Spatiotemporal distribution of phycotoxins and their co-occurrence within nearshore waters

Harmful algal blooms (HABs), varying in intensity and causative species, have historically occurred throughout the Chesapeake Bay, U.S.; however, phycotoxin data are sparse. The spatiotemporal distribution of phycotoxins was investigated using solid-phase adsorption toxin tracking (SPATT) across 12 shallow, nearshore sites within lower Bay Virginia's coastal bays over one year (2017-2018). Eight toxins, azaspiracid-1 (AZA1), azaspiracid-2 (AZA2), microcystin-LR (MC-LR), domoic acid (DA), okadaic (OA), dinophysistoxin-1 (DTX1), pectenotoxin-2 (PTX2), goniodomin A (GDA) were detected SPATT extracts. Temporally, always present region, with at least group (i.e., consisting OA DTX1) every time point. Co-occurrence also common; two or more groups observed 76% samples analyzed. Toxin maximums: 0.03 ng AZA2/g resin/day, 0.25 DA/g 15 DTX1/g 61 OA/g 72 PTX2/g 102,050 GDA/g resin/day seasonal, peaks occurring summer fall. Spatially, southern tributary bay regions harbored highest amount total on year, former contained greatest diversity phycotoxins. novel detection AZAs before a species has been identified, supports use as an explorative tool respect to emerging threats. lack karlotoxin extracts, but Karlodinium veneficum by microscopy, emphasizes that this should be considered complementary to, not replacement for, traditional HAB management monitoring methods.