Changes in the C, N, and P cycles by the predicted salps-krill shift in the southern ocean

• Published in: Frontiers in Marine Science
• Main Authors: Alcaraz, Miquel, Almeda, Rodrigo, Duarte, Carlos M., Horstkotte, Burkhard, Lasternas, Sebastien, Agustí, Susana
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Frontiers Media 2014
• Subjects: Southern Ocean; Zooplankton; Community shifts; Metabolism; Carbon cycling; C:N:P stoichiometry; Antarctic; Antarctic Peninsula; Duarte; The Antarctic; Antarc*; Euphausia superba; International Polar Year; Copepods
• Online Access: http://hdl.handle.net/10261/108732; https://doi.org/10.3389/fmars.2014.00045

13 pages, 3 figures, 6 tables The metabolic carbon requirements and excretion rates of three major zooplankton groups in the Southern Ocean were studied in the vicinity of the Antarctic Peninsula in February 2009. The research was conducted in the framework of the ATOS project (POL2006-00550/CTM), as part of the Spanish contribution to the International Polar Year. Our objective was to ascertain the possible consequences of changes on size spectrum and community structure of the Southern Ocean zooplankton for the cycling of biogenic carbon and the stoichiometry of dissolved inorganic nutrients. The carbon respiratory demands and NH4-N and PO4-P excretion rates of < 5 mm size copepods, krill (represented by furcilia spp. and adult Euphausia superba) and salps (blastozoids of Salpa thompsoni) were estimated by incubation experiments. The respiration rates and N:P metabolic quotients of salps were more than twice those of krill (furcilia spp. and adults) and copepods. The possible community shift from krill to salps in the Southern Ocean would therefore encompass not only the substitution of a pivotal zooplankton group (krill) by one with an apparently indifferent role in Antarctic food webs and with higher specific metabolic carbon demands (salps), but the changes in the proportion of zooplankton-recycled N and P would modify the N:P stoichiometry of the dissolved nutrient pool, thus inducing changes in the functional and structural properties of phytoplankton that would translate to the whole Southern Ocean ecosystem This work was supported by the Spanish funded projects ATOS (POL 2006-0550/CTM) to Carlos M. Duarte, PERFIL (CTM 2006-12344-C01) to Miquel Alcaraz, and the UE funded project ATP (www.eu-atp.org) contract # 226248 to P. Wassmann Peer Reviewed