Denitrification and Nitrogen Fixation in Alaskan Continental Shelf Sediments

• Published in: Applied and Environmental Microbiology
• Main Authors: Haines, John R., Atlas, Ronald M., Griffiths, Robert P., Morita, Richard Y.
• Format: Article in Journal/Newspaper
• Language: English
• Published: American Society for Microbiology 1981
• Subjects: Ecology; Applied Microbiology and Biotechnology; Food Science; Biotechnology; Bering Sea
• Online Access: http://dx.doi.org/10.1128/aem.41.2.412-421.1981; https://journals.asm.org/doi/pdf/10.1128/aem.41.2.412-421.1981

Rates of nitrogen fixation and denitrification were measured in Alaskan continental shelf sediments. In some regions, rates of nitrogen fixation and denitrification appeared to be equal; in other areas, rates were significantly different. Potential rates of denitrification were found to be limited primarily by the available nitrate substrate. Major regional differences in rates of denitrification were not statistically significant, but significant differences were found for nitrogen fixation rates in different regions of the Alaskan continental shelf. Estimated net losses of nitrogen from Bering Sea sediments were calculated as 1.8 × 10 12 g of N/yr. Experimental exposure of continental shelf sediments to petroleum hydrocarbons reduced rates of nitrogen fixation and denitrification in some cases but not others. Long-term exposure was necessary before a reduction in nitrogen fixation rates was observed; unamended rates of denitrification but not potential denitrification rates (NO 3 − added) were depressed after exposure to hydrocarbons.