Benign water quality and phytoplankton status during the operation of Guishan offshore wind farm in the Pearl River Estuary, China

Abstract

Wind power is a clean and renewable source of energy that plays a crucial role in the global effort to combat climate change. Yet, the effects of offshore wind farms on the marine environment remain poorly understood and there is a lack of field data analysis in this area. This study aims to address these gaps by conducting a year-long examination of water quality and phytoplankton communities around the Guishan offshore wind farm (GS-OWF) in the Lingdingyang Bay, Pearl River Estuary, China. The analysis of water quality indicators reveals repelling effect on algae dispersion but no significant contamination resulting from the running of the wind farm over the course of one year. These indicators encompassed various parameters, such as water depth (4.1 − 17.4 m), salinity (16.9 – 28.4 ‰), pH (7.41 – 8.35), temperature (20.5 − 31.2 °C), transparency (⁓ 1.5 m), dissolved oxygen (⁓ 7.5 mg L−1), chemical oxygen demand (⁓ 0.81 mg L−1), chlorophyll-a (14.7 − 0.139 μg L−1), petroleum (0 – 0.0527 mg L−1), and various heavy metals. The cell composition (4 phyla, 158 species, dominated by Bacillariophyta) and density (3 – 1809 cells m−3) demonstrate a healthy phytoplankton community. These results indicate a benign estuary environment after the construction of GS-OWF. This study provides valuable insights into the environmental effects of offshore wind farms, principles for site selection, and the integration of aquaculture convergence with offshore wind farms.