Resumo em Inglês:

Abstract The aim of this study is to analyze the waterborne metal levels in four lakes (one endorheic and three exorheic) of Harmony Point, Nelson Island, Antarctica. Water samples were analyzed by using a quadrupole type inductively coupled plasma mass spectrometer and an inductively coupled plasma optical emission spectrometer. The levels of As, Cu, Mn, Mo, and V were significantly lower and those of Cr, Mg, Na, and Sr were significantly higher in the endorheic lake than in the other lakes. Most water samples presented levels of Ag, Be, Cd, Pb, Se, Tl, and U below the limit of quantification, while for Ba, Co, and Ni around half of the samples were below this limit. The waterborne metal levels were not significantly different between the exorheic lakes. Waterborne metal levels in the freshwater lakes from Harmony Point did not show any clear relationship with their levels in the soil of the region or with bird guano, and overall, their levels indicate an environment without anthropogenic influence. Apparently, the Na levels are influenced by salt spray from the ocean, as they are related to the distance of the lakes from the ocean.

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Abstract FioAntar, FIOCRUZ’s research project in Antarctica, is based on the One Health approach. FioAntar aims to generate relevant information that will help reduce the risk of future pandemics and improve the search for chemical compounds and new biological molecules. After four expeditions to Antarctica under the scope of PROANTAR, Fiocruz has identified Influenza H11N2 virus in environmental fecal samples, as well as Histoplasma capsulatum and Bacillus cereus in soil samples. In addition, in a prospective virome analysis from different lakes in the South Shetland Islands, six viral orders were described, supporting future research related to the biodiversity and viral ecology in this extreme ecosystem. Our findings of environmental pathogens of public health importance are a warning about the urgency of establishing a surveillance agenda on zoonoses in Antarctica due to the imminent risks that ongoing environmental and climate changes impose on human health across the planet. FioAntar strives to establish a comprehensive surveillance program across Antarctica, monitoring circulation of pathogens with the potential to transcend continent boundaries, thereby mitigating potential spread. For Fiocruz, Antarctica signifies a new frontier, teeming with opportunities to explore novel techniques, refine established methodologies, and cultivate invaluable knowledge.

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Abstract Sanionia uncinata, or Sickle-leaved-Hook-moss, is a cosmopolitan pleurocarpous moss composing the Antarctic Peninsulae biodiversity, primordially forming dense mats over rocks. The species was collected in 24 different spots located at King George Island and was processed to obtain 24 ethanolic extracts (ADS#) by a serial-24h-maceration, which were prospected for antimicrobial, cytotoxic, antioxidant, and acetylcholinesterase (AChE) inhibition activities by using in vitro tests. Alien material was removed from the non-sterilized plant samples before being submitted for extraction. It was observed that extracts collected in different spots showed different biological activities. Extracts ADS04(10.66±0,17mm) and ADS14(11.37±0,11mm) were active against Staphylococcus aureus, according to the diffusion in bioautography assay. They showed significant antioxidant activity and inhibited AChE; the cytotoxicity observed to the human breast cancer cells MCF-7 and MDA-MB-231 were higher than in normal cell line MCF-10A. ADS04 was 7.62 times more cytotoxic to MCF-7, and ADS14 was 2.03 times more cytotoxic to MDA-MB-231 than to MCF-10A. The extracts showed similar cytotoxicity between PC-3, a human prostate cancer cell line, and MCF-10A. Sanionia uncinata extracts are a vital potential source of biologically active compounds, particularly ADS04 and ADS14, including further prospection on eventual bryophyte’s endophytic fungi.

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Abstract Microbial adaptations to extreme environments can lead to biotechnological applications. This study aimed to evaluate the resistance of Antarctic Cladosporium to adverse conditions (temperature, salinity, UV radiation, and nutrients) and refine their taxonomy. Sequencing and phylogenetic analysis using ITS-act markers resulted in a more accurate taxonomic identification, revealing the presence of five different species, belonging to the complexes C. cladosporioides and C. sphaerospermum. The growth at different temperatures indicates that the soil isolates LAMAI 564 and 1800 (phylogenetically closely related) and LAMAI 2541 are psychrophilic, while the other isolates are psychrotolerant. The fungi isolated from the saline samples LAMAI 595, 616, and 1369 showed better growth results at higher salinity (15%). The fungi most resistant to UV radiation were isolated from terrestrial and marine samples (LAMAI 595, 616, 1800, and 564). LAMAI 595 and 616 (phylogenetically closely related and isolated from the same kind of sample) showed the capacity of nutritional versatility, growing well in both rich and poor-nutrient media. The fungus LAMAI 595 was the most promising for biotechnological application, exceeding the other isolates in the harsh conditions studied. The resistance of the Antarctic Cladosporium to adverse conditions opens new perspectives in the field of applied microbiology of extremophiles.

