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Fine‐scale knowledge of spatiotemporal dynamics in cetacean distribution and abundance throughout the Western Antarctic Peninsula (WAP) is sparse yet essential for effective ecosystem‐based management (EBM). Cruise vessels were used as platforms of opportunity to collect data on the distribution and abundance of humpback whales (Megaptera novaeangliae) during the austral summer of 2019/2020 in a region that is also important for the Antarctic krill (Euphausia superba) fishery, to assess potential spatiotemporal interactions for future use in EBM. Data were analyzed using traditional design‐based line transect methodology and spatial density surface hurdle models fitted using a set of physical environmental covariates to estimate the abundance and distribution of whales in the area, and to describe their temporal dynamics. Our results indicate a rapid increase in humpback whale abundance in the Bransfield and Gerlache Straits through December, reaching a stable abundance by mid‐January. The distribution of humpback whales appeared to change from a patchier distribution in the northern Gerlache Strait to a significantly concentrated presence in the central Gerlache and southern Bransfield Straits, followed by a subsequent dispersion throughout the area. Abundance estimates agreed well with previous literature, increasing from approximately 7000 individuals in 2000 to a peak of 19,107 in 2020. Based on these estimates, we project a total krill consumption of between 1.4 and 3.7 million tons based on traditional and contemporary literature on per capita krill consumption of whales, respectively. When taken in the context of krill fishery catch data in the study area, we conclude that there is minimal spatiotemporal overlap between humpback whales and fishery activity during our study period of November–January. However, there is potential for significant interaction between the two later in the feeding season, but cetacean survey efforts need to be extended into late season in order to fully characterize this potential overlap. [ABSTRACT FROM AUTHOR]

Recent regional cooling has impacted the natural systems of the Antarctic Peninsula (AP); however, little is known concerning the changes in the high parts of the glacial systems. Dry-snow line (DSL), situated in the high parts of glaciers, is the uppermost limit of frequent or occasional surface melt. We analyse dry-snow line altitude (DSLA) changes on the AP during 2004–2020 using C-band synthetic aperture radar time series data. We demonstrate that the DSLA in the eastern part of the AP is usually higher than that of the western part. Moreover, using simulated climatic variables from regional climate models, the lowering in altitude of DSL of glaciers in most areas is identified as a response to a decrease in snowmelt and an increase in precipitation. Furthermore, correlation analyses between simulated climatic variables and the DSLA are conducted. These results present the sensitive response of variations in DSLA to meteorological conditions, and the capability of DSLA being a proxy of polar local climate in high-altitude areas with no in situ meteorological observations. [ABSTRACT FROM AUTHOR]

Belgica antarctica is one of the two native chironomid species of the Antarctic Peninsula. In this species, adult males and females are considerably different, yet the question of larval sex differences in morphometric parameters remains unanswered. In this paper, we analyze five morphometric parameters: head capsule length, head capsule width, mandible width, mandible length, mentum length of 140 fourth-instar larvae of B. antarctica from seven study plots in the south of Petermann Island, Wilhelm Archipelago, Antarctic Peninsula. To infer possible sexual dimorphism, we use the methods of unsupervised analysis (PCA and hierarchical clusterization). Our results suggest that the selected morphometric features of width and length are highly intercorrelated and cannot differentiate sex in the sampled larvae of B. antarctica. [ABSTRACT FROM AUTHOR]

The output of the various Weather Research and Forecasting (WRF) model configurations was compared with ground-based observations in the northern part of James Ross Island, Antarctic Peninsula. In this region, a network of automatic weather stations deployed at ice-free sites (as well as small glaciers) is operated by the Czech Antarctic Research Programme. Data from these stations provide a unique opportunity to evaluate the WRF model in a complex terrain of James Ross Island. The model was forced by the ERA5 reanalysis data and the University of Bremen sea ice data. The model configurations include a novel Three-Dimensional Scale-Adaptive Turbulent Kinetic Energy (3D TKE) planetary boundary layer scheme and a more traditional Quasi-Normal Scale Elimination (QNSE) scheme. Impact of model horizontal resolution was evaluated by running simulations in both 700 m and 300 m. The validation period, 25 May 2019 to 12 June 2019, was selected to cover different stratification regimes of air temperature and a significant snowfall event. Air temperature was simulated well except for strong low-level inversions. These inversions occurred in 44% of all cases and contributed to a higher mean bias (2.0–2.9°C) at low-elevation sites than at high altitude sites (0.2–0.6°C). The selection of the 3D TKE scheme led to improvement at low-elevation sites; at high altitude sites, the differences between model configurations were rather small. The best performance in wind speed simulation was achieved with the combination of the 3D TKE scheme and 300 m model resolution. The most important improvement was decrease of bias at a coastal Mendel Station from 3.5 m·s-1 with the QNSE scheme on the 700 m grid to 1.2 m·s-1 with the 3D TKE scheme on the 300 m grid. The WRF model was also proven to simulate a large snowfall event with a good correspondence with the observed snow height. [ABSTRACT FROM AUTHOR]

The aim of this work is a comprehensive study of the 16-year periodicity of winter surface temperature in the Antarctic Peninsula (AP) region, described earlier, and its possible source based on weather station records over the 1952–2019 period making use of the Scientific Committee on Antarctic Research (SCAR) Reference Antarctic Data for Environmental Research (READER) database, as well as Fourier and wavelet analysis methods. It is shown that interdecadal oscillation with a period of about 16 years dominates in the northern AP (Esperanza and Orcadas), which is consistent with previous results. The 16-year periodicity is found to closely correlate with the sea level pressure anomaly in the southwestern Atlantic associated with the zonal wave-3 and the Southern Annular Mode patterns. The correlation maximum in the southwestern Atlantic, having the characteristic features of the anticyclonic circulation, affects the surface temperature in the northern AP through the related structure of the zonal and meridional wind anomalies. This effect is weaker to the south, where the Vernadsky station data do not show a regular interdecadal periodicity. Due to the correlated variability in the wave-3 ridges, the pronounced 16-year periods exist also in the surface temperature of southern Australia–New Zealand region, as well as in the zonal mean sea level pressure at 30°–50° S. The sea surface temperatures are much less involved in the 16-year oscillation suggesting that atmospheric rather than oceanic processes appear to be more important for its occurrence. [ABSTRACT FROM AUTHOR]

As part of a project aiming to determine the lichenised fungal biodiversity of James Ross Island (Eastern coast of Antarctic Peninsula), we identified three infrageneric taxa which were previously not reported from Antarctica: Farnoldia micropsis (A. Massal.) Hertel, Gyalolechia epiphyta (Lynge) Vondrák and Placidium squamulosum var. argentinum (Räsänen) Breuss. Detailed morphological and anatomical properties of these species along with photographs based on the Antarctic specimens are provided here. In addition, the nrITS, mtSSU and/or RPB1 gene regions of the selected specimens are studied and the phylogenetic positions of the species are discussed. The DNA sequence data for Farnoldia micropsis are provided for the first time. Farnoldia micropsis and Gyalolechia epiphyta are also new to the Southern Hemisphere. [ABSTRACT FROM AUTHOR]

