Abstract

SANCHEZ, Alberto et al. Accumulation of total organic carbon and calcium carbonate in the oxygen minimun zone of the notheastern Pacific of Mexico. Rev. mex. cienc. geol [online]. 2013, vol.30, n.1, pp.222-232. ISSN 2007-2902.

The distribution and preservation of the total organic carbon (TOC) and CaCO₃ in marine sediments is important because its connection to the carbon cycle and the regulation of atmospheric CO₂. Studies of the sinking, accumulation and carbon burial are limited and therefore it is necessary to know, identify and quantify the content of this element in marginal sediments. In the present work was determined the distribution and accumulation of TOC and CaCO₃ in surface sediments with different conditions of oxy-genation of the water column in the southwestern margin of the Peninsula of Baja California. The highest accumulation of TOC occurred over a wide oxygen minimum zone (OMZ), TOC gradually decreases towards the coastline. The deposition and accumulation of CaCO₃ was preferentially higher in the region where the OMZ is narrow and deep. The 2 to 8% of TOC generated in the photic zone is preserved and buried in the sediment, being consistent with values calculated by models of the ocean biological pump. The TOC and CaCO₃ accumulation suggest that this region is important and key in the global carbon cycle of the ocean, and contributed significantly in regulating the climate changes in the past.

Keywords : biological pump; total organic carbon; calcium carbonate; oxygen minimum zone; northeast Mexican Pacific.

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