Antarctic subice environments are diverse, underexplored microbial habitats. Here, we describe the ecophysiology and annotated genome of a Marinobacter strain isolated from a cold, saline, iron-rich subglacial outflow of the Taylor Glacier, Antarctica. This strain (BF04_CF4) grows fastest at neutral pH (range 6-10), is psychrophilic (range: 0°C-20°C), moderately halophilic (range: 0.8%-15% NaCl) and hosts genes encoding potential low temperature and high salt adaptations. The predicted proteome suggests it utilizes fewer charged amino acids than a mesophilic Marinobacter strain. BF04_CF4 has increased concentrations of membrane unsaturated fatty acids including palmitoleic (33%) and oleic (27.5%) acids that may help maintain cell membrane fluidity at low temperatures. The genome encodes proteins for compatible solute biosynthesis and transport, which are known to be important for growth in saline environments. Physiological verification of predicted metabolic functions demonstrate BF04_CF4 is capable of denitrification and may facilitate iron oxidation. Our data indicate that strain BF04_CF4 represents a new Marinobacter species, Marinobacter gelidimuriae sp. nov., that appears well suited for the subglacial environment it was isolated from. Marinobacter species have been isolated from other cold, saline environments in the McMurdo Dry Valleys and permanently cold environments globally suggesting that this lineage is cosmopolitan and ecologically relevant in icy brines.
Summary
Antarctic subglacial environments host microbial ecosystems and are proving to be geochemically and biologically diverse. The Taylor Glacier, Antarctica, periodically expels iron‐rich brine through a conduit sourced from a deep subglacial aquifer, creating a dramatic red surface feature known as Blood Falls. We used Illumina MiSeq sequencing to describe the core microbiome of this subglacial brine and identified previously undetected but abundant groups including the candidate bacterial phylum Atribacteria and archaeal phylum Pacearchaeota. Our work represents the first microbial characterization of samples collected from within a glacier using a melt probe, and the only Antarctic subglacial aquatic environment that, to date, has been sampled twice. A comparative analysis showed the brine community to be stable at the operational taxonomic unit level of 99% identity over a decade. Higher resolution sequencing enabled deconvolution of the microbiome of subglacial brine from mixtures of materials collected at the glacier surface. Diversity patterns between this brine and samples from the surrounding landscape provide insight into the hydrological connectivity of subglacial fluids to the surface polar desert environment. Understanding subice brines collected on the surfaces of thick ice covers has implications for analyses of expelled materials that may be sampled on icy extraterrestrial worlds.
Geoengineering is the term used to describe environmental manipulation at a planetary scale. It is generally described as having two main categories: solar radiation management and carbon dioxide removal, with an aim to reduce or neutralise the effects of climate change and global warming. Techniques include carbon capture and storage, fertilising the oceans and sunshields in space. The deployment of such technologies would present ethical challenges and potential environmental and social problems. As a species we have already manipulated and impacted on the environment and a key issue remains: it is not possible to predict all of the consequences of interventions in natural systems. If such technologies were to be deployed we would be ‘locked-in’ to cycles; we would be committed to trying to innovate and engineer solutions to new problems.
Natural ecosystems provide benefits on which mankind is dependent for sustainable development. Collectively, these benefits are referred to as ecosystem services. Functioning ecosystems are important for sustainable development and the balancing of environmental, social and economic interests. Carbon dioxide is an important greenhouse-enhancing gas and soils in the UK, especially peatlands, represent significant carbon stores and the potential to absorb carbon emissions. The fragile peatland ecosystems have been severely damaged by erosion, caused by a variety of factors such as grazing, burning and drainage. This has adverse impacts on a range of ecosystem services, including the loss of stored carbon. At a landscape scale in the Peak District of England a partnership programme is underway to restore eroded peatlands through revegetation and re-wetting the moorlands to conserve biodiversity, protect the carbon store and re-start peat formation. The experience of large-scale restoration techniques gained in the Peak District can be adapted and applied elsewhere. While there remain many uncertainties about this work, in addition to conserving biodiversity, the majority of peatland restoration work could be deemed a cost-effective means of carbon mitigation.
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