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Abstract The use of yeasts has been explored as an efficient alternative to fungicide application in the treatment and prevention of post-harvest fruit deterioration. Here, we evaluated the biocontrol abilities of the Antarctic yeast strain Debaryomyces hansenii UFT8244 against the post-harvest phytopathogenic fungi Botrytis cinerea and Rhizopus stolonifer for the protection and preservation of strawberry fruit. The strongest inhibition of germination of B. cinerea (57%) was observed at 0 °C, followed by 40% at 25 °C. In addition, germ tubes and hyphae of B. cinerea were strongly surrounded and colonized by D. hansenii. Production of the enzymes β-1,3-glucanase, chitinase and protease by D. hansenii was detected in the presence of phytopathogenic fungus cell walls. The activity of β-1,3-glucanase was highest on day 12 of incubation and remained high until day 15. Chitinase and protease activities reached their highest levels on the day 15 of incubation. D. hansenii additionally demonstrated the ability to resist oxidative stress. Our data demonstrated that the main biocontrol mechanisms displayed by D. hansenii were the control of phytopathogenic fungal spore germination, production of antifungal enzymes and resistance to oxidative stress. We conclude that isolate D. hansenii UFT8422 should be further investigated for use at commercial scales at low temperatures.

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Abstract The Southern Ocean influences the planet’s biogeochemical cycles. Marine microorganisms are important in this scenario, being the main biological agents in the cycling of many elements. The Archaea domain is widely distributed in the oceans, and its presence in Antarctica is acknowledged. In this context, this work aimed to analyze the diversity and distribution of archaea according to environmental parameters in the waters surrounding the north of the Antarctic Peninsula. For environmental characterization studies, surface and bottom data were used for the ten monitoring stations of expeditions that took place in the summer of 2014 and 2015. The sequencing of the 16S rRNA gene was performed on the Illumina HiSeq platform, using the SILVA v138 database. The results revealed the presence of three main water bodies: Antarctic Surface Water, Shelf Waters, and modified Circumpolar Deep Water. Deep waters had higher diversity than surface waters, and the dominant groups were Nitrososphaeria and MGII. In the study region, the main factor responsible for the differences in the ecosystems was the presence of distinct water masses and the stratification of the water column. We argue that it is essential to consider water mass dynamics to study the microbial landscape of the Southern Ocean.

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Abstract Polar marine macroalgae thrive in extreme conditions, often displaying geographic isolation and high degree of endemism. The “phycosphere” refers to the zone around the algae inhabited by microrganisms. Our study used DNA metabarcoding to survey the eukaryotic communities associated with seven seaweed species obtained at King George Island (South Shetland Islands, maritime Antarctic), including two Rhodophyta, two Chlorophyta and three Phaeophyceae. The ITS2 region was used as a barcode and our analysis yielded 77 eukaryotic ASVs spanning five Kingdoms (Fungi, Metazoa, Chromista, Protozoa, and Viridiplantae) and ten phyla (Ascomycota, Basidiomycota, Cercozoa, Ciliophora, Ochrophyta, Amebozoa, Chlorophyta, Rhodophyta, Bryophyta and Cnidaria). Additionally, we identified 14 potential new occurrence records for Antarctica. Ciliates and green algae were the most species-rich groups. The most abundant assigned associated species was Monostroma angicava (Chrorophyta). Within the macroalgal, the Chlorophyceans Ulothrix sp. hosted the greatest number of taxa, followed by Monostroma hariotii. Our data suggested that Antarctic macroalgae host a rich diversity of associated organisms and the biodiversity associated with the phycosphere remains underestimated.

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Abstract The Brazil-Malvinas Confluence (BMC) is a significant biological frontier where distinct currents meet, fostering optimal conditions for phytoplankton development. In this study we tested the hypothesis that eddys promote an increase in phytoplankton biomass at the Brazil-Malvinas Confluence (BMC), altering species diversity. Phytoplankton were collected with Niskin bottles and nutrient concentrations assessed at two depths (Surface and Deep Chlorophyll Maximum Layer – DCML) in areas outside and under the influence of Cold-Core (CCE) and Warm-Core (WCE) Eddies. Environmental variables were determined in situ using a CTD profiler. Four regions were separated based on environmental variables and phytoplankton species, namely, the Brazil Current (BC), Malvinas Current (MC), CCE, and WCE. Species diversity was higher in the eddies. The conditions of the WCE were different from those of the CCE, with low temperature and salinity and high cell density values in the latter. The phylum Bacillariophyta was predominant in terms of species richness in all regions and was responsible for the higher cell density in the MC, while dinoflagellates were dominant in the BC and eddies. Therefore, eddy activity alters the structure, diversity and biomass of the phytoplankton community in the BMC.