The ecosystem of the sea region adjacent to the Antarctic Peninsula is undergoing remarkable physical and biological changes, in the context of global warming. However, understanding of the dynamics of phytoplankton taxonomic composition in this marginal ice zone remains unclear. In this study, seawater samples collected from 36 stations in the northeastern Antarctic Peninsula were analyzed for nutrients and phytoplankton pigments. Combining with CHEMTAX analysis, remote sensing data, and physicochemical measurements, we investigated the relationships between phytoplankton crops, taxonomic composition, and marine environmental drivers. Integrated chlorophyll a (Chl a) concentrations (200 m) varied from 8.9 mg/m2 to 64.2 mg/m2, with an average of (23.2±12.0) mg/m2 and higher phytoplankton biomass concentrated in the coastal region of South Orkney Island and South Shetland Island. Diatoms were the dominant functional group (63%±21%). Higher proportions of diatoms were associated with higher Chl a (r=0.40, p<0.01), stable water columns (r=0.20, p<0.01), higher Si/P ratios (r=0.34, p<0.01), higher photosynthetically active radiation intensity (r=0.64, p<0.01), and higher sea ice melt water contributions (MWC, r=0.20, p<0.01). Conversely, Phaeocystis antarctica contributed a smaller overall proportion (31%±18%) and was more concentrated in the offshore water masses (e.g., Philip Ridge and South Scotia Ridge) with lower light levels (r=−0.58, p<0.01), deeper mixed layer depths (r=0.17, p<0.05), higher nutrient concentrations (e.g., N, P, and Si, r>0.35, p<0.01), and lower MWC (r=−0.20, p<0.01). In comparison, the total contribution from green flagellates (4%±5%), cryptophyta (1%±3%), dinoflagellates (1%±4%), and cyanobacteria (1% ± 5%) was only 6%. In offshore regions with well-mixed water, less varied taxonomic composition and lower crops with a higher proportion of nanophytoplankton were observed. In contrast, significantly decreasing crops below the mixed layer depth was observed in water columns with strong stratification, where the dominant phytoplankter changed from diatoms to P. antarctica. These findings have important implications for better understanding the future dynamics of marine ecosystems in the sea area adjacent to the Antarctic Peninsula. [ABSTRACT FROM AUTHOR]

Here, a geomorphological map of Horseshoe Island, which is one of the most ice-free islands in Marguerite Bay of the Antarctic Peninsula, is provided. The landforms on the island were mapped by using Google Earth images. Field reconnaissance of the landforms was carried out in March 2018. The island is subdivided into three major geomorphologically different sectors. The northern sector is mostly covered by a remnant of a non-erosive ice cap and has limited glacial landforms and deposits. The central sector is rich in terms of glacial and periglacial landforms and deposits. Glaciers are still sculpting the southern sector and it has extensive features of glacial erosion and deposition. The most common landforms on the island are talus cones, moraines, patterned ground, and raised beaches. The geomorphological map of the island will be a useful base for further geomorphic and/or glaciologic research in this climate-sensitive region.

The objective of the study is to simulate using numerical methods the seasonal and intraseasonal variations of circulation, sea level, temperature and salinity in the Bellingshausen Sea and on the shelf of the western part of the Antarctic Peninsula (WAP). The Semi-implicit Cross-scale Hydroscience Integrated System Model with an unstructured triangular horizontal grid and a vertical local sigma coordinate system and ice dynamic-thermodynamic Finite-Element Sea Ice Model were applied. Heat, momentum and salt fluxes were set on the ocean surface using the ERA5 reanalysis data. At the open boundaries, the vertical distribution of temperature and salinity was determined according to the COPERNICUS reanalysis. At the western open boundary of the computational domain, the vertical distribution of velocity of currents from COPERNICUS was also specified, whereas at the open eastern boundary the level deviations were specified. Time variability analysis of sea level was performed using wavelet analysis. The results of modelling of the sea level, temperature, and salinity fields for 2014–2015 were compared with the available observational data on the shelf of the WAP, including data from the Ukrainian Antarctic Expedition. The simulated horizontal and vertical distributions of the subsurface layer with minimum of potential temperature Tmin (Winter Water) are given. The depth of the Tmin varies in the range of 10–100 m increasing to the north. The values of minimum of potential temperature Tmin also increase to the north from –1.8 to 1.2 °C. The intraseasonal oscillations of sea level computed by the model for 2014—2015 were analysed together with data of observations at the tidal stations Faraday/Akademik Vernadsky and Rothera located at the coast of WAP. In the range 1–150 days the largest amplitudes of the level scalegrams were found for a period of approximately 100 days in 2014 and 120 days in 2015 at both stations. The largest amplitudes of modelled level scalegrams were observed with a period of approximately 88 days in 2014 and 80 days in 2015 at both stations. The largest amplitudes of scalegrams for Antarctic Oscillation (AAO) were found for a period of 105 days in 2014 and 123 days in 2015. The corresponding correlation coefficients between observed sea level scalegrams and AAO for 2014 were 0.84 and 0.86, respectively, whereas for 2015 they were 0.87 and 0.90, respectively. It was concluded that the relationship between intraseasonal processes in the ocean in West Antarctica and AAO existed at a time scale of about 100 days.

Antarctica and the Southern Ocean are unique natural laboratories where organisms adapted to extreme environmental conditions have evolved in isolation for millions of years. These unique biotic communities on Earth are facing complex climatic and environmental changes. Terrestrial ecosystems in the Antarctic Peninsula Region (APR) have experienced the highest rate of climate warming and, being the most impacted by human activities, are facing the greatest risk of detrimental changes. This review provides an overview of the most recent findings on how biotic communities in terrestrial ecosystems of the Antarctic Peninsula Region (APR) are responding and will likely respond to further environmental changes and direct anthropogenic impacts. Knowledge gained from studies on relatively simple terrestrial ecosystems could be very useful in predicting what may happen in much more complex ecosystems in regions with less extreme temperature changes. The rapid warming of the APR has led to the retreat of glaciers, the loss of snow and permafrost and the increase of ice-free areas, with a consequent enhancement of soil-forming processes, biotic communities, and food web complexity. However, most human activity is concentrated in APR coastal ice-free areas and poses many threats to terrestrial ecosystems such as environmental pollution or disturbances to soil communities and wildlife. People who work or visit APR may inadvertently introduce alien organisms and/or spread native species to spatially isolated ice-free areas. The number of introduced non-indigenous species and xenobiotic compounds in the APR is likely to be greater than currently documented, and several biosecurity and monitoring activities are therefore suggested to Antarctic national scientific programs and tourism operators to minimize the risk of irreversible loss of integrity by the unique terrestrial ecosystems of APR.

Antarctic Peninsula region is experiencing one of the fastest rates of climate change on Earth. Its waters are known as important feeding grounds for the Antarctic minke whales (Balaenoptera bonaerensis). The purpose of the present study was to reveal the summer and early autumn presence of the Antarctic minke whales in the area adjacent to the Kiev Peninsula of West Antarctica and to estimate the encounter rates of the species in the area. The boat-based photo-identification cetacean studies were initiated as part of the long-term monitoring program based at the Akademik Vernadsky station near the Kiev Peninsula of West Antarctica. From 22 January to 7 April 2019, 35 boat and yacht cruises of the 821 nautical miles of total length were conducted. There were encountered 13 Antarctic minke whales in 7 sightings. The encounter rate was 0.015 whales per nautical mile. Minke whales were encountered only in 5% of the total sightings. Three more whales were opportunistically seen from the top of Galindez Island. There were single whales sighted and small groups of up to 3 specimens (Med = 2). At least 2 individuals were identified as juveniles. Primary behavior for whales in 7 sightings was foraging, and 2 groups were observed while travelling. A total 9 individuals of the Antarctic minke whales were photo-identified during the survey, and no matches were found between the different encounters. Our pilot study indicates summer and early autumn presence of the Antarctic minke whales in the area adjacent to the Kiev Peninsula. But encounter rates seem to be low in comparison with results of some previous surveys. Our results show the possibility to monitor minke whales in the area, and further long-term complex monitoring is essential for understanding the ecology and population dynamics of the Antarctic minke whales in rapidly changing marine environment of the Antarctic Peninsula.

