Experimental nitrogen and phosphorus enrichment stimulates multiple trophic levels of algal and detrital-based food webs: a global meta-analysis from streams and rivers

Marcelo Ardón; Lydia H Zeglin; Ryan M Utz; Scott D Cooper; Walter K Dodds; Rebecca J Bixby; Ayesha S Burdett; Jennifer Follstad Shah; Natalie A Griffiths; Tamara K Harms; Sherri L Johnson; Jeremy B Jones; John S Kominoski; William H McDowell; Amy D Rosemond; Matt T Trentman; David Van Horn; Amelia Ward

doi:10.1111/brv.12673

Experimental nitrogen and phosphorus enrichment stimulates multiple trophic levels of algal and detrital-based food webs: a global meta-analysis from streams and rivers

Biol Rev Camb Philos Soc. 2020 Dec 17. doi: 10.1111/brv.12673. Online ahead of print.

Authors

Marcelo Ardón¹, Lydia H Zeglin², Ryan M Utz³, Scott D Cooper⁴, Walter K Dodds², Rebecca J Bixby⁵, Ayesha S Burdett⁶, Jennifer Follstad Shah⁷, Natalie A Griffiths⁸, Tamara K Harms⁹, Sherri L Johnson¹⁰, Jeremy B Jones⁹, John S Kominoski¹¹, William H McDowell¹², Amy D Rosemond¹³, Matt T Trentman¹⁴, David Van Horn⁵, Amelia Ward¹⁵

Affiliations

¹ Department of Forestry and Environmental Resources, North Carolina State University, Raleigh, NC, 27695, U.S.A.
² Division of Biology, Kansas State University, Manhattan, KS, 66506, U.S.A.
³ Falk School of Sustainability, Chatham University, Pittsburgh, PA, 15232, U.S.A.
⁴ Department of Ecology, Evolution, and Marine Biology and Marine Science Institute, University of California - Santa Barbara, Santa Barbara, CA, 93106, U.S.A.
⁵ Department of Biology, University of New Mexico, Albuquerque, NM, 87131, U.S.A.
⁶ River Bend Ecology, Wickliffe, VIC, 3379, Australia.
⁷ Environmental and Sustainability Studies Program/Department of Geography, University of Utah, Salt Lake City, UT, 84112, U.S.A.
⁸ Climate Change Science Institute and Environmental Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN, 37831, U.S.A.
⁹ Institute of Arctic Biology and Department of Biology and Wildlife, University of Alaska Fairbanks, Fairbanks, AK, 99775, U.S.A.
¹⁰ Pacific Northwest Research Station, U. S. Forest Service, Corvallis, OR, 97731, U.S.A.
¹¹ Department of Biological Sciences and Southeast Environmental Research Center, Florida International University, Miami, FL, 33199, U.S.A.
¹² Department of Natural Resources and the Environment, University of New Hampshire, Durham, NH, 03824, U.S.A.
¹³ Odum School of Ecology, University of Georgia, Athens, GA, 30602, U.S.A.
¹⁴ Division of Biological Sciences, University of Notre Dame, Notre Dame, IN, 46556, U.S.A.
¹⁵ Department of Biological Sciences, University of Alabama, Tuscaloosa, AL, 35487, U.S.A.

PMID: 33350055
DOI: 10.1111/brv.12673

Abstract

Anthropogenic increases in nitrogen (N) and phosphorus (P) concentrations can strongly influence the structure and function of ecosystems. Even though lotic ecosystems receive cumulative inputs of nutrients applied to and deposited on land, no comprehensive assessment has quantified nutrient-enrichment effects within streams and rivers. We conducted a meta-analysis of published studies that experimentally increased concentrations of N and/or P in streams and rivers to examine how enrichment alters ecosystem structure (state: primary producer and consumer biomass and abundance) and function (rate: primary production, leaf breakdown rates, metabolism) at multiple trophic levels (primary producer, microbial heterotroph, primary and secondary consumers, and integrated ecosystem). Our synthesis included 184 studies, 885 experiments, and 3497 biotic responses to nutrient enrichment. We documented widespread increases in organismal biomass and abundance (mean response = +48%) and rates of ecosystem processes (+54%) to enrichment across multiple trophic levels, with no large differences in responses among trophic levels or between autotrophic or heterotrophic food-web pathways. Responses to nutrient enrichment varied with the nutrient added (N, P, or both) depending on rate versus state variable and experiment type, and were greater in flume and whole-stream experiments than in experiments using nutrient-diffusing substrata. Generally, nutrient-enrichment effects also increased with water temperature and light, and decreased under elevated ambient concentrations of inorganic N and/or P. Overall, increased concentrations of N and/or P altered multiple food-web pathways and trophic levels in lotic ecosystems. Our results indicate that preservation or restoration of biodiversity and ecosystem functions of streams and rivers requires management of nutrient inputs and consideration of multiple trophic pathways.

Keywords: decomposition; ecosystem metabolism; eutrophication; lotic; nutrient criteria; primary and secondary production.

Abstract

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