Resumo em Inglês:

Abstract Zooplankton plays a crucial role as the primary consumers in the Southern Ocean and its ecological processes, particularly in the Antarctic Peninsula, influenced by regional glaciological and oceanographic changes. To assess the overall composition of these communities, vertical samples were collected at various depths using a Multinet at oceanographic stations in the Antarctic Peninsula during the XXXV OPERANTAR expedition in summer 2017. Abiotic data (temperature, salinity and chlorophyll-a) were collected using a CTD and a fluoremeter. Organisms were identified to a higher level, with Chaetognatha and Euphausiacea identified to species whenever possible. Copepoda were the most abundant (73.4%), with Calanoida present in all samples and more abundant at 300m. Salpidae ranked as the second most abundant taxon (16.6%) up to 100m. Three species of Chaetognatha were identified, with Eukrohnia hamata being the most abundant, particularly at 300m. Two species of Euphausiacea were found, Euphausia superba and Thysanoesa macrura, with low abundances. Abiotic parameters showed significant relationships with the taxa. The region exhibits complex oceanography associated with zooplankton communities. The recorded data align with the zooplankton characterization of this region, uncovering a prevalence of Copepoda and surface abundant Salpidae, along with Chaetognatha (particulary E. hamata) and Euphausiacea.

Resumo em Inglês:

Abstract Extremophile organisms have been largely studied in Astrobiology. Among them, two antarctic plants emerge as good candidates to become colonizers of other celestial bodies, such as Mars and the Moon. The present research aimed to evaluate survival and growing capacity of Sanionia uncinata and Colobanthus quitensis on Martian (MGS-1) and Lunar (LMS-1) regolith simulants, under terrestrial conditions. The survival responses of both species on the simulators and the original sampling site of Antarctic soil were observed during 15 days, in laboratory conditions at ‘Comandante Ferraz’ Station. Based on physiological parameters changes under the three soil conditions tested, our results suggest that Martian soil can be too harsh for plant growth, showing expressive decay, especially for C. quitensis. While lunar soil might provide more favorable conditions, with less observed changes, similarly to how they would in Antarctic soil from their natural habitat. This preliminary study provides resources and fosters knowledge about the possibility of these Antarctic species to survive in extraterrestrial environments, starting with soil parameters; and discusses the importance and use of Antarctic plants in astrobiology.

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Abstract This work investigated the annual variations in dry snow (DSRZ) and wet snow radar zones (WSRZ) in the north of the Antarctic Peninsula between 2015-2023. A specific code for snow zone detection on Sentinel-1 images was created on Google Earth Engine by combining the CryoSat-2 digital elevation model and air temperature data from ERA5. Regions with backscatter coefficients (σ⁰) values exceeding -6.5 dB were considered the extent of surface melt occurrence, and the dry snow line was considered to coincide with the -11 °C isotherm of the average annual air temperature. The annual variation in WSRZ exhibited moderate correlations with annual average air temperature, total precipitation, and the sum of annual degree-days. However, statistical tests indicated low determination coefficients and no significant trend values in DSRZ behavior with atmospheric variables. The results of reducing DSRZ area for 2019/2020 and 2020/2021 compared to 2018/2018 indicated the upward in dry zone line in this AP region. The methodology demonstrated its efficacy for both quantitative and qualitative analyses of data obtained in digital processing environments, allowing for the large-scale spatial and temporal variations monitoring and for the understanding changes in glacier mass loss.

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Abstract This review summarizes the state of knowledge on athecate dinoflagellates occurring within the South Atlantic Ocean and Atlantic sector of the Southern Ocean. We compiled data from 105 articles and selected 33 addressing any aspect of athecate dinoflagellate studies. Our aim is to discuss the patterns in athecate dinoflagellate distribution by building a thorough species list and an occurrence map based on species recorded in coastal and oceanic waters. We found 69 species totaling 141 occurrences in the entire South Atlantic Ocean basin. Contradicting global trends, most species distributed throughout this region are subtropical. We linked this trend to a higher local effort in dinoflagellate research instead of higher biodiversity, especially when compared to usual hotspots in biodiversity attributed to tropical oceans. The Subantarctic and Antarctic regions had a low number of occurrences, with 12 and 5, respectively. Except for the occurrence of Gyrodinium lachryma in the Antarctic Zone, all records are unique, poorly described and never recorded again for species such as Gymnodinium baccatum and Gymnodinium antarcticum. This demonstrates that the state of knowledge regarding athecate dinoflagellates in the South Atlantic and especially in the Antarctic region is still limited due to a lack of directed investigation.

