Abstract

Water-column methane oxidation can represent a substantial carbon transformation pathway in lakes, and circumstantial evidence indicates that methane may be a potentially important source of carbon for pelagic food webs. We estimated methanotrophic bacterial production (MBP), methanotrophic bacterial growth efficiency (MBGE), heterotrophic bacterial production (HBP), primary production (PP), and the relative contribution of methanotrophic bacteria to overall bacterial biomass in three very different lakes during summer and winter. In addition, we measured stable carbon isotope ratios in particulate organic matter (POM), surface sediments, zooplankton, and methane. MBP corresponded to 0.3-7% of the organic C production by primary producers, and 0.5-17% of HBP during summer. During winter, MBP was 3-120% of HBR MBP generally dominated the heterotrophic bacterial production at greater depths. Methanotrophic biomass was 3-11% of total bacterial biomass on a depth-integrated basis. Zooplankton were generally more depleted in C-13 than POM. If phytoplankton delta(13)C signatures were -35 to -30parts per thousand, such as the POM signals, observed zooplankton signatures could be explained by a fraction of 5-15% methanotrophic bacteria in their diet. The results indicate that methanotrophic bacteria can provide a significant food source for zooplankton, and that methane oxidation represents a potentially important benthic-pelagic carbon and energy link in many lakes, particularly during winter

Keywords

aquatic food webs; bacterial growth efficiency; carbon cycling; methane; as source of C and energy in lake food webs; methane oxidation; methanotrophic bacteria; stable isotopes;

Published in

Ecology
2003, Volume: 84, number: 4, pages: 969-981
Publisher: ECOLOGICAL SOC AMER

SLU Authors

• Sundh, Ingvar

  • Department of Molecular Sciences, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Environmental Sciences related to Agriculture and Land-use
Fish and Aquacultural Science


Publication identifier

DOI: https://doi.org/10.1890/0012-9658(2003)084[0969:MAASOC]2.0.CO;2

Permanent link to this page (URI)

https://res.slu.se/id/publ/1308