Biogeochemistry of trace metals in the subarctic and Arctic oceans under a rapidly changing climate

微小的海洋植物和细菌构成了海洋食物网的基础。海水中存在的金属的数量和化学形式可以阻止植物和细菌生长，因为它们是稀缺的和必需的营养素，如铁或锌，或者当铅或汞过多时，它们是有毒的。金属可以通过控制哪些物种以及微生物和细菌的生长量来改变海洋食物网的生产力。最终，金属可以控制海洋吸收温室气体和减缓气候变化的能力。同样，我们渔业的健康和可持续性取决于金属营养物和毒素的生物可利用性（生物利用度）。鉴于加拿大是一个被三大洋环绕的国家，这项研究对我们的公民具有明显的经济和文化意义。*** 我的研究小组开发和使用高灵敏度的分析工具和方法，如质谱和电化学，以研究海洋中的金属化学。我的研究计划的长期目标是了解控制微量金属的分布，化学形式和生物利用度的过程，以及如何改变响应气候变化的物理和化学条件可能会影响这些金属在海洋中的属性。最近，我的研究小组通过在现场和实验室开发和应用强大的分析方法，在实现这些目标方面取得了重大进展。 我们专注于控制初级生产和微生物群落结构的金属（例如Fe，Cu和Zn），作为古海洋示踪剂，提供有关海洋作用的重要信息，是过去的气候变化（例如Cd，Ag），或可能对海洋生态系统产生负面影响的潜在有毒重金属（Cu，Ag和Cd）。在未来5年中，我的短期研究目标是：1）研究高纬度海洋表面沃茨中海冰融化的温度变化、海洋酸化和光照如何影响生物学上重要的金属; 2）揭示大陆附近海洋中增加或减少了多少金属; 3）确定海洋中氧气含量的下降如何影响金属的相对分布。 我们的数据将允许更好地将金属化学结合到耦合大气-海洋模型中，该模型旨在预测加拿大亚北极和北极地区海洋系统对区域变暖、海洋酸化、海洋脱氧以及海冰和光照制度变化的反应。此外，更彻底地了解是什么控制了微量金属的流域规模分布及其与其他海洋植物营养素的关系，将有助于验证现有的和开发新的工具，帮助我们了解海洋在过去气候变化中的作用。

Microscopic marine plants and bacteria form the base of the ocean food web. The amount and chemical form of metals present in seawater can prevent plants and bacteria from growing either because they are scarce and essential nutrients like iron or zinc, or they are toxic when too much is available like lead or mercury. Metals can change how productive the marine food web can be by controlling which species, and how much of the microscopic plants and bacteria, can grow. Ultimately, metals then can control the oceans ability to take up greenhouse gases and slow climate change. Similarly, the health and sustainability of our fisheries can depend on the biological availability (bioavailability) of metal nutrients and toxins. Given that Canada is a country surrounded by three oceans this research has clear economic and cultural relevance to our citizens. *** My research group develops and uses highly sensitive analytical tools and approaches like mass spectrometry and electrochemistry to study metal chemistry in the ocean. The long-term goals of my research program are to understand the processes that control the distribution, chemical form and resulting bioavailability of trace metals, and how altered physical and chemical conditions in response to climate change are likely to impact these metal properties in the ocean. Recently, my research group has made significant progress towards these goals through the development and application of powerful analytical methods in both the field and the laboratory. We have focused on metals that control primary production and microbe community structure (e.g. Fe, Cu and Zn), serve as paleoceanographic tracers that provide important information regarding the oceans role is past climate change (e.g. Cd, Ag), or potentially toxic heavy metals that might negatively impact the marine ecosystem (Cu, Ag and Cd). Over the next 5 years my short term research objectives are to: 1) examine how changing temperature, ocean acidification and light where sea ice melts in high latitude ocean surface waters will impact biologically important metals; 2) unravel how much metals are either added or removed from the ocean near the continents; and 3) determine how decreasing oxygen levels in the ocean impact the relative distribution of metals.*** Our data will allow for better incorporation of metal chemistry in coupled atmosphere-ocean models designed to predict the response of marine systems in the Canadian subarctic and Arctic to regional warming, ocean acidification, ocean deoxygenation and changing sea ice and light regimes. In addition, a more thorough understanding of what controls the basin scale distribution of trace metals and their relationships with other ocean plant nutrients will aide in efforts to verify existing and develop new tools that can help us understand the oceans role in past climate change.**