystems is global climate change (GCC), as prolonged increases in ocean temperature cause the coral-dinoflagellate symbioses that form coral reefs to break down. Furthermore, elevation of atmospheric pCO2 could result in such dramatic increases in ocean acidification (OA) that corals may no longer accrete the CaCO3 skeletons that form the structural foundation of reefs. Thus, there is a need to study the impacts of GCC on these symbioses at cell and molecular levels. With temperature and CO2-controlled mesocosms housed at Taiwan¡¦s National Museum of Marine Biology and Aquarium (NMMBA), the ability of the reef-building coral Seriatopora hystrix to acclimate to temperature and CO2 regimes which will mimic the expected conditions of Taiwanese reefs in 2050 is being assessed by exposing colonies to elevated temperature (2?aC higher than average summer temperatures) and pCO2 (500 ppm) and observing the effects over a months-years timescale. Corals and their endosymbiotic dinoflagellates (genus Symbiodinium) may acclimatize to increasing temperatures and OA by adjusting their metabolic dialogue, leading to changes in the osmoregulatory strategies which integrate the symbiosis. Therefore, alterations in cell volume and architecture are being monitored with scanning electron and confocal microscopy, as NMMBA is the premier venue for studying the cell biology of these symbioses using state of the art microscopes. In parallel, RNA, DNA, and protein are isolated from the experimental corals at monthly intervals for genomic and proteomic analyses carried out in the laboratory of Prof. Gretchen Hofmann at the University of California, Santa Barbara. Specifically, cDNA microarrays are being employed to study the gene level response of. S. hystrix to GCC with quantitative real-time PCR and Western blots used in tandem to confirm changes in gene and protein expression, respectively. Genes/proteins involved in establishment of osmotic homeostasis may undergo dramatic changes in expression in response to these conditions in the short term, though ultimately, after months to years of exposure to higher temperature and pCO2, an acclimation response will likely be mounted such that osmotic and metabolic balance are re-established within coral cells housing endosymbiotic dinoflagellates. The goals of these experiments are to show how corals will respond to GCC and unveil potential mechanisms of acclimatization with the hope that a better understanding of the coral stress response will lead to development of a molecular biomarker system for assessing coral reef health. By using molecular signatures (i.e., differential expression of candidate genes/proteins) to diagnose the health of ecologically important reef-building corals, a proactive means of monitoring reef health could ultimately be employed such that threatened reefs can be targeted for protection via legislation and adaptive management before episodes of mass mortality occur by alleviating the more acute anthropogenic pressures that can more readily be mitigated.