Diversity and Abundance Changes of Diatoms Due to Seasonal Temperature and Salinity Variations in Galveston Bay

Abstract

Water quality is a critical parameter in ensuring the health of Galveston Bay due to the presence of major commercial and recreational fisheries that take place there. One way to assess the health of the bay is to monitor the diversity and abundance of phytoplankton; more specifically diatoms. In doing so, it is important to be able to distinguish between the effects of natural seasonal variations such as temperature and salinity to diatom diversity and abundance from those which may be driven by human induced influences. This project was designed to determine the composition of the natural community of diatoms and examine the changes due to seasonal temperature and salinity variations. Water samples were taken daily at the lower end of Galveston Bay throughout an entire year (April 2015 – March 2016) and were run through an Imaging FlowCytobot in order to record the community composition for each day. Statistical analysis showed that temperature was weakly, negatively correlated with the changes in diatom cell counts and diversity. However, there was also a moderate, positive correlation between the diversity and salinity. These findings could potentially help researchers distinguish between which natural physical variations are having the greatest effects on the overall phytoplankton community of Galveston Bay.