Episodic Arctic CO2 Limitation in the West Svalbard Shelf

• Published in: Frontiers in Marine Science
• Main Authors: Sanz-Martín, Marina, Chierici, Melissa, Mesa, Elena, Carrillo-de-Albornoz, Paloma, Delgado-Huertas, Antonio, Agusti, Susana, Reigstad, Marit, Kristiansen, Svein, Wassmann, Paul F. J., Duarte, Carlos M.
• Other Authors: Biological and Environmental Sciences and Engineering (BESE) Division, Marine Science Program, Red Sea Research Center (RSRC), Facultat de Ciències de la Terra, Universitat de Barcelona (UB), Barcelona, , , Spain, Departament of Global Change, Instituto Mediterráneo de Estudios Avanzados (IMEDEA/CSIC-UIB), Esporles, , Spain, University Centre in Svalbard, Longyearbyen, , Norway, Institute of Marine Research, Tromsø, , Norway, Instituto Andaluz de Ciencias de la Tierra (IACT/CSIC-UGR), Armilla, , Spain, UiT The Arctic University of Tromsø, Tromsø, , Norway, Department of Bioscience, Aarhus University, Arctic Research Centre, Arhus, , Denmark
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media SA 2018
• Subjects: Arctic Ocean; CO2 additions; CO2 limitation; Gross primary production; Plankton communities; Spring blooms; Arctic; Phytoplankton; Svalbard
• Online Access: http://hdl.handle.net/10754/631527; https://doi.org/10.3389/fmars.2018.00221

The European Sector of the Arctic Ocean is characterized by low CO concentrations in seawater during spring and summer, largely due to strong biological uptake driven by extensive plankton blooms in spring. The spring plankton bloom is eventually terminated by nutrient depletion and grazing. However, low CO concentrations in seawater and low atmospheric resupply of CO can cause episodes during which the phytoplankton growth is limited by CO2. Here, we show that gross primary production (GPP) of Arctic plankton communities increases from 32 to 72% on average with CO additions in spring. Enhanced GPP with CO additions occur during episodes of high productivity, low CO concentration and in the presence of dissolved inorganic nutrients. However, during summer the addition of CO supresses planktonic Arctic GPP. Events of CO limitation in spring may contribute to the termination of the Arctic spring plankton blooms. The stimulation of GPP by CO during the spring bloom provides a biotic feedback loop that might influence the global role played by the Arctic Ocean as a CO sink in the future. We thank the crew of R/V Helmer Hanssen, I. Hendriks, M. Vernet, E. Falk, H. Hodal, and A. Granados for their help. J. Holding and L. Meire for valuable comments and V. Unkefer for improvements to the text. MS-M was supported by a La Caixa Ph. D. fellowship. This study is a contribution to the Carbon Bridge (RCN-226415) project funded by the Norwegian Research Council.