The Antarctic Peninsula region is of growing interest due to the regional climate change features and related atmospheric circulation patterns. The regional mesoscale atmospheric model Polar Weather Research and Forecasting (WRF) v4.1.1 was used in this research to study a heavy precipitation event over the Ukrainian Antarctic Akademik Vernadsky station region (Antarctic Peninsula). The passage of the cyclone over the Antarctic Peninsula as a typical synoptic process as well as a case of the daily precipitation maximum amount of 2018 were chosen for investigation in this research. The estimation of the modelling quality and downscaling was done by comparing the obtained results with in-situ observation at the Akademik Vernadsky station and cross-domain tracking of average meteorological values and their deviation. The concept of the nested domains allowed to increase the horizontal resolution of the simulated atmosphere up to 1 km and to reproduce the wind regime of this region with high quality. Comparison with measured data showed a significant improvement in wind simulation with increasing of resolution, but worse representation of surface temperature and humidity. The Polar WRF made a general cooling of near surface temperature of 2 °C during the period of simulation and increased precipitation amount by 4.6–8.4 mm (12–21%) on average over the territory relative to the initial data from Global Data Assimilation System. This can be explained by the contribution of noise and imperfection of the model (including static input data of the terrain description). Based on the modelled results, the interaction of wind flow with the mountainous terrain of the Antarctic Peninsula creates a range of complex dynamic effects in the atmosphere. These effects cause local precipitation maxima both over the Peninsula and over the adjacent ocean. These are, respectively, bay-valley areas of increased precipitation and increased precipitation on the crests of shock waves from orographic obstacles. Under certain background wind conditions, the influence of the latter effect can reach the Akademik Vernadsky station and cause the formation of heavy precipitation here.

Abstract Background Advances in biologging technology allow researchers access to previously unobservable behavioral states and movement patterns of marine animals. To relate behaviors with environmental variables, features must be evaluated at scales relevant to the animal or behavior. Remotely sensed environmental data, collected via satellites, often suffers from the effects of cloud cover and lacks the spatial or temporal resolution to adequately link with individual animal behaviors or behavioral bouts. This study establishes a new method for remotely and continuously quantifying surface ice concentration (SIC) at a scale relevant to individual whales using on-animal tag video data. Results Motion-sensing and video-recording suction cup tags were deployed on 7 Antarctic minke whales (Balaenoptera bonaerensis) around the Antarctic Peninsula in February and March of 2018. To compare the scale of camera-tag observations with satellite imagery, the area of view was simulated using camera-tag parameters. For expected conditions, we found the visible area maximum to be ~ 100m2 which indicates that observations occur at an equivalent or finer scale than a single pixel of high-resolution visible spectrum satellite imagery. SIC was classified into one of six bins (0%, 1–20%, 21–40%, 41–60%, 61–80%, 81–100%) by two independent observers for the initial and final surfacing between dives. In the event of a disagreement, a third independent observer was introduced, and the median of the three observer’s values was used. Initial results (n = 6) show that Antarctic minke whales in the coastal bays of the Antarctic Peninsula spend 52% of their time in open water, and only 15% of their time in water with SIC greater than 20%. Over time, we find significant variation in observed SIC, indicating that Antarctic minke occupy an extremely dynamic environment. Sentinel-2 satellite-based approaches of sea ice assessment were not possible because of persistent cloud cover during the study period. Conclusion Tag-video offers a means to evaluate ice concentration at spatial and temporal scales relevant to the individual. Combined with information on underwater behavior, our ability to quantify SIC continuously at the scale of the animal will improve upon current remote sensing methods to understand the link between animal behavior and these dynamic environmental variables.

Current climate in the Antarctic Peninsula (AP) region can be interpreted as a continued warming, still exceeding climatic norms but without significant rise on the Antarctic Peninsula stations. Assessments of trends in the near-air temperatures are made by applying homogeneity procedure and series of monthly SAT normalizing by amplitudes. The most intensive increase in surface air temperature at the end of XX - beginning XXI century recorded at Vernadsky and Rothera stations at the west coast of the Antarctic Peninsula. Most of inhomogeneities are observed in coldest decade, 1950s; current period is characterized by smoothening in the near-surface temperatures (SAT) ranges especially in comparison to 1950s because of changes in atmospheric circulation. Normalized SAT series is comparable between winter and summer seasons at west coast of AP, including Vernadsky and Rothera stations. Spatial and temporal characteristics of near surface temperatures are described, with significant seasonal and topography-dependant variability. Significant differences exist between stations at the west coast and those lying at Weddell Sea coast, especially in summer. By the Vernadsky data, summer warming is mainly responsible for the recession of glaciation. Modern regional warming is associated with growing influence of El Niño-Southern Oscillation, especially after well-known climatic shift in the 1970s due to increased surface temperature of the equatorial Pacific. On the background the overall warming trend some intradecadal SAT fluctuations are registered being associated with El Niño. On the basis of the recent SAT variability at other stations and multi-years’ change in climate indexes it is concluded that no further warming can be expected in the near future.

В результате исследований магнитных и плотностных свойств более чем 500 образцов мезозойских и па­лео­ценовых интрузивных и вулканогенных пород, отобранных в западной части Антарктического полу­ост­рова (район станции Академик Вернадский), получена новая информация о петрофизических харак­те­ристиках разных породообразующих комплексов. Породы характеризуются широким диапазоном значений как магнитных (магнитная восприимчивость – от 0.0016 до 0.26 ед. СИ, естественная остаточная намагниченность – от 0.0045 до 8.37 А/м), так и плотностных (от 2.57 до 3.3 гм3) параметров. Различия в плотностных и магнитных характеристиках пород разных петрографических групп укладываются в общие закономерности их изменений в породах кислого, среднего и основного составов. Соответственно средние значения плотности составляют 2.65, 2.77 и 2.9 г/см3, магнитной восприимчивости – 0.02, 0.036 и 0.068 ед. СИ, естественной остаточной намагниченности – 0.16, 0.3 и 2.08 А/м. Новый фактический материал является базовым для параметризации гравитационных и магнитных моделей, рассчитываемых по аномальным потенциальным полям.

