title: Habitat structure determines resource use by zooplankton in temperate lakes.
abstract: While the importance of terrestrial linkages to aquatic ecosystems is well appreciated, the degree of terrestrial support of aquatic consumers remains debated. Estimates of terrestrial contributions to lake zooplankton have omitted a key food source, phytoplankton produced below the mixed layer. We used carbon and nitrogen stable isotope data from 25 Pacific Northwest lakes to assess the relative importance of particulate organic matter (POM) from the mixed layer, below the mixed layer and terrestrial detritus to zooplankton. Zooplankton and deep POM were depleted in ¹³C relative to mixed layer POM in lakes that can support deep primary production. A Bayesian stable isotope mixing model estimated that terrestrial detritus contributed <5% to zooplankton production, and confirms the role of lake optical and thermal properties; deep POM accounted for up to 80% of zooplankton production in the clearest lakes. These results suggest terrestrial support of lake zooplankton production is trivial.
authors.affiliation: Department of Biology, University of Washington, Seattle, WA 98195, USA School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA. tessa.francis@noaa.gov
authors.forename: Tessa B
authors.initials: TB
authors.lastname: Francis
authors.forename: Daniel E
authors.initials: DE
authors.lastname: Schindler
authors.forename: Gordon W
authors.initials: GW
authors.lastname: Holtgrieve
authors.forename: Eric R
authors.initials: ER
authors.lastname: Larson
authors.forename: Mark D
authors.initials: MD
authors.lastname: Scheuerell
authors.forename: Brice X
authors.initials: BX
authors.lastname: Semmens
authors.forename: Eric J
authors.initials: EJ
authors.lastname: Ward
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D001955:British Columbia; D002247:Carbon Isotopes / Q000378:metabolism*; D017753:Ecosystem; D020387:Food Chain; D005618:Fresh Water / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000378:metabolism*; D052638:Particulate Matter / Q000378:metabolism*; D010839:Phytoplankton / Q000378:metabolism; D013045:Species Specificity; D014861:Washington; D015048:Zooplankton / Q000378:metabolism*
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D052638:Particulate Matter