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Abstract This study presents geophysical data from two passive seismic measurements conducted at two different sites in Antarctica. We analyzed the signals mainly in the frequency domain through the multitaper method to extract some spectral characteristics of the signals that would have been out of reach through the usual FFT approach. The power spectral density of the signals carries information about the processes that generated them, allowing its correlation with their source origin and type, either natural or anthropogenic. We deal with three different source types: calving, wind, and anthropogenic origins. The former is closely related to glacier dynamics, being modulated by the prevailing atmospheric processes. At both locations the wind noise is prevalent, complicating the analysis of other events like calving. We have used data classification, estimation of the source azimuth, and seismic apparent velocity to demonstrate the viability of using geophysical methods to study glacier elastic parameters and dynamics. Moreover, the calving rate can yield a wider and more independent understanding of glacier hydrodynamics and may help to estimate the future response of the polar areas to a changing environment.

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Abstract The Hunga Tonga–Hunga/Hunga-Haʻapai eruption on January 15, 2022 sent off a plume of ash material up to the stratosphere and triggered a meteotsunami and barometric pressure pulse that rippled through the atmosphere and oceans all around the world. The nature of the volcanic event and its global impacts on the oceans, atmosphere, lithosphere and the cryosphere are a matter of debate. Here we present a first overview of the time travel of the sound atmospheric pressure wave through the Antarctic continent based on in situ measurements, which represented a unique event observed through the polar ice sheet during the instrumental meteorological era. In addition, we estimated the tsunami travel time of the Hunga-Tonga event from a first order model to infer its impact over the Antarctic Sea ice and ice shelves. One outcome from our observations and modeling is the detection of the meteotsunami in the Antarctic Peninsula and the impact of the continental relief over the atmospheric pressure wave dispersion.

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Abstract Sea ice is a critical component of the cryosphere and plays a role in the heat and moisture exchange processes between the ocean and atmosphere, thus regulating the global climate. With climate change, detailed monitoring of changes occurring in sea ice is necessary. Therefore, an analysis was conducted to evaluate the potential of using the Gray Level Co-occurrence Matrix (GLCM) texture analysis combined with the backscattering coefficient (σ°) of HH polarization in Sentinel-1A Synthetic Aperture Radar (SAR) images, interferometric imaging mode, for mapping sea ice in time series. Data processing was performed using cloud computing on the Google Earth Engine platform with routines written in JavaScript. To train the Random Forest (RF) classifier, samples of regions with open water and sea ice were obtained through visual interpretation of false-color SAR images from Sentinel-1B in the extra-wide swath imaging mode. The analysis demonstrated that training samples used in the RF classifier from a specific date can be applied to images from other dates within the freezing period, achieving accuracies ≥ 90% when using 64-bit grayscale quantization in GLCM combined with σ° data. However, when using only σ° data in the RF classifier, accuracies ≥ 93% were observed.

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Abstract This study investigates ichnoassemblages characterized by spreite trace fossils from the Upper Cretaceous Snow Hill Island Formation on Vega Island, Antarctica. The succession reveals alternating heterolithic beds of sandy siltstones to very fine- to fine-grained sandstones, suggestive of a deltaic depositional setting influenced by fluctuating energy conditions. The dominance of spreite structures, such as Paradictyodora antarctica and Euflabella, suggests the prevalence of a colonization window for deposit- or detritus-feeding activity. Notably, the prevalence of Euflabella towards the upper levels of the succession, in more proximal and impacted depositional setting, suggests an adaptive strategy for coping with varying food resources, corroborating its role as a trophic generalist. Additionally, the absence of distinct shifts between fully marine and stressed ichnofauna challenges a clear assignation to the Phycosiphon or Rosselia ichnofacies, although in vertical succession the Euflabella dominance in upper levels is related to a lower diverse ichnoassemblage than Paradictyodora in lower levels, suggesting some freshwater impact in the top. The occurrence of horizontal and vertical sessile deposit feeding structures would align with the Rosselia ichnofacies definition, but the presence of spreite burrows and high ichnodisparity better fits into the Cruziana ichnofacies. These spreite-dominated ichonoassemblages are here attributed to Cruziana ichnofacies.

