Example of the California land-sea interface: Upland reservoir ➝ river ➝ estuary ➝ Pacific Ocean. Credit M. Howard, SCCWRP

Research sponsored by NCCOS finds harmful cyanobacteria (aka blue-green algae) and their co-occurring cyanotoxins detectable and persistent in California watersheds from rivers to the Pacific Ocean.

Recent reports of toxic events have brought a growing awareness of cyanobacteria and cyanotoxins at the land-sea interface. A recent survey in southern California documented a wealth of cyanobacteria-dominated communities and multiple cyanotoxins at a variety of locations (see Howard et al. 2017). To gain further insight into these assemblages, a new NCCOS-sponsored study repeatedly sampled several sites with different proximity and degrees of connectivity to the Pacific Ocean in four coastal watersheds along the coast of southern California.

For the study, easy-to-use Solid Phase Adsorption Toxin Tracking (SPATT) samplers were deployed to detect toxins. Credit M. Howard, SCCWRP.

The findings revealed temporal and spatial variability in potential toxin-producing cyanobacteria and toxins. Using a variety of samples (i.e., water, benthos, oysters, Solid Phase Adsorption Toxin Tracking [SPATT]) and analysis methods (i.e., high performance liquid chromatography [HPLC], liquid chromatography–mass spectrometry [LC-MS], enzyme-linked immunosorbent assay [ELISA]), multiple cyanotoxins were measured (e.g., anatoxin-a, cylindrospermopsin, microcystins) in 45 percent of all samples and 25 percent of shellfish examined. Potential toxin-producing cyanobacteria were prevalent at all study sites and appeared to persist throughout the year in some locations.

This study shows how watersheds and inland freshwater waterways are hydrologically connected to the Pacific Ocean and can provide a source of cyanotoxins to California marine and brackish estuarine environments. The findings indicate a need for implementation of coordinated monitoring programs across the land-sea interface.

This research was supported in part by the NCCOS sponsored project MERHAB 2015: Improving Tools for Monitoring Multiple HAB Toxins at the Land-Sea Interface in Coastal California (HAB-SICC) led by Dr. Meredith Howard of the Southern California Coastal Water Research Project (SCCWRP).

Citation: Tatters, Avery O., Meredith D. A. Howard, Carey Nagoda, A. Elizabeth Fetscher, Raphael M. Kudela, and David A. Caron. 2019. Heterogeneity of Toxin-Producing Cyanobacteria and Cyanotoxins in Coastal Watersheds of Southern California. Estuaries and Coasts. https://doi.org/10.1007/s12237-019-00546-w

For more information, contact Marc Suddleson.