Particulate Biogenic Silica In The Jiaozhou Bay And East China Sea

Biogenic silica (BSi) is produced in the euphotic zone of the ocean by siliceous plankton such as diatoms. Due to the major role played by diatoms in the biological pump of CO2, biogenic silica may has a close coupling in the global carbon cycle. In addition, the accumulation of biogenic silica in the ocean floor can reflect the spatial and temporal distributions of productivity.Until now no one method is accepted as the standard by the scientific community. Problems of the measurement of biogenic silica (BSi) in the suspended matter were studied. On the base of the method published by Ragueneau et al. (Ragueneau et al.,2005. A new method for the measurement of biogenic silica in suspended matter of cosastal waters: using Si:Al ratios to correct for the mineral interference. Continental Shelf Research,25,697-710.), we carried out a series of experiments. The method of Ragueneau et al.(2005) then has been modified to add another NaOH digestion with the objective of overcoming the cellulose acetate filter interference without loosing precision. The calibrated BSi concentration is given by a new equation: [BSi] = [Si]1 + [Si]2– [Al]1*(Si:Al)3- [Al]2*(Si:Al)3. The revised method and original method give no significant differences with t-test at 99% confidential.Seawater samples ware collected to measure PBSi(Particulate Biogenic Silica) concentrations during 3 cruises in neap tide in October 2002 and in both neap and spring tides in May 2003 in the Jiaozhou Bay. The relationships between PBSi and other environmental factors including nutrients, SPM, POC, were discussed in this paper. The correlation of PBSi with silicate was significant and there was a weaker positive correlation between PBSi and SPM or POC. The seasonal variability of PBSi has close link to the change of phytoplankton community structure.The PBSi content in the PN section of the East China Sea ranged from 0.01 to...