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Water‐dispersible nanocolloids and higher temperatures promote the release of carbon from riparian soil
Vadose Zone Journal ( IF 2.8 ) Pub Date : 2020-10-28 , DOI: 10.1002/vzj2.20077
Kenton A. Rod 1, 2 , A. Peyton Smith 3 , Weinan Leng 4 , Sean Colby 5 , Ravi K. Kukkadapu 6 , Mark Bowden 6 , Odeta Qafoku 6 , Wooyong Um 7 , Michael F. Hochella 1, 8 , Vanessa L. Bailey 5 , Ryan S. Renslow 5
Affiliation  

Increasing temperatures in alpine regions accompanied by glacial retreat is occurring rapidly due to climate change. This may affect riparian soils by increasing weathering rates, resulting in greater organic carbon (OC) release to rivers via movement of iron‐containing colloids and nanominerals. Increased concentrations of iron‐ or silcate‐nanominerals would result in higher surface area for OC adsorption. To test the influence of temperature on OC leaching, we examined mineral weathering and nanocolloid facilitated release of OC through a series of controlled laboratory batch and column experiments using sediment from the banks of the Nisqually River, Mount Rainier in Washington State (USA). Additional experiments were conducted using the same sediments, but with an illite amendment added to test the influence of additional surface area and nanominerals that many sediments along the Nisqually River contain. These higher‐ and lower‐surface‐area sediments (i.e., sediments with and without the illite amendment) were incubated for 90 d at 4 or 20 °C, followed by batch and column OC leaching tests. Results show that OC leaching rates for 20 °C were two to three times greater than for 4 °C. Further, our results suggest that nanocolloids are responsible for moving this increased OC load from these sediments. When hydrologically connected, OC is released from bank sediments to rivers faster than presently anticipated in fluvial environments experiencing climate change‐induced glacial retreat. Further, a one‐dimensional, finite‐element computational model developed for this study estimates that a 1 °C increase in temperature over a 90‐d summer runoff period increases the OC release rate from sediments by 79%.

中文翻译:

水分散性纳米胶体和较高温度促进了河岸土壤中碳的释放

由于气候变化,伴随冰川退缩的高寒地区气温升高正在迅速发生。这可能会通过增加风化率来影响河岸土壤,从而通过含铁胶体和纳米矿物的移动而向河流释放更多的有机碳(OC)。铁或硅酸盐纳米金属的浓度增加会导致OC吸附的表面积增加。为了测试温度对OC淋溶的影响,我们使用来自华盛顿州(美国)雷尼尔山Nisqually河两岸的沉积物,通过一系列受控的实验室分批和柱实验,研究了矿物风化和纳米胶体促进的OC释放。使用相同的沉积物进行了其他实验,但是增加了伊利石修正,以测试Nisqually河沿岸许多沉积物所包含的额外表面积和纳米矿物的影响。将这些较高和较低表面积的沉积物(即有或没有伊利石改良剂的沉积物)在4或20°C下孵育90 d,然后进行分批和柱OC浸出测试。结果表明,20°C的OC浸出速率是4°C的2-3倍。此外,我们的结果表明,纳米胶体负责移动这些沉积物中增加的OC负荷。当与水文联系时,OC从河岸沉积物中释放到河流的速度比目前在经历气候变化导致的冰川消退的河流环境中预期的要快。此外,一维
更新日期:2020-10-30
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