GEOTRACES Arctic Section: Processes affecting the biogeochemical cycling of essential and toxic metalloids in the Arctic Ocean

在这个项目中，参加2015年美国GEOTRACES北极考察的一名研究人员将建立北冰洋中砷和硒的浓度、化学形态和循环过程。与国际地质足迹计划中的其他多国倡议一样，美国北极考察的目标是确定控制海洋中关键微量元素和同位素分布的过程和量化通量，并确定这些分布对不断变化的环境条件的敏感性。有些微量元素是生命所必需的，有些是已知的生物毒素，还有一些很重要，因为它们可以用作海洋中各种物理、化学和生物过程的示踪剂。本项目研究的类金属元素砷和硒对许多海洋植物和动物有毒，它们在北极的循环尚不清楚。因此，该项目将对增加对这些潜在有毒元素的化学性质的了解具有重要意义。该项目的成果将通过与北极居民的接触以及参与此次巡游的一位polpoltrec教师分享。类金属元素砷和硒具有动态海洋循环，影响水柱的微生物，反过来又受其影响。两者都以多种氧化态存在，并且在一个氧化态中存在无机和有机物质。这种化学形态影响它们的反应性、生物吸收和毒性。在低纬度水域，溶解砷的浓度和形态可以控制初级生产者的丰度和类型。在北极，人们对砷的循环几乎一无所知，尽管加拿大河流和大气沉积可能增加了砷的人为输入。相比之下，来自高纬度北太平洋和白令海的数据强烈表明，煤炭燃烧产生的人为硒正在进入北极，并在至少一种顶级捕食者体内富集。该项目的目标是定性地描述影响砷和硒的形态和浓度的输入、去除和内部循环过程，并通过直接测量和计算确定这些过程的输入和输出速率。这项研究将极大地扩展关于砷和硒循环的知识，对不断变化的北极具有重要意义。

In this project, an investigator participating in the 2015 U.S. GEOTRACES Arctic expedition will establish the concentrations, chemical speciation, and cycling processes of arsenic and selenium in the Arctic Ocean. In common with other multinational initiatives in the International GEOTRACES Program, the goals of the U.S. Arctic expedition are to identify processes and quantify fluxes that control the distributions of key trace elements and isotopes in the ocean, and to establish the sensitivity of these distributions to changing environmental conditions. Some trace elements are essential to life, others are known biological toxins, and still others are important because they can be used as tracers of a variety of physical, chemical, and biological processes in the sea. The metalloid elements arsenic and selenium to be studied in this project are toxic to many marine plants and animals, and their cycling in the Arctic is not well known. Thus, this project will have important implications for increased knowledge on the chemistry of these potentially toxic elements. Results from the project will be shared through outreach to Arctic residents and through a PolarTREC teacher who will participate in the cruise.The metalloid elements arsenic and selenium have dynamic marine cycles that affect the microbiology of the water column and in turn are affected by it. Both exist in multiple oxidation states and inorganic and organic species within an oxidation state. This chemical speciation affects their reactivity and biotic uptake and toxicity. As shown in lower latitude waters, the concentration and speciation of dissolved arsenic can control the abundance and types of primary producers. In the Arctic virtually nothing is known about arsenic cycling, although there are possibly enhanced anthropogenic inputs from Canadian rivers and atmospheric deposition. In contrast, data from the high latitude North Pacific Ocean and Bering Sea strongly suggest that anthropogenic selenium from coal combustion is entering the Arctic and enriching its concentration in at least one top predator. The goal of this project is to qualitatively describe the input, removal, and internal cycling processes affecting the speciation and concentrations of arsenic and selenium, and determine rates of inputs and outputs of these processes using both direct measurements and computations. The study will greatly expand knowledge about arsenic and selenium cycling, with strong implications for the changing Arctic.