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Widespread sediment resuspension and transport processes on continental margins can modify deposits and influence the preservation of particulate organic carbon (POC) in marine sediments. However, it remains unclear how post‐depositional processes interact with physical mineral protection to affect the transport and fate of terrestrial POC along the river‐estuary‐shelf paths. Here, we synthesized literature data and newly obtained results from multiple analyses of sedimentology, mineralogy, and inorganic and organic geochemical tracers. Our goal was to quantitatively evaluate the impact of sediment reworking on the redistribution and further transformations of terrestrial POC at the Yangtze River‐ocean interface. Our results reveal that sediment resuspension resulting from physical forces along with mineral protection of phyllosilicates plays a crucial role in regulating the recycling and fate of terrestrial POC during its transport across the coastal ocean continuum. Physical processes lead to the resuspension of sequestered POC from suboxic/anoxic muddy sediments into the overlying water column. Concurrently, the interplay of energetic forcing and elevated oxygen levels has the potential to disrupt the organo‐mineral associations. The decrease in mineral‐carbon stabilization increases the likelihood that reactive POC inclusion/aggregation with minerals becomes accessible to surrounding microorganisms, making it susceptible to microbial/oxidative degradation. Consequently, mostly phyllosilicate‐protected 14C‐depleted POC (primarily soil‐derived) in <63 μm suspended sediment (>90% of the total mass) remains available for export and reburial in continental shelf sediments. The lateral transport of resuspended sediments from estuaries, previously underestimated, represents a potential contributor to the remobilized millennial‐aged POC components involved in active biogeochemical cycling on continental margins. Plain Language Summary: River‐dominated Ocean Margins (RiOMar) play a crucial role in the global biogeochemical cycling of organic carbon (OC) because they receive substantial riverine inputs of particulate matter and bound organic materials. Among the present‐day oceans, the largest repositories for OC burial are found in large river‐dominated estuaries and deltas. When disturbed, OC deposited in seafloor sediments can be converted to dissolved inorganic carbon—either releasing it as carbon dioxide into the atmosphere or sequestering it within marine sediments. This study found that sediment reworking and remobilization by physical forces within the Yangtze River Estuary contribute to the degradation and aging of particulate OC (POC). Such disturbed processes may reduce the potential for carbon storage in marine sediments. Repeated cycles of sediment setting and resuspension enhance the significance of residual aged terrestrial POC associated with phyllosilicate minerals. This alteration affects the distribution and quantity of fluvial POC before it reaches the coastal oceans. As estuaries are highly vulnerable to human pressures and widespread climate change, the resuspension of estuarine sediments is expected to be an essential factor influencing the long‐term preservation of OC in marine sediments. Key Points: Disruption of organo‐mineral associations by sediment reworking enhances the respiration and aging of terrestrial biosphere carbonDynamic resuspension/deposition loops in energetic estuaries modify the quality and quantity of riverine organic carbonRepeated cycles of particle deposition/resuspension within the estuary leave unreactive terrestrial carbon buried in the shelf depocenter [ABSTRACT FROM AUTHOR]

Characterizing and understanding the changes in the flow regimes of rivers have been challenging. Existing global river network data sets are not updated and can only identify rivers wider than 30 m. We propose a novel automated method to map river networks on a monthly basin scale for the first time at 10‐m resolution using Sentinel‐1 Synthetic Aperture Radar, Sentinel‐2 multispectral images, and the AW3D30 Digital Surface Model. This method achieved an overall accuracy of 95.8%. The total length of the Yellow River network produced is 40,280 km, approximately 3.2 times that of the Global River Widths from Landsat (GRWL) database, more effectively covering small and medium rivers. The monthly river geometry revealed a positive correlation between river network area and precipitation. This study is expected to provide a cost‐effective alternative to accurately mapping global river networks and advance our understanding of the changes and drivers of river systems. Plain Language Summary: Understanding the impacts of climate change and human activities on water resources across different regions greatly depends on the knowledge of river networks with high spatial and temporal resolution. Small tributaries are important components in river network evolution and water transmission. To date, several studies have mapped interannual variations in rivers with widths >30 m; however, the distribution and variations in small rivers remain unclear. By integrating multispectral and radar satellite remote sensing images as well as topographic data, we created continuous monthly river network maps at the basin scale, allowing us to capture the details of dynamic changes in river networks with higher spatiotemporal resolution. As a result, the method used in this study provides detailed information on small and medium rivers, with the length of the connected rivers being thrice that of the existing data sets. We demonstrate the possibility of mapping global river networks monthly at a resolution of 10 m, providing valuable information for global surface water resource planning and management and improving our understanding of spatial links between land and water interfaces. Key Points: We proposed a new method for mapping 10 m resolution continuous river networks on a monthly basin scale using satellite images and DEMsThis method provided detailed information on small‐ and medium‐sized rivers with an overall accuracy of 95.8%There is a strong positive correlation between monthly river network area and precipitation [ABSTRACT FROM AUTHOR]