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With solar radiation being a primary driver of melting glacial ice and snow, glaciers and high-elevation mountain snowpacks are especially sensitive to even small changes in the concentration of light absorbing particles. Surface melt of snow and glacial ice is substantially higher if impurities such as mineral dust and organic matter are present in significant quantities. Bacteria and algae further promote darkening of the glacial surface and melting by aggregating these impurities in the form of biofilm. Like many mountain glaciers of the Alaskan region, the Juneau Icefield has seen extensive mass loss. Black carbon released by human and natural activities has become a major contributor to reducing snow and ice albedo. Microbes can affect the dynamics of black carbon on glacial surfaces, with biodegradation having profound implications on its residence time, light absorbance, and output to adjacent and downstream aquatic ecosystems. This NSF Rapid Response Research (RAPID) project funded the field work necessary for the acquisition of samples from the Gilkey Glacier, Alaska in July 2024. This dataset includes sample collection types, coordinates and stream flow data. 

ABSTRACT We report the genomic sequences of 14 bacterial isolates from a supraglacial stream on the Cotton Glacier, Antarctica. Fine sediments in the streambed provide habitat for bacterial growth and biofilm formation. The stream represents a natural laboratory for studying the evolution and adaptation of microbes to a humic-free environment. 

ABSTRACT Inland meltwater ponds are common throughout the dry valley region of Antarctica, with seasonal meltwater inputs driving their biogeochemistry. Here, we report the genomic sequences of eight environmental bacterial isolates covering three major phyla from Marr Pond, Taylor Valley, Antarctica. 

ABSTRACT Sediments in cryoconite holes and meltwater streams in the McMurdo Dry Valleys, Antarctica, provide both substrates and conditions that support life in an arid polar desert. Here, we report the genomic sequences of eight environmental, bacterial isolates from Canada Glacier cryoconite holes and stream. These isolates span three major phyla. 

Abstract  Microbial biofilm contamination is a widespread problem that requires precise and prompt detection techniques to effectively control its growth. Microfabricated electrochemical impedance spectroscopy (EIS) biosensors offer promise as a tool for early biofilm detection and monitoring of elimination. This study utilized a custom flow cell system with integrated sensors to make real-time impedance measurements of biofilm growth under flow conditions, which were correlated with confocal laser scanning microscopy (CLSM) imaging. Biofilm growth on EIS biosensors in basic aqueous growth media (tryptic soy broth, TSB) and an oil–water emulsion (metalworking fluid, MWF) attenuated in a sigmoidal decay pattern, which lead to an ∼22–25% decrease in impedance after 24 Hrs. Subsequent treatment of established biofilms increased the impedance by ∼14% and ∼41% in TSB and MWF, respectively. In the presence of furanone C-30, a quorum-sensing inhibitor (QSI), impedance remained unchanged from the initial time point for 18 Hrs in TSB and 72 Hrs in MWF. Biofilm changes enumerated from CLSM imaging corroborated impedance measurements, with treatment significantly reducing biofilm. Overall, these results support the application of microfabricated EIS biosensors for evaluating the growth and dispersal of biofilm in situ and demonstrate potential for use in industrial settings. One-Sentence SummaryThis study demonstrates the use of microfabricated electrochemical impedance spectroscopy (EIS) biosensors for real-time monitoring and treatment evaluation of biofilm growth, offering valuable insights for biofilm control in industrial settings. 

During the growth of a polycrystalline ice lattice, microorganisms partition into veins, forming an ice vein network highly concentrated in salts and microbial cells. We used microfabricated electrochemical impedance spectroscopy (EIS) sensors to determine the effect of microorganisms on the electrochemical properties of ice. Solutions analyzed consisted of a 176μS cm⁻¹conductivity solution, fluorescent beads, andEscherichia coliHB101-GFP to model biotic organisms. Impedance spectroscopy data were collected at −10 °C, −20 °C, and −25 °C within either ice veins or ice grains (i.e., no veins) spanning the sensors. After freezing, the fluorescent beads andE. coliwere partitioned into the ice veins. The corresponding impedance data were discernibly different in the presence of ice veins and microbial impurities. The presence of microbial cells in ice veins was evident by decreased electrical characteristics (electrode polarization between electrode and ice matrix) relative to solid ice grains. Further, this electrochemical behavior was reversed in all bead-doped solutions, indicating that microbial processes influence sensor response. Linear mixed-effects models empirically corroborated the differences in polarization associated with the presence and absence of microbial cells in ice. We show that EIS has the potential to detect microbes in ice and differentiate between veins and solid grains. 

