Connie Lovejoy

Laval University | ULAVAL · Department of Biology

Microbial communities in the world ocean are affected strongly by oceanic circulation, creating characteristic marine biomes. The high connectivity of most of the ocean makes it difficult to disentangle selective retention of colonizing genotypes (with traits suited to biome specific conditions) from evolutionary selection, which would act on found...

Cyanobacteria produce vast quantities of long-chain alkanes in the ocean, yet these do not accumulate in the water column, suggesting rapid co-localized biodegradation. The identities of microbes in this cryptic hydrocarbon cycle are mostly unknown, and are unexplored across marine-freshwater gradients. Analyzing genes and metagenome assembled geno...

The transition from ice-covered to open water is a recurring feature of the Arctic and sub-Arctic, but microbial diversity and cascading effects on the microbial food webs is poorly known. Here, we investigated microbial eukaryote, bacterial and archaeal communities in Hudson Bay (sub-Arctic, Canada) under sea-ice cover and open waters conditions....

Little is known at the transcriptional level about microbial eukaryotic adaptations to short-term salinity change. Arctic microalgae are exposed to low salinity due to sea-ice melt and higher salinity with brine channel formation during freeze-up. Here, we investigate the transcriptional response of an ice-associated microalgae over salinities from...

Freshwater salinization is an ongoing concern for north temperate lakes; however, little is known about its impacts on microbial communities, particularly for bacteria. We tested the hypotheses that road de-icing salt induces changes in the microbial community structure of lake plankton, and that changes due to chloride would differ from those due...

Across much of the Arctic, lakes and ponds dominate the landscape. Starting in late September, the lakes are covered in ice, with ice persisting well into June or early July. In summer, the lakes are highly productive, supporting waterfowl and fish populations. However, little is known about the diversity and ecology of microscopic life in the lake...

A clear divide typically exists between freshwater and marine microbial communities, with transitional communities found in estuarine zones. The estuarine communities can derive from inflowing rivers and the sea via tidal mixing and incursions or be comprised of unique brackish species, depending on flow regimes and retention time within an estuary...

Little is known about the microbial diversity of rivers that flow across the changing subarctic landscape. Using amplicon sequencing (rRNA and rRNA genes) combined with HPLC pigment analysis and physicochemical measurements, we investigated the diversity of two size fractions of planktonic Bacteria, Archaea and microbial eukaryotes along environmen...

Marine plankton form complex communities of interacting organisms at the base of the food web, which sustain oceanic biogeochemical cycles and help regulate climate. Although global surveys are starting to reveal ecological drivers underlying planktonic community structure and predicted climate change responses, it is unclear how community-scale sp...

Lakes and ponds are dominant components of Arctic landscapes and provide food and water for northern communities. In the Greiner Lake watershed, in Cambridge Bay (Nunavut, Canada), water bodies are small (84% < 5 ha) and shallow (99% <4 m). Such characteristics make them vulnerable to eutrophication as temperatures rise and nutrient concentrations...

The North Water region, between Greenland and Ellesmere Island, with high populations of marine birds and mammals, is an Arctic icon. Due to climate related changes, seasonal patterns in water column primary production are changing but the implications for the planktonic microbial eukaryote communities that support the ecosystem are unknown. Here w...

The MALINA oceanographic campaign was conducted during summer 2009 to investigate the carbon stocks and the processes controlling the carbon fluxes in the Mackenzie River estuary and the Beaufort Sea. During the campaign, an extensive suite of physical, chemical and biological variables were measured across seven shelf–basin transects (south–north)...

One of the most striking ecological divides on Earth is between marine and nearby freshwater environments, as relatively few taxa can move between the two. Microbial eukaryotes contribute to biogeochemical and energy cycling in both fresh and marine waters, with little species overlap between the two ecosystems. Arctic and sub-Arctic marine systems...

Salinization of freshwater is increasingly observed in regions where chloride de-icing salts are applied to the roads in winter, but little is known about the effects on microbial communities. In this study, we analyzed the planktonic microbiomes of four lakes that differed in degree of urbanization, eutrophication and salinization, from an oligotr...

Photosynthetic performance in open marine waters is determined by how well phytoplankton species are adapted to their immediate environment and available light. Although there is light for 24 h a day during the Arctic summer, little is known about short-term (h) temporal variability of phytoplankton photosynthetic performance in Arctic waters. To a...

Nostoc (Nostocales, Cyanobacteria) has a global distribution in the Polar Regions. However, the genomic diversity of Nostoc is little known and there are no genomes available for polar Nostoc. Here we carried out the first genomic analysis of the N. commune morphotype with a recent sample from the High Arctic and a herbarium specimen collected duri...

