Soil erosion by water impacts soil organic carbon stocks and alters CO 2 fluxes exchanged with the atmosphere. The role of erosion as a net sink or source of atmospheric CO 2 remains highly debated, and little information is available at scales larger than small catchments or regions. This study attempts to quantify the lateral transport of soil carbon and consequent land−atmosphere CO 2 fluxes at the scale of China, where severe erosion has occurred for several decades. Based on the distribution of soil erosion rates derived from detailed national surveys and soil carbon inventories, here we show that water erosion in China displaced 180 ± 80 Mt C·y −1 of soil organic carbon during the last two decades, and this resulted a net land sink for atmospheric CO 2 of 45 ± 25 Mt C·y , equivalent to 8-37% of the terrestrial carbon sink previously assessed in China. Interestingly, the "hotspots," largely distributed in mountainous regions in the most intensive sink areas (>40 g C·m ), occupy only 1.5% of the total area suffering water erosion, but contribute 19.3% to the national erosion-induced CO 2 sink. The erosion-induced CO 2 sink underwent a remarkable reduction of about 16% from the middle 1990s to the early 2010s, due to diminishing erosion after the implementation of large-scale soil conservation programs. These findings demonstrate the necessity of including erosion-induced CO 2 in the terrestrial budget, hence reducing the level of uncertainty.land−atmosphere CO 2 flux | soil carbon displacement | water erosion | national scale T errestrial ecosystems are a net sink of anthropogenic CO 2 globally (1, 2) but can be net sources or sinks regionally [e.g., Northeast Region of China (3)]. Knowledge of the distribution, magnitude, and variability of land carbon fluxes and underlying processes is important both for improving model-based projections of the carbon cycle and for designing ecosystem management options that effectively preserve carbon stocks and enhance carbon sinks. Despite considerable efforts made by the research community, the mechanisms governing uptake or release of carbon from land ecosystems are still poorly quantified (4).Soil erosion occurs naturally but is accelerated by human cultivation of the landscape, and modifies CO 2 exchange (5) between the soil and atmosphere. Soil erosion destroys the physical protection of carbon in soil aggregates and accelerates decomposition, inducing a net CO 2 source. Continuous erosion over a long period can destabilize carbon in deeper soil horizons and trigger its decomposition e.g., as conditions of temperature and moisture become more favorable (6, 7). Soil erosion also decreases nutrient availability and reduces soil water holding capacity, affecting ecosystem productivity (8) with feedback to the ecosystem carbon balance. However, because only a fraction of eroded carbon is lost to the atmosphere, the rest may be lost to streams and rivers and eventually delivered to marine ecosystems or deposited in the landscape. With the fine and light soil particles p...

Implications of water-sediment co-varying trends in large rivers Science Bulletin 65, 4 (2020); Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow Science in China Series E-Technological Sciences 47, 186 (2004); Water demand for ecosystem protection in rivers with hyper-concentrated sediment-laden flow Science in China Series E-Technological Sciences 47, 186 (2004); Regional variation of sediment load of Asian rivers flowing into the ocean Science in China Series B-Chemistry 44, 23 (2001); Sr fluxes and isotopic compositions of the eleven rivers originating from the Qinghai-Tibet Plateau and their contributions to 87 Sr/ 86 Sr evolution of seawater

Antibiotics have received extensive attention due to their sophisticated effects on human health and ecosystems. However, there is an extreme scarcity of information on composition, content, geographic distribution, and risk of riverine antibiotics at a large spatial scale. Based on a systematic review of over 600 pieces of literature (1999-2021), we established a global dataset containing more than 90,000 records covering 169 antibiotics and their metabolites in surface water and sediment across 76 countries. The occurrence of prioritized antibiotics largely depended on socioeconomic developmental levels, and the current "hotspots" of polluted rivers were found mostly in less developed countries or emerging economies (e.g., some in Africa, South America, and Asia). By developing the screening protocol for risk-based prioritization of antibiotics, we advanced a rank list of antibiotics for guiding formulation of region-specific strategies, which highlighted the importance of whole life cycle management of antibiotics in health maintenance of the world's rivers.

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Sustainable inland waterways should meet the needs of navigation without compromising the health of riverine ecosystems. Here we propose a hierarchical model to describe sustainable development of the Golden Inland Waterways (GIWs) which are characterized by great bearing capacity and transport need. Based on datasets from 66 large rivers (basin area > 100,000 km2) worldwide, we identify 34 GIWs, mostly distributed in Asia, Europe, North America, and South America, typically following a three-stage development path from the initial, through to the developing and on to the developed stage. For most GIWs, the exploitation ratio, defined as the ratio of actual to idealized bearing capacity, should be less than 80% due to ecological considerations. Combined with the indices of regional development, GIWs exploitation, and riverine ecosystem, we reveal the global diversity and evolution of GIWs’ sustainability from 2015 to 2050, which highlights the importance of river-specific strategies for waterway exploitation worldwide.