作者：As, K., Münch, M., Trommer, G., Pudelko, A., Behrends, T. & Peiffer, S.

Climate change impacts hydrology and biogeochemistry of reservoirs. Thereby, processing of the essential nutrients nitrogen (N) and phosphorus (P) is affected. Clarifying the compounded long-term impact of changed nutrient inputs and effects of climate change on internal nutrient processing requires long-term data sets with sufficient detail. This study evaluates monitoring data from 2000 to 2019 in the German Franconian Lake District, which consists of one shallow (hypertrophic) and three deep reservoirs (meso-to eutrophic), interconnected by a transfer canal. The cascade configuration and continued external load buffer catchment variations, making nutrient trends attributable to internal processing. Mass balances were set up and statistical trends analyses performed for nutrient concentrations, duration of stratification and hypolimnetic anoxia. Across reservoirs, mean water temperature (range: +0.35 to +1.0 degrees C decade-1), stratification (+7 to +18 days decade-1) and hypolimnetic anoxia (+15 to +35 days decade-1) increased significantly. Total phosphorus increased in deep reservoirs (+0.006 to +0.01 mg P L-1 decade-1) and total nitrogen (TN) decreased in all reservoirs (-0.2 to -0.4 mg N L-1 decade-1). Increased rates of nitrate loss could be attributed to enhanced denitrification and earlier algal uptake. Increased total phosphorus concentrations were attributable to increased sediment P-release, induced by prolonged stratification and hypolimnetic anoxia. Primarily, the decrease in TN drove a strong decrease in TN:TP ratio (-4 to -15 mol:mol decade-1), triggering a shift toward N-limitation, associated with proliferation of harmful algae blooms. Identified impacts emphasize the need to consider the potential disruptive effects of intensifying climate change on health and restoration efforts for temperate, eutroph.

 气候变化影响着水库的水文学和生物地球化学过程，进而波及必需营养盐氮（N）和磷（P）的转化。要阐明变化的营养盐输入与气候变化对内部营养盐转化的复合长期影响，需要足够精细的长期数据集。本研究评估了德国弗兰肯湖区2000年至2019年的监测数据，该湖区由一个浅水（超富营养化）水库和三个通过输水渠道相连的深水（中营养至富营养化）水库组成。梯级配置和持续的外源负荷缓冲了流域变化，使得营养盐趋势可归因于内部转化。研究建立了质量平衡，并对营养盐浓度、分层持续时间及底层缺氧持续时间进行了统计趋势分析。各水库的平均水温（升温幅度：+0.35至+1.0°C/十年）、分层持续时间（+7至+18天/十年）和底层缺氧持续时间（+15至+35天/十年）均显著增加。深水水库中总磷上升（+0.006至+0.01 mg P L⁻¹/十年），而所有水库中总氮（TN）下降（-0.2至-0.4 mg N L⁻¹/十年）。硝酸盐损失速率加快可归因于反硝化作用的增强和藻类早期吸收。总磷浓度升高则归因于分层延长和底层缺氧引发的沉积物磷释放增强。总氮的下降主要驱动了TN:TP比值的急剧降低（-4至-15 mol:mol/十年），触发了向氮限制的转变，并伴随着有害藻华的增殖。已识别的影响强调了有必要考虑日益加剧的气候变化对温带富营养化水体的健康与修复工作可能造成的潜在破坏性影响。

（来源：Water Resources Research 2026 Issue 2  DOI: 10.1029/2025wr040978）