The Diversity Of Living Coccolithophore In East China Sea And South China Sea, Spring And Autumn

The living coccolithophore(LC) is one of the most important phytoplankton in the modern ocean. Researching on the diversity and distribution characters of LCs plays significant role for carbon cycle research in the China Sea(CS) due to the specific physiological ecology characters in producing calcified shells which will have strong effects on marine biogeochemistry cycle.Diversity and distribution of LCs in CS in spring and autumn are the main contents in this paper. Two parts can be divided on it:the first part is to identify and classify the LCs sampled in CS by the scanning electron microscopy (SEM) and moreover, to summarize the species lists and present the identification key for common species in CS; the second part is to study the distribution characters of LCs from the species composition, cell abundance and relatively ecological behavior by Polarized Microscope. We hope the contents above can send the information to us about the species diversity and distribution in CS and provide the fundamental data for the role in Global Carbon Cycle and for the responsible mechanism to the Global Change of LCs.This paper documents the morphology, taxonomy and diversity of LCs in CS Totally,97species have been recorded, belonging to4orders,11families, and44genera. Syracosphaera, including20species, is the most abundant LCs genus in CSW. We also list five new record species in this paper. They are Cyrtosphaera lecaliae, Syracosphaera histrica, Corisphaera strigilis, Pontosphaera discopora and Braarudosphaera bigelowii. Meanwhile, we also describe19species (include six species indeterminate) of LCs founded in CSW, based on SEM or polarizing microscope observations.The identification key for common living coccolithophores species in CSW is also presented.The second part in this paper studied on the assemblage of LC in autumn,2010and spring,2011in CS.39species(including the undetermined species) was indentified, in which Emiliania huxleyi and Gephyrocapsa oceanica were the predominant species except the South China Sea(SCS) in spring and Helicosphaera carteri, Algirosphaera robusta, Florisphaera profunda var. profunda were the common species. However, Gephyrocapsa oceanic, Emiliania huxleyi, Florisphaera profunda var. profunda and Helicosphaera carteri were the dominant species in spring in SCS. On the region for investigation, the abundance of coccoliths increased slightly from the surface to bottom layer in the inshore stations and had no obvious changing laws that in the offshore stations; generally decreased from the coastal stations to the open-sea stations. The abundance of cells(coccolithophores) increased dramatically from surface to bottom in stations depth less than200m, while, that most abundant was found in the75m-150m layers, and decreased significantly from the inshore to offshore.The abundance of coccoliths and cells were613.44coccolith/ml、18.64cells/ml in East China Sea(ECS) in autumn, respectively. The maximum abundance areas of coccoliths were founded the station near the Changjiang River Estuary and the bottom layers in each stations; that of cells were observed at the PN09station where Chaetoceros debilis bloom happened. Moreover, the abundance were416.89coccolith/ml、16.77cells/ml, respectively. The abundance in coast stations were richer than others, however, H. carteri had the maxima off the coastal stations.Abundance of that above were216.86coccolith/ml、14.48cells/ml in SCS in autumn, respectively, the distributions of coccolith and cells were strong non-uniform as the patch style. The maximum of H. carteri was founded at the inshore stations. Data were117.38coccolith/ml、6.81cells/ml in SCS in spring, respectively, however, the maximum area of H. carteri transferred to scope area and the Luzon Strait.The abundances of LCs in autumn were abundant than those in spring, and those in ECS were higher than those in SCS during the same season. We primaryly conclude that the nutrients is the important factor to control the abundance and istribution of LCs and the distribution laws of coccoliths could be too strongly effected by the other physical factor to find the changed laws in abundance and distribution, such as well-mixed sea water, the resuspension of sediments and so on. Therefore, more work on board will be needed so as to know the deeper ecological characters of LCs.