Center for Limnology, University of Wisconsin-Madison, Madison WI 53706.
Department of Agronomy, University of Wisconsin-Madison, Madison, WI 53706.
Proc Natl Acad Sci U S A. 2022 Nov 29;119(48):e2214343119. doi: 10.1073/pnas.2214343119. Epub 2022 Nov 21.
Extreme daily values of precipitation (1939-2021), discharge (1991-2021), phosphorus (P) load (1994-2021), and phycocyanin, a pigment of Cyanobacteria (June 1-September 15 of 2008-2021) are clustered as multi-day events for Lake Mendota, Wisconsin. Long-range dependence, or memory, is the shortest for precipitation and the longest for phycocyanin. Extremes are clustered for all variates and those of P load and phycocyanin are most strongly clustered. Extremes of P load are predictable from extremes of precipitation, and precipitation and P load are correlated with later concentrations of phycocyanin. However, time delays from 1 to 60 d were found between P load extremes and the next extreme phycocyanin event within the same year of observation. Although most of the lake's P enters in extreme events, blooms of Cyanobacteria may be sustained by recycling and food web processes.
威斯康星州门登霍尔湖的降水（1939-2021 年）、流量（1991-2021 年）、磷（P）负荷（1994-2021 年）和蓝藻的色素藻蓝蛋白（2008 年至 2021 年 6 月 1 日至 9 月 15 日）的极端日值都聚类为多日事件。降水的长期相关性或记忆最短，藻蓝蛋白的最长。所有变量的极值都聚类，P 负荷和藻蓝蛋白的极值聚类最强。P 负荷的极值可以从降水的极值中预测出来，降水和 P 负荷与藻蓝蛋白的后期浓度相关。然而，在同一观测年内，从 P 负荷极值到下一个藻蓝蛋白极值事件之间发现了 1 至 60 天的时间延迟。尽管湖泊中的大部分磷都在极端事件中输入，但蓝藻的水华可能是通过循环和食物网过程得以维持的。
