The Compositions,Sources,Distribution Characteristics And The Controlling Factors Of Carbon-containing Particles In Northern SCS

Ocean is one of the largest terrestrial pool of carbon,play an important role in absorbtion of carbon dioxide.In the biological pump theory,particulate organic carbon(POC)flux is an important evaluation index of the biological pump efficiency,in order to figure out the carbon fixation process of ocean,the types and sources of seawater particles should be clarified first,and then,their temporal and spatial distributions can be analysed,as well as the composition,sources and fluxes of POC.On account of the lack of single particle characteristic in previous research,our research use single particle analysis to make up for blanks,and figure out the controling factors of POC flux.Our research including four voyages of the South China Sea(SCS)in 2006,2007,2014 and 2016,there are scanning electron microscope pictures and energy dispersive spectrum analysis(SEM+EDS)of 20 surface seawater samples and 14 vertical seawater samples.Our experiment found that the particle types are similar among different sea provinces,but their concentrations have significant temporal and spatial variations.Our research shows that:1.Seawater particles can be divided into biological particles(originate from marine primary production),thin-film particles(originate from coagulation of organic matter or inorganic matter),black carbon particles(originate from artificial combustion),silicate particles(terrigenous),calcium sulfate particles(terrigenous or crystallized from residual seawater),sea salt particles(crystallized from residual seawater)and carbonate particles(terrigenous or marine autogenic).And their occupation is 24.94%,7.83%,2.82%,57.77%,2.77%,4.14%and 0.06%respectively.2.Based on the current technology,the POC we test including C-containing biological particles,C-containing thin-film particles,calcium sulfate particles C-containing silicate particles,black carbon and C-containing sea salt,their occupation were 17.16%?6.37%?1.89%?39.11%,2.82%and 1.4%respectivley.3.The controlling factors of POC flux including:(1)In order to contribute to surface seawater flux,the phytoplankton should broken and the organic matter should degraded first,therefore,no matter how large the phytoplankton instant primary productivity is,or how their community structure is,the phytoplankton has no significative contributions to instant surface seawater POC flux;(2)With the increasing of depth,organic matter from particles degraded significantly,but the extent of degradation is different in different sea area.(3)The main ballast of the Northern SCS including biological particles,silicate particles and some calcium sulfate particles,and the average occupation is 24.94%,57.77%and 2.77%respectively.(4)The formations of Marine Snow may including the cohesion of phytoplankton mucus and the aggregating function of thin-film particles.