title: Atmospheric nitrogen deposition is associated with elevated phosphorus limitation of lake zooplankton.
abstract: Here, we present data that for the first time suggests that the effects of atmospheric nitrogen (N) deposition on nutrient limitation extend into the food web. We used a novel and sensitive assay for an enzyme that is over-expressed in animals growing under dietary phosphorus (P) deficiency (alkaline phosphatase activity, APA) to assess the nutritional status of major crustacean zooplankton taxa in lakes across a gradient of atmospheric N deposition in Norway. Lakes receiving high N deposition had suspended organic matter (seston) with significantly elevated carbon:P and N:P ratios, indicative of amplified phytoplankton P limitation. This P limitation appeared to be transferred up the food chain, as the cosmopolitan seston-feeding zooplankton taxa Daphnia and Holopedium had significantly increased APA. These results indicate that N deposition can impair the efficiency of trophic interactions by accentuating stoichiometric food quality constraints in lake food webs.
authors.affiliation: School of Life Sciences, Arizona State University, Tempe, AZ 85287, USA. j.elser@asu.edu
authors.forename: James J
authors.initials: JJ
authors.lastname: Elser
authors.forename: Angela L
authors.initials: AL
authors.lastname: Peace
authors.forename: Marcia
authors.initials: M
authors.lastname: Kyle
authors.forename: Marcin
authors.initials: M
authors.lastname: Wojewodzic
authors.forename: Michelle L
authors.initials: ML
authors.lastname: McCrackin
authors.forename: Tom
authors.initials: T
authors.lastname: Andersen
authors.forename: Dag O
authors.initials: DO
authors.lastname: Hessen
mesh_terms: D000818:Animals; D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring; D020387:Food Chain; D009584:Nitrogen / Q000032:analysis*; D009664:Norway; D010758:Phosphorus / Q000032:analysis*; D014867:Water / Q000737:chemistry; D015048:Zooplankton / Q000378:metabolism*
chemical_list: D014867:Water; D010758:Phosphorus; D009584:Nitrogen