The U.S. Geological Survey (USGS) is seeking qualified laboratories to conduct surface water particulate analysis in Suisun Bay, California, as part of a Sources Sought Notice. The objective is to identify capable sources, including small businesses, for analytical testing of water samples to assess the impact of salinity stratification on phytoplankton and other particulate constituents. The selected contractors will analyze a total of 124 samples for various parameters, including Particulate Inorganic Carbon, Particulate Organic Carbon, and Chlorophyll a, while adhering to specified EPA methods and providing necessary documentation. Interested laboratories must submit a capability statement to Joel Berberena at jberberena@usgs.gov by the deadline, with the performance period running from January 26, 2026, to January 25, 2027.