Dataset: Surface pCO2, bottle-corrected Chl a, and shipboard wind speed from cruises conducted during 2010, 2011, and 2012 off the Northeast coast of Brazil in the Amazon River Plume as part of the ANACONDAS project

Final no updates expectedDOI: 10.26008/1912/bco-dmo.849870.1Version 1 (2021-04-20)Dataset Type:Cruise Results

Principal Investigator: Patricia L. Yager (University of Georgia)

Contact: Linquan Mu (University of Georgia)

BCO-DMO Data Manager: Shannon Rauch (Woods Hole Oceanographic Institution)


Program: Integrated Marine Biogeochemistry and Ecosystem Research -US (IMBER-US)

Program: Ocean Carbon and Biogeochemistry (OCB)

Program: Emerging Topics in Biogeochemical Cycles (ETBC)

Program: Marine Microbiology Initiative (MMI)

Project: Amazon iNfluence on the Atlantic: CarbOn export from Nitrogen fixation by DiAtom Symbioses (ANACONDAS)


Abstract

Surface pCO2, bottle-corrected Chl a, and shipboard wind speed from three cruises conducted off the Northeast coast of Brazil in the Amazon River Plume as part of the ANACONDAS project. Cruise AN10 took place on R/V Knorr (KN197-08) from May-June 2010; cruise AN11 took place on R/V Melville (MV1110) from September-October 2011; and cruise AN12 took place on R/V Atlantis (AT21-04) during July 2012.

Methodology Summary
SST and SSS were continuously monitored using an in-line Seabird thermosalinograph. Chlorophyll a fluorescence (FLR) was recorded by a fluorometer mounted 5-7 m below sea surface, which was then converted to chlorophyll a concentration (Chla) using a linear regression of FLR against discrete Chla measurements of surface water samples collected with Niskin bottles during each cruise. True wind speed was measured shipboard by meteorological instruments on each vessel. Wind speed at 10 m above sea surface (U10) was corrected from instrument heights based on Thomas et al. (2005). Partial pressure of carbon dioxide at sea surface (pCO2_sw) was determined with a showerhead-type pCO2 analyzer (Bates et al., 1998; Sweeney et al., 2000; Takahashi et al., 1997) and an infrared CO2 detector at in-situ SST (Cooley et al., 2007).

pCO2 sampling procedures
The volumetric concentration of CO₂ (xCO₂(sw), in ppm) was automatically calibrated at least hourly against six CO₂-N₂ gas mixtures containing 0–510 ppm CO2 (Certified by the National Oceanographic and Atmospheric Administration Climate Monitoring and Diagnostics Laboratory, NOAA CMDL, Boulder, Colorado, USA). Sea surface pCO₂ was converted from xCO₂(sw) and corrected to in-situ SST (see Weiss & Price, 1980, and Takahashi et al., 1993, for details). The gas stream between the equilibrator and the detector was dried, but this filter sometimes failed, leaving gaps in the data along the cruise track where water vapor overwhelmed infrared detection of CO₂. These system failures were apparent and easily removed manually. Instrument accuracy was ±1 µatm and the response (e-folding; Cooley et al., 2007) time was 6, 2, 10 mins for cruises during June 2010, July 2012, and September 2011, respectively.

More details on methodology can be found in Mu et al. (2021).


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Results

Mu, L., Gomes, H. do R., Burns, S. M., Goes, J. I., Coles, V. J., Rezende, C. E., Thompson, F. L., Moura, R. L., Page, B., & Yager, P. L. (2021). Temporal Variability of Air‐Sea CO2 flux in the Western Tropical North Atlantic Influenced by the Amazon River Plume. Global Biogeochemical Cycles, 35(6). Portico. https://doi.org/10.1029/2020gb006798
General

Weiss, R. F., & Price, B. A. (1980). Nitrous oxide solubility in water and seawater. Marine Chemistry, 8(4), 347–359. doi:10.1016/0304-4203(80)90024-9
Methods

Bates, N. R., Takahashi, T., Chipman, D. W., & Knap, A. H. (1998). Variability of pCO2 on diel to seasonal timescales in the Sargasso Sea near Bermuda. Journal of Geophysical Research: Oceans, 103(C8), 15567–15585. doi:10.1029/98jc00247
Methods

Cooley, S. R., & Yager, P. L. (2006). Physical and biological contributions to the western tropical North Atlantic Ocean carbon sink formed by the Amazon River plume. Journal of Geophysical Research, 111(C8). doi:10.1029/2005jc002954
Methods

Sweeney, C., Hansell, D. A., Carlson, C. A., Codispoti, L. ., Gordon, L. I., Marra, J., … Takahashi, T. (2000). Biogeochemical regimes, net community production and carbon export in the Ross Sea, Antarctica. Deep Sea Research Part II: Topical Studies in Oceanography, 47(15-16), 3369–3394. doi:10.1016/s0967-0645(00)00072-2