UCB Moorea Class: Biology and Geomorphology of Tropical Islands

The study of microorganisms and filamentous blue-green algae holds great ecological and geological importance; such microbial communities to be on of the first forms of life as well as the initial source of atmospheric oxygen. In Moorea, an island in the South Pacific, the microbial communities found on the intertidal mudflats have been widely studied and characterized. However, little is known about the marine mats that are consistently covered with seawater. This study surveyed the algal communities present in the shallow lagoon formed at Temae Beach, a public sand beach located on the northeast tip of Moorea. Seven morphologically different mats were observed and their distributions determined and mapped throughout two regions: the littoral (intertidal and sub-tidal) and back reef. The majority of mats were found within the sub-tidal while none were seen within the intertidal and very few observed within the back reef region. A common trend observed within this distribution found specific morphological types consistently located within the same general areas. Additional observations of fish herbivory as well as shear stress and current flow over these mats were also briefly investigation. Overall, while this study provides a brief characterization of what is found in the lagoon, further studies of these marine mats are needed to strengthen these initial findings and, in particular, to investigate specific factors attributing to why the mats disperse as they do.