Cooperative Agreement for CESU-affiliated Partner with USGS- Californian Cooperative Ecosystem Studies Unit | G23AS00376

Opportunity Information: Apply for G23AS00376

The U.S. Geological Survey (USGS) is soliciting proposals under a Cooperative Agreement to support research by an eligible partner within the Californian Cooperative Ecosystem Studies Unit (CESU) network. This opportunity is focused on improving how mercury risk is predicted in managed freshwater ecosystems by building a revised, more useful framework that combines biogeochemistry, microbiology, and the influence of other stressors occurring at the same time. The overall problem the USGS is trying to address is that mercury biomagnification through aquatic food webs remains common in several freshwater settings, and mercury-driven water quality concerns continue to complicate management and restoration. The agency is looking for work that helps explain why methylmercury forms, when it forms, and how changing conditions affect that formation, since methylmercury is the key transformation that drives exposure and risk to fish, wildlife, and people.

The research emphasis is clearly targeted to three types of freshwater environments where mercury issues are persistent and management decisions are ongoing. First, the USGS highlights data synthesis and interpretation for arid-land reservoirs, signaling a need to pull together existing datasets, reconcile findings across studies, and extract more generalizable insights relevant to reservoir operations and conditions typical of arid landscapes. Second, the opportunity calls for field measurements paired with synthesis and interpretation in subtropical wetlands, where hydrology, organic matter dynamics, microbial activity, and seasonal cycles can strongly influence methylmercury production and movement through food webs. Third, the opportunity includes mine-impacted lakes, where historical or active mining can elevate mercury and related contaminants, complicating both the chemistry and biological uptake pathways. Across all three settings, the expected end goal is not just site-specific results, but a more robust predictive framework that resource managers can rely on when making decisions.

A central theme of the notice is identifying and separating the roles of internal versus external drivers that control the biogeochemical processes leading to methylmercury formation. Internal drivers include factors like water management actions (for example, water-level regulation, flow timing, reservoir drawdown schedules, and wetland inundation patterns) and co-occurring stressors (such as nutrient loading, salinity changes, dissolved organic carbon, temperature shifts, oxygen conditions, or other contaminants). External drivers include broader climate-related influences that can alter hydrology, temperature regimes, wildfire impacts, and the frequency of extreme events, all of which can change microbial activity and mercury cycling. The USGS frames this as a practical challenge shared by scientists and resource managers: without a better understanding of how these drivers interact, it is difficult to predict when and where methylmercury risk will increase, or which management levers can realistically reduce exposure.

This funding is offered as a discretionary financial assistance award using the Cooperative Agreement instrument, which typically indicates that substantial involvement by the USGS is expected during the project (for example, collaboration on study design, data integration, interpretation, or dissemination). The activity category is Science and Technology and other Research and Development, and the opportunity is listed under CFDA 15.808. Eligibility is limited to participants in the Californian CESU Program, meaning applicants must already be recognized CESU partners to apply. CESUs are partnership-based structures intended to deliver research, technical assistance, and education tied to federal land and resource management needs, and this award is being issued specifically through that program.

Key administrative details from the posting include the Funding Opportunity Title "Cooperative Agreement for CESU-affiliated Partner with USGS- Californian Cooperative Ecosystem Studies Unit," Funding Opportunity Number G23AS00376, and the issuing agency identified as the Geological Survey (USGS). The opportunity lists an award ceiling of $13,500,000, with the original closing date of 2023-06-19 and a creation date of 2023-05-17.

• The Geological Survey in the science and technology and other research and development sector is offering a public funding opportunity titled "Cooperative Agreement for CESU-affiliated Partner with USGS- Californian Cooperative Ecosystem Studies Unit" and is now available to receive applicants.
• Interested and eligible applicants and submit their applications by referencing the CFDA number(s): 15.808.
• This funding opportunity was created on 2023-05-17.
• Applicants must submit their applications by 2023-06-19. (Agency may still review applications by suitable applicants for the remaining/unused allocated funding in 2026.)
• Each selected applicant is eligible to receive up to $13,500,000.00 in funding.
• Eligible applicants include: Others.

Apply for G23AS00376

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