The content and distribution of biogenic silica were investigated in sedi- ment cores from Prydz Bay,Antarctica,during the CHINARE-18/21.cruise.The re- sults show that the content of biogenic silica(BSiO_2) is ranged from 4.89% to 85. 41%,and the average content of biogenic silica is 30.90%,the highest value oc- curred at theⅣ-10 station.The profile of BSiO_2 in sediment is contrast to that of sili- cate in the interstitial water.The content of biogenic silica and organic carbon in the surface sediments in the central area of Prydz Bay gyre were much higher than those in other area,and closely related to the Chla content and primary productivity of phyto- plankton in the surface water column.
The concentration and profile characters of nutrients in sediment pore water of the South Ocean,sampled during the cruise of CHINARE-18 of the austral summer 2001/02 were determined.The results show that the content of SiO3-Si and NH4-N were much higher than other nutrients.The profile of SiO3-Si was characterized with sharp gradients near the sediment-water interface,profile distribution of silicate show that during the diagenetic reaction of silicate,dissolution was the main part.The organic matter decomposition was occurred under the anaerobic condition.Benthic fluxes of SiO3-Si,NH4-N were from pore water to overlying water,and regeneration of silicate and ammonium were the main part of the nutrient regeneration from the pore water of the study area.
