The distribution of diverse lithology and human activities impacts the water chemistry and carbon biogeochemistry of river systems.Major ion chemistry and dissolved inorganic carbon(DIC)in the urban rivers at Tianjin ...The distribution of diverse lithology and human activities impacts the water chemistry and carbon biogeochemistry of river systems.Major ion chemistry and dissolved inorganic carbon(DIC)in the urban rivers at Tianjin City,China,were examined based on a temporal and spatial sampling scheme in 2021.The concentrations of major ions exhibited significant spatial variations,showing agricultural input in the upstream and urban pollution in the downstream.The isotopic composition(δ^(13)C)of DIC in the rivers ranges from-12.39‰to-0.45‰,indicating partial equilibrium between the water and the atmosphere in some waters due to long residence time,whereδ^(13)C is typically 0‰.The waters with more negativeδ^(13)C values showed that biological CO_(2) was a major contributor to DIC in most rivers.It experienced slightly more depletion during the wet season than in the dry season,reflecting strong degradation of organic matter in summer.The seasonal variations likely reflected changes in metabolic processes in the river in addition to alterations in the hydrological regime,highlighting the implications of freshwater given geoscientific,ecological,and environmental aspects.Essential aspects of human activities,including agriculture,urban development,and dam construction,significantly influence the dynamics of water chemistry and DIC.The study highlighted that variations in lithology and hydrology significantly affect the spatial and temporal changes in water chemistry and carbon geochemistry within river systems.展开更多
基金funded by the National Natural Science Foundation of China[grant No.42221001]。
文摘The distribution of diverse lithology and human activities impacts the water chemistry and carbon biogeochemistry of river systems.Major ion chemistry and dissolved inorganic carbon(DIC)in the urban rivers at Tianjin City,China,were examined based on a temporal and spatial sampling scheme in 2021.The concentrations of major ions exhibited significant spatial variations,showing agricultural input in the upstream and urban pollution in the downstream.The isotopic composition(δ^(13)C)of DIC in the rivers ranges from-12.39‰to-0.45‰,indicating partial equilibrium between the water and the atmosphere in some waters due to long residence time,whereδ^(13)C is typically 0‰.The waters with more negativeδ^(13)C values showed that biological CO_(2) was a major contributor to DIC in most rivers.It experienced slightly more depletion during the wet season than in the dry season,reflecting strong degradation of organic matter in summer.The seasonal variations likely reflected changes in metabolic processes in the river in addition to alterations in the hydrological regime,highlighting the implications of freshwater given geoscientific,ecological,and environmental aspects.Essential aspects of human activities,including agriculture,urban development,and dam construction,significantly influence the dynamics of water chemistry and DIC.The study highlighted that variations in lithology and hydrology significantly affect the spatial and temporal changes in water chemistry and carbon geochemistry within river systems.