Objective of the study is an assessment of possible climate change in the region of the Antarctic Peninsula from 1986 until the end of the 21st century projected by the RCMs’ ensemble. During the last decades Antarctica has undergone predominantly warming, with the highest rate of surface air temperature increase found over the Antarctic Peninsula, where the Ukrainian Antarctic Akademik Vernadsky station is located. There is a unique ecosystem in the region which is vulnerable and under the growing impact of a changing weather regime due to rapid climate changes with consequent changes in sea ice, land distribution under snow/ice, etc. Thus, an important task for the region is an estimation of climate change trends and definition of possible subregionalization. Data and methods. Data of two regional climate models HIRHAM5 and RACMO21P forced by two global climate models EC-EARTH and HadGEM from the Polar-CORDEX (Coordinated Regional Downscaling Experiment - Arctic and Antarctic Domains) as part of the international CORDEX initiative were used in the study. Spatial distribution of the model output is 0.44°. Set of scripting codes developed by Climate4R project (An R Framework for Climate Data Access and Postprocessing) was modified in order to extract data for the Antarctic Peninsula region from the Antarctic domain and obtain climatological characteristics for individual RCMs and their ensemble mean. Projected changes in wet/dry climate indices for scenarios RCP4.5 and RCP8.5 for two periods 2041—2060 and 2081—2100 were assessed with respect to the historical experiment 1986—2005. Results. An analysis of projected wet/dry climate indices for both RCP4.5 and RCP8.5 scenarios is presented in Part II of the paper. An analysis of the cold temperature indices (FD, ID) is presented in Part I of the study. In the historical experiment Larsen Ice Shelf and leeward east coast are the regions with the lowest total precipitation in wet days (PRCPTOT, 200—300 mm) and simple daily intensity index (SDII, about 5 mm/day) with under 10 days of consecutive wet days (CWD) and up to 30 days consecutive dry days (CDD). In the cross of the 21st century, duration of dry spell is projected to shorten for the whole peninsula and for Akademik Vernadsky station by about 7—10% under the scenario RCP4.5 and 10—15% under the RCP8.5. Projected SDII changes are up to +20% till the end of the century under the scenario RCP8.5 at north-west coast of the Antarctic Peninsula. Conclusions. Over the Antarctic Peninsula region both scenarios project an average increase in total PRCPTOT and SDII; overall the maximum length of CWD is extended while the maximum length of the CDD is reduced. In combination with decreasing number of frost (FD) and ice (ID) days, the pattern of changes differs notably across the peninsula. It is shown in the first part of the paper that over the Antarctic Peninsula region, both scenarios project an average decrease in the cold season period. The most pronounced changes of ID and FD climate indices are for the Larsen Ice Sheet area. Analyzing results presented in both parts of the paper we can distinguish a few subregions with different projected changes in climate conditions based on obtained climate indices. Obtained results can be used for studies of the climate changes impact on ecosystems in the region and for the strategic planning of future activities (scientific, touristic, fishery, etc.).

Abstract The classification of Synthetic Aperture Radar (SAR) images by knowledge-based algorithms with elevation and backscatter thresholds were used in several studies to detect the Wet Snow Radar Zone (WSZ) in the Antarctic Peninsula. To identify it more accurately based on its seasonal variations, this study proposed the additional use of a threshold in synthetic images, created by rationing summer and winter sigma linear images. In our algorithm we used the following thresholds to detect the WSZ in Envisat ASAR imageries, using the Radarsat Antarctic Map Digital Elevation Model as ancillary data: i) -25 dB < s0 < -14 dB; ii) slinear summer / slinear winter < 0.4; iii) elevation H < 1,200 m for northern tip and H < 800 m for southern tip of the Antarctic Peninsula. The classified images were post-processed by a focal majority 5 x 5 filter and superimposed by an image of rock outcrops derived from the Antarctic Digital Database. The ratio image threshold allowed discriminating the WSZ from the Dry Snow Radar Zone and radar shadows, as well as transitional areas between this glacier zone and the Frozen Percolation Radar Zone, which would be classified incorrectly if we used only elevation and backscatter thresholds.

Benthic samples were collected during two expeditions near the Antarctic Peninsula and in the South-Eastern Weddell Sea. During these studies, a new species of Ampharetidae Malmgren, 1867, Anobothrus konstantini Säring & Bick sp. nov., was found. Here we present a detailed description of this species. We used the traditional light microscope and scanning electron microscope (SEM) to identify and describe the diagnostic characters: a circular glandular band on segment 6; an elongate ridge between the notopodia on segment 12 and modified notochaetae on this segment; 16 thoracic, two intermediate and ten abdominal segments. For the first time, micro-computed tomography (micro-CT) was used for a species description of Anobothrus. Micro-CT provided information on the shape of the prostomium (Ampharete-type) and the arrangement of branchiae (four pairs in two rows, without a gap). In addition, we provide quantitative information on the environmental niche based on sediment parameters (chlorophyll a content, organic matter content, chloroplast equivalent, grain size) for the new Anobothrus species, relevant for, e.g., species distribution modelling. Finally, an identification key for all Anobothrus species is provided.

Abstract Fine‐scale knowledge of spatiotemporal dynamics in cetacean distribution and abundance throughout the Western Antarctic Peninsula (WAP) is sparse yet essential for effective ecosystem‐based management (EBM). Cruise vessels were used as platforms of opportunity to collect data on the distribution and abundance of humpback whales (Megaptera novaeangliae) during the austral summer of 2019/2020 in a region that is also important for the Antarctic krill (Euphausia superba) fishery, to assess potential spatiotemporal interactions for future use in EBM. Data were analyzed using traditional design‐based line transect methodology and spatial density surface hurdle models fitted using a set of physical environmental covariates to estimate the abundance and distribution of whales in the area, and to describe their temporal dynamics. Our results indicate a rapid increase in humpback whale abundance in the Bransfield and Gerlache Straits through December, reaching a stable abundance by mid‐January. The distribution of humpback whales appeared to change from a patchier distribution in the northern Gerlache Strait to a significantly concentrated presence in the central Gerlache and southern Bransfield Straits, followed by a subsequent dispersion throughout the area. Abundance estimates agreed well with previous literature, increasing from approximately 7000 individuals in 2000 to a peak of 19,107 in 2020. Based on these estimates, we project a total krill consumption of between 1.4 and 3.7 million tons based on traditional and contemporary literature on per capita krill consumption of whales, respectively. When taken in the context of krill fishery catch data in the study area, we conclude that there is minimal spatiotemporal overlap between humpback whales and fishery activity during our study period of November–January. However, there is potential for significant interaction between the two later in the feeding season, but cetacean survey efforts need to be extended into late season in order to fully characterize this potential overlap.

The bulk of the chinstrap penguin (Pygoscelis antarcticus) global population inhabits the Antarctic Peninsula and Scotia Sea, which is a region undergoing rapid environmental changes. Consequently, regional level decreases for this species are widespread. This study aimed to evaluate the level of breeding colony changes in the Antarctic Peninsula and South Orkney Islands, which, roughly, hold 60% of the global chinstrap penguin population. The results indicated that within a period of 40 to 50 years, 62% of colonies underwent decreases, and the majority of colonies experienced decreases over 50%, which is represented by numbers in the range of 2000 to 40,000 pairs. Within three generations’ time, the whole population for the area had experienced decreases of around 30%. These levels of decrease add to the fact that the suspected causes are not likely reversible in the short- to mid-term, calling for increased concern about the conservation of this species.

We applied multi–temporal 1D magnetotelluric (MT) surveys to identify space–time anomalies of apparent resistivity (ρa) in the upper lithosphere in the Antarctic Peninsula (the border between the Antarctic and the Shetland plates). We used time series over several weeks of the natural Earth’s electric and magnetic fields registered at one MT station of the Universidad Nacional de Colombia (RSUNAL) located at Seymour–Marambio Island, Antarctica. We associated resistivity anomalies with contrasting earthquake activity. Anomalies of ρa were detected almost simultaneously with the beginning of a seismic crisis in the Bransfield Strait, south of King George Island (approximately 85.000 events were reported close to the Orca submarine volcano, with focal depths < 20 km and MWW < 6.9). We explained the origin of these anomalies in response to fluid migration near the place of the fractures linked with the seismic swarm, which could promote disturbances of the pore pressure field that reached some hundreds of km away.

