杭州湾南岸20 a水质净化功能变化及预测

区域水质净化功能及其影响因素的研究，对深入了解区域水质净化潜力，指导因地制宜的区域总体规划方案与环境保护措施具有重要的现实意义.研究区位于杭州湾南岸，是陆海相互作用的典型区域，承载着重要的经济发展及生态环境功能.基于收集的地形和土地利用类型数据，结合基于站点的气象数据，采用生态系统服务和权衡的综合评估模型（InVEST模型）中的水质净化模型，研究杭州湾南岸氮（N）、磷（P）的负荷量、输出量和净化量的时空演变特征，探索不同发展情境下研究区域水质净化功能的差异.结果表明，时间上，N和P的输出量以及净化量在两年中存在明显差异，相比2000年，2020年研究区域N总负荷量减少276.72 t，输出量减少140.86 t，净化量减少137.86 t；P总负荷量增加93.65 t，输出量增加28.91 t，净化量增加64.74 t；空间上，N、P输出量空间分布趋势大致相同，总体呈现北高南低以及南部部分区域为高值的特征，与土地利用类型密切相关；基于不同情景的模拟分析表明，在自然发展优先情景下，研究区N、P的输出量分别为1 682.36 t和115.50 t，在经济发展优先情景下，区域N、P的输出量分别增加约83.02%和79.93%，在环境保护情景下，区域N、P的输出量分别减少约为79.96%和56.44%.因此环境保护发展优先情景，能有效地减少区域N和P的输出，提高水质净化功能.研究结果为制定区域陆海统筹的规划方案，促进研究区域内经济和生态的协同发展提供了坚实的理论基础.

Change and Prediction of Water Purification Function in the South Bank of Hangzhou Bay in the Past 20 Years

The investigation of regional water purification functionality and its influencing factors holds significant pragmatic implications in understanding the potential of regional water purification, guiding context-specific regional comprehensive planning schemes, and environmental conservation measures. The study site, situated along the southern coast of Hangzhou Bay, represents a prototypical region characterized by intricate land-sea interactions that bear substantial economic and ecological functions. By assimilating a meticulously collected topographical and land-use dataset, in conjunction with site-specific meteorological records, the water purification model embedded within the integrated valuation of ecosystem services and trade-offs (InVEST) framework was employed to scrutinize the spatiotemporal dynamics of nitrogen (N) and phosphorus (P) loads, discharges, and removals within the southern coast of Hangzhou Bay. The prime objective of this study was to unravel the differentials in water purification functionality under diverse developmental scenarios. The investigation unearthed distinct temporal discrepancies in N and P discharges and removals over two temporal dimensions. Relative to the benchmark year 2000, the total N load experienced a reduction of 276.72 t, whereas the N discharge and removals decreased by 140.86 and 137.86 t, respectively, in the year 2020. In contrast, the total P load observed an increase of 93.65 t, accompanied by a surge in P discharge and removals by 28.91 and 64.74 t, respectively. Spatially, the distribution pattern of N and P discharges exhibited a general inclination of elevated values in the northern region and subdued values in the southern region, with certain pockets in the southern region exhibiting pronounced peaks, intimately associated with land-use typologies. Simulation analyses conducted under distinct scenarios unveiled that under the natural development priority scenario, the N and P discharges within the study area amounted to 1 682.36 and 115.50 t, respectively. Conversely, under the scenario emphasizing economic development, the regional N and P discharges showed an approximate escalation of 83.02% and 79.93%, correspondingly. In contrast, under the scenario emphasizing environmental conservation, the regional N and P discharges exhibited a notable decline of approximately 79.96% and 56.44%, respectively. Hence, the scenario prioritizing the amalgamation of environmental conservation and development effectively reduced the N and P discharges within the region, bolstering the water purification functionality. The results derived from this study furnish a solid theoretical foundation for effectuating region-specific planning schemes fostering coordinated economic and ecological advancement within the study area.