Search Results (50)

Antarctica harbors some of the most extreme ecosystems on earth, where only two vascular plants persist. The native grass Deschampsia antarctica provides a model for plant–microbe interactions under intense abiotic stress. We present the first multi-compartmental and multi-kingdom characterization of bacterial and fungal communities associated with D. antarctica across three South Shetland Islands. Metabarcoding revealed strong compartmentalization: the rhizosphere displayed the highest richness and complex bacterial–fungal networks; the root endosphere showed intermediate diversity with keystone taxa such as Rhizobiales and Streptomyces; and the leaf endosphere was simplified, dominated by stress-tolerant taxa including Pseudomonas and Helotiales. Despite marked soil heterogeneity, phosphorus enrichment at Admiralty Bay, base cations at Coppermine Cove, and iron at Byers Peninsula, a conserved core (20 bacterial and 5 fungal genera) persisted, mainly cold-adapted saprotrophs and plant-associated taxa. Fungal assemblages were more responsive to soil chemistry, with site-specific enrichments such as Zymoseptoria and Herpotrichia. Overall, D. antarctica holobionts exhibited a dual strategy: conserved microbial backbones confer stability, while localized assemblages shaped by soil chemistry and geography enhance adaptability. Together, these findings provide one of the most integrative characterizations of the D. antarctica holobiont to date, revealing how conserved and adaptive microbial components support plant resilience under extreme Antarctic conditions and offering valuable insights for predicting biological responses to ongoing climate change. Full article

Antarctic krill (Euphausia superba) is a keystone species in the marine ecosystem of the Antarctic Ocean, bringing about significant ecological and economic value. The spatio-temporal distribution of Antarctic krill directly affects commercial fishing; meanwhile, changes in krill population structure play a crucial role in maintaining the balance of the Southern Ocean ecosystem. This study analyzed six years of midwater trawl data, including over 160,000 krill length measurements, to elucidate spatio-temporal dynamics and population composition, providing actionable insights for improved fishery management. Here, we reveal southward migration shifts in krill fishing grounds, with smaller individuals favoring ice-rich southern latitudes. Commercial krill fishing operations preferentially targeted high-density fishing grounds rather than selecting larger individuals. Among the catches, the age 1+ class accounted for the highest proportion at 42.80%, followed by the age 2+ class at 39.42%, with individuals ≥3+ accounting for 17.44%. Although the mean krill length experienced a decline in 2017, it demonstrated a sustained recovery in subsequent years, reaching peak dimensions in 2022. This maximum-growth year also exhibited the highest proportion (12.6%) of individuals within ≥4 age classes. Consequently, the sustained increase in fishing effort in recent years has not resulted in a reduction in the size of individual krill. The mean krill length showed a significant positive correlation with the depth (r = 0.36, p < 0.01) and temperature (r = 0.26, p < 0.01) of the krill cluster, and a significant negative correlation with resource density (r = −0.20, p < 0.01), year (ρ = −0.31, p < 0.01) and latitude (ρ = −0.31, p < 0.01). The length exhibited U-shaped temporal trends, and latitudinal and longitudinal nonlinearity. Body size was positively correlated with depth (p < 0.01), whereas as temperature increased, body size first increased and then remained constant. As density increased, the mean krill length increased first and then slowly decreased. Recent warming intensifies population shifts, with potential cascading effects on ecosystem structure and carbon sequestration. Full article

During China’s 41st Antarctic research expedition, samples were collected from wildlife on the Fildes Peninsula, South Shetland Islands, Antarctica. Real-time RT-PCR screening confirmed H5N1 positivity, representing the first identification of the virus in brown skuas on the Fildes Peninsula. Whole-genome sequences obtained from positive samples via next-generation sequencing were subjected to phylogenetic and phylogeographic analyses. The results revealed that these Antarctic strains are most closely related to H5N1 viruses circulating in South America, particularly from Peru and Chile, suggesting a likely introduction via avian migration routes. Furthermore, a unique 17-amino-acid deletion was identified in the stalk region of the neuraminidase (NA) gene, which is uncommon among globally sampled clade 2.3.4.4b variants. This study confirms the arrival of HPAI H5N1 in the Antarctic continent and underscores the necessity for enhanced surveillance to understand the viral ecology and potential risks within this unique ecosystem. Full article

