Oceanographic Records of Microorganisms in the Surface Sediments from the Bering and Chukchi Seas
Based on the quantitative study of calcium (foraminifera and ostracoda) and siliceous (diatom, radiolarian and sponge spicule) microorganisms as well as the content of calcite in 41 surface sediments of the Chukchi and Bering Seas, we find that planktonic foraminifera are almost absent in the surface sediments, which could be attributed to the low surface primary productivity and strong carbonate dissolution in the studied area. On the contrary, benthic foraminifera are widely observed in most surface sediments. It has been revealed that the distributions of benthic foraminifera and siliceous microorganisms are mainly controlled by the sedimentary types, surface primary productivity, carbonate dissolution and water masses. On the shelf of Chukchi Sea the surface primary productivity is low due to the influence of sea ice, low sea surface temperature and salinity. As a consequence, benthic foraminiferal abundance and diversity are low, radiolarian disappear and only few ostracoda are counted, while diatoms and sponge spicules are abundant in the surface sediments. The surface primary productivity is much higher in the surface sediments on the slope of Bering Sea than that on the shelf of Chukchi Sea. Benthic foraminiferal abudance on the slope of Bering Sea is one order higher than that in the shelf of Chukchi Sea, and higher diversity is also observed in Bering Sea. Similar to calcium microorganisms, siliceous microorganisms (diatom, radiolarian and sponge spicule) are more abundant in Bering Sea than that in Chukchi Sea. According to the abundances of benthic foraminifera and siliceous microorganisms, as well as the ratio of benthic foraminiferal fauna of agglutinated tests and the contents of calcite changing with the water depth in the Bering Sea, carbonate lysocline and compensation depth (CCD) are probably located at the water depths of 2000 m and 3800 m respectively.
Berger, W.H. and E.L. Winterer (1974). Plate stratigraphy and the fluctuating carbonate line. In: Hsu, K.J. and H. Jenkins, (eds), Pelagic sediments on the land and in the ocean. Spec. Publs. Int. Assoc Sediment. 1: 11-48.
Blueford, J.R. (1981). Radiolaria from the Navarin Basin. In: Sea floor geologic hazards, sedimentology, and bathymetry: Navarin Basin Province, Northwest Bering Sea. Carlson, and H. Karl, (eds), U. S. Geological Survey Open-file Report, 1981, 81-1217, pp. 130-137.
Bond, G.C. and R. Lotti (1995). Iceberg discharges into the North Atlantic on millennial time during the last glaciation. Science, 267: 1005-1010.
Broecker, W.S. and G.H. Denton (1990). What drives Glacial cycles? Scientific American, 1: 49-56.
Carstens, J., Hebbeln, D. and G. Wefer (1997). Distribution of planktonic foraminifera at the ice margin in the Arctic (Fram Strait). Marine Micropalaeontology, 29(3-4): 257-269.
Chen Zhenbo, Shi Xuefa, Gao Aiguo and Ju Xiaohua (2000). Radiolaria fossils of the surface sediments in the Bering Sea and its sedimentary environment. Chinese Journal of Polar Research, 12(1): 24-31.
Chen, Ronghua, Xu Jian and Meng Yi (2003). Microfossils, carbonate lysocline and compensation depth in surface sediments of the northeastern South China Sea. Acta Oceanologica Sinica, 22(4): 597-606.
Douglas, R. and F. Woodruff (1981). Deep-sea benthic foraminifera. In: The Sea, The Oceanic Lithosphere. Emiliani, C. (ed.), John Willey & Sons, New York, 1: 1233- 1328.
Green, K.E. (1960). Ecology of some Arctic foraminifera. Micropalaeontology, 6(1): 57-78.
Lagoe, M.B. (1977). Recent benthic foraminifera from the central Arctic Ocean. Journal of Foraminiferal Research,7(2): 106-129.
Lagoe, M.B. (1979). Recent benthonic foraminiferal biofacies in the Arctic Ocean. Micropalaeontology, 25(2): 214-224.
Ling, H.Y. (1973). Radiolaria: Leg 19. In: Initial reports of the Deep Sea Drilling Project, Vol, 19, Creager, J.S., et al.,(eds.), U. S. Government Printing Office, Washington,pp. 777-797.
Ling, H.Y., Stadum, C.J. and M.L. Vilks (1970). Polycystine Radiolaria from Bering Sea surface sediment. Proceedings of the II Planktonic Conference, Edizioni Technoscienza, Roma, pp. 705-729.
Meng, Yi, Chen, Ronghua and Zheng Yulong (2002). Foraminifera in the surface sediments of the Bering and Chukchi Seas and its sedimentary environment. Acta Oceanologica Sinica, 21(1): 67-76.
Nigrini, C. (1970). Radiolarian assemblages in the North Pacific and their applications to a study of Quaternary sediments in core V 20-130. Geological Society of America Memoir, 126: 139-183.
Schröder, C.J., Cole, F., Medioli, F.S., Mudie, P.J., Scott, D.B. and L. Dobbin (1990). Recent Arctic shelf foraminifera: Seasonally ice covered vs. perennial ice covered areas. Journal of Foraminiferal Research, 20(1): 8-36.
Scott, D.B. and G. Vilks (1991). Benthonic foraminifera in the surface sediments of the deep-sea Arctic Ocean. Journal of Foraminiferal Research, 21(1): 20-38.
Takahashi, K. (1994). Opal particle flux in the subarctic Pacific and Bering Sea and sidocoenosis preser em. Proceedings of the 1994 Sapporo IGBP Symposium, Hokkaido University, Sapporo Hokkaido, Japan, 458-466.
Takahashi, K., Fujitani, N and M. Yanada et al. (1997). Five year long particle fluxes in the central subarctic Pacific and Bering Sea. In: Biogeochemical Processes in the North Pacific, Proc. Int. Mar. Sci. Sym., Mutsu, Japan,1996. Tsunogai S, Ed., Japan Marine Science Foundation, 277-289.
Vilks, G. (1969). Recent foraminifera in the Canadian Arctic. Micropalaeontology, 15(1): 35-60.
Wang, Pinxian, Bian, Y. and L. Wang (1995). Deep-Sea carbonate cycles[A]. Wang Pinxian et al. (eds.), The South China Sea since 150,000 years. Shanghai: Tongji University Press, 96-114.
Wollenburg, J.E. and W. Kuhnt (2000). The response of benthic foraminifers to carbon flux and primary production in the Arctic Ocean. Marine Micropalaeontology, 40(3): 189-231.