Seasonal and spatial variations of water quality and trophic status in Daya Bay, South China Sea

• Published in: Marine pollution bulletin Vol. 112; no. 1-2; pp. 341 - 348
• Main Authors: Wu, Mei-Lin, Wang, You-Shao, Wang, Yu-Tu, Sun, Fu-Lin, Sun, Cui-Ci, Cheng, Hao, Dong, Jun-De
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 15.11.2016
• Subjects: Assessment of Estuarine Trophic Status; Bays - chemistry; China; Climate Change; Cluster Analysis; coastal water; Ecosystem management; Environmental Monitoring - methods; estuaries; Eutrophication; freshwater; Humans; monitoring; monsoon season; Multivariate statistical analyses; Nutrients; Principal Component Analysis; seasonal variation; Seawater - analysis; South China Sea; summer; trophic levels; wastewater; water pollution; Water Quality; winter; ISEW, South China Sea; ISEW, China, People's Rep., Guangdong Prov., Daya Bay; South China Sea; Multivariate statistical analyses; Assessment of Estuarine Trophic Status; Nutrients; Ecosystem management; Water quality; Eutrophication
• ISSN: 0025-326X; 1879-3363
• DOI: 10.1016/j.marpolbul.2016.07.042

Coastal water quality and trophic status are subject to intensive environmental stress induced by human activities and climate change. Quarterly cruises were conducted to identify environmental characteristics in Daya Bay in 2013. Water quality is spatially and temporally dynamic in the bay. Cluster analysis (CA) groups 12 monitoring stations into two clusters. Cluster I consists of stations (S1, S2, S4–S7, S9, and S12) located in the central, eastern, and southern parts of the bay, representing less polluted regions. Cluster II includes stations (S3, S8, S10, and S11) located in the western and northern parts of the bay, indicating the highly polluted regions receiving a high amount of wastewater and freshwater discharge. Principal component analysis (PCA) identified that water quality experience seasonal change (summer, winter, and spring–autumn seasons) because of two monsoons in the study area. Eutrophication in the bay is graded as high by Assessment of Estuarine Trophic Status (ASSETS). •Water quality is evaluated in the Daya Bay, South China Sea.•The spatial variation of water quality was related to human activities.•The seasonal variation of water quality was associated with monsoons.•Multivariate statistical analysis identifies spatial-temporal changes of water quality.•Eutrophication in the bay is graded as high by Assessment of Estuarine Trophic Status.