Description
The Moorea Coral Reef (MCR) LTER (17.50 S, 149.83 W) is comprised of the coastal fringe of coral reefs and lagoons that surround the volcanic island of Moorea in the society islands of French Polynesia. The MCR LTER project is co-managed by the University of California Santa Barbara and California State University, Northridge, and field operations are conducted from the University of California Berkeley''s Gump Research Station situated on Cooks Bay. Primary research interests include studies of population dynamics of local corals, nutrient dynamics and diversity studies. For the MCR portion of the MIRADA project we have incorporated investigators from the Marine Biological Laboratory, UCSB faculty, faculty at Moorea''s Gump research station, the Sea Education Association''s semester at sea cruise, and have incorporated an NSF REU undergraduate in 2009 for water sampling and sample analyses. The fringing reefs off the MCR LTER lie at the interface between populated terrestrial coastlines and unproductive, oligotrophic oceanic waters. Our goal within the MIRADA project is to study the changes in microbial population patters along a transect from the island, through Cooks Bay, into the lagoon and across the fringing reef into the open ocean. In 2008 and 2009 the Marine Biological Laboratory MIRADA project partnered with the Sea Education Association to undertake offshore water sampling and geochemical analyses, incorporating an REU student in the 2009 cruise and subsequent laboratory sample analyses. We are primarily interested in the effects of the island and the fringing reef on the microbial population in terms of diversity, species richness, and correlations of specific microbial groups with local geochemical conditions. We are also interested in seasonal comparisons from samples taken in January, 2008 (summer, rainy season) and samples from the same stations collected in June, 2009 (winter, dry season) to assess the impacts of anthropogenic inputs on near- and off-shore communities. We will look for the presence of landscape-scale patterns of diversity and richness from near shore, lagoon and offshore microbial communities within all three domains, signature communities representative of specific geographic and geochemical milieu, and the co-occurrence of specific groups within the ecosystem. Preliminary sequence data analyses suggest that there is a significant correlation between the geographical region (bay, lagoon, offshore open water) and bacterial sequence diversity. We found that significant differences in community diversity can be identified from samples taken from inside and outside the fringing reef, as well as those taken from the bay and the adjacent lagoon. In further analyses we hope to identify seasonal profiles and include environmental variables to assess the breadth of this pattern. We are also in the process of completing a seasonal comparison of the MCR LTER cyanobacterial community using v6 rRNA and ntcA gene sequence data, as well as gene sequences culled from the Global Ocean Survey metagenomic dataset samples that were collected in close proximity to our offshore sites. This data can then be compared to other coastal ocean MIRADA LTER sites (e.g. Palmer Station, Santa Barbara Coastal and Virginia Coast Reserve) to identify patterns in nearshore and coastal ocean microbial populations.
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