Use of lipids and their degradation products as biomarkers for carbon cycling in the northwestern Mediterranean Sea |
| |
| Authors: | Stéphane Christodoulou Jean-Claude Marty Juan-Carlos Miquel John K Volkman Jean-François Rontani |
| |
| Institution: | 1. Laboratoire de Microbiologie, Géochimie et Ecologie Marines (UMR 6117), Centre d''Océanologie de Marseille (OSU), Campus de Luminy-case 901, 13288 Marseille, France;2. CNRS, UMR7093, Laboratoire d''Océanographie de Villefranche, 06230 Villefranche-sur-Mer, France;3. Université Pierre et Marie Curie-Paris 6, Laboratoire d''Océanographie de Villefranche, 06230 Villefranche-sur-Mer, France;4. IAEA Marine Environment Laboratories, 4 Quai Antoine 1er, MC-98000, Monaco;5. CSIRO Marine and Atmospheric Research and Wealth from Oceans National Research Flagship, GPO Box 1538, Hobart, 7001, Australia;1. Organic Geochemistry Group, MARUM Center for Marine Environmental Sciences & Dept. of Geosciences, University of Bremen, 28359 Bremen, Germany;2. Heisenberg Group Marine Kerogen, MARUM Center for Marine Environmental Sciences & Dept. of Geosciences, University of Bremen, 28359 Bremen, Germany;1. Southeast Environmental Research Center, and Department of Chemistry and Biochemistry, Florida International University, Miami, FL 33199, USA;2. 72 Marina Lakes Drive, Richmond, CA 94804, USA;3. Department of Pure and Applied Chemistry, University of Calabar, Calabar, Cross River State, Nigeria;4. Department of Chemistry, Oregon State University, Corvallis, OR 97331, USA;1. Division for Marine and Environmental Research, Ru?er Bo?kovi? Institute, POB 180, HR-10002 Zagreb, Croatia;2. Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany;3. University of Applied Sciences, An der Karlstadt 8, 27568 Bremerhaven, Germany;4. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, No. 3663 North Zhongshan Road, Shanghai 200062, PR China;5. Graduate School of Life and Environmental Sciences, Osaka Prefecture University, Sakai, Osaka 599-8531, Japan;6. International Centre for Diarrhoeal Disease Research, Bangladesh, 68 Shaheed Tajuddin Ahmed Sarani, Mohakhali, Dhaka 1212, Bangladesh;7. Leibniz Centre for Tropical Marine Ecology GmbH, Fahrenheitstr. 6, 28359 Bremen, Germany;1. College of Marine Science, University of South Florida, 140 7th Avenue South, St. Petersburg, FL 33701, USA;2. Skidaway Institute of Oceanography, 10 Ocean Science Circle Savannah, GA 31411, USA;1. Royal Netherlands Institute for Sea Research, Department of Marine Organic Biogeochemistry, PO Box 59, 1790AB Den Burg, The Netherlands;2. Limnology Unit, Ghent University, K. L. Ledeganckstraat 35, B-9000 Gent, Belgium;1. Department of Earth Sciences, University of Southern California, 3651 Trousdale Pkwy, Los Angeles, CA 90089, USA;2. Department of Biological Sciences, University of Southern California, 3616 Trousdale Pkwy, Los Angeles, CA 90089, USA |
| |
| Abstract: | Changes in phytoplankton composition and degradation of particulate organic matter (POM) in the northwestern Mediterranean Sea were studied using time-series sediment trap samples collected during the spring of 2003 at the DYFAMED station. Lipid biomarkers (pigments, fatty acids, sterols, acyclic isoprenoids, alkenones and n-alkanols) were used to identify the main contributors to the POM produced during two phytoplankton blooms, while the effects of photooxidation, autoxidation and biodegradation were differentiated using characteristic lipid degradation products. Traps collected material corresponding to pre-bloom, bloom and post-bloom periods. Pigment analyses in the integrated (0-200 m) water column samples indicated that diatoms dominated the initial stages of the bloom event, with smaller amounts of haptophytes and pelagophytes. During the second part of bloom event there was a switch to haptophyte dominance with significant contributions from diatoms and pelagophytes, and an increased contribution from cryptophytes. Fatty acid distributions in the trap samples reflected contributions from marine bacteria, phytoplankton and zooplankton. Photooxidation and autoxidation products of monounsaturated oleic, cis-vaccenic and palmitoleic acids were detected along with photooxidation products from the chlorophyll side-chain. The relatively good correlation between the variation of U37K′ index and specific phytol autoxidation product percentage allowed us to attribute the alterations of U37K′ observed during the pre-bloom period and in the deeper traps to the involvement of selective autoxidative degradation processes. A variety of sterol oxidation products formed by biohydrogenation, autoxidation and photooxidation were detected. Sterol degradation products appeared to be less suited than oxidation products of monounsaturated fatty acids for the precise monitoring of the degradation state of POM, but their stable functionalized cyclic structure constitutes a useful tool to estimate the part played by biotic and abiotic processes. In these waters, biotic degradation generally predominates, but abiotic degradation is not negligible and, as expected, the extent of biotic degradation increases with depth. To obtain a more complete picture of POM degradation, the use of a pool of lipid degradation products (i.e. from unsaturated fatty acids, the phytyl side-chain and sterols) should be employed. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
