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Marine Ecology Progress Series

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MEPS 491:1-14 (2013)  -  DOI:

Amplification and attenuation of increased primary production in a marine food web

Kelly A. Kearney1,4,*, Charles Stock2, Jorge L. Sarmiento3

1Department of Geosciences, Princeton University, Princeton, New Jersey 08544, USA
2Geophysical Fluid Dynamics Laboratory (GFDL), National Oceanic and Atmospheric Administration (NOAA),
201 Forrestal Road, Princeton, New Jersey 08540, USA
3Program in Atmospheric and Ocean Sciences, Princeton University, Princeton, New Jersey 08544, USA
4Present address: Marine Biology and Fisheries, University of Miami Rosenstiel School of Marine and Atmospheric Sciences,
4600 Rickenbacker Causeway, Miami, Florida 33149, USA

ABSTRACT: We used an end-to-end ecosystem model that incorporates physics, biogeochemistry, and predator-prey dynamics for the Eastern Subarctic Pacific ecosystem to investigate the factors controlling propagation of changes in primary production to higher trophic levels. We found that lower trophic levels respond to increased primary production in unexpected ways due to complex predatory interactions, with small phytoplankton increasing more than large phytoplankton due to relief from predation by microzooplankton, which are kept in check by the more abundant mesozooplankton. We also found that the propagation of production to upper trophic levels depends critically on how non-predatory mortality is structured in the model, with much greater propagation occurring with linear mortality and much less with quadratic mortality, both of which functional forms are in common use in ecosystem models. We used an ensemble simulation approach to examine how uncertainties in model parameters affect these results. When considering the full range of potential responses to enhanced productivity, the effect of uncertainties related to the functional form of non-predatory mortality was often masked by uncertainties in the food-web parameterization. The predicted responses of several commercially important species, however, were significantly altered by non-predatory mortality assumptions.

KEY WORDS: End-to-end model · Trophic efficiency · Primary production · Food web · Subarctic Pacific Ocean · Ecosystem model

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Cite this article as: Kearney KA, Stock C, Sarmiento JL (2013) Amplification and attenuation of increased primary production in a marine food web. Mar Ecol Prog Ser 491:1-14.

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