Funding Agencies:

Core Research Funding Program, Northern Gulf Institute (NGI)

Partners:

NOS/NCCOS/CCFHR - Center for Coastal Fisheries and Habitat Research (CCFHR), NOAA

Project Description:

The Gulf of Mexico Alliance's (GOMA) Action Plan II includes Water Quality as a critical area of concern. Within this area, "Mercury and Other Contaminants" is one of four priority topics, detailed in section WQ-3 . Our proposed work specifically targets section WQ 3.1: Identify Sources of Mercury in Gulf of Mexico Seafood. The proposed research would address the following Action Steps: WQ3.1.2, Quantify the major input pathways for mercury to the Gulf of Mexico, WQ3.1.3, Determine where mercury methylation occurs and what processes govern its occurrence, and WQ 3.1.4 Determine how and where methylmercury enters into the food webs and bioaccumulates in fish (collaboration with Nutrients PIT).

Two previous NGI projects dealt with sediment and mercury in the Mobile Bay area. Mobile Bay Sediment Modeling tested existing transport models and created a suite of models for sediment and related contaminants, such as mercury. Mercury Bioaccumulation in Mobile Bay provided initial information on mercury inputs, cycling, and bioaccumulation in fish useful both for specific concerns in Mobile Bay and as a model approach used in the larger gulf-wide program. This project will build on those two efforts and extend them into new areas of the coastal Gulf of Mexico.

Sediments are the main repository of mercury in the coastal Gulf of Mexico as well as the site of transformation of inorganic mercury to methylmercury, the more toxic form that is bioaccumulated through food webs. Resuspended sediments are a major transport vector for total mercury and methylmercury. The redistribution of mercury-containing sediments is a critical determinant of where in the coastal environment mercury will become a problem. Sediment characteristics such as texture and organic matter content help determine the extent to which inorganic mercury is transformed to methylmercury. Our proposed work finds common cause with GOMA's Nutrient Impacts Action Plan because algal production that results from eutrophication is a source of sediment-deposited organic matter and consequent hypoxia, both of which can stimulate mercury methylation. Nutrient inputs and their control are likely drivers leading to mercury bioaccumulation. Another area of extension will include the measurement of sulfide in sediments to determine potential inhibition of mercury uptake by methylating bacteria and hence methylmercury production.

Our ultimate goal is to provide a suite of methods to predict the path and fate of sediment and mercury in the Gulf coastal region from entry point to fish stocks.

Project Goals:

The specific objectives of this project are to:

(1) Improve sediment and mercury modeling capabilities
(2) Determine potential sulfide accumulation effects on methylmercury production
(3) Establish a method to predict mercury bioaccumulation in fish
(4) Extend the new technologies to other areas of the Gulf of Mexico.

Project Deliverables:

1) Database of sediment and mercury data, with metadata

2) Report and 2 journal papers on improved sediment path and fate modeling.

3) Report and 2 journal papers on mercury path and fate modeling

4) Report and 1 journal paper on methylmercury bioaccumulation modeling

5) Suite of models for use in predicting sediment and mercury path and fate

6) New content for Water Resources Management Course

7) Plain Language material for outreach and education

8) Two annual progress reports

9) Final summary report