Predicting the impacts of environmental variability on phytoplankton communities of a sub-tropical estuary

Abstract

Phytoplankton are the floating microscopic organisms which form the base of aquatic food chain, and their ecology is controlled by biotic and abiotic variables. However, a little is known about the response of phytoplankton to changed environmental conditions especially in the sub-tropical regions. Therefore, this study aimed to understand the response of phytoplankton community in variable temperature and salinity conditions in the Naf River estuary of Bangladesh. Phytoplankton, temperature and salinity data were collected from the Naf River estuary of Bangladesh from February 2022 to December 2022. Predicted data of temperature and salinity under two climate change scenarios were also gathered from a hydrodynamic model. Response of phytoplankton to different temperature and salinity scenarios were then analyzed by using a logistic model. This study identified about 154 phytoplankton species from the study area. Temperature had significant negative impacts on the 50 phytoplankton species while 83% species were correlated to the change in salinity. About four phytoplankton species disappeared under the changed environmental conditions. Abundance of one species significantly reduced (50% reduction) while environmental conditions were changed. About 18 phytoplankton species responded positively to the changed environmental conditions. This study provides necessary insights to understand the consequences of climate change on phytoplankton ecology in the sub-tropical ecosystems.