Rivers and other inland waters play a critical role in connecting the biogeochemical cycles of land, oceans, and atmosphere. They transport and process large amounts of carbon (C) and other elements, with the magnitude of C fluxes comparable to the net ecosystem C balance of the terrestrial ecosystems in their watersheds. Much of this C is returned to the atmosphere as CO₂ or buried in sedimentary deposits within inland waters, lakes, and wetlands. Human activities significantly influence these processes, affecting carbon and mineral cycles through erosion, chemical weathering, and changes in land use. Rivers are not merely passive conduits but active agents in biogeochemical coupling, influencing the transfer of nutrients and carbon between land and ocean. The amount of C delivered to the oceans is only a fraction of that entering rivers from terrestrial ecosystems. Most of this C is returned to the atmosphere as CO₂ or stored in sedimentary deposits. Human-induced chemical weathering of minerals in watersheds can lead to coastal acidification, altering the carbonate buffering system and affecting marine organisms that rely on calcium carbonate for shell and skeleton formation. The study highlights the importance of rivers in the global carbon cycle, emphasizing the need to consider lateral C exports when assessing terrestrial net ecosystem carbon balance. It also underscores the significant role of erosion in C sequestration, with human activities accelerating this process and increasing continental C burial. The study further discusses the impact of riverine alkalinity and major ions on coastal responses to ocean acidification, showing how human activities within watersheds can influence mineral weathering and coastal chemistry. The research concludes that rivers and inland waters are essential for understanding and managing the Earth's biogeochemical systems, linking terrestrial, oceanic, and atmospheric processes. The traditional view that rivers export only 1% of terrestrial gross primary production is being replaced by the understanding that rivers receive, transport, and process the equivalent of terrestrial net ecosystem production. This highlights the critical role of rivers in the global carbon cycle and the need for integrated approaches to manage the impacts of climate change and land-use change on these systems.Rivers and other inland waters play a critical role in connecting the biogeochemical cycles of land, oceans, and atmosphere. They transport and process large amounts of carbon (C) and other elements, with the magnitude of C fluxes comparable to the net ecosystem C balance of the terrestrial ecosystems in their watersheds. Much of this C is returned to the atmosphere as CO₂ or buried in sedimentary deposits within inland waters, lakes, and wetlands. Human activities significantly influence these processes, affecting carbon and mineral cycles through erosion, chemical weathering, and changes in land use. Rivers are not merely passive conduits but active agents in biogeochemical coupling, influencing the transfer of nutrients and carbon between land and ocean. The amount of C delivered to the oceans is only a fraction of that entering rivers from terrestrial ecosystems. Most of this C is returned to the atmosphere as CO₂ or stored in sedimentary deposits. Human-induced chemical weathering of minerals in watersheds can lead to coastal acidification, altering the carbonate buffering system and affecting marine organisms that rely on calcium carbonate for shell and skeleton formation. The study highlights the importance of rivers in the global carbon cycle, emphasizing the need to consider lateral C exports when assessing terrestrial net ecosystem carbon balance. It also underscores the significant role of erosion in C sequestration, with human activities accelerating this process and increasing continental C burial. The study further discusses the impact of riverine alkalinity and major ions on coastal responses to ocean acidification, showing how human activities within watersheds can influence mineral weathering and coastal chemistry. The research concludes that rivers and inland waters are essential for understanding and managing the Earth's biogeochemical systems, linking terrestrial, oceanic, and atmospheric processes. The traditional view that rivers export only 1% of terrestrial gross primary production is being replaced by the understanding that rivers receive, transport, and process the equivalent of terrestrial net ecosystem production. This highlights the critical role of rivers in the global carbon cycle and the need for integrated approaches to manage the impacts of climate change and land-use change on these systems.