CSIC, Bellaterra, Barcelona, Spain.
CREAF, Cerdanyola del Vallés, Barcelona, Spain.
Sci Rep. 2024 May 30;14(1):12408. doi: 10.1038/s41598-024-62810-9.
Eutrophication is a main threat to continental aquatic ecosystems. Prevention and amelioration actions have been taken under the assumption of a stable climate, which needs reconsideration. Here, we show that reduced precipitation can bring a lake ecosystem to a more productive regime even with a decline in nutrient external load. By analyzing time series of several decades in the largest lake of the Iberian Peninsula, we found autocorrelated changes in the variance of state variables (i.e., chlorophyll and oxygen) indicative of a transient situation towards a new ecosystem regime. Indeed, exceptional planktonic diatom blooms have occurred during the last few years, and the sediment record shows a shift in phytoplankton composition and an increase in nutrient retention. Reduced precipitation almost doubled the water residence time in the lake, enhancing the relevance of internal processes. This study demonstrates that ecological quality targets for aquatic ecosystems must be tailored to the changing climatic conditions for appropriate stewardship.
富营养化是大陆水生生态系统的主要威胁。在假设气候稳定的情况下，已经采取了预防和改善措施，这需要重新考虑。在这里，我们表明，即使在营养物质外部负荷下降的情况下，减少降水也可以使湖泊生态系统达到更高的生产力状态。通过分析伊比利亚半岛最大湖泊几十年来的时间序列，我们发现状态变量（即叶绿素和氧气）的方差存在自相关变化，表明正在向新的生态系统状态过渡。事实上，过去几年中出现了异常的浮游硅藻大量繁殖，沉积物记录显示浮游植物组成发生了变化，营养物质的保留也有所增加。降水减少几乎使湖泊的水停留时间增加了一倍，从而增强了内部过程的重要性。这项研究表明，水生生态系统的生态质量目标必须根据不断变化的气候条件进行调整，以进行适当的管理。