Phylogeographic studies in Antarctica allow us to understand the demographic events of populations during glacial periods. In this study, the polyplacophoran Tonicina zschaui was analyzed in several localities on the West Antarctic Coast using the mitochondrial gene cytochrome oxidase subunit I (COI). Two genetically distinct populations were identified: one in the Weddell Sea and another across the Antarctic Peninsula and South Shetland Islands. Genetic diversity was generally low to moderate, suggesting limited gene flow and the influence of historical climatic events. Star-like haplotype networks and demographic analyses indicate population contractions during the Last Glaciation followed by postglacial expansion, especially in the Antarctic Peninsula–South Shetland Islands population. Several sites in this region were identified as potential glacial refugia, exhibiting proportionally elevated genetic diversity and exclusive haplotypes. Conversely, the small Weddell Sea population displayed signs of long-term isolation, limited expansion, and low diversity, likely due to stronger environmental constraints and genetic drift. Ocean currents such as the Antarctic Coastal Current, the Antarctic Peninsula Coastal Current and the Weddell Gyre appear to restrict larval dispersal, reinforcing genetic discontinuities. These findings support the hypothesis of glacial survival in localized refugia and postglacial recolonization, a pattern observed in other Antarctic marine invertebrates. Full article

The formation and development of mushrooms depend on suitable conditions of humidity, substrate, and temperature. These environmental factors are directly influenced by ongoing climate change, which may alter fungal growth patterns, distribution, and morphology. However, these attributes remain inadequately investigated in Antarctic mushrooms. In this study, we examined 334 basidiomes of Arrhenia antarctica, discovered on Livingston Island in 2023. The morphological characteristics of these basidiomes were analyzed to explore how recent variations may be linked to and explained by climatic changes. Comparing the original description from over 60 years ago with the recent literature on the subject, we observed a larger pileus diameter (47.3% of basidiomes with diameters exceeding 23 mm, up to 75 mm) than previously documented (reported as up to 23 mm). Additionally, there were changes in pileus morphology, with not all of them exhibiting an umbilicate form, contrary to the references. We propose that these morphological variations may be attributed to climatic changes. The basidiomata were also found in association with pure Antarctic grass banks, prompting the question of whether Arrhenia antarctica is indeed a moss parasite. The information presented in this study aims to support ongoing research on the taxonomy and diversity of Agaricales fungi in Antarctica. Full article

The South Shetland Islands and Antarctic Peninsula (SHETPENANT region) constitute a geodynamically active area shaped by the interaction of major tectonic plates and active magmatic systems. This study analyzes GNSS time series spanning from 2017 to 2024 to investigate surface deformation associated with the 2020–2021 seismic swarm near the Orca submarine volcano. Horizontal and vertical displacement velocities were estimated for the preseismic, coseismic, and postseismic phases using the CATS method. Results reveal significant coseismic displacements exceeding 20 mm in the horizontal components near Orca, associated with rapid magmatic pressure release and dike intrusion. Postseismic velocities indicate continued, though slower, deformation attributed to crustal relaxation. Stations located near the Orca exhibit nonlinear, transient behavior, whereas more distant stations display stable, linear trends, highlighting the spatial heterogeneity of crustal deformation. Stress and strain fields derived from the velocity models identify zones of extensional dilatation in the central Bransfield Basin and localized compression near magmatic intrusions. Maximum strain rates during the coseismic phase exceeded 200 $\mathrm{\nu }$strain/year, supporting a scenario of crustal thinning and fault reactivation. These patterns align with the known structural framework of the region. The integration of GNSS-based displacement and strain modeling proves essential for resolving active volcano-tectonic interactions. The findings enhance our understanding of back-arc deformation processes in polar regions and support the development of more effective geohazard monitoring strategies. Full article

This study aimed to evaluate the presence of emerging pollutants [perfluorinated compounds, phthalates and bisphenol A (BPA)] in chinstrap penguins (Pygoscelis antarctica) and krill (Euphausia superba) from Deception Island (South Shetland Islands, Antarctica) to provide data on the occurrence of emerging pollutants in Antarctica. For this purpose, thirty-four samples were studied, including four samples of adult tissue and six samples of chick tissue, as well as krill samples from the area. The selected samples were subjected to extraction processes and subsequent analytical determination of perfluorooctane sulfonate, perfluorooctanoic acid, di(2-ethylhexyl) phthalate, mono(2-ethylhexyl) phthalate and BPA using high-performance liquid chromatography coupled with electrospray ionization mass spectrometry. Our results highlight that the analyzed organic pollutants, except for BPA, are clearly present in Pygoscelis antarctica and Euphausia superba from Deception Island. Full article

