South China Institute of Environmental Science, Ministry of Ecology and Environment, No.18 Ruihe RD., Guangzhou, 510535, China; National Key Laboratory of Urban Ecological Environmental Simulation and Protection, Guangzhou, 510535, China.
State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering, Nanjing Hydraulic Research Institute, Nanjing, 210029, China.
Chemosphere. 2023 Aug;332:138836. doi: 10.1016/j.chemosphere.2023.138836. Epub 2023 May 1.
Monitoring the long-term spatiotemporal variations in particulate organic phosphorus concentration (C) is imperative for clarifying the phosphorus cycle and its biogeochemical behavior in waters. However, little attention has been devoted to this owing to a lack of suitable bio-optical algorithms that allow the application of remote sensing data. In this study, based on Moderate Resolution Imaging Spectroradiometer (MODIS) data, a novel absorption-based algorithm of C was developed for eutrophic Lake Taihu, China. The algorithm yielded a promising performance with a mean absolute percentage error of 27.75% and root mean square error of 21.09 μg/L. The long-term MODIS-derived C demonstrated an overall increasing pattern over the past 19 years (2003-2021) and a significant temporal heterogeneity in Lake Taihu, with higher value in summer (81.97 ± 3.81 μg/L) and autumn (82.07 ± 3.8 μg/L), and lower C in spring (79.52 ± 3.81 μg/L) and winter (78.74 ± 3.8 μg/L). Spatially, relatively higher C was observed in the Zhushan Bay (85.87 ± 7.5 μg/L), whereas the lower value was observed in the Xukou Bay (78.95 ± 3.48 μg/L). In addition, significant correlations (r > 0.6, P < 0.05) were observed between C and air temperature, chlorophyll-a concentration and cyanobacterial blooms areas, demonstrating that C was greatly influenced by air temperature and algal metabolism. This study provides the first record of the spatial-temporal characteristics of C in Lake Taihu over the past 19 years, and the C results and regulatory factors analyses could provide valuable insights for aquatic ecosystem conservation.
监测水体中颗粒态有机磷浓度（C）的长期时空变化对于阐明磷循环及其生物地球化学行为至关重要。然而，由于缺乏可应用于遥感数据的合适生物光学算法，这方面的研究很少受到关注。本研究基于中分辨率成像光谱仪（MODIS）数据，为中国富营养化太湖开发了一种新的基于吸收的 C 算法。该算法的平均绝对百分比误差为 27.75%，均方根误差为 21.09μg/L，性能良好。在过去的 19 年（2003-2021 年）中，长期的 MODIS 衍生 C 呈现出总体增加的趋势，且在太湖内存在显著的时间异质性，夏季（81.97±3.81μg/L）和秋季（82.07±3.8μg/L）的 C 值较高，而春季（79.52±3.81μg/L）和冬季（78.74±3.8μg/L）的 C 值较低。在空间上，竹山区（85.87±7.5μg/L）的 C 值相对较高，而胥口湾（78.95±3.48μg/L）的 C 值较低。此外，C 与空气温度、叶绿素-a 浓度和蓝藻水华面积之间存在显著相关性（r>0.6，P<0.05），表明 C 受空气温度和藻类代谢的影响较大。本研究提供了过去 19 年来太湖 C 的时空特征的首份记录，C 结果和调控因子分析可为水生态系统保护提供有价值的见解。
