Nitrogen (N) input to marine ecosystems has increased significantly over the past century due to human activities, resulting in an array of serious environmental impacts. The primary N removal mechanism in these systems is production of dinitrogen gas (N2) via the microbially-mediated processes of denitrification and anammox. These two processes occur predominantly in marine sediments, particularly along the continental shelf. Over recent decades multiple methods have been developed to directly measure N2 production in surface sediments. These include (1) whole-core incubations that quantify net N2 fluxes, (2) whole-core incubations that use the isotope pairing technique (IPT), in which 15N tracer is added as 15NO3- and followed into N2 to quantify denitrification (3) and into N2O to distinguish anammox from denitrification, (4) and slurry approaches that add 15NO3- and/or 15NH4+ and follow into N2 to quantify potential denitrification and anammox rates. In this presentation we compare all four approaches, which were used concurrently to measure seasonal N2 fluxes at estuarine and continental shelf sites along the southern New England coast, making it, to our knowledge, the first comparison of its kind.


Hardison, A. K., University of Texas Marine Science Institute, USA, amber.hardison@utexas.edu

Brin, L., Agriculture and Agri-Food Canada, Canada, lindsay.brin@gmail.com

Heiss, E. M., Boston University, USA, emheiss@bu.edu

Fulweiler, R. W., Boston University, USA, rwf@bu.edu

Rich, J. J., Brown University, USA, jeremy_rich@brown.edu

Giblin, A., Marine Biological Laboratory, USA, agiblin@mbl.edu


Oral presentation

Session #:060
Date: 5/23/2014
Time: 10:45
Location: B 110 - 112

Presentation is given by student: No