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
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Church, M. J.
Right arrow Articles by Karl, D. M.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Church, M. J.
Right arrow Articles by Karl, D. M.
Agricola
Right arrow Articles by Church, M. J.
Right arrow Articles by Karl, D. M.

 Previous Article  |  Next Article 

Applied and Environmental Microbiology, July 2004, p. 4079-4087, Vol. 70, No. 7
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.7.4079-4087.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.

Light Dependence of [3H]Leucine Incorporation in the Oligotrophic North Pacific Ocean{dagger}

Matthew J. Church,1* Hugh W. Ducklow,1 and David M. Karl2

School of Marine Science, The College of William and Mary, Gloucester Point, Virginia 23062,1 School of Ocean and Earth Science and Technology, University of Hawaii, Honolulu, Hawaii 968222

Received 26 November 2003/ Accepted 11 March 2004

The influence of irradiance on bacterial incorporation of [3H]leucine was evaluated at Station ALOHA in the oligotrophic North Pacific subtropical gyre. Six experiments were conducted on three cruises to Station ALOHA to examine how [3H]leucine incorporation varied as a function of irradiance. Two experiments were also conducted to assess the photoautotrophic response to irradiance (based on photosynthetic uptake of [14C]bicarbonate) in both the upper and lower photic zones. Rates of [3H]leucine incorporation responded to irradiance in a photosynthesis-like manner, increasing sharply at low light and then saturating and sometimes declining with increasing light intensity. The influence of irradiance on bacterial growth was evaluated in both the well-lit (5 to 25 m) and dimly lit regions of the upper ocean (75 to 100 m) to determine whether the bacterial response to irradiance differed along the depth-dependent light gradient of the photic zone. [3H]leucine incorporation rates were analyzed with a photosynthesis-irradiance model for a quantitative description of the relationships between [3H]leucine incorporation and irradiance. Maximum rates of [3H]leucine incorporation in the upper photic zone increased 48 to 92% relative to those of dark-incubated samples, with [3H]leucine incorporation saturating at light intensities between 58 and 363 µmol of quanta m–2 s–1. Rates of [3H]leucine incorporation in the deep photic zone were photostimulated 53 to 114% and were susceptible to photoinhibition, with rates declining at light intensities of >100 µmol of quanta m–2 s–1. The results of these experiments revealed that sunlight directly influences bacterial growth in this open-ocean ecosystem.

* Corresponding author. Present address: Department of Ocean Sciences, University of California Santa Cruz, Santa Cruz, CA 95064. Phone: (831) 459-5846. Fax: (831) 464-4882. E-mail: mchurch{at}es.ucsc.edu.

{dagger} This is School of Ocean and Earth Science (SOEST) contribution 6399 and Joint Global Ocean Flux Study (JGOFS) contribution 1045.

Applied and Environmental Microbiology, July 2004, p. 4079-4087, Vol. 70, No. 7
0099-2240/04/$08.00+0     DOI: 10.1128/AEM.70.7.4079-4087.2004
Copyright © 2004, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Cottrell, M. T., Kirchman, D. L. (2009). Photoheterotrophic Microbes in the Arctic Ocean in Summer and Winter. Appl. Environ. Microbiol. 75: 4958-4966 [Abstract] [Full Text]  
  • Scanlan, D. J., Ostrowski, M., Mazard, S., Dufresne, A., Garczarek, L., Hess, W. R., Post, A. F., Hagemann, M., Paulsen, I., Partensky, F. (2009). Ecological Genomics of Marine Picocyanobacteria. Microbiol. Mol. Biol. Rev. 73: 249-299 [Abstract] [Full Text]  
  • Michelou, V. K., Cottrell, M. T., Kirchman, D. L. (2007). Light-Stimulated Bacterial Production and Amino Acid Assimilation by Cyanobacteria and Other Microbes in the North Atlantic Ocean. Appl. Environ. Microbiol. 73: 5539-5546 [Abstract] [Full Text]  
  • Cottrell, M. T., Mannino, A., Kirchman, D. L. (2006). Aerobic Anoxygenic Phototrophic Bacteria in the Mid-Atlantic Bight and the North Pacific Gyre. Appl. Environ. Microbiol. 72: 557-564 [Abstract] [Full Text]  


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