Organic matter mineralization and sulfate reduction Dr. Samantha B. Joye University of Georgia

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

mjoye@uga.edu http://www.marsci.uga.edu/directory/samantha-b-joye Georgia Coastal Ecosystems LTER Project

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

gcelter@uga.edu https://gce-lter.marsci.uga.edu/ Dr. Samantha B. Joye University of Georgia

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

mjoye@uga.edu http://www.marsci.uga.edu/directory/samantha-b-joye Principal investigator 2003-01-01 2005-12-31 Dr. Nathaniel B. Weston University of Georgia

Dept. of Marine Sciences University of Georgia Athens Georgia 30602-3636 USA

nweston@uga.edu Graduate research assistant 2026

N. Weston (Ph.D. student, UGA) and S. Joye (UGA) conducted a multi-site, multi-season survey of estuarine porewater profiles in Georgia and South Carolina. The survey demonstrated system-scale correlations between the inorganic products of terminal metabolism (dissolved inorganic carbon, ammonium and phosphate) and sulfate depletion. DOC, as the substrate for terminal metabolism, was not correlated with other variables, indicating that production and consumption of DOC were tightly coupled and bulk DOC is largely a recalcitrant pool. Controls on the coupling between the hydrolytic/fermentative and terminal metabolic bacterial communities in estuarine sediments were further investigated using anaerobic flow-through bioreactors. They documented the temperature-driven decoupling of the production and consumption of key DOC intermediates due to variable temperature responses of these functional microbial groups. Production of labile DOC exceeded terminal oxidation at colder temperatures, resulting in accumulation of labile DOC. At higher temperatures, potential terminal oxidation rates exceeded those of labile DOC production and labile DOC availability limited rates of terminal oxidation.

Question 2: How do the spatial and temporal patterns of biogeochemical processes, primary production, community dynamics, decomposition, and disturbance vary across the estuarine landscape, and how do they relate to environmental gradients? (more information)

LTER NSF Georgia South Carolina GCE bioreactors DOC metabolism porewater Overall geographic extent of the research project -81.295506 -81.258908 31.497026 31.462320 2003-01-01 2005-12-31

National Science Foundation grant number OCE-9982133. Additional funding from 2002-2004 provided by the Georgia Sea Grant: 'Groundwater-derived nitrogen and phosphorus inputs to the Satilla River estuary: impacts on coastal ecosystem health'

estuary marsh complex Hunt Camp - Barrier island/marsh site on western Sapelo Island. This site is located at the upper reaches of the Duplin River, and is within the Sapelo Island National Estuarine Research Reserve. Existing well fields border small marsh area to northwest, some wells have been installed to south end of hammock where marsh is more extensive and permanent plots are located. Two existing hydrographic sondes and weather stations within this site are operated by SINERR (Hunt Camp dock) and UGAMI (flume dock). -81.295506 -81.258908 31.497026 31.462320 Weston, N.B. and Joye, S.B. 2005. Temperature-driven decoupling of key phases of organic matter degradation in marine sediments. Proceedings of the National Academy of Sciences (USA). 102(47):17036-17040. http://www.pnas.org/cgi/content/full/102/47/17036?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=weston+%2B+joye&searchid=1136415104224_10182&FIRSTINDEX=0&journalcode=pnas Weston, N.B. and Joye, S.B. 2004. Presentation: Seasonal patterns of coupling between hydrolytic/fermentative and terminal metabolic microbial communities in an estuarine sediment. ASLO Aquatic Sciences Meeting. American Society of Limnology and Oceanography, 2004, Salt Lake City, Utah. POR-GCED-0210 - Porewater nutrients, dissolved organics, redox species, and gasses in estuarine intertidal sediments at sites on Sapelo Island and near the Satilla River from Fall 2000 through Fall 2002 https://gce-lter.marsci.uga.edu/public/app/dataset_details.asp?id=22