Permeable Sediments

Characterization of Microbial Communities that Catalyze Carbon and Nitrogen Cycling in Permeable Shelf Sediments

The shorline of the Gulf Coast, showing the sandy sediments that are the focus of this research
Drs. Kostka and Huettel sampling sandy sediments at a research site on St. George Island in Florida.

In a project sponsored by the National Science Foundation, the Kostka laboratory is investigating the concept that coastal marine sands act as giant filters, filtering out dead plant or animal bodies, and releasing inorganic nutrients to be used as food for plants. Our research closely couples chemistry and microbiology to determine what controls nutrient release from the sandy seafloor at two contrasting sites near St. George Island, Florida. One site represents conditions found in Apalachicola Bay, while the other is more typical of conditions found in the northeastern Gulf of Mexico.

We have determined how fast organic matter is processed by microbial activities in the giant filter using radiotracers, stable isotope tracers, and flux chambers. Using the latest genetic methods, we have documented “who’s there” or which microbe groups are present to degrade organic matter in the sands. By combining our estimates of microbial activity along with genetic identification of microbe groups, we will find out how the giant filter works in the Bay vs. the Gulf.

From the Kostka Lab:



T. M. Gihring, A. Canion, A. Riggs, M. Huettel, and J. E. Kostka. 2009. Denitrification in shallow, sublittoral Gulf of Mexico permeable sediments. Limnology and Oceanography (in review).

L. Chipman, D. Podgorski, S.J. Green, J.E. Kostka, W. Cooper, and M. Huettel. 2009. Decomposition of plankton-derived DOM in permeable coastal sediments. Limnology and Oceanography (in review).

T.M. Gihring, M. Humphrys, H.J. Mills, M. Huettel, J.E. Kostka. 2009. Identification of phytodetritus-degrading microbial communities in sublittoral Gulf of Mexico sands. Limnol. Oceanogr., 54: 1073–1083.

H. J. Mills, E. Hunter, M. Humphrys, L. Kerkhof, L. McGuinness, M. Huettel, and J. E. Kostka. 2008. Characterization of Nitrifying, Denitrifying, and Overall Bacterial Community Structure in Permeable Marine Sediments of the Northeastern Gulf of Mexico. Applied and Environmental Microbiology 74: 4440-4453.

E.M. Hunter, H.J. Mills, and J.E. Kostka. 2006. Microbial community diversity associated with carbon and nitrogen cycling in permeable shelf sediments. Applied and Environmental Microbiology 72: 5689-5701.