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At least 19 recordsLinked to original sources
PubMed2026

Genomic detection of highly pathogenic avian influenza H5N1 in Antarctic seabirds reveals connectivity with South American viral lineages.

Emerging avian viruses increasingly threaten Antarctic wildlife, raising concerns about ecosystem health and biodiversity. In this study, we conducted a comprehensive investigation of avian influenza virus (influenza A virus, IAV) in both resident and migratory birds inhabiting the South Shetland Islands, Antarctica. During the 2024-2025 austral summer, 278 samples were collected and screened using real-time RT-PCR targeting the IAV M gene. IAV RNA was detected in 30 samples, and eight of these were found to be positive for H5. Complete genome sequencing was performed on samples from a gentoo penguin (Pygoscelis papua) and a southern giant petrel (Macronectes giganteus), revealing the presence of highly pathogenic avian influenza virus H5N1, clade 2.3.4.4b. Phylogenetic analysis demonstrated that these viral genomes closely cluster with contemporary South American strains, indicating a direct connectivity between Antarctic seabirds and the broader H5N1 transmission network. Our findings highlight the heightened vulnerability of Antarctic ecosystems to emerging infectious diseases and emphasize the critical need for sustained genomic surveillance. These efforts are essential to monitor wildlife health, inform conservation strategies, and implement effective biosecurity measures to safeguard Antarctic biodiversity.

Animals↗
PubMed2026

Antarctic Peninsula soil carbon stock and efflux: A complex interplay of soil properties and heavy metals.

This study establishes a quantitative framework for understanding surface soil carbon dynamics and ecosystem connectivity in Fildes Peninsula and Ardley Island, King George Island, South Shetland Islands, Antarctic Peninsula. The mean soil organic carbon (SOC) stock across all study sites was 1.10 ± 1.93 kg C/m². Restricting net carbon balance analysis to Fildes Peninsula, where soil respiration (Rs) data were available, yielded a site-specific SOC stock of 0.45 ± 0.45 kg C/m². Scaling Rs to a realistic 120-day active season and assuming stable SOC stocks resulted in estimated annual carbon loss of 15 g C/(m2·yr), equivalent to 3.3 % of standing SOC. Comprehensive sensitivity analyses spanning plausible winter respiration (0 %-20 % of summer rates) and annual change in SOC stocks (-1 %-2 %) consistently supported a net carbon sink, with turnover rates constrained to 3.3 %/yr-4.7 %/yr. Principal component analysis showed that ornithogenic processes as the dominant control on SOC, total nitrogen (TN), zinc (Zn), copper (Cu), and cadmium (Cd) provide a clear multivariate signature of marine-derived nutrient, while Pb was decoupled from this gradient and associated instead with fine-particle size controls. These results reveal dual but independent drivers of soil metal enrichment in this region. Despite their limited spatial extent, ornithogenic soils store disproportionately large carbon pools. Overall, this integrated analysis reveals how marine-terrestrial subsidies regulate Antarctic carbon cycling and provides a quantitative and reproducible framework for assessing carbon dynamics under ongoing climate change.

Antarctic Regions↗
PubMed1979

Renal conservation of antifreeze peptide in Antarctic eelpout, Rhigophila dearborni.

In Antarctic notothenioid fishes large amounts (3% w/v) of small molecular weights of 2,600-23,500 and would be expected to be filtered into the urine, they remain in the blood because the kidneys of these fishes contain only aglomerular nephrons. Unlike the situation in most fishes, urine formation is the result of secretion rather than filtration and reabsorption. On the other hand, the peptide antifreezes in Northern Hemisphere fishes such as the winter flounder. Pseudopleuronectes americanus, are retained by the glomerular kidney even though inulin, of comparable weight, is rapidly filtered from the blood into the urine. The Antarctic eelpout (zoarcid), Rhigophila dearborni, which is unrelated to either the Antarctic notothenioids or P. americanus, also uses a peptide antifreeze (molecular weight 6,000) which is maintained at a concentration of 3% (w/v) in the blood plasma. We report here that the lack of antifreeze in the urine of R. dearborni probably reflects the fact that the glomeruli are not functional and cannot filter. We support this conclusion with morphological and physiological evidence and relate our findings to the conservation of biological antifreeze necessary for life in ice-laden polar waters.

