POSTER SESSION 1
15:30–17:30, Monday, September 14
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
ABSTRACT 1112 | POSTER 249
WATER QUALITY CHANGES IN CHINA’S COASTAL WATERS OVER THE PAST TWO DECADES
Under the combined influences of climate change and human activities, China’s coastal ecosystems have undergone substantial changes over the past two decades. Using MODIS satellite observations from 2003 to 2022 together with improved coastal aerosol correction models, this study systematically assessed the spatiotemporal variations in water clarity, represented by Secchi disk depth (Zsd), and its major optical drivers, including total suspended matter (TSM), colored dissolved organic matter (CDOM), and chlorophyll-a (Chl-a). Results show that water clarity increased in 74.3% of China’s coastal waters, with 21.8% exhibiting a persistent upward trend and 52.5% showing a nonlinear recovery pattern characterized by an initial decline followed by an increase. The reduction in TSM was the primary driver of Zsd changes, accounting for up to 80% of the variation in nearshore waters, whereas CDOM played a more important role offshore.
We further examined long-term changes in phytoplankton biomass based on satellite-derived Chl-a. Phytoplankton biomass declined by 23.8% over the study period, mainly in spring, summer, and autumn. Machine-learning analysis identified rising sea surface temperature as the dominant driver, likely through enhanced water-column stratification and reduced nutrient supply to the upper ocean. Together, these results reveal pronounced long-term changes in both the optical and biological properties of China’s coastal waters and highlight the need for integrated assessment of coastal water quality under ongoing climate change.
Youlv Wu*, Eastern Institute of Technology, Ningbo, [email protected], https://orcid.org/0000-0002-6777-4196
Lian Feng, Wuhan University, [email protected]
Chunmiao Zheng, Eastern Institute of Technology, Ningbo, [email protected]
Poster Session | 1 | 2 | 3 | 4 | Schedule at a Glance
