Fig. 6.

Estuarine TA or DIC mixing lines between the river and ocean endmembers with additional CO₂ added in from anthropogenic sources and respiration. Line 1 is river-ocean mixing of TA, line 2 is river-ocean mixing of DIC, line 3 is mixing DIC plus anthropogenic CO₂ addition, line 4 is mixing DIC plus respiratory CO₂ addition, and line 5 is mixing DIC plus both anthropogenic and biological CO₂ additions. The crossover points are river–ocean mixing lines of TA with A river–ocean mixing lines of DIC, B mixing plus anthropogenic CO₂, C mixing plus CO₂ from respiration, and D mixing plus CO₂ from both B and C