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Andrew D. SteenAndrew D. Steen

Assistant Professor
Environmental Geology

Department of Earth and Planetary Sciences
1412 Circle Drive
Knoxville, TN 37996-1410

Phone: (865) 456-0851

Typical seawater contains tens of thousands of individual organic molecules, most of which are at picomolar concentrations or less, and thousands of distinct microbial species, most of which are rare. Yet those microorganisms metabolize something like 99% of the organic carbon that enters the oceans.

How does that work?

Research Areas:

  1. Kinetics of aquatic extracellular enzymes
  2. Functional variation among heterotrophic microbial communities
  3. Novel methods for marine organic geochemistry

For more information about Andrew Steen's research, visit his website at

  • Steen, A.D., B. B. Jurgensen and B. Aa. Lomstein. (2013). Abiotic racemization kinetics of amino acids in marine sediments. PLOS ONE 8(8): e71648. doi:10.1371/journal.pone.0071648.
  • Lloyd, K.G., L. Schreiber, D.G. Petersen, K. U. Kjeldsen, M.A. Lever, A.D. Steen, R. Stepanauskas, M. Richter, S. Kleindienst, S. Lenk, A. Schramm, and B. B. Jurgensen (2013). Predominant archaea in marine sediments degrade detrital proteins. Nature 496: 215-218.
  • Steen, A.D., and C. Arnosti (2013). Extracellular peptidase and carbohydrate hydrolase activities in an Arctic fjord (Smeerenburgfjord, Svalbard). Aquatic Microbial Ecology (in press).
  • Steen, A.D., K. Ziervogel, S. Ghobrial, and C. Arnosti (2012). Functional variation among polysaccharide-hydrolyzing microbial communities in the Gulf of Mexico. Marine Chemistry 138-139: 13-20.
  • Steen, A.D. and K. Ziervogel (2012). Comment on the review by German et al (2011) Optimization of hydrolytic and oxidative enzyme methods for ecosystem studies [Soil Biology & Biochemistry 43: 1387-1397]. Soil Biology & Biochemistry 48: 196-197.
  • Arnosti, C., A.D. Steen, K. Ziervogel, S. Ghobrial, and W.H. Jeffrey (2011). Latitudinal gradients in degradation of marine dissolved organic carbon. PLoS One 6(12): e28900. doi:10.1371/journal.pone.0028900
  • Steen, A.D., and C. Arnosti (2011). Long lifetimes of �-glucosidase, leucine aminopeptidase, and phosphatase in Arctic seawater. Marine Chemistry 123(1-4) 127-132.
  • Steen, A.D, K. Ziervogel, and C. Arnosti (2010). Comparison of multivariate microbial datasets with the Shannon index: An example using enzyme activity from diverse marine environments. Organic Geochemistry 41(9) 1019-1021

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