Arctic microbial communities in a changing climate

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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.