Carbon regeneration in the Cariaco Basin, Venezuela.

Marquez, Arístides, Dale, Andrew W. , Ghinaglia, Luis Troccoli, Monroy, Fabiola López, Senior, William, Ríos, Aida, Karger, Frank Muller, Astor, Yrene and Varela, Ramón (2017) Carbon regeneration in the Cariaco Basin, Venezuela. Open Access Brazilian Journal of Oceanography, 65 (1). pp. 19-28. DOI 10.1590/S1679-87592017121406501.

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Abstract

The carbon regeneration in the water column of the Cariaco Basin (Venezuela) was investigated using a regression model of total alkalinity (TA) and the concentration of total inorganic carbon (TCO2). Primary productivity (PP) was determined from the inorganic carbon fraction assimilated by phytoplankton and the variation of the 22 and 23ºC isotherm was used as an indicator of coastal upwelling. The results indicate that CO2 levels were lowest (1962 µmol/kg) at the surface and increased to 2451 µmol/kg below the oxic-anoxic redox interface. The vertical regeneration distribution of carbon was dominated (82%) by organic carbon originating from the soft tissue of photosynthetic organisms, whereas 18% originated from the dissolution of biogenic calcite. The regeneration of organic carbon was highest in the surface layer in agreement with the primary productivity values. However, at the oxic-anoxic interface a second more intense maximum was detected (70-80%), generated by chemotrophic respiration of organic material by microorganisms. The percentages in the anoxic layers were lower than in the oxic zone because aerobic decomposition occurs more rapidly than anaerobic respiration of organic material because more labile fractions of organic carbon have already been mineralized in the upper layers.

Document Type: Article
Keywords: Cariaco Basin, Carbon regeneration, Water column, Coastal upwelling, R/V Hermano Gines
Research affiliation: OceanRep > GEOMAR > FB2 Marine Biogeochemistry > FB2-MG Marine Geosystems
Refereed: Yes
Open Access Journal?: Yes
DOI etc.: 10.1590/S1679-87592017121406501
ISSN: 1679-8759
Projects: Cariaco (Carbon Retention in a Colored Ocean)
Date Deposited: 27 Apr 2017 07:55
Last Modified: 01 Feb 2019 15:02
URI: http://oceanrep.geomar.de/id/eprint/37697

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