Zooplankton excretion metabolites stimulate Southern Ocean phytoplankton growth

• Published in: Polar Biology
• Main Authors: Camba, Alexandra, Llabrés, M., Duarte, Carlos M., Agusti, Susana
• Other Authors: Biological and Environmental Sciences and Engineering (BESE) Division, Marine Science Program, Red Sea Research Center (RSRC), Department of Global Change Research, Instituto Mediterráneo de Estudios Avanzados, IMEDEA (CSIC-UIB), Esporles, Spain, Department of Arctic and Marine Biology, Faculty of Bioscience, Fishery and Economy, University of Tromsø, Tromso, Norway
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Springer Nature 2017
• Subjects: Phytoplankton; Nutrient recycling; Ammonia Southern Ocean; Antarc*; Antarctic; Antarctic Peninsula; Antarctica; Euphausia superba; Polar Biology; Southern Ocean; Copepods
• Online Access: http://hdl.handle.net/10754/623302; https://doi.org/10.1007/s00300-017-2123-2

Warming over Antarctica is leading to changes in the zooplankton communities inhabiting the Southern Ocean. It has been observed that zooplankton not only regulates phytoplankton through grazing, but also through the recycling of nutrients that are essential for phytoplankton growth. In this way, the effects of warming on zooplankton populations will change the amount or proportion at which recycled nutrients are restored. To estimate how the recycled nutrients released by zooplankton populations, dominated by krill (Euphausia superba), amphipods or copepods, affect the phytoplankton uptake and communities, we performed four incubation experiments: two close to the Antarctic Peninsula and two at the Southern Atlantic Ocean. Our results showed a stimulating effect of the addition of metabolites on ammonia removal rates and on the net growth of phytoplankton communities, with different responses amongst the different phytoplankton groups. According to our results, phytoplankton net growth and community composition may be altered if this relevant source of nutrients is lost due to projected changes in the abundance or distribution of these zooplankton populations. This is a contribution to the projects ATOS (Aportes Atmosféricos de Carbono Orgánico y Contaminantes al Océano Polar) and ICEPOS (REN2002-04165-C03-02⁄ANT) funded by the Spanish Ministry of Education and Science, and to the LOHAFEX project, funded by the Max Planck Society. We thank S. W. A. Naqvi, chief scientist of the LOHAFEX project, for his leadership, Victor Smetacek, Regino Martínez for experiment setup and sampling, and Maria Grazia Mazzocchi (Stazione Zoologica Anton Dohrn, Napoli, Italy) for help with zooplankton information. We also thank the crew of the RV Polarstern and BIO Hespérides for their help.