Surfactants, both synthetic and natural, are used in a wide range of industrial applications, including the degradation of petroleum hydrocarbons. Organisms from extreme environments are well-adapted to the harsh conditions and represent an exciting avenue of discovery of naturally occurring biosurfactants, yet microorganisms from cold environments have been largely overlooked for their biotechnological potential as biosurfactant producers. In this study, four cold-adapted bacterial isolates from Antarctica are investigated for their ability to produce biosurfactants. Here we report on the physical properties and chemical structure of biosurfactants from the genera Janthinobacterium, Psychrobacter, and Serratia. These organisms were able to grow on diesel, motor oil, and crude oil at 4 °C. Putative identification showed the presence of sophorolipids and rhamnolipids. Emulsion index test (E24) activity ranged from 36.4–66.7%. Oil displacement tests were comparable to 0.1–1.0% sodium dodecyl sulfate (SDS) solutions. Data presented herein are the first report of organisms of the genus Janthinobacterium to produce biosurfactants and their metabolic capabilities to degrade diverse petroleum hydrocarbons. The organisms’ ability to produce biosurfactants and grow on different hydrocarbons as their sole carbon and energy source at low temperatures (4 °C) makes them suitable candidates for the exploration of hydrocarbon bioremediation in low-temperature environments. 

Micro-fabricated sensors enable the study of chemical and physical dynamics in aqueous environments such as rivers, lakes or oceans at low cost. Sensors must work reliably in these environments, which include both biological and chemical challenges. However, sensor thin films have not been studied in detail for aqueous applications, and more specifically how biotic interactions may change sensor material properties. In this study, the long-term effects of biofilm formation on the properties of aluminum (electric conductor) and a-Si x N y :H (insulating material) were investigated. Material degradation caused by Escherichia coli K12 biofilm growth was determined by electrical sheet resistance measurements (collinear four-point-probe) and Fourier-transform infrared spectroscopy (FTIR) absorption spectra over a time period of 7 weeks. Changes of the surface topography were tested using scanning electron microscopy (SEM) and white light interferometry. Aluminum was found to be heavily degraded at three weeks, whereas a-Si x N y :H was inert during the entire investigation period. As differences between thin film sensor materials are evident, more detailed investigations including a broader range of materials should be explored. 

As many bacteria detected in Antarctic environments are neither true psychrophiles nor endemic species, their proliferation in spite of environmental extremes gives rise to genome adaptations. Janthinobacterium sp. CG23_2 is a bacterial isolate from the Cotton Glacier stream, Antarctica. To understand how Janthinobacterium sp. CG23_2 has adapted to its environment, we investigated its genomic traits in comparison to genomes of 35 published Janthinobacterium species. While we hypothesized that genome shrinkage and specialization to narrow ecological niches would be energetically favorable for dwelling in an ephemeral Antarctic stream, the genome of Janthinobacterium sp. CG23_2 was on average 1.7 ± 0.6 Mb larger and predicted 1411 ± 499 more coding sequences compared to the other Janthinobacterium spp. Putatively identified horizontal gene transfer events contributed 0.92 Mb to the genome size expansion of Janthinobacterium sp. CG23_2. Genes with high copy numbers in the species-specific accessory genome of Janthinobacterium sp. CG23_2 were associated with environmental sensing, locomotion, response and transcriptional regulation, stress response, and mobile elements—functional categories which also showed molecular adaptation to cold. Our data suggest that genome plasticity and the abundant complementary genes for sensing and responding to the extracellular environment supported the adaptation of Janthinobacterium sp. CG23_2 to this extreme environment.