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Abstract Some Antarctic ice-free areas have been affected by changes in lacustrine zones and permafrost thawing due to rising air temperatures over the last 60 years Temperature time-series were analyzed to understand the processes leading to the changes of Boeckella and Buenos Aires lakes, north Antarctic Peninsula. Statistical calculations were applied to average, maximum, and minimum temperatures, as well as to indexes such as Positive Degrees Day, Freezing/Thaw Day, and days with temperatures ≥ 0 °C and ≥ 10 °C. Changes in the region over recent decades were observed in mean and maximum temperatures and an increase in minimum temperature since the mid-1990s. In addition, the Normalized Difference Water Index was extracted from Landsat images from 2003, 2016, 2020, and 2021. These images were used to calculate changes in the areas of Boeckella and Buenos Aires lakes. These data revealed an 87% decrease in the area (m²) of Boeckella Lake and a 60% increase in Buenos Aires Lake´s area (m²). Concern has been raised about the modifying lake areas in the Antarctic Peninsula, where the collapse of Boeckella Lake could be the first case recorded in ice-free areas of Antarctica continent.

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Abstract Glaciers are sensitive to environmental climatic conditions and show their variability over time. This study investigates the environmental characteristics and variation in glacial cover of the Greenwich, Livingston, Robert and Snow islands, Antarctica, between 1956 and 2023. The glacier extension mapping was based on visual interpretation of the Landsat 4, 7 and 8 optical images and normalised difference indexes combination. The REMA 8 digital elevation model was applied to the islands’ geomorphometric analysis. Results were compared to climatic series and environmental characteristics. The glacial coverage decreased by 16.9% from 1956 to 2023, equivalent to 209.95 ± 0.113 km². Snow Island, with shallow bathymetry near glacial margins and land-terminating ice-fronts, exhibited the smallest retreat rate values. The glacial coverage of Livingston Island decreased significantly (18%, equivalent to 153.2 ± 0.113 km²) from 1956-2021, representing the highest values in the study. The changes in glacial coverage of the Robert and Greenwich islands were more substantial in the 1989-2023 period than in 1956-1989. Sectors with marine-terminating glaciers, associated with high bathymetric amplitudes, exhibited more significant variations compared to other sectors, contributing to the evolution of fjord-type bays. Glacial coverage has been lost in recent decades due to regional atmospheric and oceanic warming.

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Abstract Dissolved organic carbon (DOC) is a key component of the biogeochemical carbon cycle in the Southern Ocean. However, there are still significant gaps in understanding the role of DOC in polar environments, due to the limitations of spatiotemporal sampling. In this study, we investigated the regional aspects controlling the distribution and diffusive and advective fluxes of DOC along the northern Antarctic Peninsula (NAP) during austral late summers of 1995 and between 2015 and 2019. DOC concentrations ranged from 33.1 to 157.6 μmol kg-1. The NAP showed regional differences in both its hydrographic conditions and DOC distribution. The regional variability reflected the main biogeochemical sources and fates of DOC associated with the Antarctic Circumpolar Current inflows, the Weddell Gyre transport and the meltwater input. The intensity of the advective fluxes of DOC was 106 times greater than the diffusive fluxes. However, ocean fronts along NAP environments are mesoscale structures for observations of downward and upward diffusive fluxes of DOC. This study adds insights on the role of DOC as a proxy for a better understanding of the coupling between physical and biogeochemical processes over time in an environment sensitive to climate change.

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Abstract The Antarctic Peninsula is undergoing rapid climate changes, impacting its surrounding marine ecosystem. At that site, sea ice plays a crucial role in this ecosystem by serving as a habitat for organisms and influencing primary productivity. Studying sea ice variability and primary productivity is essential for understanding environmental changes in Antarctica. This research focused on Joinville Island, located at the tip of the Antarctic Peninsula, where meteorological data and glaciochemical analysis were conducted on snow/firn cores for Cl-, Na+, Ca2+, Mg2+, SO4 2-, NO3 -, K+, MSA, NH4 + and F- to retrieve recent past environmental variabilities. The study revealed that Joinville Island experienced a net accumulation rate of 0.40 meters per year in water equivalent between 1993 and 2005. In snow/firn cores, Na+ correlated with both wind strength and sea ice extent (r=0.59 and r=0.66, respectively) while correlations were higher for MSA and Cl- with respect to sea ice (r=0.80 and r=0.74, respectively), considering both the Weddell and Amundsen-Bellingshausen sub-sectors. This analysis contributes to our understanding of sea ice dynamics and its influence on primary productivity in the area.

