"Nutrient additions to mitigate for loss of Pacific salmon: consequence" by Amy Marcarelli, Colden V. Baxter et al.

Department of Biological Sciences Publications

Title

Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics

Authors

Amy Marcarelli, Michigan Technological UniversityFollow
Colden V. Baxter, Idaho State University
Mark S. Wipfli, University of Alaska, Fairbanks

Document Type

Article

Publication Date

6-13-2014

Abstract

Mitigation activities designed to supplement nutrient and organic matter inputs to streams experiencing decline or loss of Pacific salmon typically presuppose that an important pathway by which salmon nutrients are moved to fish (anadromous and/or resident) is via nutrient incorporation by biofilms and subsequent bottom-up stimulation of biofilm production, which is nutrient-limited in many ecosystems where salmon returns have declined. Our objective was to quantify the magnitude of nutrient incorporation and biofilm dynamics that underpin this indirect pathway in response to experimental additions of salmon carcasses and pelletized fish meal (a.k.a., salmon carcass analogs) to 500-m reaches of central Idaho streams over three years. Biofilm standing crops increased 2–8-fold and incorporated marine-derived nutrients (measured using ¹⁵N and ¹³C) in the month following treatment, but these responses did not persist year-to-year. Biofilms were nitrogen (N) limited before treatments, and remained N limited in analog, but not carcass-treated reaches. Despite these biofilm responses, in the month following treatment total N load was equal to 33–47% of the N added to the treated reaches, and N spiraling measurements suggested that as much as 20%, but more likely 2–3% of added N was taken up by microbes. Design of biologically and cost-effective strategies for nutrient addition will require understanding the rates at which stream microbes take up nutrients and the downstream distance traveled by exported nutrients.

Publisher's Statement

Publication Title

Ecosphere

Creative Commons License

This work is licensed under a Creative Commons Attribution 3.0 License.

Recommended Citation

Marcarelli, A., Baxter, C. V., & Wipfli, M. S. (2014). Nutrient additions to mitigate for loss of Pacific salmon: consequences for stream biofilm and nutrient dynamics. Ecosphere, 5(6), 1-22. http://doi.org/10.1890/ES13-00366.1
Retrieved from: https://digitalcommons.mtu.edu/biological-fp/5

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