Accumulation of Suspended Barite at Mesopelagic Depths and Export Production in the Southern Ocean

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Science  20 Nov 1992:
Vol. 258, Issue 5086, pp. 1332-1335
DOI: 10.1126/science.258.5086.1332


The relation between the accumulation of barite (BaSO4) microcrystals in suspended matter from the mesopelagic depth region (100 to 600 meters) and the type of production in the euphotic layer (new versus recycled) was studied for different Southern Ocean environments. Considerable subsurface barite accumulated in waters characterized by maintained new production and limited grazing pressure during the growth season. On the other hand, little if any barite accumulated in areas where relatively large amounts of photosynthetically fixed carbon were transferred to the microheterotrophic community and where recycled production became predominant.