Adaptation, Biological↗
PubMed2026

Widespread horizontal transfer and strong selection enhance microbial adaptation in Antarctic soils.

Terrestrial Antarctica harbors compositionally diverse and functionally distinct microbial life. Yet the eco-evolutionary processes underlying adaptation to Antarctica's polyextreme conditions remain largely unknown. Here, we address how horizontal gene transfer (HGT) and de novo mutations influence microbial adaptation in 16 Antarctic soils using combined short- and long-read datasets. Phylogenetic reconciliation and mobile genetic element analysis of 676 metagenome-assembled genomes show frequent HGT across communities. While transferred genes span diverse functional categories, those involved in energy metabolism are exchanged at higher frequency. Genes for aerotrophy, i.e. the consumption of atmospheric trace gases to provide energy, carbon, and hydration, are among the most frequently disseminated. Approximately a quarter of carbon monoxide dehydrogenases and [NiFe]-hydrogenases are predicted to be horizontally acquired and are often associated with mobile genetic elements. Analysis of polymorphisms suggests widespread purifying selection, particularly for aerotrophy genes, providing further evidence that aerotrophy is critical for microbial survival in Antarctica. Genetic variation in hydrogenases is tightly associated with predicted protein structures, with intense selection acting on critical sites preserving stability and function. Together, these findings show that previously unrecognized eco-evolutionary dynamics shape the composition and function of Antarctic microbial communities, and confirm aerotrophy is a strongly selected and horizontally disseminated trait.

Antarctic Regions↗
PubMed1976

Prolonged eradication of urogenital mycoplasmas after administration of tetracycline to men in the Antarctic.

Meatal swabs were obtained at intervals over 1 year from 23 men in the Antarctic. A 5-day course of tetracycline was given to twelve of them. In retrospect it was found that the antibiotic had been received by two men who were harbouring ureaplasmas, one of whom also had M. hominis. After treatment, these organisms were not found in any of the swabs taken over the next year, except in a swab from one of the men following sexual contact after this time. One of the twelve men developed N.S.U. just before arriving in the Antarctic. He responded clinically to a shorter course of tetracycline and ureplasmas were not recovered from a meatal swab immediately thereafter. However, without further sexual contact, ureaplasmas and disease recurred about a month later. This time, after a 5-day course of tetracycline, disease was not seen, and ureaplasmas were not isolated, over the next year. In contrast, ureaplasmas were isolated consistently over a year from two men who were not given the antibiotic. The evidence strongly suggests that, under natural conditions, the most likely cause of mycoplasmas, particularly ureaplasmas, recurring in the genital tract after apparently adequate tetracycline therapy, is re-infection as a result of sexual re-exposure.

Antarctic Regions↗
PubMed2026

Unveiling microbial communities and biogeochemical cycles in Antarctic colored snow.

