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This study characterized cultivable fungi present in sediments obtained from Boeckella Lake, Hope Bay, in the north-east of the Antarctic Peninsula, and evaluated their production of enzymes and biosurfactants of potential industrial interest. A total of 116 fungal isolates were obtained, which were classified into 16 genera within the phyla Ascomycota, Basidiomycota and Mortierellomycota, in rank. The most abundant genera of filamentous fungi included Pseudogymnoascus, Pseudeurotium and Antarctomyces; for yeasts, Thelebolales and Naganishia taxa were dominant. Overall, the lake sediments exhibited high fungal diversity and moderate richness and dominance. The enzymes esterase, cellulase and protease were the most abundantly produced by these fungi. Ramgea cf. ozimecii, Holtermanniella wattica, Leucosporidium creatinivorum, Leucosporidium sp., Mrakia blollopis, Naganishia sp. and Phenoliferia sp. displayed enzymatic index > 2. Fourteen isolates of filamentous fungi demonstrated an Emulsification Index 24% (EI 24% ) ≥ 50%; among them, three isolates of A. psychrotrophicus showed an EI 24%  > 80%. Boeckella Lake itself is in the process of drying out due to the impact of regional climate change, and may be lost completely in approaching decades, therefore hosts a threatened community of cultivable fungi that produce important biomolecules with potential application in biotechnological processes., (© 2024. The Author(s), under exclusive licence to Springer Nature Japan KK.)

We studied the fungal diversity present in soils sampled along a deglaciated chronosequence from para- to periglacial conditions on James Ross Island, north-east Antarctic Peninsula, using DNA metabarcoding. A total of 88 amplicon sequence variants (ASVs) were detected, dominated by the phyla Ascomycota , Basidiomycota and Mortierellomycota . The uncommon phyla Chytridiomycota , Rozellomycota , Monoblepharomycota , Zoopagomycota and Basidiobolomycota were detected. Unknown fungi identified at higher hierarchical taxonomic levels (Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. and Rozellomycotina sp.) and taxa identified at generic and specific levels ( Mortierella sp., Pseudogymnoascus sp., Mortierella alpina , M. turficola , Neoascochyta paspali , Penicillium sp. and Betamyces sp.) dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Only 12 of the fungal ASVs were detected in all chronosequence soils sampled. Sequences representing saprophytic, pathogenic and symbiotic fungi were detected. Based on the sequence diversity obtained, Clearwater Mesa soils contain a complex fungal community, including the presence of fungal groups generally considered rare in Antarctica, with dominant taxa recognized as cold-adapted cosmopolitan, endemic, saprotrophic and phytopathogenic fungi. Clearwater Mesa ecosystems are impacted by the effects of regional climatic changes, and may provide a natural observatory to understand climate change effects over time.

We detected the fungal assemblages present in lake sediments on James Ross Island, Antarctica, using DNA metabarcoding. A total of 132 amplicon sequence variants (ASVs) were assigned, dominated by taxa of the phyla Ascomycota, Basidiomycota, Mortierellomycota and Mucoromycota. The less common phyla Chytridiomycota, Rozellomycota, Monoblepharomycota, Basidiobolomycota, Aphelidiomycota and the fungus-like Straminopila were also detected. Fungal sp. 1, Fungal sp. 2, Spizellomycetales sp. 1, Rozellomycotina sp. 1, Talaromyces rubicundus and Betamyces sp. dominated the assemblages. In general, the assemblages displayed high diversity and richness, and moderate dominance. Saprophytic, pathogenic and symbiotic fungi were detected. The metabarcoding data indicated that Antarctic lakes may represent a hotspot of fungal diversity in Antarctica. The sediments of these lakes may accumulate different fungal fragments and active fungal mycelia and their propagules, deposited over long periods of time. Lakes in the Antarctic Peninsula region are sensitive environments threatened by the effects of regional climatic changes. The abundance of sequences of little-known Rozellomycota and Chytridiomycota (Spizellomycetales) taxa in these ecosystems highlights the need for further studies to identify if they are metabolically active in the sediments and whether they have potentially pathogenic capabilities., (Copyright © 2022 British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

We assessed fungal diversity in sediments obtained from four lakes in the South Shetland Islands and James Ross Island, Antarctica, using DNA metabarcoding. We detected 218 amplicon sequence variants (ASVs) dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota and Chytridiomycota. In addition, the rare phyla Aphelidiomycota, Basidiobolomycota, Blastocladiomycota, Monoblepharomycota, Rozellomycota and Zoopagomycota as well as fungal-like Straminopila belonging to the phyla Bacillariophyta and Oomycota were detected. The fungal assemblages were dominated by unknown fungal taxa (Fungal sp. 1 and Fungal sp. 2), followed by Talaromyces rubicundus and Dactylonectria anthuriicola. In general, they displayed high diversity, richness and moderate dominance. Sequences representing saprophytic, pathogenic and symbiotic fungi were detected, including the phytopathogenic fungus D. anthuriicola that was abundant, in the relatively young Soto Lake on Deception Island. The lake sediments studied contained the DNA of rich, diverse and complex fungal communities, including both fungi commonly reported in Antarctica and other taxa considered to be rare. However, as the study was based on the use of environmental DNA, which does not unequivocally confirm the presence of active or viable organisms, further studies using other approaches such as shotgun sequencing are required to elucidate the ecology of fungi in these Antarctic lake sediments., (© 2022. The Author(s).)

