Remote Sensing-based Chlorophyll-a as a Proxy for Harmful Algal Bloom Public Health Advisories
Brittany N Lopez Barreto, University of California, Merced, blopezbarreto@ucmerced.edu (Presenter)
Erin L. Hestir, University of California Merced, ehestir@ucmerced.edu
Christine M. Lee, Jet Propulsion Laboratory, christine.m.lee@jpl.nasa.gov
Marc Beutel, University of California, Merced, mbeutel@ucmerced.edu
Cyanobacterial harmful algal blooms (cyanoHABs) can harm people, animals, and affect the water quality and recreational use of inland water bodies. Measuring and monitoring cyanobacteria is limited, while chlorophyll-a (chl-a) is a more common water quality metric and has been shown to have a shared relationship with cyanobacteria. The World Health Organization (WHO) has recently updated (2021) their previous 1999 cyanoHAB guidance values (GVs) to be more practical by basing the GVs on chl-a concentration. This creates an opportunity for widespread monitoring of cyanoHABs based on chl-a proxy measures, with satellite remote sensing (SRS) being a potentially powerful tool. This study assessed the comparability of SRS of chl-a for cyanotoxin public health advisories. We used Sentinel-2 and 3 to map chl-a and cyanobacteria, respectively, and classified the values according to WHO GVs. We then compared them to the existing GVs set by the California Department of Water Resources (DWR) at San Luis Reservoir, the largest off-stream reservoir in the United States, and a key piece of infrastructure in California’s water system. We found mismatches between the SRS-derived WHO 2021 chl-a GV and DWR GVs. However, SRS-based chl-a GVs never missed a bloom detected by DWR, and warning levels were typically no more than one level off. SRS can help fill temporal data gaps and provide greater spatial information not available from using in-situ measurements only. Thus, using SRS-based chl-a GVs as an early indicator for possible exposure advisories and as a trigger for in situ sampling may be an effective approach to improving public health warnings.
Poster: Poster_Lopez_Barreto_2-42_5_35.pdf
Associated Project(s):
Poster Location ID: 2-42
Presentation Type: Poster
Session: Poster Session 2
Session Date: Wed (May 10) 5:15-7:15 PM
CCE Program: OBB