Effects of sea surface warming on marine plankton |
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Authors: | Aleksandra M. Lewandowska Daniel G. Boyce Matthias Hofmann Birte Matthiessen Ulrich Sommer Boris Worm |
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Affiliation: | 1. Marine Ecology, GEOMAR Helmholtz Center for Ocean Research Kiel, , 24105 Kiel, Germany;2. German Centre for Integrative Biodiversity Research (iDiv) Halle‐Jena‐Leipzig, , 04103 Leipzig, Germany;3. Department of Biology, Dalhousie University, , Halifax, NS, B3H 4R2 Canada;4. Department of Biology, Queen's University, , Kingston, ON, K7L 3N6 Canada;5. Ocean Sciences Division, Bedford Institute of Oceanography, , Dartmouth, NS, B2Y 4A2 Canada;6. Potsdam Institute for Climate Impact Research, , 14412 Potsdam, Germany |
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Abstract: | Ocean warming has been implicated in the observed decline of oceanic phytoplankton biomass. Some studies suggest a physical pathway of warming via stratification and nutrient flux, and others a biological effect on plankton metabolic rates; yet the relative strength and possible interaction of these mechanisms remains unknown. Here, we implement projections from a global circulation model in a mesocosm experiment to examine both mechanisms in a multi‐trophic plankton community. Warming treatments had positive direct effects on phytoplankton biomass, but these were overcompensated by the negative effects of decreased nutrient flux. Zooplankton switched from phytoplankton to grazing on ciliates. These results contrast with previous experiments under nutrient‐replete conditions, where warming indirectly reduced phytoplankton biomass via increased zooplankton grazing. We conclude that the effect of ocean warming on marine plankton depends on the nutrient regime, and provide a mechanistic basis for understanding global change in marine ecosystems. |
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Keywords: | Climate warming mesocosm experiment phytoplankton POTSMOM‐C |
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