We studied the fungal DNA present in a lake sediment core obtained from Trinity Peninsula, Hope Bay, north-eastern Antarctic Peninsula, using metabarcoding through high-throughput sequencing (HTS). Sequences obtained were assigned to 146 amplicon sequence variants (ASVs) primarily representing unknown fungi, followed by the phyla Ascomycota, Rozellomycota, Basidiomycota, Chytridiomycota and Mortierellomycota. The most abundant taxa were assigned to Fungal sp., Pseudeurotium hygrophilum, Rozellomycota sp. 1, Pseudeurotiaceae sp. 1 and Chytridiomycota sp. 1. The majority of the DNA reads, representing 40 ASVs, could only be assigned at higher taxonomic levels and may represent taxa not currently included in the sequence databases consulted and/or be previously undescribed fungi. Different sections of the core were characterized by high sequence diversity, richness and moderate ecological dominance indices. The assigned diversity was dominated by cosmopolitan cold-adapted fungi, including known saprotrophic, plant and animal pathogenic and symbiotic taxa. Despite the overall dominance of Ascomycota and Basidiomycota and psychrophilic Mortierellomycota, members of the cryptic phyla Rozellomycota and Chytridiomycota were also detected in abundance. As Boeckella Lake may cease to exist in approaching decades due the effects of local climatic changes, it also an important location for the study of the impacts of these changes on Antarctic microbial diversity., (© 2022. The Author(s), under exclusive licence to Springer Japan KK, part of Springer Nature.)

Background: Vega Island is located off the eastern tip of the Antarctic Peninsula (Maritime Antarctica), in the Weddell Sea. In this study, we used metabarcoding to investigate green algal DNA sequence diversity present in sediments from three lakes on Vega Island (Esmeralda, Copépodo, and Pan Negro Lakes)., Methods and Results: Total DNA was extracted and the internal transcribed spacer 2 region of the nuclear ribosomal DNA was used as a DNA barcode for molecular identification. Green algae were represented by sequences representing 78 taxa belonging to Phylum Chlorophyta, of which 32% have not previously been recorded from Antarctica. Sediment from Pan Negro Lake generated the highest number of DNA reads (11,205), followed by Esmeralda (9085) and Copépodo (1595) Lakes. Esmeralda Lake was the richest in terms of number of taxa (59), with Copépodo and Pan Negro Lakes having 30 taxa each. Bray-Curtis dissimilarity among lakes was high (~ 0.80). The Order Chlamydomonadales (Chlorophyceae) gave the highest contribution in terms of numbers of taxa and DNA reads in all lakes. The most abundant taxon was Chlorococcum microstigmatum., Conclusions: The study confirms the utility of DNA metabarcoding in assessing potential green algal diversity in Antarctic lakes, generating new Antarctic records., (© 2021. The Author(s), under exclusive licence to Springer Nature B.V.)

We assessed the diversity of fungal DNA present in sediments of three lakes on Vega Island, north-east Antarctic Peninsula using metabarcoding through high-throughput sequencing (HTS). A total of 640,902 fungal DNA reads were detected, which were assigned to 224 taxa of the phyla Ascomycota, Rozellomycota, Basidiomycota, Chytridiomycota and Mortierellomycota, in rank order of abundance. The most abundant genera were Pseudogymnoascus, Penicillium and Mortierella. However, a majority (423,508, 66%) of the reads, representing by 43 ASVs, could only be assigned at higher taxonomic levels and may represent taxa not currently included in the sequence databases used or be new or previously unreported taxa present in Antarctic lakes. The three lakes were characterized by high sequence diversity, richness, and moderate dominance indices. The ASVs were dominated by psychrotolerant and cosmopolitan cold-adapted Ascomycota, Basidiomycota and Mortierellomycota commonly reported in Antarctic environments. However, other taxa detected included unidentified members of Rozellomycota and Chytridiomycota species not previously reported in Antarctic lakes. The assigned diversity was composed mainly of taxa recognized as decomposers and pathogens of plants and invertebrates.

This article presents analytical observations on physicochemical parameters and major and trace element concentrations of water, ice, and sediment samples from the lake systems of Clearwater Mesa (CWM), northeast Antarctic Peninsula. Geochemical analyses include inductively coupled plasma mass spectrometry (ICP-MS) for cations and trace elements and ion chromatography for anions. Some figures are included (i.e. Piper and Gibbs diagrams) which indicate water classification type and rock-water interactions in CWM, respectively. It also contains PHREEQC software output, listing the chemical speciation for dissolved elements, Saturation Indexes (SI), and modelling outputs. Each lake SI are also illustrated in a figure. Finally, total organic and inorganic carbon (TOC and TIC, respectively) were determined for bottom lake sediments and marginal salt samples. This information will be useful for future research assessing the impacts of anthropogenic pollution and the effects of climate change, providing insights into naturally occurring geochemical processes in a pristine environment, and evaluating geochemical behaviour of dissolved elements in high-latitude hydrological systems. These data correspond to the research article "Dissolved major and trace geochemical dynamics in Antarctic Lacustrine Systems" [1]., (© 2020 The Authors.)

