Consequences of increased temperature and CO2 for phytoplankton community structure in the Bering Sea

• Published in: Marine Ecology Progress Series
• Main Authors: Hare, C.E., Leblanc, Karine, Ditullio, G.R., Kudela, R., Zhang, Y., Lee, P.A., Riseman, S., Hutchins, D.A.
• Other Authors: College of Marine Studies (CMS), University of Delaware Newark, Laboratoire d'océanographie et de biogéochimie (LOB), Université de la Méditerranée - Aix-Marseille 2-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Hollings Marine Laboratory, College of Charleston, Grice Marine Laboratory Charleston, Ocean Sciences Department, University of California Santa Cruz (UC Santa Cruz), University of California (UC)-University of California (UC), Department of Biological Sciences Los Angeles, University of Southern California (USC)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.STU.OC]Sciences of the Universe [physics]/Earth Sciences/Oceanography; Bering Sea
• Online Access: https://hal.science/hal-00702676; https://hal.science/hal-00702676/document; https://hal.science/hal-00702676/file/m352p009.pdf; https://doi.org/10.3354/meps07182

International audience Global climate change is predicted to have large effects on the ocean that could cause shifts in current algal community structure, major nutrient cycles, and carbon export. The Bering Sea is already experiencing changes in sea surface temperature (SST), unprecedented algal blooms, and alterations to trophic level dynamics. We incubated phytoplankton communities from 2 Bering Sea regimes under conditions of elevated SST and/or partial pressure of carbon dioxide (pCO2) similar to predicted values for 2100. In our 'greenhouse ocean' simulations, maximum biomass-normalized photosynthetic rates increased 2.6 to 3.5 times and community composition shifted away from diatoms and towards nanophytoplankton. These changes were driven largely by elevated temperature, with secondary effects from increased pCO2. If these results are indicative of future climate responses, community shifts towards nanophytoplankton dominance could reduce the ability of the Bering Sea to maintain the productive diatom-based food webs that currently support one of the world's most productive fisheries.