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Research article - Peer-reviewed, 2012

Terrestrial organic matter support of lake food webs: Evidence from lake metabolism and stable hydrogen isotopes of consumers

Karlsson, Jan; Berggren, Martin; Ask, Jenny; Byström, Pär; Jonsson, Anders; Laudon, Hjalmar; Jansson, Mats


We quantified the utilization of terrestrial organic matter (OM) in the food web of a humic lake by analyzing the metabolism and the consumers' stable isotopic (C, H, N) composition in benthic and pelagic habitats. Terrestrial OM inputs (3 g C m(-2) d(-1)) to the lake greatly exceeded autochthonous OM production (3 mg C m(-2) d(-1)) in the lake. Heterotrophic bacterial growth (19 mg C m(-2) d(-1)) and community respiration (115 mg C m(-2) d(-1)) were high relative to algal photosynthesis and were predominantly (> 85%) supported by terrestrial OM in both habitats. Consequently, terrestrial OM fueled most (85%) of the total production at the base of the lake's food web (i.e., the sum of primary and bacterial production). Despite the uncertainties of quantitatively estimating resource use based on stable isotopes, terrestrial OM clearly also supported around half the zooplankton (47%), macrozoobenthos (63%), and fish (57%) biomass. These results indicate that, although rates of terrestrial OM inputs were around three orders of magnitude greater than that of autochthonous OM production, the use of the two resources by higher trophic levels was roughly equal. The disproportionally low reliance on terrestrial OM at higher trophic levels, compared with its high rates of input and high support of basic biomass production in the lake, suggests that autochthonous resources could not be completely replaced by terrestrial resources and indicates an upper limit to terrestrial support of lake food webs.

Published in

Limnology and Oceanography
2012, volume: 57, number: 4, pages: 1042-1048

Authors' information

Karlsson, Jan
Berggren, Martin
Ask, Jenny
Umeå University
Byström, Pär
Umeå University
Jonsson, Anders
Swedish University of Agricultural Sciences, Department of Forest Ecology and Management
Jansson, Mats

Sustainable Development Goals

SDG14 Life below water

UKÄ Subject classification

Forest Science

Publication Identifiers


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