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Abstract This study investigated the chemical content of a shallow snow core (4.95 m) named TT 6, collected during a Brazilian traverse of the West Antarctic Ice Sheet in the 2014/2015 Austral summer. Stable isotope ratios (δD and δ18O) and ionic content, determined at the Centro Polar e Climático of the Federal University of Rio Grande do Sul (CPC/UFRGS), were used to date the core and reconstruct the climatic conditions at the site. The core represents approximately 11 years ± 6 months of precipitation, i.e., a mean net snow accumulation rate of 0.19 ± 0.02 m a-1 in water equivalent. Using the non-sea-salt sulfate values, we identified the 2011 Puyhue-Cordón (Chile) volcanic eruption signal, providing a reference horizon for dating. Anions represent 53.73% of the ionic content. We identified that 96.86% of calcium and 84.50% of sulfate are non-sea origin, while the acidic contribution is 25.62% H+. We observed high peaks in marine aerosols containing Na+, Cl-, and Mg2+ during winter, and results from the ERA5 global model (NOAA) indicated that El Niño events could influence Antarctic temperatures, facilitating the transport of marine aerosols to the continent.

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Abstract Regional sea level rise varies from the global average and is influenced by climate variability. We studied sea level anomalies in southern Brazil from 1993 to 2022, finding increasing trend from 1993 to 2022. We used oceanic and atmospheric dynamics to understand the rapid sea level rise. Positive trends in the Southern Annular Mode and the South Atlantic Ocean subtropical gyre intensified wind stress curl and Ekman transport. If global warming continues and the Southern Annular Mode remains in a positive trend, sea level rise in southern Brazil is likely to persist and increase risks for the population in this low-lying coastal area.

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Abstract The region of the Maritime Antarctic suffers significantly from climate change, resulting in regional warming and consequently affecting coverage. This study characterized three surface zones of Collins Glacier and three other zones in ice-free areas on the Fildes Peninsula, which has an area of 29.6 km². We used TerraSAR-X satellite images from 2014 to 2016 and analyzed the influence of meteorological and environmental conditions on these surface zones. We used five images from the TerraSAR-X satellite, three of these data were obtained during the same period of fieldwork. The classification considered three classes on the glacier (higher moisture, transition in moisture, and lower moisture) and three on the ice-free areas (wet snow, transition wet snow-bare ice, and bare ice), using Maximum Likelihood and ISODATA methods. In low-altitude glaciers with maritime influence, such as Collins, monitoring variations in surface zones is essential because the continuous increase in exposed ice may indicate potential retreat. The TerraSAR-X images enabled the classification of land features, highlighting the potential for continuous monitoring in the Maritime Antarctic, regardless of weather conditions and solar illumination.

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Abstract Shell beds, or coquinas, have a complex origin, limiting their utility in paleoecology. However, such accumulations can serve as crucial paleoenvironmental indicators, since their bioestratinomic and diagenetic properties explain the physical-chemical and biological processes of their formation, as well as the ancient environments linked to their development. In 2016, the PALEOANTAR Project sampled coquinas from the James Ross Island (Antarctic Peninsula) in Passo São José (PSJ – San José Way) and Muro do Castelo (MDC – Castle Wall), two new localities with outcrops of the lower Lachman Crags Member, Santa Marta Formation, Marambio Group, Cretaceous of Larsen Basin. The paleontological content and sedimentary structures indicate a shallow marine depositional system. The PSJ coquina are composed by gastropods bioclasts, with predominantly dense/loose packing. The MDC presents a larger variety of bioclasts with bivalve dominance on a loose packing and conglomeratic horizons, that varies from granule to pebble. Sedimentary and biostratinomic features observed in samples from both localities indicate their genesis from high-energy events, characterized as a proximal tempestite. These descriptions allow a more accurate reconstruction of the depositional environments, highlighting the importance of these rocks in the geological record during the Cretaceous of Antarctica.

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Abstract We describe the seldom observed event of a group of type A killer whale (Orcinus orca) predating on an Antarctic minke whale (Balaenoptera bonaerensis) in austral summer 2019. A pod of 11-13 individuals was observed – and documented by photographs and video – as they killed and fed on the minke whale in the Bransfield Strait, northern Antarctic Peninsula. The pod was being observed for about one hour, when some killer whale’s individuals were noticed to be performing hunting behaviour. This lasted about 10 minutes, at the end of which the minke whale was killed. Three different species of seabirds were observed feeding on the minke carcass. A video of the encounter is provided.