Clearwater Mesa (James Ross Island, northeast Antarctic Peninsula) provides a unique opportunity to study solute dynamics and geochemical weathering in the pristine lacustrine systems of a high latitude environment. In order to determine major controls on the solute composition of these habitats, a geochemical survey was conducted on 35 lakes. Differences between lakes were observed based on measured physico-chemical parameters, revealing neutral to alkaline waters with total dissolved solids (TDS) < 2500 mg L -1 . Katerina and Trinidad-Tatana systems showed an increase in their respective TDS, total organic carbon values, and finner sediments from external to internal lakes, indicating an accumulation of solutes due to weathering. Norma and Florencia systems exhibited the most diluted and circumneutral waters, likely from the influence of glacier and snow melt. Finally, isolated lakes presented large variability in TDS values, indicating weathering and meltwater contributions at different proportions. Trace metal abundances revealed a volcanic mineral weathering source, except for Pb and Zn, which could potentially indicate atmospheric inputs. Geochemical modelling was also conducted on a subset of connected lakes to gain greater insight into processes determining solute composition, resulting in the weathering of salts, carbonates and silicates with the corresponding generation of clays. We found CO 2 consumption accounted for 20-30% of the total species involved in weathering reactions. These observations allow insights into naturally occurring geochemical processes in a pristine environment, while also providing baseline data for future research assessing the impacts of anthropogenic pollution and the effects of climate change., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

BA42 is a protein belonging to the psychrophilic bacteria Bizionia argentinensis sp. nov. Bioinformatics analysis showed that it presents significant sequence identity with a Pfam A family, DUF 477, found both in eukarya and eubacteria but of unknown function in all these organisms. Here, we report the NMR spectra assignment of this 145 amino acid protein. These data will allow performing NMR structural studies with the aim of using the three-dimensional structure as relevant information in order to determine the function of this family of proteins.

A psychrotolerant marine bacterial strain, designated JUB59(T), was isolated from Antarctic surface seawater and classified as a new species of the genus Bizionia. Here, we present the first draft genome sequence for this genus, which suggests interesting features such as UV resistance, hydrolytic exoenzymes, and nitrogen metabolism.

A marine bacterial strain, designated strain JUB59(T), was isolated from surface seawater in Antarctica and subsequently characterized. Cells were found to be Gram-negative, non-motile rods forming butyrous, shiny, yellowish orange colonies on marine agar. Growth occurred at 2-28 degrees C (optimally at 22-25 degrees C) but not at 30 degrees C; Na+ ions were required, but 9 % NaCl (w/v) was not tolerated. Phylogenetic analysis, based on comparisons of the complete 16S rRNA gene sequence of the novel isolate with the sequences of closely related strains, showed that strain JUB59(T) belonged to the family Flavobacteriaceae, representing a novel species of the genus Bizionia. The highest levels of sequence similarity were found with respect to Bizionia myxarmorum ADA-4(T) (97.4 %) and Bizionia algoritergicola APA-1(T) (97.1 %). However, the DNA-DNA relatedness of strain JUB59(T) with respect to these two strains was low (15.9-17.3 and 19.3-22.1 %, respectively). The predominant fatty acids of strain JUB59(T) were iso-15 : 1omega10c (18.1 %), iso-15 : 0 (17.3 %), anteiso-15 : 0 (13.9 %), iso-17 : 0 3-OH (9.2 %), 15 : 0 (6.0 %) and iso-16 : 0 3-OH (5.3 %). The main polar lipids were phosphatidylethanolamine, an aminolipid, an amino-positive phospholipid and two unidentified lipids. MK-6 was the major respiratory quinone (>90 %) and the DNA G+C content was 34 mol%. On the basis of the data obtained, strain JUB59(T) represents a novel species of the genus Bizionia, for which the name Bizionia argentinensis sp. nov. is proposed. The type strain is JUB59(T) (=DSM 19628(T)=CCM-A-29 1259(T)).

Extracellular proteases from 8 Antarctic psychrotolerant Pseudomonas sp. strains were purified and characterised. All of them are neutral metalloproteases, have an apparent molecular mass of 45kDa, optimal activity at 40 degrees C and pH 7-9, retaining significant activity at pH 5-11. With the exception of P96-18, which is less stable, all retain more than 50% activity after 3 h of incubation at pH 5-9 and show low thermal stability (their half-life times range from 20 to 60 min at 40 degrees C and less than 5 min at 50 degrees C). These proteases can be used in commercial processes carried out at neutral pH and moderate temperatures, and are of special interest for their application in mixtures of enzymes where final thermal selective inactivation is needed. Results also highlight the relevance of Antarctic biotopes for the isolation of protease-producing enzymes active at low temperatures.