Background: The sulfur cycle encompasses a series of complex aerobic and anaerobic transformations of S-containing molecules and plays a fundamental role in cellular and ecosystem-level processes, influencing biological carbon transfers and other biogeochemical cycles. Despite their importance, the microbial communities and metabolic pathways invol...

Marine plankton form complex communities of interacting organisms at the base of the food web, which sustain oceanic biogeochemical cycles, and help regulate climate. Though global surveys are starting to reveal ecological drivers underlying planktonic community structure, and predicted climate change responses, it is unclear how community-scale sp...

The MALINA oceanographic campaign was conducted during summer 2009 to investigate the carbon stocks and the processes controlling the carbon Fluxes in the Mackenzie River estuary and the Beaufort Sea. During the campaign, an extensive suite of physical, chemical and biological variables was measured across seven shelf–basin transects (south-north)...

Background The sulfur cycle encompasses a series of complex aerobic and anaerobic transformations of S-containing molecules, and plays a fundamental role in cellular and ecosystems level-processes, influencing biological carbon transfers and other biogeochemical cycles. Despite their importance, the microbial communities and metabolic pathways invo...

Long-term trends in the formation and reduction of ice cover in Hudson Bay have demonstrated that the ice-free season increased by more than 3 weeks between 1981 and 2010. The early opening of the ice and the extension of the ice-free period is therefore likely to influence the timing and composition of the planktonic communities. During the 2018 B...

The candidate phyla radiation (CPR) is a diverse group of uncultured bacterial lineages with poorly understood metabolic functions. CPR bacteria can represent a large proportion of the total planktonic microbial community in subarctic thermokarst lakes, but their functional roles remain unexplored. We applied sequential water filtration and metagen...

The thawing of ice-rich permafrost soils in northern peatlands leads to the formation of thermokarst ponds, surrounded by organic-rich soils. These aquatic ecosystems are sites of intense microbial activity, and CO2 and CH4 emissions. Many of the pond systems in northern landscapes and their surrounding peatlands are hydrologically contiguous, but...

The Arctic Ocean is relatively isolated from other oceans and consists of strongly stratified water masses with distinct histories, nutrient, temperature, and salinity characteristics, therefore providing an optimal environment to investigate local adaptation. The globally distributed SAR11 bacterial group consists of multiple ecotypes that are ass...

Freshwater within the Greater Hudson Bay Marine region originates from rivers with large drainage basins and is modified by sea ice formation and melting. Within the BaySys project, which aims to provide a scientific basis to separate climate change and water regulation impacts, our subproject aims to provide baseline data on microbial biodiversity...

Estuaries are commonly defined as an intermediate transition zone linking freshwater and marine systems In these coastal environments, combinations of hydrodynamic processes such as river runoff and tidal currents induce strong gradients in light, nutrients, heat and salinity In Hudson Bay, these systems are now facing additional perturbations such...

Nares Strait is the northern most outflow gateway of the Arctic Ocean, with a direct connection to the remaining multi-year ice covered central Arctic Ocean. Nares Strait itself flows into the historically highly productive North Water Polynya (Pikialasorsuaq). Satellite data show that Nares Strait ice is retreating earlier in the season. The early...

Permafrost thawing results in the formation of thermokarst lakes, which are biogeochemical hotspots in northern landscapes and strong emitters of greenhouse gasses to the atmosphere. Most studies of thermokarst lakes have been in summer, despite the predominance of winter and ice-cover over much of the year, and the microbial ecology of these water...

To better understand the diversity of primary producers in the Arctic Ocean, we targeted a nitrogen cycle gene, NR, which is required for phytoplankton to assimilate nitrate into organic forms of nitrogen macromolecules. We compared this to the more detailed taxonomy from ice-influenced stations using a general taxonomic gene (18S rRNA). NR genes w...

Multiple studies indicate that climate warming threatens ice-dependent ecosystems but less is known about its effect on marine phytoplankton communities. As the Arctic Ocean freshens due to multiyear ice and Greenland Ice Sheet melt, the microbial communities are being exposed to greater salinity fluctuations over the growth season and across wide...

The Arctic Ocean is relatively isolated from other oceans and consists of strongly stratified water masses with distinct histories, nutrient, temperature and salinity characteristics, therefore providing an optimal environment to investigate local adaptation. The globally distributed SAR11 bacterial group consists of multiple ecotypes that are asso...

Arctic marine ecosystems provide numerous benefits and services of economic, societal and ecological value, including the provision of food resources, the conservation of biodiversity, carbon storage and nutrient recycling, among others. The Arc3Bio project combines the multidisciplinary skills of several experts to evaluate how climate variability...