Snow cover, the extensive terrestrial habitat in Antarctica, sometimes exhibits vivid coloration, yet the structure and function of its microbial communities remain poorly characterized. Using metagenomic sequencing of red snow (RS) and green snow (GS) from the Fildes Peninsula, we found that bacterial, eukaryotic, and archaeal relative abundances were 85.82%, 13.52% and 0.16%, respectively. &#x3b2;-Diversity differed significantly between RS and GS across these three domains (P&#x2009;<&#x2009;0.05). Dominant bacterial phyla included Bacteroidota (RS: 62.61%; GS: 38.72%) and Pseudomonadota (RS: 32.80%; GS: 54.10%). Among eukaryotes, Chlorophyta (RS: 58.10%; GS: 52.98%) and Basidiomycota (RS: 14.80%; GS: 8.08%) were prevalent. Nanobdellota dominated archaea, with lower abundance in RS than GS. In the algal community, Sanguina, Gonium and Chloromonas were significantly enriched in red snow, while Chlorella and Micractinium were enriched in green snow (P&#x2009;<&#x2009;0.05). Marker genes associated with carbon (C), nitrogen (N), phosphorus (P) and sulfur (S) cycles were identified in green and red snow. Aerobic respiration and phosphate regulation were significantly enriched in red snow, while CO oxidation, fermentation, and denitrification were significantly enriched in green snow. Key microbial genera associated with these functional pathways also varied. In the denitrification of red snow, Stutzerimonas was the most abundant genus, while Janthinobacterium was abundant in green snow. Nitrification-related genes were detected only in red snow based on the present metagenomic data. The network of the red snow microbial community was potentially more complex and resistant based on topology, which not only benefited its own long-term survival but might also have potentially influenced the positive feedback effect of snowmelt by maintaining a low-albedo snow surface. This provided an ecological implication under climate warming: the expansion of red snow patches showed the potential to the increase nitrate runoff export, which would affect nitrogen nutrient levels in coastal Antarctic waters. Overall, this study used metagenomics to compare the multidomain (bacteria, archaea and eukaryotes) composition and diversity between red snow and green snow, and directly linked key microbial taxa with functional genes of biogeochemical cycles. This study provided new insights into the biological characteristics and functional potential of Antarctic colored snow.

Snow↗
PubMed1975

Some anatomical aspects of the cardiovascular system of Antarctic seals and their possible functional significance in diving.

The hearts and ascending aortae of 11 Weddell seals, Leptonychotes weddelli, three adult Crabeater seals, Lobodon carcinophagus, two adult Ross seals, Ommatophoca rossi, and one adult Leopard seal, Hydrurga leptonyx, were examined for comparison with terrestrial forms. The Weddell seal specimens were from animals ranging in age from midterm in fetal development to mature adults. All specimens were collected in 1971, 1972, and 1973, from McMurdo Sound and the Ross Sea, Antarctica. The phocid hearts were characteristically broader and flatter than those of other carnivore families and they tended toward bifid apices. The heart form indices (height/circumference) averaged 31.5 compared to 39.0 for felids. The right ventricular chambers of the Antarctic seals were found to average longer in Weddells and narrower in all, than those reported for four other carnivore families. An elastic enlargement was present in the ascending aortae of all seals. The largest diameter of the aortic bulb averaged 25.5 mm more than the base of the aorta in the adult Weddell seals which represented an increase of 72.5% over the base. It is suggested that the general heart form, and especially the ascending aortae, are anatomical adaptations to diving. The compressed heart makes possible unimpaired function when the chest is compressed during deep dives. The aortic bulb maintains mean arterial blood pressure and perfusion of the brain and cardiac tissue during diving bradycardia.

Adaptation, Physiological↗
PubMed1975

Diurnal and seasonal variation in oral glucose tolerance: studies in the Antarctic.

Oral glucose tolerance tests were performed in 12 young men in the Antarctic. Tests were done in the morning and afternoon at three monthly intervals (March, June, September, December). The characteristic diurnal variation in glucose tolerance persisted throughout the year, but was greater in the warmer months (March and December). There were significant seasonal differences in glucose tolerance; blood glucose values were lowest, both morning and afternoon, in December (midsummer). In one pair of tests performed during a reversal of normal sleep/activity pattern, the direction of the normal diurnal variation of glucose tolerance was also reversed.

Activity Cycles↗
PubMed1978

Lipids of the antarctic sei whale, Balaenoptera borealis.

