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Microorganisms in Warming Arctic Environments

Periodic Reporting for period 2 - MicroArctic (Microorganisms in Warming Arctic Environments)

Reporting period: 2018-04-01 to 2020-03-31

The Arctic plays a key role in the Earth’s climate system and there is a need to estimate the impact that environmental change will have in this area. One third of the global carbon pool is stored in northern latitude ecosystems and microbial processes are at the heart of transformations in this carbon pool. Thus, there is considerable socio-economic interest in predicting how the carbon balance in the Arctic will respond to ongoing climate warming.

The initial objectives of the MicroArctic network were to:

(1) provide urgently needed training in Arctic microbiology and biogeochemistry preparing a new generation of professionals for critical roles in the coming years of Arctic meltdown and;
(2) significantly advance our understanding of changes and adaptation in Arctic microbial communities and feedbacks with biogeochemical cycles to the fast Arctic warming and climate change.

In this ITN, we trained the next generation of Arctic microbiology and biogeochemistry experts to be able to respond to the need for governance and leadership in public, policy and commercial interests in the region. The training was both diverse and unique because it combined a range of practical skills for work in a challenging environment with specific knowledge about microbiology and biogeochemistry in order to deliver a detailed framework and database of the functional diversity and potential of Arctic microorganisms adequate for exploitation in economic and environmental services.
MicroArctic addressed key gaps in our knowledge about the biogeochemical cycles and microbial communities in a range of terrestrial Arctic habitats. One such gap concerned the sources and both temporal and spatial variations of nutrient and microbial communities across relevant Arctic ecosystems such as air, snow, ice and soil. Through laboratory simulations, MicroArctic demonstrated that microbial activity and biogeochemical processes can take place even during the dark and colder periods of the winter. Field sampling of aerosols and precipitation demonstrates the importance of those conduits of nutrients and microbial cells to the Arctic environment. The beginning of the summer season is a critical period for stimulating higher microbial activity and nutrient cycling during the summer. MicroArctic identified ionic pulses of nutrients during the first melt of the summer season as an important phase in stimulating and sustaining algal blooms on the surface of the Greenland ice sheet which are very important in promoting additional glacier melt.

MicroArctic attempted to look at responses of microbial communities and biogeochemical cycles to climate change over a long-term perspective (past and future). Stratigraphic analyses on molecular-level microbial community structure and functionality were combined with microscale geochemical and mineralogical quantifications applied on glacier forefield chronosequences and on permafrost deposits as an archive for glacial-interglacial changes. Results demonstrate that thaw, currently experienced in permafrost, can stimulate release of methane, when an initial active community was present at the scale of thousands of years. MicroArctic also used an altitudinal gradient and contrasting microclimatic conditions between north versus south slopes in alpine glaciers as a proxy for climate and soils exposed to their “future conditions” in a soil transfer approach. Based on the results obtained during winter fieldwork in Svalbard in a recent deglaciated region (past 100 years), bedrock weathering was identified as the dominant process controlling the initial build-up of a labile nutrient pool in Arctic environments feeding microbial communities. A broad scale sampling approach of Arctic soils indicated pH as the dominant factor in explaining microbial distribution in the Arctic.

In additition to a microbial community approach, MicroArctic aimed to evaluate changes at protein to population level in Arctic ecosystems associated with warming. This included determinations of diversity, stress response, and interactions of fungi from glacial ice and soils, glacier metatranscriptomic thermal response and cold-adaptation mechanisms of enzymes in psychrophilic organisms, analyses of the composition, and activity and fate of cyanobacterial and bacterial populations in natural and simulated habitat types in the warming Arctic. Of the metagenomes from Arctic habitats and other environments used for comparison, the relative abundance of plasmid-related sequences involved in both plasmid replication and conjugation were over orders of magnitude higher in snow metagenomes than any other metagenome tested. At the population level, fungal abundance and diversity associated with algal blooms on the Greenland Ice Sheet provided evidence for a strong association between these populations, even suggesting some interdependency processes.

MicroArctic explored both socio-economic opportunities for development and threats to the environment in the warming Arctic. Researchers looked at glacier ecosystem services by investigating the biotechnology potential of the Arctic cryospheric biome, developing bioinformatics approaches to mine data of economically important genes from Arctic environments and determining the significance of pathogens in Arctic environments. Samples from a variety of glaciers in the Arctic were collected and their metagenomes analysed. The most abundant enzyme classes found in the metagenomics were carbohydrate-active enzymes, lipases and peroxidases, all of which have high utility in industry. Potentially pathogenic bacteria isolated from diverse habitats in Spitsbergen, Svalbard were also investigated. Ability to break down cells was observed in 32 out of 78 bacterial species isolated from Arctic habitats. Much of the work in MicroArctic was done using a suite of molecular tools. Pipelines written in Python, R and bash scripting were generated and can be useful for approaching microbial community analyses from other habitats too.

In summary, > 30 papers have been published in peer-reviewed literature, including appearance in high impact journals, such as Scientific Reports, GigaScience and Environmental Microbiology.
Outreach activities conducted over the course of the MicroArctic project have made the general public more aware of the challenges and necessity of work in the Arctic. ESRs participated in over 60 outreach events targeting people of all ages and backgrounds and were also active in international conferences.

The cryosphere contains bacteria capable of synthesizing diverse secondary metabolites. Screening metagenomes to investigate biosynthetic gene clusters of interest from uncultivable bacteria is a key step in developing strategies to heterologously express compounds with high antimicrobial potential. Metagenomes collected in Svalbard harbour many genes for enzymes with applications in industry. MicroArctic hopes that results achieved over the course of the project can be used for biotechnological mining.

The success of the project is evidenced by the the fact that many fellows have already found post-doctoral positions thanks to their work on the MicroArctic project. The research performed over the course of the MicroArtic project generated interest from other research groups and has led to a number of new and ongoing collaborations.