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

来自国际北极研究中心/阿拉斯加费尔班克斯大学的一位科学家试图了解控制育空河流域有机碳物种的组成、反应性、转化和通量的生物地球化学过程，包括溶解的、胶体的和颗粒的有机碳。育空河流域是一个原始的河流流域，受冰雪和永久冻土动态的严重影响，对环境和气候变化非常敏感。由于世界上高达50%的土壤有机碳储存在北部地区，北极/亚北极河流在有机碳再动员以及海洋和全球碳循环中的作用远比以前认识到的重要。由于育空河地处偏远，气候条件极端，经育空河进入海洋的有机碳种类的组成和反应性在很大程度上仍然未知，河流碳输出通量的量化也很差。观察将包括有机碳在溶解相、胶体相和颗粒相之间的相分配，以及浓度、光学性质、分子和同位素(d13C、d15N和？粒度分馏有机碳的组成和反应性。现场和实验室实验也将进行，以检查在冰形成过程中有机碳分馏的程度，以及分馏如何驱动碳分配和转化。该项目将是第一个结合分子水平和流域尺度观测的项目之一，以了解在一个大但原始和较少人为影响的流域中有机碳物种组成和通量的时空变化。该研究将为流域间的比较研究提供有价值的数据，并为综合碳循环规划和模型开发以及气候变化对环境影响的认识提供有效的投入和贡献。

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.