The blubber, liver, and muscle of the Antarctic sei whale were analyzed for total lipid content, composition of lipid by classes and positional distribution of fatty acids in individual lipids. The major glycerolipids (triglycerides, phosphatidylcholine, and phosphatidylethanolamine) were fractionated by silver nitrate thin layer chromatography. The phospholipid fractions were analyzed for fatty acid positional distribution. The whale stomach contained almost exclusively the amphipod Parathemisto gaudichaudi. Its lipids were also studied and compared with the lipids of the body tissues. The results indicate that the stomach content lipids are subjected to modifications before being deposited in the blubber, liver, and muscle. According to the silver nitrate thin layer chromatographic studies, liver and blubber triglycerides resembel each other in their patterns of positional distribution of fatty acids and in molecular species composition. The phospholipids of liver and blubber also exhibited closely related fatty acid distribution patterns. In general, while the proportions of lipid classes and their predominant fatty acids varied from tissue to tissue, the patterns according to which the lipids had been synthesized seemed to be common.

Adipose Tissue↗
PubMed1979

Antarctic wintering--over, suggestion and transient olfactory stimulation: EEG evoked potential and electrodermal responses.

EEG evoked potential and electrodermal responses to real and suggested olfactory stimulation were recorded on a team of nine men who wintered-over at Scott Base, Antarctica. Multi-variate analysis of variance findings indicated some consistent trends despite adverse conditions and marked inter-individual differences. Consistent with studies of secondary afferentation olfaction-related EEGs were evidenced in the occipital area (O1 and O2) as well as the temporal area (T3 and T4). Skin conductance (SC) showed significant responses for real and suggested odorants pre and post wintering-over. Suppression of EEG amplitudes for real and suggested stimuli was evidenced prior to wintering-over. Following wintering-over experience suppression of EEG amplitudes for real stimuli showed a decrease while suppression increased for suggested stimuli. The implications of the suggestion findings are discussed in possible explanation of the apparent conflict between different sources of information about human responses to isolation in the Antarctic environment.

Alpha Rhythm↗
PubMed1975

The aglomerular nephron of antarctic teleosts: a light and electron microscopic study.

Complete serial sections demonstrated that ten species of Antarctic teleost fishes representing two families had aglomerular kidneys. The aglomerular nephron of such kidneys consists of two distinct regions: (1) a highly contorted principal segment and (2) a system of collecting tubules and ducts. Throughout the principal segment the cells are characterized by densely packed microbilli and a single cilium projecting into the lumen. Within the cytoplasm, lysosomes are rarely encountered, as would be expected if there is little or no reabsorption of protein from the urine. At the base of these cells, the plasma membrane is prominently infolded in close association with abundant mitochondria. The overall fine structure of the principal segment cells is consistent with their probable function in the secretion of ions into the formative urine. Between the principal segment and the collecting tubule is a very short transitional zone characterized by transitional mucus cells and multiciliated cells. The collecting tubule and duct system is lined entirely by mucus cells. In comparison with principal segment cells, the mucus cells have a well-developed Golgi complex and abundant secretory granules in the apical cytoplasm; these granules presumably contain the non-sulfated acid mucopolysaccharide demonstrable by light microscopic histochemistry.

Animals↗
PubMed1977

Megadosage of ascorbic acid in an Antarctic expedition.

1. No difference in health was observed between men on megadosage of ascorbic acid and controls during the year of an Antarctic expedition. 2. All men appeared to have a satisfactory intake of ascorbic acid throughout the year. 3. There was a statistically significant decrease in excretion of ascorbic acid by men on megadosage over the year, and by the controls. 4. The decline in excretion by the control group may be explained by dietary change, but the decline in those on megadosage may be due to altered handling of ascorbic acid by the body. 5. No complications due to megadosage of ascorbic acid were observed.

Antarctic Regions↗
PubMed1977

Microsporum magellanicum and Cunninghamella antarctica, new species isolated from Australic and Antarctic soil of chile.

