Tracing Upper Arctic Circulation Via Barium, Oxygen Isotopesand DOM Fluorescence

世界上大约10%的河流流量流入北冰洋，强烈影响其物理和化学性质。 确定流入北极的河流沃茨的命运，对于了解北极的海洋环流及其与全球气候的联系，以及评估倾倒到北极河流和边缘浅海中的放射性废物和工业废物的运输，都是必要的。 各种物理和化学示踪剂，包括温度，盐度，碱度，3He，氚，卤烃，营养物质和氧同位素，已被应用于北极环流的调查。这些示踪剂已被成功地用于简单的线性混合模型，以区分从海冰融水，太平洋，北冰洋沃茨大西洋组件的河流成分。 然而，这些示踪剂都无法区分北极地区不同河流的沃茨。 过去的工作表明，溶解钡（Ba）作为一种天然存在的地球化学示踪剂，可以提供新的见解在北极的海洋环流，特别是关于其河流的组成部分的效用。 相对于任何欧亚北极河流（即直接流入北极的十大河流中的其他九条），麦肯齐河（北美唯一直接流入北极的主要河流）中的钡浓度非常高。 调查人员将分析1993年至1996年收集的水样，以验证北冰洋表层沃茨中Ba的地理分布反映了麦肯齐河和欧亚北极河流中Ba浓度的显著差异，Ba可以用来区分北美和欧亚河流排放到北极的来源，从而提供其他来源无法提供的信息。北极海洋环流的示踪剂。 Ba数据还将与同期获得的其他示踪剂场相结合，以定量绘制整个北极北部的淡水贡献。 利用这些背景信息，研究人员将检查1996年在整个北极内部进行SCICEX96考察期间安装在核潜艇USS Pogy船体上的传感器产生的连续紫外荧光记录。 这些数据将提供有关海洋和陆地来源的溶解有机物（DOM）分布的信息。 陆地DOM可能被证明是有用的河流排放到北冰洋的示踪剂，同时，连续记录的两个组成部分将提高我们的知识在北极的碳循环。

Approximately ten percent of the world's total river discharge flows into the Arctic Ocean, strongly influencing its physical and chemical properties. Determining the fate of river waters flowing into the Arctic is necessary for understanding oceanic circulation in the Arctic and its links to global climate, and for assessing the transport of radioactive and industrial wastes dumped into the rivers and shallow marginal seas of the Arctic. A variety of physical and chemical tracers, including temperature, salinity, alkalinity, 3He, tritium, halocarbons, nutrients, and oxygen isotopes, have been applied to investigations of Arctic circulation. These tracers have been successfully used with simple linear mixing models to distinguish the riverine component from sea-ice meltwater, Pacific, and Atlantic components of Arctic Ocean waters. None of these tracers, however, are able to distinguish between waters from different rivers within the Arctic. Past work has shown the utility of dissolved barium (Ba) as a naturally occurring geochemical tracer that can offer new insights into oceanic circulation in the Arctic, particularly with regards to its riverine component. Ba concentrations are highly elevated in the Mackenzie River (the only major North American river flowing directly into the Arctic) relative to any of the Eurasian Arctic rivers (i.e. the other nine of the ten largest rivers flowing directly into the Arctic). The investigators will analyze water samples collected from 1993 to 1996 to verify that the geographical distribution of Ba in the surface waters of the Arctic Ocean reflect the significant difference between Ba concentrations in the Mackenzie and Eurasian Arctic rivers, and that Ba can be used to distinguish between North American and Eurasian sources of river discharge to the Arctic and thus provide information not available from other tracers of oceanic circulation in the Arctic. Ba data will also be combined with other tracer fields obtained over the same period of ti me to quantitatively map freshwater contributions throughout the upper Arctic. Using this background information, the investigators will examine continuous UV-fluorescence records generated from sensors mounted on the hull of the nuclear submarine USS Pogy in 1996 during the SCICEX96 expedition throughout the Arctic interior. These data will provide information about the distributions of both marine and terrestrial derived dissolved organic matter (DOM). Terrestrial DOM may prove useful as a tracer of riverine discharge to the Arctic Ocean and the simultaneous, continuous records of both components will improve our knowledge of carbon cycling within the Arctic.