Diatom and Dinoflagellate abundance and ecology in waters off the Hawaiian Coast
The purpose of this study is to measure diatom and dinoflagellate diversity and abundance at a few sites around the islands of Hawaii and compare these findings with a site representative of the oligotrophic Pacific. The central question of this research is to determine if the Hawaiian coastal regions have a similar or different ecology than that of comparable oligotrophic waters. A 1984 paper by Laws et al shows that the waters around Hawaii have a higher phytoplankton growth rate than previous oligotrophic studies have measured, suggesting that perhaps the Hawaiian coast is different. Diatom ecology is an important area to further research because they play a key role in carbon cycling due to their dense, silica shells which cause them to sink into sediments (Melillo 2003). There exists a general understanding that diatoms dominate phytoplankton in coastal environments whereas picoplankton are more prevalent in the open ocean, but the amount of land needed to constitute a coastal environment is unknown (Venrick 1990, Venrick 1997). Researching diatom diversity at the midocean coasts of the Hawaiian Islands will help estimate carbon sequestration due to diatoms in near-island waters. To sample diatom ecology, 25 μm plankton net tows at the chlorophyll maximum as determined by fluorometer measurements will be used. Light microscopy will be employed to identify diatoms to species. Inverted micrsocopy will also be used for cell abundance counts (Hasle 1978). Some live counts will be preformed while on ship, but most counts will take place on samples preserved in formalin after the cruise. A flow meter will be attached to the plankton net to measure water volume to allow a second measure of diatom abundance. As mentioned above, the equipment needed includes a plankton net, flow meter, formalin for samples, jars for samples and a light microscope. Nutrient data analysed in Kathy Krogslund’s lab will also be used for site comparisons.