Table 3 Dissolved Inorganic Carbon (DIC) distributions and fluxes in Tagus estuary. Equations are polynomial equations used to fit the data from DIC versus salinity for each sampling transects. All equations have p < 0.05. C0 and CS are, respectively, freshwater and seawater DIC concentrations. The flux of freshwater DIC is defined as (Q · C0), whereas the flux of internal DIC is (Q · (CS − C0)) and the estuarine flux is (Q · CS). Q represents the Tagus River flow.
From: Inorganic carbon distribution and CO2 fluxes in a large European estuary (Tagus, Portugal)
Season | Sampling dates | DIC (µmol kg−1) as a function of S | r2 | C0 a (µmol kg−1) | CS b (µmol kg−1) | Freshwater DIC Flux (106 mol C d−1) | Internal DIC Flux (106 mol C d−1) | Estuarine DIC Flux (106 mol C d−1) |
|---|---|---|---|---|---|---|---|---|
Spring | May 2000 | 43.1 S + 1540.7 | 0.774 | 1540.7 | 1540.7 | 51.0 | 0 | 51.0 |
Winter | March 2001 | −29.2 S2 + 230.0 S + 1110.5 | 0.628 | 1110.5 | 2151.2 | 179.2 | 167.9 | 347.1 |
Summer | July 2001 | 23.5 · S + 1815.0 | 0.903 | 1815.0 | 1815.0 | 16.6 | 0 | 16.6 |
Summer | June 2002 | −1.5 S2 + 63.4 S + 2481.5 | 0.527 | 2481.5 | 4243.2 | 17.8 | 12.6 | 30.5 |
Spring | May 2003 | 14.4 S + 1818.4 | 0.948 | 1818.4 | 1818.4 | 37.6 | 0 | 37.6 |
Winter | February 2004 | 0.7 S2 + 6.7 · S + 1832.7 | 0.602 | 1832.7 | 1445.8 | 42.5 | −9.0 | 33.5 |
Spring | May 2006 | −1.3 · S2 + 59.6 S + 1704.1 | 0.629 | 1704.1 | 3018.7 | 18.9 | 14.6 | 33.5 |
Autumn | November 2006 | 21.2 S + 2010.5 | 0.739 | 2010.5 | 2010.5 | 136.4 | 0 | 136.4 |
Annual mean values (Tg C yr−1) | 0.27 | 0.10 | 0.37 | |||||
