Arctic microbial communities in a changing climate

加拿大拥有世界上最长的海岸线，其中70%的海岸线位于北极。全球气候变化已经对北极产生了深远的影响，多年冰的减少，开放水域季节的延长，永久冻土的融化和风暴事件的增加，所有这些都导致北冰洋的新鲜。北极自然特征的这些变化正在对北极浮游植物产生影响；这种微藻从太阳中获取能量，从大气中吸收二氧化碳，是支持北极鱼类、海洋哺乳动物和鸟类生存的食物网的基础。尽管浮游植物在北极发挥着关键作用，但人们对北极的变冷以及相关的光照和养分供应变化如何直接影响物种知之甚少。我们所知道的是，物种组成正在发生变化，这将对北冰洋从大气中吸收二氧化碳的能力产生影响，并支持更高的营养水平。我们的研究旨在调查北极浮游植物适应北极新环境的遗传能力。在过去的几十年里，对微藻耐盐性的研究大多是从淡水物种耐盐化的角度出发的。很少有研究直接涉及暴露于较新鲜盐度的海洋物种耐盐性的遗传基础。这一点很重要，因为例如，在环境中，有害藻华（HAB）事件与风暴或高春季径流带来的淡水输入有关。由于许多北极浮游植物种类被限制在北极，可能是因为它们在没有光线的极夜中持续存在的能力，或者它们与冰有关，因此对低纬度物种的研究是不合适的。该项目结合了使用北极物种培养和环境宏基因组学（样本中所有微生物的基因组学）的实验室工作，从物种组成变化、代谢途径和食物网复杂性的角度确定可用于指示海洋和沿海地区健康状况的标记基因。然后，我们将使用这些标记进行泛北极调查，并开发可供研究人员和相关公民社区使用的工具。因此，这里提出的研究将使人们更好地了解北极的碳和能源途径，以及鱼类、海洋哺乳动物和海鸟的食物供应。这种资料对于北方人的渔业和其他当地食物的持续管理是必需的。这项工作将对加拿大周围寒冷海洋的生物多样性、结构、生物稳定性和功能产生新的见解。这些发现具有区域意义，为管理人员提供了工具和指标，并有助于政府政策顾问的信息需求。

Canada has the longest coastline in the world and 70% these coastal regions are in the Arctic. Global climate change is already having a profound effect on the Arctic with loss of multiyear ice, longer open water seasons, melting permafrost and increased storm events, all of which are leading to a freshening of the Arctic Ocean. These changes in the physical character of the Arctic are having an impact on arctic phytoplankton; microalgae that take energy from the sun and carbon dioxide from the atmosphere and are the base of the food web that supports the fish, marine mammals and birds living in the Arctic. Despite the pivotal role of phytoplankton in the Arctic, very little is known about how species are directly affected by the freshening of the Arctic and related changes in light and nutrient availability. What is known is that species composition is changing and that this will have an influence on the capacity of the Arctic Ocean to take up carbon dioxide from the atmosphere and support higher trophic levels. Our research is aimed at investigating the genetic capacity of arctic phytoplankton to adjust to the new conditions in the Arctic. Over the last several decades research on microalgae salinity tolerance has mostly been from the perspective of freshwater species tolerating salinization. Few if any studies have directly addressed the genetic underpinning for salinity tolerance in marine species exposed to fresher salinities. This is important because for example, in the environment there is an association of harmful algal bloom (HAB) events with freshwater inputs from storms or high spring runoff. Since many arctic phytoplankton species are restricted to the Arctic, likely because of their ability to persist during the polar night in the absence of light, or their association with ice, studies on low latitude species are not appropriate. This project combines laboratory work using cultures of arctic species and environmental metagenomics (genomics of all the microbes in a sample) to identify marker genes that can be used to indicate the health of the ocean and coastal regions from the perspective of changes in species composition, metabolic pathways and food web complexity. We will then carry out pan-arctic surveys using these markers and develop tools that can be used by researchers and eventually concerned citizen communities. The research proposed here will thereby lead to an improved understanding carbon and energy pathways in the Arctic and food availability for fish, marine mammals and seabirds. Such information is required for the sustained management of fisheries and other local food for Northerners. This work will generate new insights into the biodiversity, structure, biological stability and functioning of the cold oceans around Canada. These discoveries be of regional significance, providing mangers with tools and indexes, and contribute to informational needs of government policy advisers.