Particulate organic carbon export fluxes and size-fractionated POC/234Th ratios in the Ligurian,Tyrrhenian and Aegean Seas |
| |
| Institution: | 1. Graduate School of Oceanography, University of Rhode Island, Narragansett, RI 02882 1197, USA;2. Department of Marine Sciences, University of Georgia, Athens, GA 30602 3636, USA;3. ENEA, Marine Environment Research Centre, La Spezia 19100, Italy;4. Department of Oceanography, Hellenic Centre for Marine Research, Anavyssos GE 19013, Greece;5. Marine and Environmental Sciences Division, Bedford Institute of Oceanography, Dartmouth, N.S., Canada B2Y 4A2;6. Department of Marine Sciences, University of the Aegean, Mytilene GR 81100, Greece;1. Key Laboratory of Marine Hydrocarbon Resources and Environmental Geology, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;2. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China;3. Key Laboratory of Tectonics and Petroleum Resources, China University of Geosciences (CUG), Wuhan 430074, China;4. College of Marine Science and Technology, China University of Geosciences (CUG), Wuhan 430074, China;5. Tech Team Solutions, Stavanger 4034, Norway;6. CNOOC EnerTech-Drilling & Production Co., Tianjin 300452, China;1. Department of Physics, Institute of Technical Education and Research, SOA University, Bhubaneswar 751030, India;2. Department of Physics, Government Junior College, Bhawanipatna, Kalahandi 766001, India;1. Division of Materials Science, Luleå University of Technology, SE-971 87 Luleå, Sweden;2. Institut Jean Lamour, Ecole Européenne d’Ingénieurs en Génie des Matériaux, 6 Rue Bastien Lepage, F-54010 Nancy Cedex, France;3. Swerea SICOMP, SE-431 22 Mölndal, Sweden;1. LSCE/IPSL, Laboratoire des Sciences du Climat et de l’Environnement, CEA-CNRS-UVSQ, Gif-sur-Yvette, France;2. CNRM-GAME UMR1357, Météo-France, Centre National de Recherches Météorologiques, 42 avenue G. Coriolis, 31057 Toulouse cedex 1, France;3. Laboratoire d’Océanographie et de Climatologie: Expérimentation et Approches Numériques, LOCEAN/IPSL, 4 Place Jussieu, 75005 Paris, France;4. LISA, CNRS UMR7583, Université Paris-Diderot et Université Paris-Est Créteil, 61, av du Général de Gaulles, Créteil, France;5. LOV: Laboratoire d’Océanographie de Villefranche/Mer, CNRS-INSU UMR7093, Observatoire Océanologique, 06230 Villefranche-sur-Mer, France;6. Mediterranean Institute of Oceanography, MIO UMR110, Aix-Marseille Université, CNRS/INSU, Université de Toulon, IRD, 13288 Marseille, France;7. Mercator-Océan, Parc Technologique du Canal, 8-10 rue Hermès Ramonville, Saint-Agne, France;1. Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA;2. MIT‐WHOI Joint Program in Oceanography, Massachusetts Institute of Technology/Woods Hole Oceanographic Institution, Woods Hole, MA 02543, USA |
| |
| Abstract: | Measurements of 234Th/238U disequilibria and particle size-fractionated (1, 10, 20, 53, 70, 100 μm) organic C and 234Th were made to constrain estimates of the export flux of particulate organic C (POC) from the surface waters of the Ligurian, Tyrrhenian and Aegean Seas in March–June 2004. POC exported from the surface waters (75–100 m depth) averaged 9.2 mmol m?2 d?1 in the Ligurian and Tyrrhenian Seas (2.3±0.5–14.9±3.0 mmol m?2 d?1) and 0.9 mmol m?2 d?1 in the Aegean Sea. These results are comparable to previous measurements of 234Th-derived and sediment-trap POC fluxes from the upper 200 m in the Mediterranean Sea. Depth variations in the POC/234Th ratio suggest two possible controls. First, decreasing POC/234Th ratios with depth were attributed to preferential remineralization of organic C. Second, the occurrence of maxima or minima in the POC/234Th ratio near the DCM suggests influence by phytoplankton dynamics. To assess the accuracy of these data, the empirical 234Th-method was evaluated by quantifying the extent to which the 234Th-based estimate of POC flux, PPOC, deviates from the true flux, FPOC, defined as the p-ratio (p-ratio=PPOC/FPOC=STh/SPOC, where S=particle sinking rate). Estimates of the p-ratio made using Stokes’ Law and the particle size distributions of organic C and 234Th yield values ranging from 0.93–1.45. The proximity of the p-ratio to unity implies that differences in the sinking rates of POC- and 234Th-carrying particles did not bias 234Th-normalized POC fluxes by more than a factor of two. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