Ice scouring is one of the strongest agents of disturbance in nearshore environments at high latitudes. In depths, less than 20 m, grounding icebergs reshape the soft-sediment seabed by gouging furrows called ice pits. Large amounts of drift algae (up to 5.6 kg/m2) that would otherwise be transported to deeper water accumulate inside these features, representing an underestimated subsidy. Our work documents the distribution and dimensions of ice pits in Fildes Bay, Antarctica, and evaluates their relationship to the biomass and species composition of algae found within them. It also assesses the rates of deposition and advective loss of algae in the pits. The 17 ice pits found in the study area covered only 4.2% of the seabed but contained 98% of drift algal biomass, i.e., 60 times the density (kg/m2) of the surrounding seabed. Larger ice pits had larger and denser algal accumulations than small pits and had different species compositions. The accumulations were stable over time: experimentally cleared pits regained initial biomass levels after one year, and advective loss was less than 15% annually. Further research is needed to understand the impacts of ice scouring and subsequent algal retention on ecosystem functioning in this rapidly changing polar environment.

This study presents an analysis of OH airglow images observed from an all‐sky camera (ASC) at King Sejong Station (KSS), Antarctic for the 2012–2016 period. The two‐dimensional power spectra of short‐period gravity waves (<1 hr) as a function of phase velocities are obtained using the M‐transform method that employs the time sequence of ASC images. The amplitudes of the power spectral densities show that the mesospheric wave activity is the largest during winter (May, June, and July) and is the smallest in fall (February, March, and April). Wind‐blocking diagrams are constructed on the same two‐dimensional domain as in the two‐dimensional spectra using horizontal winds obtained from MERRA‐2 reanalysis at z = 0–80 km and from KSS meteor radar data at z = 80–90 km. Climatologically, the spectral regions of slowly propagating gravity waves (<30 m s−1) are overlaid by the wind‐blocking areas, which suggests the filtering of gravity waves with small phase speeds by winds below the upper stratosphere. Eastward propagating gravity waves in winter and intense south‐eastward waves in spring (October) are found to be unfiltered by the stratospheric winds. It is also found from the spectral analysis that these unfiltered gravity waves can originate from the upper stratosphere or the lower mesosphere, and not from the troposphere, which suggests the possibility of ASC observation of the secondary gravity waves generated near the stratopause. Key Points: Spectra of gravity waves in the Antarctic mesosphere are examined through an analysis of 5‐year all‐sky OH airglow imagesEffects of wind filtering on slowly propagating gravity waves are shown through wind‐blocking diagramsEastward and southeastward propagating mesospheric gravity waves in winter and spring can be generated near the stratopause [ABSTRACT FROM AUTHOR]

Volcanism can play a key role in modulating climate; however, a lack of historical records has limited our comprehension of Antarctic volcanism and its role on the cryosphere. Remote sensing can provide insight into active volcanism in Antarctica during the satellite era, although the evidence is often inconclusive. Here, we use independent evidence from ice cores to validate one such potential volcanic eruption from the sub‐Antarctic Balleny Islands in 2001 CE. Multiple ice cores from downwind of the eruption site, record elevated input of sulfate, microparticles, and the presence of tephra, coincident with the eruption. In‐phase deposition of volcanic products confirmed a rapid tropospheric transport of volcanic emissions from a small‐to‐moderate, local eruption during 2001. Air mass trajectories demonstrated some air parcels were transported over the West Antarctic ice sheet from the Balleny Islands to ice core sites at the time of the potential eruption, establishing a route for transport and deposition of volcanic products over the ice sheet. The data presented here validate previous remote sensing observations and confirms a volcanic event in the Balleny Islands during 2001 CE. This newly identified eruption provides a case study of recent Antarctic volcanism. Key Points: Evidence from ice cores is used to verify a volcanic eruption in the Balleny islands in 2001 CE, supporting evidence from satellitesCharacterization and timing of microparticles and tephra associated with this eruption provide a chronostratigraphic marker for ice cores [ABSTRACT FROM AUTHOR]

Understanding the tectonic framework of the Antarctic Peninsula is hindered by a paucity of paleomagnetic data from key locations. In this study, we present paleomagnetic data from the South Shetland Islands, to the northwest of the Antarctic Peninsula, which provides valuable paleoposition constraints on the Western domain of the Antarctic Peninsula. We report a key reliable paleopole (58.1°S, 354.3°E, A95 = 6.3°) from Livingston Island in the South Shetland Islands at ∼102 Ma. Plate reconstruction models from the Early Cretaceous attach the South Shetland Islands to the Pacific margin of southern Patagonia‐Fuegian Andes at ∼140 Ma. The South Shetland Islands then experienced southward translation to its current position to the northwest of the Antarctic Peninsula following counterclockwise rotation during ∼100–90 Ma. A similar counterclockwise rotation has also been identified from southern Patagonia‐Fuegian Andes but is absent in the Antarctic Peninsula, suggesting a direct affinity between the South Shetland Islands and southern Patagonia‐Fuegian Andes. However, the consistent, almost northward Cretaceous paleomagnetic declination in the Antarctic Peninsula, and the near‐synchronous tectonic‐magmatic history between the Antarctic Peninsula and the southern Patagonia‐Fuegian Andes support an autochthonous continental subduction model for most of the Antarctic Peninsula. Plain Language Summary: In this study, we applied paleomagnetic constraints on the autochthonous continental subduction model and allochthonous terrane accretion model in the explanation of the tectonic framework of the Antarctic Peninsula. Our new data reveal a consistent counterclockwise rotation occurred both at the South Shetland Islands and southern Patagonia‐Fuegian Andes during ∼100–90 Ma, suggesting the affinity of these places. This is supported by the previous reported ∼140 Ma plate reconstruction, which attached the South Shetland Islands to the Pacific margin of southern Patagonia‐Fuegian Andes. However, the lack of significant tectonic rotation suggests that most parts of the Antarctic Peninsula were formed during the Pacific plate subduction and support an autochthonous continental subduction model. Key Points: We have obtained a key mid‐Cretaceous paleopole (58.1°S, 354.3°E, A95 = 6.3°) from the Byers Peninsula, South Shetland IslandsSouth Shetland Islands located at the Pacific margin of southern Patagonia‐Fuegian Andes during the Early to mid‐CretaceousConsistent almost northward paleomagnetic declination support an autochthonous model for most part of the Antarctic Peninsula [ABSTRACT FROM AUTHOR]

• Antarctic environments and biodiversity are vulnerable to climate change. • Antarctic protected areas can help promote resilience to climate change impacts. • Climate change is little considered in ATS protected area guidelines and agreements. • Existing protected area management plans little consider climate change impacts. • International efforts to enhance resilience and protection should be supported. Antarctica is increasingly vulnerable to climate change impacts, with the continent predicted to warm by ∼4 °C by 2100 under a 'business as usual' greenhouse gas emission scenario. Simultaneously, human activity, primarily in the form of scientific research and the fishing and tourism industries, is putting increasing pressure on Antarctic and Southern Ocean environments and ecosystems. We evaluate the effectiveness of the Antarctic area protection system in promoting resilience to climate change impacts. Under the framework of the Antarctic Treaty System (ATS), terrestrial and marine areas can be designated to protect locations of scientific, environmental, historic and intrinsic value and to facilitate operational coordination to minimise environmental impact. However, climate change is not mentioned explicitly in the Protocol on Environmental Protection to the Antarctic Treaty and is little considered in guidelines for the designation and management of the region's existing protected areas. Climate change impacts are considered in only 17% of Antarctic Specially Protected Area (ASPA) management plans and, at a time when threats to Antarctic environments are increasing, the last decade has seen an 84% decline in ASPA designation rate compared with levels in the 1980s. Nevertheless, momentum is building within the Scientific Committee on Antarctic Research (SCAR) and the ATS's Committee on Environmental Protection (CEP) to deliver an evidence-based, integrated response to climate change that includes the use of protected areas. The Antarctic scientific community is well-placed to support decision-makers in the use of existing conservation management tools through provision of climate change forecasts at sub-regional scales, data on anticipated environmental change, and predicted species and ecosystems responses. Ultimately, reducing global greenhouse gas emission will provide the greatest protection from climate change impacts within Antarctica. [ABSTRACT FROM AUTHOR]

