The Last Ice Microbiome

Conservation policies for the fast changing Polar Regions are an urgent global priority in the face of ongoing climate change, yet little attention has been given to the microbial communities that underpin high latitude ecosystems and dominate biodiversity and functioning. To address this gap in understanding and knowledge transfer, we target two conservation areas at the top of Canada: the Last Ice Area (LIA), the band of thickest ice along the northern coast of Nunavut (under interim protection as the Marine Protected Area Tuvaijuittuq), and the adjacent land-based conservation area of Quttinirpaaq National Park. Our approach will be from an integrated microbiome perspective on the structure, functioning, climate-sensitivity and monitoring of diverse microbial ecosystems. The project has three interlocking modules, with emphasis on technology innovation, novel approaches connecting disciplines, and knowledge exchange among laboratories and partner networks in the largescale international projects MOSAiC and T-MOSAiC. In the Marine Module, we will test hypotheses about the genomic diversity of microbes in LIA sea ice and coastal waters, including ice-covered bays and fjords, and develop an innovative opto-microfluidic system for field flow cytometry to characterize and quantify aquatic microbes. In the Ice Module, we will evaluate the microbial, including viral, diversity of glaciers, ice shelves, ice domes, and perennial snowbanks on the landward side of the LIA, and develop an advanced microfluidic bioassay system to assess the environmental responses of microbial biofilms. In the Lakes Module, we will address questions about microbial connectivity, conceive novel biogeochemical models for lake oxygen dynamics and sulfur cycling via in situ and metagenomic studies, and apply a suite of methods, including paleo-DNA, to place the LIA region in a long-term historical context. The project will yield new transdisciplinary perspectives on cryo-biomes, and will provide extensive training across research centres on Arctic environmental issues of broad significance.

Viruses in permafrost thaw ponds

Global warming due to climate change has caused an increase in the number of permafrost thaw ponds (thermokarst) in the northern polar region. Thermokarst ponds are supersaturated in carbon dioxide and methane and are thus important sources of greenhouse gases (GHG). Microbial activity is responsible for the majority of GHG production in these ponds. However, little is known about the sources of mortality in these communities. One potentially major top down factor is the viruses. Viruses play an essential ecological role in all aquatic ecosystems, yet these assemblages remain essentially uncharacterized in thermokarst ponds. Towards this end, we have focused on cultivation dependent and independent approaches to characterizing the viral community in this ecosystem of global importance.

Myriam Labbé, Denis Sarrazin & Alex Culley sampling in Neige Bay, Milne Fjord (Photo courtesy of D. Sarrazin)

Wild viruses in the High Arctic

The most abundant and diverse biological entities in aquatic environments are the protists, prokaryotes, and viruses that comprise the microbial community. Microbes play a critical role in the cycling of nutrients and energy, and therefore understanding the dynamics and interactions of this group is vital to understanding the ecology of aquatic ecosystems as a whole. An important, but relatively understudied, component of the microbial community is the viruses. As well as being the most abundant and diverse biological entities on Earth, viruses influence the community structure and evolution of their hosts, and ultimately the productivity of the entire biota. I am building my research program around two major themes, aquatic viral ecology in a changing climate and viral discovery. The Arctic is a model environment to pursue these two themes because the region is experiencing some of the most dramatic changes due to climate change on Earth and it harbors a wide diversity of aquatic habitats whose viral communities are largely uncharacterized. The long-term goal of my research is thus to gain a deeper understanding of the impact, diversity and dynamics of the in situ virus communities in diverse Arctic aquatic habitats, and how viral ecology is affected by the rapid and evolving changes in this ecosystem. Short-term: Towards this end, I propose to work in two locations in the Arctic that exemplify the dynamism of the region attributable to climate change to answer some important first order ecological questions about viruses. The first sampling site is an epishelf lake located on the northern coast of Ellesmere Island in the Canadian High Arctic and the second is Cambridge Bay, a location in the Canadian Arctic Archipelago on the southeastern coast of Victoria Island

Catherine Girard and Elise Imbeau collecting aerosols near the lagoon on Ward Hunt Island

Aerosols in the High Arctic

In collaboration with the Bioaerosols lab at Université Laval headed by Caroline Duchaine, we have started a project to characterize the diversity of microbes, and viruses in particular, in aerosols in the High Canadian Arctic. Led by Catherine Girard, a Sentinel North Postdoctoral Fellow, the overarching themes of this research are to characterize the diversity, functionality and activity of Arctic microbes in aerosols, how aerosols contribute to the hydrological cycles of representative aquatic systems, and elucidate the aerosol fingerprint of anthropogenically-influenced regions in the High North