| Deep ocean benthic foraminiferal assemblages were analyzed for a quantitative relationship to surface ocean biological productivity. This analysis is based on the response of benthic foraminiferal assemblages to the surface ocean biological productivity for a global data set. Two-hundred-seven samples from the Atlantic, Pacific and Indian Ocean were selected from a restricted water depth range, so that the other environmental variables, such as temperature, salinity, pressure and nutrient concentration were nearly constant or uncorrelated to the productivity.;Statistical analysis demonstrates a strong relationship between benthic foraminiferal assemblage composition and the biological productivity of the surface ocean. Factor analysis of the Atlantic data set revealed distinct patterns of species abundance variation. Multivariate Regression Analysis has been used to quantify the relationship between the deep sea benthic foraminiferal assemblages composition and surface ocean productivity. The regression for the productivity yielded an r2 of 0.89, which reflects the clear relationship between benthic foraminiferal assemblage composition and the surface ocean productivity.;The response of benthic foraminiferal assemblages to the seasonality of the phytoplankton productivity, which controls the flux of the organic carbon to the sea bed, has also been tested using the global ocean data set. The response of benthic foraminiferal assemblage composition to seasonality was examined with Discriminant Function Analysis. A clear separation among the sample groups based on surface ocean productivity and the seasonality index has been found. Discriminant Function Analysis was also applied to test the response of benthic foraminiferal assemblages to different modes of seasonality observed in the Atlantic, Pacific and Indian Ocean. The analysis distinctly separates the samples into groups representing strong seasonality and low seasonality settings.;The results show that there is an intimate relationship between benthic foraminiferal assemblages and surface ocean productivity. The distribution of benthic foraminiferal assemblages can be used as proxies for the surface ocean productivity during the geological past, if a reasonable calibration of the data set is developed. This descriptive ability will aid in modeling the global response of the marine biotic system to climate change and the behavior of marine biogeochemical cycles. |
