Data release: early warning indicators for harmful algal bloom assessments in the Illinois River, 2013 - 2020

Harmful algal blooms (HABs) have recently been observed in rivers, including the Illinois River in the Midwest United States. The Illinois River Basin has a history of eutrophication issues, primarily caused by the excessive loading of nitrogen and phosphorus from urban and agricultural sources. Recent events have seen the emergence of cyanobacterial harmful algal blooms in the area. This data release provides early warning indicator (EWI) metrics derived from a continuous chlorophyll concentration dataset obtained from seven water quality monitoring sites along the Illinois River. These metrics include the first-order autoregressive process (Ar1) and the standard deviation (SD) of chlorophyll, which serve as leading indicators of a potential shift in the ecological system, as documented in the ecological literature. For more in-depth information on the methodology used to calculate these metrics and a detailed interpretation of the results as they relate to the Illinois River, please refer to Stackpoole et al. 2024. This work was completed as part of the USGS Proxies Project, an effort supported by the Water Mission Area (WMA) Water Quality Processes program to develop estimation methods for PFAS, harmful algal blooms, and metals, at multiple spatial and temporal scales.

近期在美国中西部的多条河流中观测到了有害藻华（Harmful Algal Blooms, HABs），其中包括伊利诺伊河。伊利诺伊河流域长期存在富营养化问题，其主要成因是城镇与农业源排放的过量氮、磷负荷。近期该区域已出现蓝藻有害藻华事件。本次数据发布提供了基于伊利诺伊河沿岸7个水质监测站点的连续叶绿素浓度数据集所衍生的早期预警指标（Early Warning Indicator, EWI）。此类指标包括叶绿素的一阶自回归过程（First-order Autoregressive Process, Ar1）与标准差（Standard Deviation, SD），正如生态学文献所记载，二者可作为生态系统潜在转变的先行预警指标。如需了解计算这些指标的详细方法，以及针对伊利诺伊河相关结果的深度解读，请参阅Stackpoole等人2024年的研究成果。本工作是美国地质调查局代理项目（USGS Proxies Project）的组成部分，该项目由水任务区（Water Mission Area, WMA）水质过程项目资助，旨在开发多时空尺度下全氟和多氟烷基物质（Per- and Polyfluoroalkyl Substances, PFAS）、有害藻华与重金属的估算方法。