Abstract
Trichodesmium sp. is a filamentous, colonial cyanobacterium which contributes substantially to the input of nitrogen in tropical and subtropical oceanic waters through nitrogen fixation (N2 fixation). We applied a 15N tracer technique to assess the rate of release of dissolved organic nitrogen (DON) from this cyanobacterium and compared those rates with rates of N2 fixation determined for the same assemblages at the same times of day. Rates of release of DON showed considerable variation within replicate experiments and were variable depending on time of day and duration of time course experiments. On average, rates of DON release were ca. 50% the rates of N2 fixation. We also fractionated the DON released by using ultrafiltration and found that 60 to 80% of the total organic release was of the size class <10,000 Da. The release of these organic compounds by Trichodesmium spp. is likely a significant source of new nitrogen for the associated bacteria or the non-nitrogen-fixing filaments of the Trichodesmium colonies.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Capone D. G., Ferrier M. D., Carpenter E. J. Amino Acid Cycling in Colonies of the Planktonic Marine Cyanobacterium Trichodesmium thiebautii. Appl Environ Microbiol. 1994 Nov;60(11):3989–3995. doi: 10.1128/aem.60.11.3989-3995.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Capone D. G., O'neil J. M., Zehr J., Carpenter E. J. Basis for Diel Variation in Nitrogenase Activity in the Marine Planktonic Cyanobacterium Trichodesmium thiebautii. Appl Environ Microbiol. 1990 Nov;56(11):3532–3536. doi: 10.1128/aem.56.11.3532-3536.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]