From molecules to mountain ranges: Remote sensing of extremophilic algae blooms, Saharan dust deposition events, and meta-omic analysis of the bloom community

Background and aims

Highly pigmented extremophilic algae communities, “Blood Snow”,  accelerate the retreat of glaciers and snowcaps by depressing the reflectivity of surfaces by up to 13%. In the European Alps these snow algae interact with depositions of Saharan dust, a plausible source of vital nutrients. Using a novel ML-based remote-sensing algorithm, we have tracked blooms and dust deposition events in the Alps, but we now seek molecular-level insight to better understand how, where and when these blooms occur. Unculturable key strains, remote field-sites and low biomass per unit volume has kept meta-omic analysis of functional microbial ecology impractical in these ecosystems. Standard sampling techniques require cryogens or expensive, heavy and limited portable freezers to preserve protein for multi-omics: These are, at minimum, logistically challenging if not unobtainable in remote locations. We aimed to develop ambient temperature concentration, fixation and transportation of field samples for meta-omics, expanding the ability of researchers to probe the ecology of remote extremophile communities in-situ. Better in-vitro understanding of these significant unconstrained cryospheric effects may help untangle the interactions, behavior and uncertain future of these phenomena.

Methods

Traditional flash-freezing requires the sourcing and transportation of cryogens to preserve samples as-is. Using cryogens in remote locations is hazardous, and results in bulky samples that must reach a freezer within hours. Another approach is to use in-situ concentration followed by macromolecule fixation with broad-spectrum enzyme inhibitors. This allows preservation of approximately equal quality to LN2, concentrated samples, safer fieldwork and a generous timescale for samples to reach long-term storage. This then fed into a SP3 proteomic and WGS metagenomic pipeline to identify proteins and infer what the community is capable of on its own, and what must be outsourced.

Results

We show that quality DNA and Protein can be extracted from samples gathered in this manner and present preliminary meta-omic analysis of the same, synthesised with the results of our whole Alp survey of Algal Blooms and dust deposition events. This method also solves an adjacent problem: the low biomass per volume of remote extremophiles via in-situ concentration. We will also discuss how these molecular-level insights may provide clues into community functioning, interaction with other geophysical cycles such as Saharan dust circulation, and outline future opportunities.

 

Conclusion

A novel sampling technique allows meta-omic exploration of microbial ecological dynamics in remote locations without cryogens. This lower barrier to entry enables affordable, compact, time-insensitive, meta-omics in remote microbial ecosystems, helping to sidestep issues in understanding these currently unculturable but highly influential organisms.