Terrestrial support of lake food webs:synthesis reveals controls over cross-ecosystem resource use

Tanentzap, Andrew J. and Kielstra, Brian W. and Wilkinson, Grace M. and Berggren, Martin and Craig, Nicola and del Giorgio, Paul A. and Grey, Jonathan and Gunn, John M. and Jones, Stuart E. and Karlsson, Jan and Solomon, Christopher T. and Pace, Michael L. (2017) Terrestrial support of lake food webs:synthesis reveals controls over cross-ecosystem resource use. Science Advances, 3 (3).

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Abstract

Widespread evidence that organic matter exported from terrestrial into aquatic ecosystems supports recipient food webs remains controversial. A pressing question is not only whether high terrestrial support is possible but also what the general conditions are under which it arises. We assemble the largest data set, to date, of the isotopic composition (δ2H, δ13C, and δ15N) of lake zooplankton and the resources at the base of their associated food webs. In total, our data set spans 559 observations across 147 lakes from the boreal to subtropics. By predicting terrestrial resource support from within-lake and catchment-level characteristics, we found that half of all consumer observations that is, the median were composed of at least 42% terrestrially derived material. In general, terrestrial support of zooplankton was greatest in lakes with large physical and hydrological connections to catchments that were rich in aboveground and belowground organic matter. However, some consumers responded less strongly to terrestrial resources where within-lake production was elevated. Our study shows that multiple mechanisms drive widespread cross-ecosystem support of aquatic consumers across Northern Hemisphere lakes and suggests that changes in terrestrial landscapes will influence ecosystem processes well beyond their boundaries.

Item Type:
Journal Article
Journal or Publication Title:
Science Advances
Subjects:
ID Code:
85859
Deposited By:
Deposited On:
06 Apr 2017 12:22
Refereed?:
Yes
Published?:
Published
Last Modified:
30 Sep 2020 06:50