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Abstract At the beginning of the 20th century, intense whaling activity took place in the South Shetland Islands, which is represented today in the form of ruins and numerous whale bones scattered along several Antarctic beaches. Despite being exposed to a harsh environment throughout the last decades, the present manuscript tried to answer if these bone remains still have viable DNA to allow species’ identification using molecular methods. Several individuals were collected from the shores of Keller Peninsula, Admiralty Bay, Antarctica, and submitted to DNA extraction, amplification and Sanger sequencing. The challenging identification of these bone fragments proved to be still feasible. Mitochondrial DNA was successfully extracted, amplified and sequenced. A database with 43 sequences including previously published and newly determined sequences were built and enabled the precise identification to species level for some of the collected samples, therefore shedding light on the whales species that inhabited the region and how their overexploitation seems to have affected modern day presence of these species within the study area.

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Abstract The exploration of extraterrestrial environments has become a focal point of scientific inquiry, driven by advancements in technology and a growing interest in the potential for life beyond Earth. This study investigates the adaptability of Antarctic nematodes, known for thriving in extreme cold and isolation, to simulated Martian (MGS-1) and Lunar (LMS-1) soils. The experiment revealed differential responses in nematode survivability to the two simulants, with Lunar soil demonstrating better adaptability compared to Martian soil. Our study provides valuable insights into the potential survivability of Antarctic nematodes on real Martian and Lunar substrates with the use of the MGS-1 and the LMS-1 under terrestrial conditions. The observed results suggest differential survival responses to Lunar (6.92 ± 0.74) and Martian (5.58 ± 1.91) regolith simulants and highlight the complexity of factors influencing organismal survival. Considering their crucial role in soil food webs, and their relation with nutrient cycling and carbon dioxide emissions, the observed capacity of nematodes to thrive in Martian and Lunar regoliths positions them as potential candidates to sustain human habitats, helping on the development of in-situ resource utilization (ISRU) systems, and forming the basis for a biological life-support system to facilitate human survival in extraterrestrial environments.

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Abstract This research was conducted for the purpose to evaluate the contribution Giant petrels and Brown skuas nestings in the formation of ornithogenic soils by the phosphatization process in Harmony Point, Maritime Antarctic. Ten nests were selected to collect topsoil samples (0-20 cm), from 0 m up to 20 m away, with regular spacing of 2 m. The analysis of the samples included the physical, chemical, mineralogical and geochemical analyzes. Phosphate minerals were identified. The presence of high content of some trace elements, such as Zn, Cu and Sr is associated with the bird’s excrements. Total-P and bioavailable-P recorded higher levels. This result demonstrates the importance of the time factor in the bird’s nesting, as well as in the development of the soil in these soil-forming environment. Phosphatization in these areas is not restricted to the specific location of the nest, since high values of P have been identified at distances between 8 and 12 m, from de nest’s top. This suggests the transport of P rich solutions and phosphatized material along fractures by the freeze-thaw cycles, contributing to increase the geographical expression of this phenomenon in this ice-free area, consequently the development of soils and the establishment of vegetation.

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Abstract Antarctica represents an isolated continent devoted to conservation and scientific research, although it accumulates records of increasing anthropic contamination. The historical continued use of fuel for power generation in Antarctic settlements is a potential source of toxic elements to the soil. We investigate Cd, Cr, Cu, Mn, Ni, Pb, V and Zn levels in surface soils in the vicinity of the Henryk Arctowski Antarctic Station, aiming to identify anthropic effects on their local pedochemical variability. Pollution indices were used and compared to evaluate possible cumulative anthropic impacts, whereas correlation analyzes were explored to identify potential sources of contamination. High concentrations of Pb and Zn were locally observed near fuel tanks and machinery facilities. Correlation and principal component analysis suggest that old fuel tanks, vehicle traffic and machinery disturbance are key, and contrasting, sources of contamination. Among the eight indices we compared, Enrichment Factor and Modified Degree of Contamination were chosen, showing very high enrichment for Pb and moderate for Zn. All other elements presented minimal or null enrichment. The evidence of potentially toxic elements enrichment on Antarctic soils associated with the long-term occupation of Antarctic research stations highlights the need for further monitoring and mitigation measures, especially in energy-generating systems.

