Pulsed export of carbon in the north-western Mediterranean Sea

作     者：Michel DENIS Dominique LEFEVRE Melilotus THYSSEN Ian RJENKINSON Gérald GRÉGORI Michel DENIS;Dominique LEFEVRE;Melilotus THYSSEN;Ian R.JENKINSON;Gérald GREGORI

作者机构：Aix Marseille UniversitéUniversitéde ToulonCNRS/INSUIRDInstitut Méditerranéen d'Océanologie(MIO)Marseille cedex09 13288France Key Laboratory of Marine Ecology and Environmental SciencesInstitute of OceanologyChinese Academy of SciencesQingdao 266071China Agency for Consultation and Research in OceanographyLavergne19320 La Roche CanillacFrance 

出 版 物：《Journal of Oceanology and Limnology》 (海洋湖沼学报（英文）)

年 卷 期：2023年第41卷第1期

页      面：189-202页

核心收录：

学科分类：07[理学] 0707[理学-海洋科学] 

基　　金：Supported by the PROOF Grant provided by the INSU-CNRS and was part of the PECHE project“Production and exportation of carbon:control by heterotrophic organisms at small time scales” 

主　　题：north-western Mediterranean Sea heterotrophic prokaryote(HP) cell viability cell respiration transparent exopolymeric particle(TEP) aggregation flow cytometry 

摘      要：The short term(hourly scale)variability of heterotrophic prokaryote(HP)vertical distribution and respiratory activity,was investigated in the north-western(NW)Mediterranean *** vertical distribution was determined on board by flow cytometry analysis of seawater samples collected by series of CTD *** counts and viability were determined for all *** respiratory rates were determined later in the laboratory from filtered seawater samples(23 dm^(3))from 300-1150-m *** average cell viability was 94.8%±2.2%(n=240).There was no accumulation of dead cells,due to quick decay of damaged *** the epipelagic layer,three HP groups were distinguished,two(HNA1,HNA2)who se cells exhibited a high nucleic acid content and one(LNA)with low nucleic acid content ***2 was most populated at 50 m but not detected at 90 m and below,presumably aerobic anoxygenic photoheterotrophic bacteria(AAPs).The variability in HP abundance was mainly confined in the upper 80 m.A few secondary peaks of HP abundance were observed(80-150 m)in connection with abundance troughs in the surface *** cells were continuously present in a wide layer around 500 m(mean 191×10^(3)cells/cm^(3)).Below this layer,HP abundance randomly exhibited peaks,coupled to respiratory rate *** HP abundance and variability in the water column was suppressed during a strong wind *** observed sporadic variability was tentatively interpreted through a pulsed carbon-export mechanism induced by the microorganism production of dissolved poly saccharide s,followed by flocculation and rapid *** mechanism would thus contribute to(ⅰ)preventing organic matter accumulation in the epipelagic layer,(ⅱ)seeding the water column with live HP cells,and(ⅲ)supplying the aphotic water column with fre sh and labile organic *** important vertical flux mechanism needs further observations and modelling.