Distribution Of Diatoms In Surface Sediment In Chinese Inshore Waters And Their Environmental Significance

Chinese inshore waters, is the edge of the northwestern Pacific, witharch distribution from north to south, including Bohai Sea, Yellow Sea,East China Sea and South China Sea. Bohai Sea and the north of Yellow Seawas significantly affected by the continental climate, while the southof Yellow Sea and East China Sea was obviously influenced by the warmcurrent in open sea (Kuroshio and its branches). South China Sea waslocated between subtropical and tropical, which has the deep-sea andtropical characteristics. The community structure, portfoliocharacteristics and distribution of state of the diatom in the study areawas different from the Pacific, Indian Ocean and other oceanic areas inthe world because of their bio-geographical characteristics. It had greatsignificance in the academic aspect that to know about the ecologicaldistribution characteristics of diatoms in each sea and to analysis thecorresponding degree and its error range between the ecology and thedeposition of diatoms was, as well as to analysis the relationship betweenthe ecological environment and their deposition conditions. Toinvestigate the reliability and particularity of sediment diatoms in eachsea for using the ecological characteristics to indicate environment andto establishment the discriminant index using diatoms to interpretenvironment was necessary, which would be helpful to the further studyon the inshore marine geological resources and environment, global changeand its regional response, and circle effect and geological events.The diatoms in145surface sediment samples freshly obtained fromChinese inshore waters were analyzed. Moreover, based on908survey data,previous results and historical data, taxonomic studies were developed. The characteristics of surface sediment diatom genera and species werealso studied, which were compared with previous results, and so as toexplore relationship between surface sediment diatoms and environmentalfactors. Then try to establish a transfer function between them. The mainfindings were as follows:(1)211surface sediment diatom species and their varieties belongedto43genera in the study area were identified. Two new record specieswere found in Chinese inshore waters, which were Coscinodiscus lineatusvar.confusus Chen et Lan and Surirella fluminensis var.constricta Chenet Lan.(2) The distribution characteristics of diatoms are similar in a widerange in the Yellow Sea coastal waters, because it contacts closely withthe open ocean. While the Bohai Sea was an inland sea, its coastal waterswas impacted by geographical environments, resulting the distributioncharacteristics of diatoms a larger differences in inshore of every gulf.The inshore waters of the East China Sea, the Taiwan Strait and the SouthChina Sea are the edge of the western Pacific, and the diatom populationsare similar in a wide range. The Taiwan Strait and the South China Sealie in the transition zone between tropical and subtropical areas, whichare impacted by the open sea waters, resulting the content of warm-waterspecies rise in the various stations.(3) The absolute abundance of sedimentary diatom decreases in thecoastal waters of the Bohai Sea and the East China Sea with the water depthincreasing. Contrast with the first two waters, the absolute abundanceof sedimentary diatom increases in coastal waters of the Yellow Sea withthe water depth increasing. While the relationship between the absoluteabundance of sedimentary diatom in coastal waters of the Taiwan Straitand the South China Sea and the water depth is not obvious.(4) Water depth of sampling （h） and winter sea-surface temperature (WST) play an important role for the diatom distribution. Between theenvironmental factors, water depth of sampling is the most important,controlling the distribution of diatoms in the surface sediments fromChinese inshore waters.(5) We have developed a transfer function between modern surfacesediment diatom species in Chinese inshore waters and temperature andwater depth. While they cannot be applied to the Holocene drillingsediments in coastal areas of China. In order to build a transfer functionwhich can be applied to the whole Chinese coastal waters, the modernsurface sediment diatom database in inshore areas should be expanded intoa database which contain minor diatoms and micro diatoms gradually.