Biogeochemical Tracers in Arctic Rivers: Linking the Pan-Arctic Watershed to the Arctic Ocean

本提案的总体目标是利用河流水化学作为研究大陆径流的起源和命运的手段。除了温度和盐度之外，还需要示踪剂来确定河流对北冰洋地表水的贡献，因为海冰融化会混淆温度-盐度混合模型的解释。此外，示踪剂提供了一种区分不同河流区域贡献的方法。提出了一个为期5年的项目，其中将在流经北冰洋流域的6条最大河流中测量以河水示踪剂为重点的选定参数：叶尼塞河、莱拿河、奥比河、麦肯齐河、育空河和科雷马河。要测量的示踪剂包括H218O、钡、有机物、碱度和营养物质。采样将在第一年和第四年的高流量季节进行，而在第二年和第三年的所有季节进行。综合和建模将贯穿整个5年的项目。样品将在河口附近（但在潮汐影响之上）收集，以便获得完全综合的分水岭信号和最相关的淡水末端成员值，用于海洋学跟踪。为了研究河流流经北冰洋的运输路径，将在现有和不断增长的海洋示踪剂数据库的背景下研究新定义的端元值。为了研究流域来源，将在地貌学、土地覆盖和水文模型的背景下检查示踪剂。拟议的工作还将产生一个关于河流生物地球化学的泛北极天气数据库，以便在趋势分析中与过去和未来的数据进行比较。一个专家协作网络成功地对6条最大的北极河流进行了采样。来自4个国家的科学家参与其中，包括负责俄罗斯、加拿大和美国北极水质监测机构的代表。由于水文学家、生物地球化学家和海洋学家为该项目带来了不同的专业知识，该研究小组在分析和综合进入和流经北冰洋的泛北极尺度的河流示踪剂通量信息方面也处于有利地位。外展活动将包括居住在研究地点附近村庄的高中生的参与。在当地教师或研究人员的监督下，这些学生将从他们的河流中采集水样。他们将执行基本的分析，如温度，pH值和电导率。参与的学生也将积极地通过网络交换数据。研究小组的科学家将访问学生并讨论项目，向他们的班级讲课，并让学生尽可能多地参与项目的各个方面。

The overall objective of this proposal is to use river water chemistry as a means to study the origins and fates of continental runoff. Tracers in addition to temperature and salinity are needed to identify river contributions to surface waters of the Arctic Ocean because melting of sea ice confounds interpretation of temperature-salinity mixing models. Furthermore, tracers provide a means to distinguish contributions from different rivers regionally. A 5-year project is proposed in which selected parameters focusing on tracers of river water will be measured in the largest 6 rivers that drain the watershed of the Arctic Ocean: the Yenisey, Lena, Ob', Mackenzie, Yukon, and Kolyma. Tracers to be measured include H218O, barium, organic matter, alkalinity, and nutrients. Sampling will be conducted during the high flow season in Years 1 and 4 and during all seasons in Years 2 and 3. Synthesis and modeling will occur throughout the 5-year project. Samples will be collected near the mouths of the rivers (but above tidal influence) in order to get fully integrated watershed signals and the most relevant freshwater end member values for oceanographic tracking. To investigate transport pathways of river waters through the Arctic Ocean, newly defined end member values will be examined in the context of existing and growing oceanographic tracer databases. To study watershed sources, tracers will be examined in the context of geomorphology, land cover, and hydrology models. The proposed work will also generate a synoptic pan-arctic database on river biogeochemistry for comparison with past and future data in trend analyses. A collaborative network of expertise to successfully sample the 6 largest arctic rivers was assembled. Scientists from 4 nations are involved, including representatives of agencies responsible for water quality monitoring in the Russian, Canadian, and US Arctic. The research group is also in a strong position to analyze and synthesize information on river tracer fluxes into and through the Arctic Ocean at the pan-Arctic scale because of the diverse expertise brought to the project by hydrologists, biogeochemists, and oceanographers. Outreach will involve participation of high school students living in villages near the study sites. Under the supervision of local teachers or researchers, these students will collect water samples from their rivers. They will perform basic analyses such as temperature, pH, and conductivity. Participating students will also be active in exchange of data via the web where available. Scientists from the research group will visit the students and discuss the project, present lectures to their classes, and involve the students in as many aspects of the project as possible.