This study estimated the density distribution of Antarctic krill inhabiting an area near the South Shetland Islands using two acoustic analysis methods recommended by the Commission for the Conservation of Antarctic Marine Living Resources, based on data collected using an echosounder installed on commercial fishing vessels. Mean Antarctic krill density for the entire survey area was estimated with two methods recommended by the Commission for the Conservation of Antarctic Marine Living Resources. The mean body length of krill collected using trawl gear was 49.06 ± 4.15 mm (range: 22.0–67.0 mm), with mode of krill observed at 50 mm body length. Using the swarm-based method and the frequency differences according to krill size, the mean densities of krill for stations and transects were 14.86 g/m² (CV = 47.09%) and 13.10 g/m² (CV = 41.16%), respectively. Furthermore, using the dB-difference method for the entire survey area, the average densities were 10.76 g/m² (CV = 43.83%) and 10.14 g/m² (CV = 53.48%), respectively, using the frequency difference based on krill size determined at all stations and per transect. Full article

The aim of this study was to evaluate the concentration of polychlorinated biphenyls (PCBs) in chinstrap penguins (Pygoscelis antarctica) and krill (Euphausia superba) from Deception Island (South Shetland Islands, Antarctica) to provide additional data of the PCB presence in Antarctica. To this end, 34 samples of different tissues corresponding to four adult specimens and six chicks, and krill from the area were studied. The selected samples were analyzed for the determination of 27 congeners of PCBs by gas chromatography. Adult specimens accumulated PCBs mainly in the liver (33%, 1330.82 ± 733.69 pg·g⁻¹ wet weight, w.w.) and muscle (25%, 1029.73 ± 823.4 pg·g⁻¹ w.w.), whereas the brain showed the highest levels in chicks (36%, 1215.83 ± 955.19 pg·g⁻¹ w.w.). Regarding krill, our results were five to eight times lower than the levels found in krill from King George Island and from the Ross Sea. Further, a distribution analysis of PCBs in penguins according to Regulation 2013/39/UE and Commission Regulation (EU) No 277/2012 was also performed, and PCBs were categorized into three groups (dioxin-like-mono-ortho, non-dioxin-like-indicators, and others-non-dioxin-like). The data indicate that the content of the other group was generally higher than that of the other two PCB groups for both adults and chicks. Notably, the liver consistently exhibited the highest proportion of the other group. Full article

(1) Background: The unique geographical and climatic conditions of the Antarctic Peninsula contribute to distinct regional ecosystems. Microorganisms are crucial for sustaining the local ecological equilibrium. However, the variability in soil microbial community diversity across different regions of the Antarctic Peninsula remains underexplored. (2) Methods: We utilized metagenome sequencing to investigate the composition and functionality of soil microbial communities in four locations: Devil Island, King George Island, Marambio Station, and Seymour Island. (3) Results: In the KGI region, we observed increased abundance of bacteria linked to plant growth promotion and the degradation of pollutants, including PAHs. Conversely, Marambio Station exhibited a significant reduction in bacterial abundance associated with iron and sulfur oxidation/reduction. Notably, we identified 94 antibiotic resistance genes (ARGs) across 15 classes of antibiotics in Antarctic soils, with those related to aminoglycosides, β-lactamase, ribosomal RNA methyltransferase, antibiotic efflux, gene regulatory resistance, and ABC transporters showing a marked influence from anthropogenic activities. (4) Conclusions: This study carries substantial implications for the sustainable use, advancement, and conservation of microbial resources in Antarctic soils. Full article

In January 2023, an active surveillance initiative was undertaken in the South Shetland Islands, Antarctica, with the specific objective of ascertaining evidence for the presence of avian influenza, and specifically the highly pathogenic avian influenza virus subtype H5N1 (HPAIV H5N1). The investigation encompassed diverse locations, including Hanna Point (Livingston Island), Lions Rump (King George Island), and Base Escudero (King George Island), with targeted observations on marine mammals (southern elephant seals), flying birds (the kelp gull, snowy sheathbill and brown skua), and penguins (the chinstrap penguin and gentoo penguin). The study encompassed the examination of these sites for signs of mass mortality events possibly attributable to HPAIV H5N1, as well as sampling for influenza detection by means of real-time RT-PCR. Two hundred and seven (207) samples were collected, including 73 fecal samples obtained from the environment from marine mammals (predominantly feces of southern elephant seals), and 77 cloacal samples from penguins of the genus Pygoscelis (predominantly from the gentoo penguin). No evidence of mass mortality attributable to HPAIV H5N1 was observed, and all the collected samples tested negative for the presence of the virus, strongly suggesting the absence of the virus in the Antarctic territory during the specified period. This empirical evidence holds significant implications for both the ecological integrity of the region and the potential zoonotic threats, underscoring the importance of continued surveillance and monitoring in the Antarctic ecosystem. Full article

