A source of CO2 to the atmosphere throughout the year in the Maranhense continental shelf (2°30'S, Brazil)

• DOI: 10.1016/j.csr.2017.05.004
• Publication Date: 2017-05-12T23:30:19Z
• Authors: Nathalie Lefèvre; Francisco Jose da...; Audálio Rebelo de...; Carlos Noriega; Moacyr Araujo; Antonio Carlos Le...; Carlos Rocha; Shan Jiang; J. Severino P. Ib...
• Keywords: Alkalinity

To reduce uncertainty regarding the contribution of continental shelf areas in low latitude regions to air-sea CO2 exchange, more data are required understand carbon turnover these and cover gaps coverage. For first time, inorganic alkalinity were measured along a cross-shelf transect off coast Maranhão (North Brazil) 9 cruises spawning from April 2013 September 2014. On last 4 transects, dissolved organic matter nutrients also measured. The highest concentrations observed close land. As result productivity significant remineralization, heterotrophy dominates throughout year. Although temporal variability is significantly reduced at offshore station with decreasing seaward, fugacity (fCO2) this remains higher, especially during wet season, than open ocean values routinely by merchant ship further west. Overall, weak source atmosphere year an annual mean flux 1.81±0.84 mmol m−2 d−1. magnitudes fCO2 season when winds weakest. result, does not show clear seasonal pattern. Further offshore, lower on shelf. However, oceanic flux, 2.32±1.09 d−1, statistically different because wind stronger ocean.