TY - JOUR

T1 - Terrestrial support of lake food webs

T2 - synthesis reveals controls over cross-ecosystem resource use

AU - Tanentzap, Andrew J.

AU - Kielstra, Brian W.

AU - Wilkinson, Grace M.

AU - Berggren, Martin

AU - Craig, Nicola

AU - del Giorgio, Paul A.

AU - Grey, Jonathan

AU - Gunn, John M.

AU - Jones, Stuart E.

AU - Karlsson, Jan

AU - Solomon, Christopher T.

AU - Pace, Michael L.

PY - 2017/3/22

Y1 - 2017/3/22

N2 - 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.

AB - 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.

KW - allochthony

KW - food webs

KW - land-water linkages

KW - organic carbon

U2 - 10.1126/sciadv.1601765

DO - 10.1126/sciadv.1601765

M3 - Journal article

VL - 3

JO - Science Advances

JF - Science Advances

SN - 2375-2548

IS - 3

M1 - e16001765

ER -