Arctic marine ecosystems provide numerous benefits and services of economic, societal and ecological value, including the provision of food resources, the conservation of biodiversity, carbon storage and nutrient recycling, among others. The Arc3Bio project combines the multidisciplinary skills of several experts to evaluate how climate variability...

Living, harvestable resources in the upper Arctic Ocean ultimately depend on the production of marine microalgae. Microalgal production also mitigates global warming by fixing the greenhouse gas CO2 into biomass, of which a portion sinks to the seafloor. This process, called the ‘biological CO2 pump’, supplies food to the benthic organisms living a...

Microbial mats are ubiquitous in polar freshwater ecosystems and sustain high concentrations of biomass despite the extreme seasonal variations in light and temperature. Here we aimed to resolve genomic adaptations for light-harvesting, bright-light protection and carbon flow in mats that undergo seasonal freeze-up. To bracket a range of communitie...

Protists (microbial eukaryotes) are diverse, major components of marine ecosystems, and are fundamental to ecosystem services. In the last 10 years, molecular studies have highlighted substantial novel diversity in marine systems including sequences with no taxonomic context. At the same time, many known protists remain without a DNA identity. Sinc...

The HBS is a large inland sea, which receives one third of the total Canadian river discharge (ca. 522 km 3 each year) from 23 rivers and multiple streams that drain into it [1]. Physical, biological and geochemical processes in the HBS, are influenced by this massive freshwater inflow [3,4]. Microbial communities support higher food webs and are s...

Climate warming now occurring in the polar regions threatens ice-dependent ecosystems and could be expected to affect marine phytoplankton communities. Ice conditions across the Arctic influence the geographic distribution, intensity and timing of phytoplankton production and consequently the Arctic food chain and higher trophic levels, including m...

Aquatic ecosystems in the High Arctic are facing unprecedented changes as a result of global warming effects on the cryosphere. Snow pack is a central feature of northern landscapes, but the snow microbiome and its microbial connectivity to adjacent and downstream habitats have been little explored. To evaluate these aspects, we sampled along a hyd...

Twenty years ago an Arctic cryptophyte was isolated from Baffin Bay and given strain number CCMP2045. Here it was described using morphology, water‐ and non‐water soluble pigments and nuclear‐encoded SSU rDNA. The influence of temperature, salinity and light intensity on growth rates was also examined. Microscopy revealed typical cryptophyte featur...

The Arctic Ocean currently receives a large supply of global river discharge and terrestrial dissolved organic matter. Moreover, an increase in freshwater runoff and riverine transport of organic matter to the Arctic Ocean is a predicted consequence of thawing permafrost and increased precipitation. The fate of the terrestrial humic-rich organic ma...

Oceanic gateways are sensitive to climate driven processes. By connecting oceans, they have a global influence on marine biological production and biogeochemical cycles. The furthest north of these gateways is Nares Strait at the top of the North Water between Greenland and Ellesmere Island (Canada). This gateway is globally beneficial, first by su...

The Arctic Ocean currently receives a large supply of global river discharge and terrestrial dissolved organic matter. Moreover, an increase in freshwater runoff and riverine transport of organic matter to the Arctic Ocean is a predicted consequence of thawing permafrost and increased precipitation. The fate of the terrestrial humic-rich organic ma...

Phytoplankton and single celled microzooplankton are the base of the food chain, ultimately supporting fish, marine mammals, and birds across the Arctic, many of which are economically or culturally important. Different microbial communities may be more advantageous for either pelagic or benthic harvestable species. Ice conditions across the Arctic...

Lakes and ponds derived from thawing permafrost are strong emitters of carbon dioxide and methane to the atmosphere, but little is known about the methane oxidation processes in these waters. Here we investigated the distribution and potential activity of aerobic methanotrophic bacteria in thaw ponds in two types of eroding permafrost landscapes in...

Fig A in S1 File. Rarefaction curve of the pmoA. OTUs were clustered at 93%. Table A in S1 File. Ponds sampled during the 2012 and 2013 field campaign and the availability of data. Table B in S1 File. Properties of the pmoA primers fused with the Trueseq sequencing primers. Table C in S1 File. Physico-chemical properties of the surface and bottom (...

Significance Viruses often carry genes acquired from their host. In the present work, we show that a virus of a marine alga carries a gene encoding a transporter protein that mediates nutrient uptake. We confirm that the viral transporter protein is expressed during infection and show that the protein functions to take up sources of nitrogen. This...

Shallow lakes are common across the Arctic landscape and their ecosystem productivity is often dominated by benthic, cyanobacterial biofilms. Many of these water bodies freeze to the bottom and are biologically inactive during winter, but full freeze-up is becoming less common with Arctic warming. Here we analyzed the microbiome structure of newly...