Fig 1.
Reference map of the study site.
Northeastern continental margin of Brazil, within the Sergipe–Alagoas sedimentary basin. Blue shades, local depth; yellow lines, sampling transects A, B, C, and D; blue line, São Francisco river; dark green filled shape, Brazilian states that are adjacent to transects.
Table 1.
Profiling stations by transect A, B, C, and D.
Station: Identification number; Dist: Distance from the shoreline to each station (km).
Table 2.
Fieldwork recognition of the water masses (Wm).
Thermohaline limits, sampling depths, and referential depths [20].
Fig 2.
T-S diagram indicating the distinct water masses from the studied area (maritime sedimentary SEAL basin).
Table 3.
Total alkalinity measured from 5 replicates of the certified reference material (Dickson, oceanic CO2 measurements, batch 134).
Table 4.
Temperature (°C) and salinity (g/kg) for each water mass (Wm).
Comparison with previously published results.
Table 5.
Calcium and total boron concentrations (μmol/kg; mean ± standard deviation) in water samples from 34 stations.
Analytically obtained levels: microwave-induced plasma atomic emission spectrometry. Predicted concentrations: calculated using the AQM program using the absolute salinity scale (g/kg). When calculating the relative error (RE%), the expected value is the analyzed value.
Table 6.
Variations in the carbonate system parameters as a function of the minimum (a, c) and maximum (b, d) values found for Ca2+ and BT (Table 5).
Values obtained with the AQM program keeping the temperature (25°C), salinity (35 g/kg), pHT (8.0), and TA (2300 μmol/kg) variables constant at the program entry. The expected value is the analyzed value.
Table 7.
Effects of the practical (psu) and absolute salinity (g/kg) scales when generating the carbonate system parameters.
Values obtained from calculated total alkalinity with the AQM program [1, 13–15]. Further information can be found in the methodology section. In calculating the relative error (RE%), the parameters obtained by the absolute salinity (g/kg) are the expected values.
Table 8.
Variations in TA (μmol/kg) were obtained analytically and calculated with the AQM program [1, 13–15].
In calculating the relative error (RE%), the values obtained analytically are the expected values (see item Analytical Procedure: TA and Table 3).
Fig 3.
Temperature, Salinity, pH, and Normalized Total Alkalinity (NTA) of the sampling transects, from the internal platform to the abyssal plain.
Fig 4.
Aragonite saturation state (S-Aragonite), carbon dioxide, total dissolved carbon (DIC), carbonate, and calcite saturation state (S-Calcite) from sampling transects: From the internal platform to the abyssal plain.