Implications of nutrient enrichment and related environmental impacts in the pearl river estuary, china

Implications of nutrient enrichment and related environmental impacts in the pearl river estuary, china: Characterizing the seasonal influence of riverine input

Niu, Lixia (Sun Yat-sen University; Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai))
van Gelder, P.H.A.J.M. (TU Delft Safety and Security Science)
Luo, Xiangxin (Sun Yat-sen University; Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai))
Cai, Huayang (Sun Yat-sen University; Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai))
Zhang, Tao (Sun Yat-sen University)
Yang, Qingshu (Sun Yat-sen University; Guangdong Provincial Engineering Research Center of Coasts, Islands and Reefs; Southern Laboratory of Ocean Science and Engineering (Guangdong, Zhuhai))

2020

The Pearl River estuary is an ecologically dynamic region located in southern China that experiences strong gradients in its biogeochemical properties. This study examined the seasonality of nutrient dynamics, identified related environmental responses, and evaluated how river discharge regulated nutrient sink and source. The field investigation showed significant differences of dissolved nutrients with seasons and three zones of the estuary regarding the estuarine characteristics. Spatially, nutrients exhibited a clear decreasing trend along the salinity gradient; temporally, their levels were obviously higher in summer than other seasons. The aquatic environment was overall eutrophic, as a result of increased fluxes of nitrogen and silicate. This estuary was thus highly sensitive to nutrient enrichment and related pollution of eutrophication. River discharge, oceanic current, and atmospheric deposition distinctly influenced the nutrient status. These factors accordingly may influence phytoplankton that are of importance in coastal ecosystems. Phytoplankton (in terms of chlorophyll) was potentially phosphate limited, which then more frequently resulted in nutrient pollution and blooms. Additionally, the nutrient sources were implied according to the cause–effect chains between nutrients, hydrology, and chlorophyll, identified by the PCA-generated quantification. Nitrogen was constrained by marine-riverine waters and their mutual increase-decline trend, and a new source was supplemented along the transport from river to sea, while a different source of terrestrial emission from coastal cities contributed to phosphate greatly.

Estuary
Nutrient dynamics
River discharge
Seasonality
Water quality

http://resolver.tudelft.nl/uuid:9d886868-cca8-452b-9138-fa9a777a6699

https://doi.org/10.3390/w12113245

2073-4441

Water, 12 (11)

Institutional Repository

journal article

© 2020 Lixia Niu, P.H.A.J.M. van Gelder, Xiangxin Luo, Huayang Cai, Tao Zhang, Qingshu Yang