This Article
Right arrow Full Text
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Google Scholar
Right arrow Articles by Cottrell, M. T.
Right arrow Articles by Kirchman, D. L.
PubMed
Right arrow PubMed Citation
Right arrow Articles by Cottrell, M. T.
Right arrow Articles by Kirchman, D. L.
Agricola
Right arrow Articles by Cottrell, M. T.
Right arrow Articles by Kirchman, D. L.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, August 2009, p. 4958-4966, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00117-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.

Photoheterotrophic Microbes in the Arctic Ocean in Summer and Winter{triangledown}

Matthew T. Cottrell and David L. Kirchman*

University of Delaware, College of Earth, Ocean, and Environment, 700 Pilottown Road, Lewes, Delaware 19958

Received 17 January 2009/ Accepted 1 June 2009

Photoheterotrophic microbes, which are capable of utilizing dissolved organic materials and harvesting light energy, include coccoid cyanobacteria (Synechococcus and Prochlorococcus), aerobic anoxygenic phototrophic (AAP) bacteria, and proteorhodopsin (PR)-containing bacteria. Our knowledge of photoheterotrophic microbes is largely incomplete, especially for high-latitude waters such as the Arctic Ocean, where photoheterotrophs may have special ecological relationships and distinct biogeochemical impacts due to extremes in day length and seasonal ice cover. These microbes were examined by epifluorescence microscopy, flow cytometry, and quantitative PCR (QPCR) assays for PR and a gene diagnostic of AAP bacteria (pufM). The abundance of AAP bacteria and PR-containing bacteria decreased from summer to winter, in parallel with a threefold decrease in the total prokaryotic community. In contrast, the abundance of Synechococcus organisms did not decrease in winter, suggesting that their growth was supported by organic substrates. Results from QPCR assays revealed no substantial shifts in the community structure of AAP bacteria and PR-containing bacteria. However, Arctic PR genes were different from those found at lower latitudes, and surprisingly, they were not similar to those in Antarctic coastal waters. Photoheterotrophic microbes appear to compete successfully with strict heterotrophs during winter darkness below the ice, but AAP bacteria and PR-containing bacteria do not behave as superior competitors during the summer.

* Corresponding author. Mailing address: University of Delaware, College of Earth, Ocean, and Environment, 700 Pilottown Rd., Lewes, DE 19958. Phone: (302) 645-4375. Fax: (302) 645-4007. E-mail: kirchman{at}udel.edu

{triangledown} Published ahead of print on 5 June 2009.

Applied and Environmental Microbiology, August 2009, p. 4958-4966, Vol. 75, No. 15
0099-2240/09/$08.00+0     doi:10.1128/AEM.00117-09
Copyright © 2009, American Society for Microbiology. All Rights Reserved.





Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»