Temperature analysis is of special interest in polar areas because temperature is an essential variable in the energy exchange between the Earth’s surface and atmosphere. Although land surface temperature (LST) obtained using satellites and air temperature (T_a) have different physical meanings and are measured with different techniques, LST has often been successfully employed to estimate T_a. For this reason, in this work, we estimated T_a from LST MODIS collection 6 (C6) and used other predictor variables. Daily mean T_a was calculated from Spanish State Meteorological Agency (AEMET) stations data on the Livingston and Deception Islands, and from the PERMASNOW project stations on Livingston Island; both islands being part of the South Shetland Islands (SSI) archipelago. In relation to our previous work carried out in the study area with collection 5 (C5) data, we obtained higher R² values (R²_CV = 0.8, in the unique model with Terra daytime data) and lower errors (RMSE_CV = 2.2 °C, MAE_CV = 1.6 °C). We corroborated significant improvements in MODIS C6 LST data. We analyzed emissivity as a possible factor of discrepancies between C5 and C6, but we did not find conclusive results, therefore we could not affirm that emissivity is the factor that causes differences between one collection and another. The results obtained with the applied filters indicated that MODIS data can be used to study T_a in the area, as these filters contribute to the reduction of uncertainties in the modeling of T_a from satellites. Full article

This paper analyses the lichen flora of Navarino Island (Tierra del Fuego, Cape Horn Region, Chile), identifying species shared with the South Shetland Islands (Antarctic Peninsula). In this common flora, species are grouped by their biogeographic origin (Antarctic–subantarctic endemic, austral, bipolar, and cosmopolitan), their habitat on Navarino Island (coastal, forest, and alpine), their morphotype (crustaceous, foliaceous, fruticulose, and cladonioid), and the substrate from which they were collected (epiphytic, terricolous and humicolous, and saxicolous). A total of 124 species have been recognised as common on both sides of the Drake Passage, predominantly bipolar, crustaceous, and saxicolous species, and with an alpine distribution on Navarino Island. The most interesting fact is that more than 30% of the flora is shared between the southern tip of South America and the western Antarctic Peninsula, which is an indication of the existence of a meridian flow of propagules capable of crossing the Antarctic polar front. Full article

We assessed fungal diversity in water and sediment samples obtained from five Arctic lakes in Ny-Ålesund (Svalbard Islands, High Arctic) and five Antarctic lakes on Livingston and Deception Islands (South Shetland Islands), using DNA metabarcoding. A total of 1,639,074 fungal DNA reads were detected and assigned to 5980 ASVs amplicon sequence variants (ASVs), with only 102 (1.7%) that were shared between the two Polar regions. For Arctic lakes, unknown fungal taxa dominated the sequence assemblages, suggesting the dominance of possibly undescribed fungi. The phylum Chytridiomycota was the most represented in the majority of Arctic and Antarctic samples, followed by Rozellomycota, Ascomycota, Basidiomycota, and the less frequent Monoblepharomycota, Aphelidiomycota, Mortierellomycota, Mucoromycota, and Neocallimastigomycota. At the genus level, the most abundant genera included psychrotolerant and cosmopolitan cold-adapted fungi including Alternaria, Cladosporium, Cadophora, Ulvella (Ascomycota), Leucosporidium, Vishniacozyma (Basidiomycota), and Betamyces (Chytridiomycota). The assemblages displayed high diversity and richness. The assigned diversity was composed mainly of taxa recognized as saprophytic fungi, followed by pathogenic and symbiotic fungi. Full article

To assess the diversity of bacterial taxa in Antarctic soils and obtain novel microbial resources, 15 samples from 3 sampling sites (DIS5, GWS7, FPS10) of South Shetland Islands and 2 sampling sites (APS18, CIS17) of Antarctic Peninsula were collected. High-throughput sequencing (HTS) of 16S rRNA genes within these samples was conducted on an Illumina Miseq platform. A total of 140,303 16S rRNA gene reads comprising 802 operational taxonomic units (OTUs) were obtained. After taxonomic classification, 25 phyla, 196 genera, and a high proportion of unidentified taxa were detected, among which seven phyla and 99 genera were firstly detected in Antarctica. The bacterial communities were dominated by Actinomycetota (40.40%), Pseudomonadota (17.14%), Bacteroidota (10.55%) and Chloroflexota (10.26%). Based on the HTS analyses, cultivation-dependent techniques were optimized to identify the cultivable members. A total of 30 different genera including 91 strains were obtained, the majority of which has previously been reported from Antarctica. However, for the genera Microterricola, Dyadobacter, Filibacter, Duganella, Ensifer, Antarcticirhabdus and Microvirga, this is the first report in Antarctica. In addition, seven strains represented novel taxa, two of which were psychropoilic and could be valuable resources for further research of cold-adaptability and their ecological significance in Antarctica. Full article