The Antarctic krill (Euphausia superba) fishery is the largest fishery in the Southern Ocean, and it has been operating for over 45 years. In the past decade, the spatial distribution of the krill fishery has focused on the Bransfield Strait off the Antarctic Peninsula (subarea 48.1). However, the high fishing effort and climate change have placed great pressure on krill resources in this region, and conservation concerns have been raised. Because aging krill is difficult and uncertain, we developed an integrated size-structured model to estimate the fishing mortality, recruitment and spawning biomass of krill. The results indicated that in 1992–2011, the average spawning biomass of krill ranged from 1.14 × 106 to 1.45 × 106 tons, the estimated biomass of the maximum sustainable yield (BMSY) ranged from 3.96 × 105 to 4.90 × 105 tons and the estimated average recruitment ranged from 2.3 × 1012 to 5.03 × 1012 individuals in the research area. We explored the effect of different data weighting schemes for the length data on the assessment output. However, our estimates also have uncertainties. In addition, an attempt was made to analyze the correlation between model-estimated recruitment and mature biomass with climate change. Future stock assessments of krill resources should be comprehensive and multimethod, and the management of krill resources should be based on science that considers the demand of fishing communities and ecosystem protection.

To study how Odontaster validus can influence the spatial structure of Antarctic benthic communities and how they respond to disturbance, it is necessary to assess potential dietary shifts in different habitats. We investigated the diets of O. validus from Maxwell Bay and South Bay in the West Antarctic Peninsula. A multifaceted approach was applied including in situ observations of cardiac stomach everted contents, isotopic niche, and trophic diversity metrics. Results confirm the flexible foraging strategy of this species under markedly different environmental conditions, suggesting plasticity in resource use. The data also showed evidence of isotopic niche expansion, high δ15N values, and Nacella concinna as a common food item for individuals inhabiting a site with low seasonal sea ice (Ardley Cove), which could have significant ecological implications such as new trophic linkages within the Antarctic benthic community. These results highlight the importance of considering trophic changes of key species to their environment as multiple ecological factors can vary as a function of climatic conditions.

Antarctica is a continent that presents extreme conditions for life. Numerous buildings that served as housing for expeditioners and scientists are considered historical heritage, including Casa Moneta Museum, located at the Orcadas Base on Laurie Island, South Orkney Islands (Antarctic Peninsula). It is built entirely of wood, and currently shows visible signs of deterioration. In this work, we studied the mycobiota present in the deteriorated wood of the museum to characterize the fungal diversity present. Macro-, micro-morphological and phylogenetic studies were carried out to identify the fungi isolated. Temperature tests were also performed to study the growth of different strains. Almost 20% of the fungi isolated belonged to Cadophora. Other frequently obtained genera were Tulasnella (16%), Cerinosterus (12%), Coniochaeta (7%), Geomyces (7%), Acremonium (7%) and Penicillium (7%). Temperature tests indicated all strains isolated are psychrotolerant. Five species have been reported for the first time for Antarctica. Deterioration of historic wooden structures and artifacts in extreme environments is currently causing great concern, and in this study the identification of the fungi present in Casa Moneta's wood and the characterization of their metabolism could be a guide to the development of preservation strategies for this historical building. [ABSTRACT FROM AUTHOR]

We assessed fungal diversity present in air samples obtained from King George Island, Antarctica, using DNA metabarcoding through high-throughput sequencing. We detected 186 fungal amplicon sequence variants (ASVs) dominated by the phyla Ascomycota, Basidiomycota, Mortierellomycota, Mucoromycota, and Chytridiomycota. Fungi sp. 1, Agaricomycetes sp. 1, Mortierella parvispora, Mortierella sp. 2, Penicillium sp., Pseudogymnoascus roseus, Microdochium lycopodinum, Mortierella gamsii, Arrhenia sp., Cladosporium sp., Mortierella fimbricystis, Moniliella pollinis, Omphalina sp., Mortierella antarctica, and Pseudogymnoascus appendiculatus were the most dominant ASVs. In addition, several ASVs could only be identified at higher taxonomic levels and may represent previously unknown fungi and/or new records for Antarctica. The fungi detected in the air displayed high indices of diversity, richness, and dominance. The airborne fungal diversity included saprophytic, mutualistic, and plant and animal opportunistic pathogenic taxa. The diversity of taxa detected reinforces the hypothesis that the Antarctic airspora includes fungal propagules of both intra- and inter-continental origin. If regional Antarctic environmental conditions ameliorate further in concert with climate warming, these fungi might be able to reactivate and colonize different Antarctic ecosystems, with as yet unknown consequences for ecosystem function in Antarctica. Further aeromycological studies are necessary to understand how and from where these fungi arrive and move within Antarctica and if environmental changes will encourage the development of non-native fungal species in Antarctica. [ABSTRACT FROM AUTHOR]

• Corg and bSi burial rates were 3 to 15 g m−2y−1 and 15 to 126 g m−2y−1, respectively. • Sediment focusing, cold temperatures enhanced Corg and bSi preservation efficiencies. • Bransfield Strait had comparatively high biogenic matter accumulation rates • Results useful to refine paleo-reconstructions of primary production in the area. Burial fluxes of organic carbon and biogenic silica were determined in 17 continental shelf sediment cores collected from the northern Weddell Sea, the Bransfield Strait, and the southern Drake Passage. Coring sites included open-shelf stations as well as slope and glacial trough environments, with water depths varying from 220 to 760 m. Apparent 210Pb accumulation rates from these cores ranged from 0.04 g m−2y−1 to 0.21 g m−2y−1 (1 to 3 mm y−1), with organic carbon burial rates ranging from 3 to 15 g OC m−2y−1 and biogenic silica accumulation rates ranging from 15 to 126 g SiO 2 m−2y−1. OC contents below the surface mixed layer ranged from 0.26 to 1.51 wt. % (avg. 0.64 %). Biogenic silica contents at depth ranged from 2.3 to 11.2 wt. % (avg. 7.5%), with an average bSi/OC ratio (wt. %/wt. %) at depth of 12. Annual OC primary production rates and biogenic silica production rates in the euphotic zone were estimated from satellite chlorophyll- a data in the literature and from a seasonal model for biogenic particle export from surface waters. Based on these biogeochemical data, preservation efficiencies (i.e., mass burial rate/water column production rate) were calculated for organic carbon and biogenic silica. These preservation efficiency values ranged from 2 to 18% (avg. 9%) for OC and 8 to 106% (avg. 54%) for bSi. These relatively high preservation efficiencies resulted from extensive lateral sediment focusing (210Pb Psi (Ψ) values [burial flux/water column production rate] ranging from 2 to 33; avg. of 16), cold bottom water temperatures (2 to −2°C), and relatively high biogenic Si and OC production rates in the euphotic zone. The enhanced preservation efficiency for bSi relative to OC (i.e., 54% vs. 9%) in these Antarctic settings is consistent with the change in the phytoplankton bSi/OC (wt. %/wt. %) value of 2 for this area to the burial bSi/OC value of 12. Excess 210Pb activities in surface sediments varied from 4 to 47 dpm g−1. The surface mixed layer in the seabed varied in thickness from 0 to 4 cm. The penetration of excess 210Pb into these Antarctic Peninsula sediments varied from 6 to 28 cm (avg. 18 cm). The inventory of excess 210Pb in the seabed varied from 13 to 230 dpm cm−2 (avg. 110 dpm cm−2). Although 210Pb was the only radionuclide measured in this study, "apparent" 210Pb sediment accumulation rate (SAR) values from these 17 cores (assuming that deep bioturbation is negligible) are believed to be accurate SAR values because of good agreement between 210Pb and 14C chronologies from nearby cores reported in the literature. [ABSTRACT FROM AUTHOR]

