THE EFFECT OF ANNUAL RESOURCE STABILITY ON DEEP-SEA BENTHIC BIODIVERSITY

The effects of primary productivity and seasonality of productivity on North Atlantic benthos are assessed by comparing benthic foraminifera, isopod, bivalve, and gastropod data with productivity and seasonality of productivity estimates from SeaWiFS. Benthic foraminifera exhibit high values of H(S), species number, and species equitability from 0-40^oN and are associated with low seasonality, while generally lower values are found from 40 to 60^oN in areas with high seasonality and phytodetritus deposition. Diversity data are not correlated with mean annual productivity or temperature, salinity, dissolved oxygen, and pH of the bottom waters. Isopod, gastropod, and bivalve diversity data from Rex et al. (2000) show strong relationships with seasonality, with low biodiversity found in northern latitudes with high seasonality. In addition, a multiple regression of the isopod, bivalve, and gastropod data shows that isopod species number and H are correlated with both dissolved bottom water oxygen and seasonality.

Low diversity found in areas experiencing highly seasonal productivity, organic carbon flux and phytodetritus deposition does not support the suggestions that patch dynamics or biological disturbance create high diversity in the deep sea. The meiofaunal and macrofaunal data suggest that annual resource stability, as reflected in seasonal food availability, has a significant effect on benthic biodiversity patterns in the North Atlantic.