sentences:  His work has shed light on the factors responsible for the wide compositional variability of marine sediments, the controls on organic matter burial and nutrient utilization in the ocean.Calvert utilizes a combination of organic, inorganic and stable isotopic information to reconstruct past sea surface temperatures, plankton production, terrestrial sediment supply and transport modes, nutrient utilization and bottom water oxygen concentrations.Calvert was born in London, England in 1935.