In the current context of climate change, southern South America and the Southern Ocean are undergoing profound environmental transformations that impose challenges to marine species. Shifts in species distribution ranges will occur through expansions or contractions of the range edges. Invertebrates such as Nacella spp., that being template-cold water species, will be more vulnerable to increasing temperature and will therefore suffer range contraction as temperatures increase southward. To understand the future of this sensitive group of gastropods, the potential impact of future climate on the distribution ranges of six species of the genus Nacella was studied using ensemble ecological niche models and representative concentration pathway 8.5 scenarios for the years 2050 and 2100. The results indicate that all the species studied will undergo a shift in their distribution in response to the projected changes in climate with a decline in habitat suitability. Particularly, the species will lose suitable areas mainly in the northern edge of their current distribution. Nevertheless, the species may not change their distribution equally. Our study suggests that N. magellanica , N. clypeater , and N. concinna appear to exhibit vulnerability, albeit with potentially lesser impact. Nacella magellanica is the limpet that shows the least distribution change in 2100. Both species, N. clypeater and N. concinna , will move southward while the Antarctic species will expand their distribution to other Antarctic areas. The most significant impact is expected for three Magellanic species (N. deaurata, N. flammea, and N. mytilina), currently distributed across the southern tip of South America. With restricted geographical ranges, these species face increased vulnerability to habitat loss as they cannot migrate southward. This comprehensive analysis offers invaluable insights into how Nacella species could tackle the challenges of climate change. The emphasis on specific species' vulnerabilities and the differential impacts on their distribution enhances our understanding of the potential consequences of climate change in the studied region. Furthermore, it will aid in formulating effective conservation and management strategies to protect Antarctic and sub-Antarctic ecosystems. [Display omitted] • A shift in habitat suitability for Nacella spp. is expected in 2050 and 2100. • All species would lose suitable areas in the northern edge of their distribution. • Nacella clypeater and N. concinna could be classified as "winner" species. • N. magellanica , N. deaurata , N. mytilina , and N. flammea would be "loser" species. • All these species will be vulnerable more or less to future climate change. [ABSTRACT FROM AUTHOR]

The aim of the study is to analyze seasonal and interannual changes in sea level on the western coast of the Antarctic Peninsula. Objects of study are seasonal and interannual variability of sea level, air temperature, pressure at sea level, precipitation in the period 1960–2018 at the Faraday/Akademik Vernadsky station, which was considered as representative site for the Antarctic Peninsula. Statistical methods of study were used, including estimates of linear trends of time series using the nonparametric Sen’s estimator of slope. The Mann-Kendall test was used to assess the significance of the slope of the trend. Time variability analysis was performed using wavelet analysis. Using the MATrix LABoratory (MATLAB) software package, squared of wavelet coefficients were calculated depending on the scale and shift or scalograms that characterize the local energy spectrum, and scalegrams calculated by averaging the scalograms by time shifts. The Morlet wavelet transformations were used. The results of the calculations showed that the trend of sea level at the Faraday/ Akademik Vernadsky station in the period 1960—2018, according to observations and correction on glacial isostatic adjustment of the crust is in the range from 3.05 to 3.45 mm/year, which is significantly higher than the global trend of 2.1 mm/year. Sea level scalograms allow estimating time-averaged periods and amplitudes of the coefficients for each season. In the austral winter and spring characteristic periods were 4—6 years, whereas the summer and autumn periods are characterized by 6–8 years, as well as by the highest amplitudes of the coefficients. All seasons are characterized by the appearance of a weakly pronounced period of about 4 years. The presence of peaks in the scalegrams at 6–8 and 3–4 years confirms the relationship of atmospheric and oceanic processes in West Antarctica to the natural variations of the ocean-atmosphere system, such as the Southern Annular Mode and El Niño-Southern Oscillation, which varies with typical 3–4 and 6–8 year periods. It was concluded that, unlike air temperature, the sea level trend is relatively weakly depends on the season, with the exception of autumn, when sea level trend is three times smaller than the average value. At the same time, the air temperature trend is the largest in the austral winter and the lowest in the summer.

Objective. This paper deals with an estimation of the climate change at the Antarctic Peninsula region. During last decades, the most significant warming is observed in Polar regions, particularly in the Antarctic Peninsula region, where the Ukrainian Antarctic Akademik Vernadsky station is located. Therefore, the providing of the complex estimation of climate change trend is an important task for the region. These changes are taking place nowadays and will happen in the future. So, the main objective of the study is to estimate changes of climate characteristics in the Antarctic Peninsula region in the 21st century, based on calculation of the relevant climate indices. The projections of the temperature and precipitation characteristics in the Antarctic Peninsula region and Akademik Vernadsky station area for RCP4.5 and RCP8.5 scenarios are the objects of the research. Methods of the research are numerical simulation and statistical analysis of the regional climate model data for the Antarctic Peninsula region from the International Project Polar-CORDEX. Spatial distribution of this data is 0.44° and three periods are under consideration: historical climatic period (1986—2005) and two future periods 2041—2060 and 2081—2100. The R-code language and the modified computing code developed by Climate4R Hub project in Jupiter Notebook environment were used for climate data analysis in this research. Six parameters were chosen to estimate climate change in the Antarctic Peninsula region: number of frost days with minimal air temperature (Т) less 0 °C, number of ice days with maximal Т less 0 °C, annual total precipitation, mean precipitation rate, maximum yearly duration of periods without precipitation, maximum yearly duration of periods with precipitation more than 1 mm per day. Results as an analysis of the cold temperature indices are presented in the Part I of the paper, while an analysis of the wet/dry indices will be presented in the Part II of the paper. Conclusions. Over the Antarctic Peninsula region, both scenarios project an average decrease in the cold season period. This process will be more pronounced for the RCP 8.5 scenario, when even to the middle of the century the period with negative temperatures is rapidly decreasing over the Larsen Ice Sheet area, which may cause its total or partial collapse. Over Akademik Vernadsky station area, the climate indices changes will almost triple as high as the averaged values over the Antarctic Peninsula for the two scenarios, indicating a greater vulnerability to the climate change in the area.

