Environmental distribution of Recent benthic foraminifera on the northeast United States continental slope

Abstract

Several bathymetrically consistent Recent benthic foraminiferal biofacies have been recognized from the continental slope south-east of Cape Cod. Faunal assemblages are dominated by Globobulimina / Bulimina (upper slope; less than 1,000 m) and Uvigerina peregrina (lower slope-uppermost rise; water depths between 1,000 and 2,500 m). The Globobulimina / Bulimina assemblage coincides with the oxygen minimum zone; this agrees with the occurrence of Globobulimina in Mediterranean sapropels, organic-rich sediments deposited under anoxic conditions. Previous studies have noted the association of U. peregrina with bathyal water depths, deep-water temperatures of 3 to 4 ° C, and water of low oxygen content. However, correlations between abundance of U. peregrina and water depth or temperature are not the same everywhere, and no correlation with dissolved oxygen in the water column is seen on the United States continental slope and rise. The highest abundances of U. peregrina coincide with maxima of organic carbon and silt within the slope sediments. This suggests that the distribution of U. peregrina in this region may be influenced more by low oxygen in the sediments, rather than by low oxygen content of the overlying water.