During this period, organic matter becomes the central lens for marine pollution, with attention to dissolved organic carbon, detritus, and organic acids as drivers of seawater chemistry and contaminant dynamics. Oil pollution research expands to address occurrence, fate, and ecological effects, while nutrient biogeochemistry highlights nitrate cycling and nitrogen isotope signals as key controls on seawater composition. Studies of trace metals and particulate matter reveal how metal distributions, speciation, and detrital fluxes influence pollutant behavior and vertical mixing.