RAPID: Effect of wildfire on stream mercury and organic carbon in a southern Appalachian forested watershed

汞以低浓度存在于环境中，但可在食物链中积累，并可对人类和野生动物造成神经损伤。水生环境中汞的动态变化与这些环境中的碳循环有关。河流生态系统中碳和汞的运动受到河流所经过的陆地环境的影响，当流域发生野火时，从土地转移到河流的碳和汞量可能会增加。2016年4月和5月，弗吉尼亚州谢南多厄国家公园内的落基山野火完全烧毁了Twomile Run周围的分水岭。自1987年以来，人们一直在监测这条河流的水质，并将与附近一条流经未燃烧森林流域的河流潘恩河（Paine Run）进行为期一年的研究，以评估野火对河流生态系统中碳和汞运输的影响。这项工作的结果将与公园内的土地管理人员分享，因为这可能有助于他们了解如何使用火作为一种管理工具。这项研究将为一名本科生提供实地和实验室技术方面的培训，以测量运输中的碳和汞。这项研究的目标是确定火灾对中大西洋地区森林流域碳和汞通量的影响。碳和汞的通量将从排放燃烧流域的Twomile Run与排放未燃烧流域的Paine Run进行比较。人工抓取样本和自动化高流量样本将在12个月的时间内从两个流域收集。将对样品进行pH值、碱度、阴离子、阳离子、溶解有机碳、紫外线吸收度、总悬浮沉积物、挥发性固体和汞的分析。对河流流量的连续估计将用于计算两个流域的碳和汞通量，这些数据还将提供这些输出的时空动态的详细特征。迄今为止，还没有关于河流生态系统的研究探讨了火灾对碳和汞运输的影响，而这项研究将填补这一知识空白。由于野火发生后立即发生的风暴预计会导致高水平的碳和能源动员，因此需要RAPID资金来实现快速采样。

Mercury is present in the environment in low concentrations, but can accumulate in food chains and can cause neurological damage to humans and wildlife. The dynamics of mercury in aquatic environments are coupled to the cycling of carbon in those environments. The movement of carbon and mercury in stream ecosystems is influenced by the terrestrial environment through which the stream passes, and when wildfires occur in the watershed, there can be increases in the amounts of carbon and mercury that are transferred from the land to the stream. In April and May of 2016, the Rocky Mountain wildfire within the Shenandoah National Park, Virginia, completely burned the watershed surrounding Twomile Run. That stream has been monitored for water quality since 1987 and will be paired with a nearby stream draining an unburned forested watershed, Paine Run, in a year-long study to assess the influence of wildfire on the transport of carbon and mercury from stream ecosystems. The results of this work will be shared with land managers within the Park as it may help inform their use of fire as a management tool. The research will provide training for an undergraduate student in field and laboratory techniques for measuring carbon and mercury in transport.The research has the goal of determining the impacts of fire of the fluxes of carbon and mercury from forested watersheds in the mid-Atlantic region. The fluxes of carbon and mercury from Twomile Run that drains the burned watershed will be compared with those from Paine Run that drains an unburned watershed. Manual grab samples and automated highflow samples will be collected from the two watersheds over a 12-month period. The samples will be analyzed for pH, alkalinity, anions, cations, dissolved organic carbon, UV absorbance, total suspended sediments, volatile solids and mercury. Continuous estimates of stream flow will be used to calculate the flux of carbon and mercury from both watersheds and the data will also provide a detailed characterization of the spatial and temporal dynamics of those exports. To date, no studies of stream ecosystems have explored the impacts of fire on carbon and mercury transport, and this study will fill that knowledge gap. Because storms that occur immediately after a wildfire are expected to induce high levels of carbon and energy mobilization, RAPID funding is needed to make prompt sampling possible.