Objective. To investigate the qualitative changes in the habitats of two most common species penguin populations in the Wilhelm Archipelago Pygoscelis papua and P. adeliae (Spheniscidae) penguins in the CCAMLR Subarea 48.1 under the impact of climate changes and krill fishery. Methods. The new method of time-lapse camera registration to observe the breeding success of penguins was applied to minimize the effect of human disturbance on the breeding and survival of chicks and to avoid disturbance of penguins. Installed in penguin colonies cameras were used to record next parameters: arrival to colony, copulation, egg lay, hatch and crèche. This method was introduced for the first time in the framework of the international CEMP project “Establishing a CEMP Camera Network in Subarea 48.1”. More than five years’ timeline of the project is expected. The traditional visual observation of penguin colonies from time to time has been used as well. Results. Over the last decade, P. papua has been shifted nearly 30 km southward and formed six new nesting colonies. Annual breeding success of P. papua on Petermann Island has ranged from 0.87 to 1.58 chicks crèche per nest over the nine seasonal observations during 2003—2017. 1.27 chicks per nest was found in 2016/17 season; a low breeding success rate in comparison to most of other seasons. The breeding success of P. adeliae was more stable ranging from 1.11 to 1.42 over the six seasonal observations; with highest in 2003/04. The range of prey for P. papua was studied. Conclusions. Changes in the penguin species habitat have been observed on the territory of the Wilhelm Archipelago. It was established that at the beginning of the ХХІ century the nesting areas of P. papua was significantly extended probably due to the climate warming in the region. It was shown that P. papua is more ecologically plastic species than P. adeliae. It is well know that the breeding success of predators such as penguins can be used as an indication of the status of lower trophic levels. Since, the Antarctic krill Euphausia superba (Euphausiidae) is the main feeding object of the both penguin species diet (84%) in the Wilhelm Archipelago area, we propose a model of key elements for qualitative and quantitative analysis of the changes in the krill- based ecosystem of the Argentine Islands. Future development of the penguin nesting colonies monitoring using the CEMP Camera Network under the CCAMLR will contribute significantly to the real-time estimates of relative prey availability. The results of the gentoo and Adelie penguin’s chronology and breeding success studies might be used (1) in development of the krill fishery management strategy in the CCAMLR for the rational use of Antarctic marine living resources; (2) to develop a resettlement model to predict the ecological risks due to climate changes for both penguin species.

In this study, we used the stable water isotope record (δ18O) from an ice core drilled in Palmer Land, southern Antarctic Peninsula (AP). Utilizing δ18O we identified two climate regimes during the satellite era. During the 1979–1998 positive interdecadal Pacific oscillation (IPO) phase, a low-pressure system north of the Weddell Sea drove southeasterly winds that are associated with an increase in warm air mass intrusion onto the Larsen shelves, which melted and a decreased sea ice concentration in the Weddell Sea/increase in the Bellingshausen Sea. This climate setting is associated with anomaly low δ18O values (compared with the latter IPO period). There is significantly more melt along the northern AP ice shelf margins and on the Larsen D and southern Larsen C during the 1979–1998 IPO positive phase. The IPO positive climatic setting was coincidental with the Larsen A ice shelf collapse. In contrast, during the IPO negative phase (1999–2011), northerly winds caused a reduction in sea ice in the Bellingshausen Sea/Drake Passage region. Moreover, a Southern Ocean north of the Weddell Sea high-pressure system caused low-latitude warm humid air over the tip and east of the AP, a setting that is associated with increased northern AP snowfall, a high δ18O anomaly, and less prone to Larsen ice shelf melt.

Expansive study areas, such as those used by highly-mobile species, provide numerous logistical challenges for researchers. Community science initiatives have been proposed as a means of overcoming some of these challenges but often suffer from low uptake or limited long-term participation rates. Nevertheless, there are many places where the public has a much higher visitation rate than do field researchers. Here we demonstrate a passive means of collecting community science data by sourcing ecological image data from the digital public, who act as “eco-social sensors,” via a public photo-sharing platform—Flickr. To achieve this, we use freely-available Python packages and simple applications of convolutional neural networks. Using the Weddell seal (Leptonychotes weddellii) on the Antarctic Peninsula as an example, we use these data with field survey data to demonstrate the viability of photo-identification for this species, supplement traditional field studies to better understand patterns of habitat use, describe spatial and sex-specific signals in molt phenology, and examine behavioral differences between the Antarctic Peninsula’s Weddell seal population and better-studied populations in the species’ more southerly fast-ice habitat. While our analyses are unavoidably limited by the relatively small volume of imagery currently available, this pilot study demonstrates the utility an eco-social sensors approach, the value of ad hoc wildlife photography, the role of geographic metadata for the incorporation of such imagery into ecological analyses, the remaining challenges of computer vision for ecological applications, and the viability of pelage patterns for use in individual recognition for this species.

Abstract It is estimated that the explosive Hudson volcano eruption in Southern Chile injected approximately 2.7 km3 of basalt and trachyandesite tephra into the troposphere between August 8-15, 1991. The Hudson signal has been detected in Antarctica at the eastern sector and in South Pole snow. In this work, we track the Hudson volcanic plume using a dispersion model, remote sensing, and a re-analysis of a high-resolution ice core analysis from the Detroit Plateau in the Antarctic Peninsula and sedimentary records from shallow lakes from King George Island (KGI). The Hudson eruption imprint in these records is confirmed by using a weekly resolved aerosol concentration database from KGI demonstrating that the regional impact of Hudson eruption predominates over the Mount Pinatubo/Phillippines volcanic signal, dated from June 1991, in terms of particulate matter depositions. The aerosol elemental composition of Ca, Fe, Ti, Si, Al, Zn, and Pb increases from 2 to 3 orders of magnitude in background level during the days following the eruption of the Hudson volcano.

Here, we report on two tarsometatarsi assignable to relatively small-sized Eocene Antarctic penguins, housed in the palaeozoological collections of Naturhistoriska riksmuseet, Stockholm. The Priabonian fossils were collected by museum staff during two joined Argentinean and Swedish expeditions from the Submeseta Formation on Seymour Island, Antarctic Peninsula. One specimen represents a new early sphenisciform, Marambiornopsis sobrali gen. et sp. nov., the sixth small-sized tarsometatarsus-based penguin species known from the Antarctic Eocene. Micro-CT scanning revealed the presence of quite large and essentially empty metatarsal medullary cavities. The second fossil can unequivocally be assigned to Mesetaornis polaris. The specimen represents only the second record of this species and supposedly a relatively young bird. Micro-CT scanning showed that in M. polaris the metatarsal medullary cavities are less developed than in M. sobrali – the cortical and trabecular bone tissues left rather little room for significant hollow spaces. Both specimens also differ in overall density of their trabecular networks.Genus name: Species name: [ABSTRACT FROM AUTHOR]

The waters near the Antarctic Peninsula have always been a study hot spot because of their variable and unique oceanographic conditions. To determine the distribution and possible influencing factors on phytoplankton size and abundance near the Antarctic Peninsula, a large-scale survey was conducted during the austral summer of 2018. Samples were collected in 27 stations located in the Drake Passage (DP), South Shetland Islands (SSI), and South Orkney Islands (SOI). Phytoplankton communities were described using chlorophyll a (Chl a), flow cytometry and light microscopy to cover a size range from pico- to microphytoplankton. Nanophytoplankton, especially small nanophytoplankton (2–6 µm) with abundance ranging from 0.66 × 103 cells/mL to 8.46 × 103 cells/mL, was predominant throughout the study area. Among different regions, there was an obvious size shift. The proportion of picophytoplankton near the Elephant Island (EI) and DP was higher than other regions, and larger cells were found mainly in east of SOI. The distribution of phytoplankton abundance detected by flow cytometry was not completely consistent with Chl a concentrations due to the contribution of larger cells to Chl a. Possible influencing factors on the phytoplankton size distribution were discussed. The properties of water masses such as temperature and salinity can influence the phytoplankton size distribution. Correlation analysis revealed that only picophytoplankton is significantly correlated with salinity. Light and Fe availability might affect phytoplankton abundance and size distribution especially near the waters of SSI and EI in this study. It was also speculated that the abundance of cryptophytes is possibly related to ice melting. [ABSTRACT FROM AUTHOR]