Biogeochemistry of trace metals in Canada's subarctic and Arctic oceans under a rapidly changing climate

海洋提供的生态系统服务使所有加拿大人受益，但这些服务日益受到人类活动的威胁。其中两项面临风险的服务是通过光合作用封存大气中的二氧化碳，这有助于减缓气候变化，以及通过渔业生产食物。光合作用的海洋微生物提供这些服务，因为它们消耗二氧化碳，形成海洋食物网的基础。作为一个海洋国家，了解是什么控制着海洋微生物的生长，从而了解海洋环境提供的服务，对加拿大人来说具有明显的经济和文化意义。微量金属是在海水中发现的浓度非常低的元素，要么是因为它们在我们的星球上很稀有，要么是因为它们通过化学和/或生物过程迅速从海洋中去除。海水中微量金属的数量和化学形式可以阻止光合微生物的生长，因为它们是必需的限制性营养物质，或者当它们过多时是毒素。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可能取决于金属营养物和毒素的生物可得性。所以，虽然微量金属在海洋中并不丰富，但它们的影响比它们的小浓度所暗示的要大得多。我的研究小组开发并使用高度敏感的分析工具来研究海洋中的痕量金属化学。我研究计划的长期目标是了解控制微量金属对微生物的分布、化学形式和由此产生的可用性的过程，以及气候变化如何可能影响未来的微量金属化学。我们专注于控制初级生产和微生物群落结构的金属（如铁，铜和锌），作为古海洋学示踪剂，提供有关海洋作用的重要信息是过去的气候变化（如银，镉），或可能对海洋生态系统产生负面影响的潜在有毒重金属（铜，银和镉）。在接下来的5年里，我的短期研究目标是：1)研究高纬度海洋表层海水中海冰融化的温度、海洋酸化和光照变化如何影响生物上重要的金属；2)揭示出有多少金属从靠近大陆的海洋中被添加或移除；3)确定海洋中氧气含量的减少如何影响金属的相对分布。我们的数据将允许在计算机模型中更好地结合金属化学，旨在预测有益于加拿大人的海洋服务对气候变化的反应。这种理解将使决策者能够制定有效的计划，以缓和和减轻正在进行的人类造成的气候变化，并在未来可持续地管理和管理我们的海洋资源。

The oceans provide ecosystem services that benefit all Canadians but these services are increasingly threatened by human activity. Two of these services at risk are the sequestration of atmospheric carbon dioxide through photosynthesis, which helps to mitigate climate change, as well as the production of food through our fisheries. Photosynthetic marine microbes provide these services because they consume CO2 and form the base of the marine food web. As a maritime nation, understanding what controls the growth of marine microbes and thereby the services the marine environment provides has clear economic and cultural relevance for Canadians. Trace metals are elements that are found in very small concentrations in seawater either because they are rare on our planet or because they are rapidly removed from the ocean by chemical and/or biological processes. The amount and chemical form of trace metals in seawater can prevent photosynthetic microbes from growing either because they are essential limiting nutrients, or they are toxins when too abundant. Ultimately, metals 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 of metal nutrients and toxins. So, while trace metals are not abundant in the ocean they have impacts that are much greater than their small concentrations might suggest. My research group develops and uses highly sensitive analytical tools to study trace 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 availability of trace metals to microbes, and how climate change is likely to impact trace metal chemistry in the future. We focus on metals that control primary production and microbe community structure (e.g. iron, copper and zinc), serve as paleoceanographic tracers that provide important information regarding the oceans role is past climate change (e.g. silver, cadmium), or potentially toxic heavy metals that might negatively impact the marine ecosystem (copper, silver and cadmium). 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 computer models designed to predict the response of marine services that benefit Canadians to climate change. This understanding will allow policy makers to make effective plans to moderate and mitigate ongoing human caused climate change and to sustainably manage and steward our marine resources into the future.