Keratinophilic fungi were isolated from samples of soil collected in the extremity of Chile, in Southern Shetland and Antarctic continent. Two new species, Microsporum magellanicum and Cunninghamella antarctica are described. Microsporum magellanicum is characterized by verrucose or verruculose clavate macroconidia predominantly uniseptate, 4-87-2micronx14-4-21-6micron. Cunninghamella antarctica has conidiophores usually verticillately, pseudoverticillately and sympodially branched; and globose conidia with evident spines, 12-8-16micron in diameter.

Antarctic Regions↗
PubMed1979

Parainfluenzavirus upper respiratory tract illnesses in partially immune adult human subjects: a study at an Antarctic station.

Outbreaks of respiratory tract illnesses (RTI) in adult humans during October and November 1975 at McMurdo Station, Antarctica, were investigated by viral isolation and serologic procedures. The recovery of viral agents was enhanced by use of cell cultures in the field. Recoveries of parainfluenzaviruses types 1 and 3 and rhinoviruses were made from 10 of 39 nasal washings. Parainfluenzaviruses types 1 and 3 accounted for 50 and 30 per cent, respectively, of the total viruses recovered during October and November 1975. Acute and convalescent sera collected from 32 adult humans were examined for antiviral antibody by hemagglutination inhibition (HI) and radioimmunoassay (RIA) techniques. Serologic responses (HI and RIA) confirmed that parainfluenzaviruses were the predominent cause of RTI at McMurdo Station during that time. The temporal relationship between parainfluenzaviral diseases occurring in US communities and at McMurdo suggests that these viruses are transported to the Antarctic by personnel originating within the US. Standardization of the RIA allowed sequential assay of large numbers of sera using multiple preparations of radiolabeled indicator antibody, while ensuring the reproducibility of antiviral antibody titers to within one twofold dilution between subsequent labeled antibody preparations. The RIA detected both lower levels of virus specific antibody and more serologic responses than could be detected by HI.

Adult↗
PubMed1977

Preparation and galactosyltransferase acceptor activity of derivatives of antifreeze glycoproteins of an Antarctic fish.

A series of 12 closely related glycoproteins containing alpha-linked N-acetyl-D-galactosamine (GalNAc) as the sole carbohydrate moiety have been prepared by degradation of the antifreeze glycoproteins from the serum of the Antarctic fish Trematomus borchgrevinki. The polypeptide moieties of these glycoproteins contain substitutions in the normal -Ala-Ala-Thr- repeating tripeptide sequence which introduce alterations in the amount of alpha-helical structure and the density of acceptor sites, and theoretically also in the amount of rigidity, polarity, and hydrophobicity of the polypeptide. Of these alterations only density of acceptor sites has a statistically significant effect on the ability of the GalNAc alpha leads to Thr moiety to act as a substrate for galactosyltransferase (EC 2.4.1.22) activity solubilized from rat liver microsomes. This result suggests that in the biosynthesis of rat liver glycoproteins these structural features of the polypeptide moiety of glycoproteins are not part of the substrate specificity of the galactosyltransferase activity that transfers the second monosaccharide. Hence, these structural features do not play a major role in determining the structure of the threonine-linked oligosaccharide after its synthesis has been initiated.

Adaptation, Physiological↗
PubMed1975

Antarctic medicine, 1775-1975. I.

An historical review is made of Antarctic medical practice, which is unique because of the absence of an indigenous population. This review begins with the primitive shipboard practice of doctors accompanying Captain James Cook around 1775 and concludes with the modern era of permanent stations and vast scientific endeavour. The heroic era of Scott, Shackleton, Amundsen and Mawson and the highly mechanized transition period are contrasted with the present day. Medical practice on modern expeditions has reached a high standard, but there is still much to be learned concerning human adaptation. Comment is made on the possible utilization of Antarctica's natural resources bringing increases in polar populations and facilitating the expansion of medical research in the future era of polar medicine.

Anesthesia, Inhalation↗