Phytoplankton assemblages as an indicator of water quality in seven temperate estuarine lakes in South-East Australia

Abstract

Phytoplankton species diversity and their ecological characteristics in seven coastal estuaries of different eutrophication status in southeast Australia were described. Seasonal patterns in physical and chemical properties of the waters were assessed over 2 years, along with chlorophyll a data and phytoplankton numbers and diversity. It was found that the phytoplankton species composition and biomass pattern reflected the characteristics of temperature, salinity, nutrients, and habitat in the studied estuaries. A total of 145 species were identified in the different lakes with Diatom and Dinoflagellete species being the main contributors to phytoplankton diversity. Seasonal patterns of phytoplankton assemblages showed that maxima occurred in winter or spring, being mainly affected by temperature and nutrient availability. The eutrophic indicative signals of the phytoplankton species distributions appear to be diminished by the presence of large seagrass beds and extensive macroalgae growth.