Seasonal and Long-term Changes in Water Quality in the River-impacted Coastal Waters in the Greater Bay Area

Abstract

Our study aims to investigate the spatiotemporal variations and stoichiometric characteristics of phytoplankton biomass and nutrient elements in the Pearl River Estuary, as well as the regulation of nutrients by the Pearl River Estuary and sewage input. In addition, this paper analyzes the impact of bacteria on the aquatic ecosystem, nitrogen and phosphorus limitations, and temperature-induced stratification of water flow. The results of the investigation show that the nutrient salt concentration in the Pearl River Estuary exhibits significant spatiotemporal variations. The high nutrient salt concentration in the Pearl River Estuary makes it the main hotspot for the growth of phytoplankton. Furthermore, bacteria play an important role in the aquatic ecosystem. Our study found that the activity and distribution of bacteria have a significant impact on the spatiotemporal variations of nutrient salt concentration and phytoplankton biomass. Changes in the nitrogen-to-phosphorus ratio also have an impact on the phytoplankton biomass in the Pearl River Estuary. In certain seasons and regions, nutrient limitations may lead to a decline in phytoplankton biomass. In addition, temperature changes can cause water flow stratification, thereby affecting the growth and distribution patterns of organisms in the water. Overall, this study reveals the complex interaction between nutrient elements and phytoplankton biomass in the Pearl River Estuary, as well as the impact of bacteria, nitrogen and phosphorus limitations, and temperature-induced water flow stratification.