HARMFUL ALGAL BLOOM HISTORIES: DATA TO SUPPORT TREND ANALYSES IN THE ILLINOIS RIVER BASIN AND BEYOND

Harmful algal blooms (HABs) are a growing concern in freshwaters as apparent increases in these events impinge on water availability for humans, animals, ecosystems, and local economies. Efforts have been made to track the occurrence of these events over time in lake and marine environments, but fewer efforts have focused on rivers. Recent high-profile river blooms have led to the question: Are HABs becoming more common in rivers? Algal taxa, cell counts, biovolume, pigment measurements, visual observations, and toxin concentrations acquired through field sampling, in situ florescence sensors, and remote sensing via satellites could be used to answer this question. In the Illinois River Basin, we compiled a database of multisource discrete chlorophyll and algal toxin data from multiple agencies across Illinois, HAB reports from field staff and the public, estimates of chlorophyll and trophic status from remotely sensed spectra, and high frequency pigment measurements. These datasets have various sampling densities, frequencies, and temporal periods and a variety of statistical techniques are used to characterize changes over time. For this presentation, our workflow and “lessons learned” for the acquisition, compilation, and harmonization of this HABs database are summarized. Additionally, we will discuss various methods to integrate these datasets and their trends to better understand how HAB occurrence has varied over time.

Primary Presenter: Jennifer Murphy, US Geological Survey (jmurphy@usgs.gov)

Authors:

Jennifer Murphy, US Geological Survey  (jmurphy@usgs.gov)

Mackenzie Marti, US Geological Survey  (mmarti@usgs.gov)

Jaqueline Ortiz, US Geological Survey  (jortiz@usgs.gov)