Evidences of climate change impacts on the global carbon cycle in upwelling areas

Chair: Yuri Artioli

Melchor González-Dávila*, J. Magdalena Santana Casiano and Francisco Machín

Instituto de Oceanografía y Cambio Global, Grupo QUIMA, Universidad de Las Palmas de Gran Canaria, 35017, Las Palmas de Gran Canaria. Spain.

Coastal upwelling along the eastern margins of major ocean basins are regions of large economic importance due the high biological production. However, the physical forcing of upwelling processes that favor the production in these areas are being affected by global warming. For this reason, the role of observations in addressing climate change impacts on the global carbon cycle in upwelling areas is of primary importance.

A monthly high resolution surface experimental data for temperature and partial pressure of carbon dioxide in the Mauritanian upwelling from 2005 to 2012 has been realized.

This data set provides directly evidence of seasonal and interannual changes in the physical and biochemical processes that confirm an uwpelling intensification and an increase in the CO2 outgassing in the 10ºN – 27ºN region, one of the four most important upwelling regions of the planet.
The integrated CO 2 fluxes for the area were between 2.3 to 3.1 106 mol, with an increase during the studied period of 0.1106 mol yr-1. The increase in FCO2 is related to the observed increase in wind speed north of 16ºN that far surpassed the effect of the smaller annual rate of increase in fCO2sw that in fCO2atm north of 19ºN. South of 16ºN, the decrease in wind speed does not exceed the effect of the increase in ΔfCO2, and FCO2 is still slightly increasing.

The Mauritanian upwelling has being shown as an important area sensitive to climate changes due to upwelling intensification, which strongly affects the CO2 surface distribution, ocean acidification rates and air-sea CO2 exchange.