Department of Environmental Studies, University of Tampa, Tampa, FL, 33606, USA; Department of Geosciences, Auburn University, Auburn, AL, 36849, USA.
Department of Geosciences, Auburn University, Auburn, AL, 36849, USA.
Harmful Algae. 2024 Nov;139:102721. doi: 10.1016/j.hal.2024.102721. Epub 2024 Sep 4.
Nutrient enrichment and climate change promote algal blooms, leading to many lakes being characterized as eutrophic (i.e., green) worldwide. We examined recent eutrophication trends of freshwater lakes at a national scale by collating 32 years (1990-2021) of growing season (July-September) in situ chlorophyll-a, nutrient, transparency, and climate data for 1,082 lakes across 32 freshwater ecoregions in the United States. Based on chlorophyll-a, 78.2 % (427/546) of lakes initially exhibited eutrophic conditions and have remained eutrophic. Moreover, non-eutrophic lakes converged toward a eutrophic state, with oligotrophic (i.e., clear) or mesotrophic (i.e., moderately clear) lakes becoming greener, and hypereutrophic (i.e., very green) becoming less green. Optimized Hot Spot Analysis suggests lakes in the Appalachian Piedmont and Apalachicola freshwater ecoregions eutrophied more rapidly than other locations. Results suggest nutrient management targeting eutrophic lakes has hindered further degradation, but poor preventative management of clear lakes has led to their eutrophication.
富营养化和气候变化促进藻类大量繁殖，导致世界上许多湖泊呈现富营养化（即绿色）特征。我们通过整理美国 32 个淡水生态区的 1082 个湖泊的 32 年（1990-2021 年）生长季节（7 月至 9 月）的原位叶绿素-a、养分、透明度和气候数据，来研究国家尺度上淡水湖泊的富营养化趋势。根据叶绿素-a，78.2%（427/546）的湖泊最初呈现富营养化条件且一直保持富营养化。此外，非富营养化湖泊向富营养化状态收敛，贫营养（即清澈）或中营养（即适度清澈）湖泊变得更加绿色，而富营养化（即非常绿色）湖泊变得不那么绿色。优化热点分析表明，阿巴拉契亚山麓高原和阿巴拉契科拉淡水生态区的湖泊比其他地区富营养化速度更快。研究结果表明，针对富营养化湖泊的营养管理已经阻止了进一步的退化，但对清澈湖泊的预防管理不善导致了它们的富营养化。
