This Sources Sought Notice is for market research to identify potential sources, including small businesses (Small Business, 8(a), HUBZone, SDVOSB, WOSB, EDWOSB), capable of cyanotoxin analysis for USGS. The work involves analyzing 70 Solid Phase Adsorption Toxin Tracking (SPATT) samples for microcystin, anatoxin, cylindrospermopsin, and saxitoxin congeners using LC/MS/MS and approved cyanotoxin standards with QA/QC. USGS staff will deploy and collect SPATT samplers from Maurepas Swamp in Louisiana, keep them frozen, and ship them to the laboratory for extraction and analysis; results and ScienceBase-ready data with QA/QC metadata must be delivered to USGS. The period of performance is one base year with four option years, and the work relates to baseline pre-diversion conditions for harmful algal blooms before the planned 2027 Mississippi River water diversion into Maurepas. The applicable NAICS code is 541380, Testing Laboratories, with a $19 million size standard.