Zhou Tao, Yang Xiankun, Cai Shirong, Yang Qianqian, Zhang Wenxin, Li Zhen, Ran Lishan
School of Geography and Remote Sensing, Guangzhou University, Guangzhou, 510006, China.
Rural Non-Point Source Pollution Comprehensive Management Technology Center of Guangdong Province, Guangzhou University, Guangzhou, 510006, China.
Environ Monit Assess. 2025 Jan 9;197(2):154. doi: 10.1007/s10661-024-13548-4.
Excessive total suspended matter (TSM) concentrations can exert a considerable impact on the growth of aquatic organisms in fishponds, representing a significant risk to aquaculture health. This study revised existing unified models using empirical data to develop an optimized TSM retrieval model tailored for the Guangdong-Hong Kong-Macao Greater Bay Area (GBA) (R = 0.69, RMSE = 7.78 mg/L, and MAPE = 0.23). Employing top-of-atmosphere (TOA) reflectance data from Landsat satellites, accessed via Google Earth Engine (GEE), the refined model facilitated the generation of TSM datasets for fishponds across the GBA from 1986 to 2019. Over these 34 years, there was a marked decline in TSM levels in fishponds, with an approximate 50% reduction in annual average TSM. This decline was particularly notable in the northern, western, and eastern GBA regions, leading to a spatial distribution characterized by higher TSM concentrations in the central and southern regions and lower concentrations in the peripheral regions. Seasonally, TSM levels in GBA fishponds are significantly higher during spring and summer compared to autumn and winter. Regarding natural factors, wind speed shows a significant positive correlation with long-term TSM fluctuations in these environments (p < 0.01). Stocking density, regulated artificially, emerges as a pivotal factor affecting TSM fluctuations. Specifically, TSM concentrations are elevated during periods of high stocking density in the rapid growth phase, and decrease during the mature and harvesting phases when stocking densities are reduced. Furthermore, fishponds situated in impervious areas exhibit significantly higher TSM concentrations compared to those in cropland or forested areas. The economic costs associated with aquaculture drive variations in stocking densities across different land uses within the GBA, contributing to the observed spatial variations in TSM levels. Given the status of the GBA as one of China's most advanced aquaculture regions, the insights from this study hold substantial value from both economic and ecological viewpoints.
总悬浮物质（TSM）浓度过高会对鱼塘中水生生物的生长产生重大影响，对水产养殖健康构成重大风险。本研究利用经验数据对现有的统一模型进行修订，开发了一个针对粤港澳大湾区（GBA）量身定制的优化TSM反演模型（R = 0.69，RMSE = 7.78 mg/L，MAPE = 0.23）。该改进模型利用通过谷歌地球引擎（GEE）获取的陆地卫星的大气层顶（TOA）反射率数据，生成了1986年至2019年粤港澳大湾区鱼塘的TSM数据集。在这34年中，鱼塘中的TSM水平显著下降，年平均TSM下降了约50%。这种下降在大湾区北部、西部和东部地区尤为明显，导致了一种空间分布特征，即中部和南部地区的TSM浓度较高，周边地区的浓度较低。季节性来看，与秋冬相比，大湾区鱼塘的TSM水平在春夏季节显著更高。关于自然因素，风速与这些环境中TSM的长期波动呈现显著正相关（p < 0.01）。人工调控的放养密度是影响TSM波动的关键因素。具体而言，在快速生长阶段放养密度高时TSM浓度升高，而在成熟和收获阶段放养密度降低时TSM浓度下降。此外，与位于农田或森林地区的鱼塘相比，位于不透水区域的鱼塘TSM浓度显著更高。水产养殖的经济成本导致大湾区不同土地利用类型的放养密度存在差异，这促成了所观察到的TSM水平的空间变化。鉴于大湾区是中国最先进的水产养殖地区之一，本研究的见解从经济和生态角度都具有重要价值。
