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Patterns in planktonic metabolism in the Mediterranean Sea
Department of Global Change Research, IMEDEA (CSIC-UIB), Instituto Mediterráneo de Estudios Avanzados, Miquel Marqués 21, 07190 Esporles, Spain
Abstract. Planktonic gross community production (GPP), net community production (NCP) and community respiration (CR) across the Mediterranean Sea was examined in two cruises, THRESHOLDS 2006 and 2007, each crossing the Mediterranean from West to East to test for consistent variation along this longitudinal gradient. GPP averaged 2.4±0.4 mmol O2m−3 d−1, CR averaged 3.8±0.5 mmol O2m−3 d−1, and NCP averaged -0.8±0.6 mmol O2m−3 d−1across the studied sections, indicative of a tendency for a net heterotrophic metabolism, prevalent across studied sections of the Mediterranean Sea as reflected in 70% of negative NCP estimates. The median P/R ratio was 0.58, also indicating a strong prevalence of heterotrophic communities (P/R<1) along the studied sections of the Mediterranean Sea. The communities tended to be net heterotrophic (i.e. P/R<1) at GPP less than 3.5 mmol O2m−3 d−1. Although the Western Mediterranean supports a higher gross primary production than the Eastern basin does, it also supported a higher community respiration. The net heterotrophy nature of the studied sections of the Mediterranean Sea indicates that allochthonous carbon should be important to subsidise planktonic metabolism, and that the planktonic communities in the Mediterranean Sea acted as CO2 sources to the atmosphere during the study.
Discussion Paper (PDF, 1493 KB) Interactive Discussion (Closed, 4 Comments) Final Revised Paper (BG)
Citation: Regaudie-de-Gioux, A., Vaquer-Sunyer, R., and Duarte, C. M.: Patterns in planktonic metabolism in the Mediterranean Sea, Biogeosciences Discuss., 6, 8569-8588, 2009. Bibtex EndNote Reference Manager