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Abstract The harsh Antarctic climate limits soil formation and the development of terrestrial ecosystems, with most biological activity concentrated in the short summer season in ice-free areas. There, penguins play a crucial role in nutrient transport from marine to terrestrial environments, significantly impacting soil properties through guano deposition. This study focuses on characterizing the ornithogenic soils of Half Moon Island in Maritime Antarctica, examining how lithology, vegetation, and geomorphology influence their formation and distribution. Fieldwork conducted during the 2014/2015 austral summer included excavating and sampling 21 soil profiles. Soils were analyzed for physical and chemical properties and classified. Half Moon Island’s soils are predominantly Cryosols and Leptosols, characterized by little development, high gravel content (skeletic), and significant cryoturbation. High variability in soil chemical properties was observed, with principal component analysis highlighting distinct clusters based on landscape position, geology, vegetation and ornithogenic influence. The findings underscore the diverse pedoenvironments of Half Moon Island, shaped by past and present ornithogenic activity and post-glacial geomorphological processes. This research highlights the soil variability in Antarctic environments and the significant ecological importance of seabird colonies on small, isolated islands.

Resumo em Inglês:

Abstract Salinization is one of the main pedogenetic processes occurring on the semiarid zone of the Weddel sea, like in Seymour Island, where salt-affected soils are widespread. This study aimed to investigate whether topography controls the distribution of salt-affected soils on Seymour Island, particularly with reference to the Lopez de Bertodano Formation. Chemical and physical results from 45 soil profiles were used, where morphometric variables were extracted. Descriptive statistical analysis, extraction of morphometric variables, cluster analysis and principal component analysis were carried out in this database. The separation of soils associated with the López de Bertodano Formation into two groups is explained by topographic atributes, and not by soil properties. Hence, the salts in soils have a geogenic origin, and despite differences in geological units, the uniform mineralogical composition of all Lopez de Bertodano Formation results in the widespread accumulation of salts in soils, influenced by the saline parent material and the semi-desert climate. Despite the lack of topographic control in the distribution of saline soils as a whole, geomorphology play a distinct role in the formation of secondary saline features, such as crusts, efflorescences, and columnar structures, or in salt composition of salts present in the soils.

Resumo em Inglês:

Abstract The Byers Peninsula, the largest ice-free area in Maritime Antarctica, is vital for studying landscape-scale natural processes due to its diverse periglacial landforms. This study aim to characterize the soils and environments of its southern sector, focusing on soil-landform-lithology interactions. Thirty-seven soil profiles were classified, collected, and chemically and physically analyzed. Principal component analysis explored relationships among variables in these profiles and 36 others from the Peninsula project database. The soils are generally shallow, with lithic or paralithic contact within the first meter. Four main soil groups were identified: patterned-ground soils on plateaus, ornithogenic soils, non-ornithogenic soils, and non-ornithogenic sodic and sandy soils on beaches and marine terraces. The Peninsula, divided into six geological units, represents a diverse periglacial morphogenetic system. Sixteen landform types were identified, each associated with different processes, topographies, lithologies, altitudes, and orientations, highlighting the importance of periglacial morphogenesis. Stable soilscapes, such as upper cryoplanation platforms, raised beaches, volcanic plugs, and ornithogenically influenced areas, show greater soil development and weathering. In contrast, dynamic periglacial landforms like scree stony slopes and talus exhibit minimal soil development and instability. The Byers Peninsula’s pedodiversity is due to its varied lithologies, landforms, extensive ornithogenic influences from seabirds, and long-term vegetation establishment.

Resumo em Inglês:

Abstract Ground temperature’s sensitivity to climate change has garnered attention. This study aimed to monitor and analyze temporal trends and estimate Active Layer Thickness from a monitoring point at Fildes Peninsula, King George Island, in Antarctica. Quality control and consistency analysis were performed on the data. Methods such as serial autocorrelation, Mann-Kendall, Sen-Slope, Pettitt, and regression analysis tests were applied. Spearman’s correlation examined the relationship between air temperature and ground depths. The active layer thickness was estimated using the maximum monthly temperature, and the permafrost lower limit used the minimum monthly temperature. Significant summer seasonal trends were observed with Mann-Kendall tau, positive Sen-Slope, and Pettitt slope at depths of 67.5 and 83.5 cm. The regression analysis was significant and positive for all ground depths and in different seasons. The highest correlation (r=0.82) between air temperature and surface ground depth was found. Freezing prevailed at all depths during 2008-2018. The average Active Layer Thickness (ALT) was 92.61 cm. Temperature is difficult to monitor, and its estimation is still complex. However, it stands out as a fundamental element for studies that refer to the impacts of climate change