Composition and Fluxes of Organic Carbon Species from the Yukon River Basin

育空地区河流域有机碳物种的组成和通量阿拉斯加费尔班克斯大学国际北极研究中心的一位科学家试图了解控制有机碳物种的组成、反应性、转化和通量的地球化学过程，包括来自育空地区河流域的溶解、胶体和颗粒有机碳。 育空地区河流域是一个原始河流流域，受冰雪和冻土动态的影响很大，对环境和气候变化很敏感。由于世界土壤有机碳的50%储存在北方地区，北极/亚北极河流在有机碳再活化以及海洋和全球碳循环中的作用远比以前认识到的重要。 由于育空地区河的偏远和极端的天气条件，通过育空地区进入海洋的有机碳物种的组成和反应性在很大程度上仍然是未知的，河流的碳输出通量是很差的量化。 观测将包括溶解，胶体和颗粒相之间的有机碳相分配，浓度，光学性质，分子和同位素（d13 C，d15 N和？14 C）尺寸分级的有机碳的组成和反应性。 还将进行实地和实验室实验，以研究有机碳在冰形成过程中分馏的程度，以及分馏如何驱动碳的分配和转化。 该项目将是第一个联合收割机结合分子水平和流域规模的观测，以了解在一个大的，但原始的和较少受人为影响的河流流域的有机碳物种的组成和流量的时间和空间变化。 拟议的研究将为流域之间的比较研究提供有价值的数据，并为综合碳循环计划和模型开发提供投入和有效贡献，以及了解气候变化对环境的影响。

Composition and flux of organic carbon species from the Yukon River BasinA scientist from the International Arctic Research Center/University of Alaska Fairbanks seeks to understand the biogeochemical processes governing the composition, reactivity, transformation and flux of organic carbon species, including dissolved, colloidal and particulate organic carbon from the Yukon River Basin. Being heavily influenced by ice, snow and permafrost dynamics, the Yukon River Basin, a pristine river basin, is sensitive to environmental and climate change. With up to 50% of the world's soil organic carbon stored in the northern region, the role of arctic/subarctic rivers in the remobilization of organic carbon and thus marine and global carbon cycles is far more important than previously recognized. Due to the Yukon River's remoteness and the extreme weather conditions, the composition and reactivity of organic carbon species entering the ocean via the Yukon remain largely unknown and the riverine carbon export flux is poorly quantified. Observations will include phase partitioning of organic carbon between dissolved, colloidal and particulate phases, and concentrations, optical properties, molecular and isotopic (d13C, d15N and ?14C) composition and reactivity of size fractionated organic carbon. Field and laboratory experiments will also be carried out to examine the extent to which organic carbon fractionates during ice formation and how the fractionation drives carbon partitioning and transformation. This project will be among the first to combine both molecular-level and basin-scale observations to understand temporal and spatial variations in composition and flux of organic carbon species in a large but pristine and less anthropogenically influenced river basin. The proposed research will provide valuable data for comparative studies between drainage basins, and provide inputs for and contribute effectively to the integrated carbon cycle program and model development, and the understanding of the environmental impacts from a changing climate.