Factors Controlling the Abundance of 13C in Algal and Sedimentary Biomarkers from the Amundsen and Bellingshausen Seas, Antarctica

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9418833 Hayes This project deals with the general question of the interpretation of paleoceanographic information that is encoded in the organic debris of sea floor muds and sediment cores, that is, what is the relationship between the sedimentary carbon and nitrogen isotopes of organic molecules and contemporary oceanographic conditions. Specifically the linkages among types of algae, conditions of their growth, and the concentration of organic and inorganic nutrients will be examined through the analysis of seawater and sediment samples obtained from the Bellinghausen and Amundsen Seas in early 1994. Particular emphasis will be placed on the relationship between the Carbon-13 content of specific species of algae, and the concentrations of nitrate, phosphate, and dissolved carbon dioxide in the water column. The seas surrounding Antarctica are important in this context because of their presumptive importance in regulating global climate patterns. On the global scale, measurements of sedimentary Carbon-13 are made routinely in the context of biogeochemical cycling studies. However the association of Carbon-13 isotopic variability with particular processes or phenomena that appear statistically valid in one region are generally found not to be valid in others, implying that small-scale relationships cannot simply be generalized to large-scale relationships. The advantage of analyzing this particular data set lies in the fact that a large body of ancillary information was obtained on the cruise, and therefore the strong potential exists to tie together existing, but less complete, data sets in addition to elucidating temperature effects on underlying biochemical processes, and defining specifically antarctic processes. ***