Antarctic Science最新文献

{"title":"Seasonal shifts in microbial diversity in the lakes of Fildes Peninsula, King George Island, Maritime Antarctica","authors":"Florencia Bertoglio, C. Piccini, R. Urrutia, D. Antoniades","doi":"10.1017/S0954102023000068","DOIUrl":"https://doi.org/10.1017/S0954102023000068","url":null,"abstract":"Abstract Fildes Peninsula, on King George Island, has been greatly influenced by recent rapid climate warming. Lakes are pervasive features of Fildes Peninsula landscapes, some of which are used as water sources for Antarctic stations. We studied seven Fildes Peninsula lakes to explore differences among lakes and between seasons in phytoplankton and bacterioplankton communities. We measured environmental variables, analysed pigments using high-performance liquid chromatography and examined bacterial DNA through high-throughput sequencing of the 16S rRNA gene. The main driver structuring microbial communities was the season (i.e. spring vs autumn). Chlorophyceae were the dominant phytoplankton group in all lakes and both seasons. Indicator bacteria for each season were identified, including Flavobacterium, Polaromonas and Oxalobacteraceae as indicators of spring conditions under thick ice, whereas Frankiales and Verrucomicrobia were indicator species of autumn following the ice-free summer. The indicator species for spring are generally observed in oligotrophic conditions, whereas many of the autumn indicators are commonly found in soils. There were lesser between-lake differences in microbial communities in autumn, at the end of the open-water period, than in spring at the end of the ice-covered period. This study will act as the basis for future assessments of changes in aquatic microbial communities.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45043470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The sub-Antarctic islands are increasingly warming in the 21st century","authors":"W. Nel, D. Hedding, E. Rudolph","doi":"10.1017/S0954102023000056","DOIUrl":"https://doi.org/10.1017/S0954102023000056","url":null,"abstract":"WERNER NEL 1, DAVID W. HEDDING 2 and ELIZABETH M. RUDOLPH 3 Department of Geography and Environmental Science, University of Fort Hare, 1 King Williamstown Road, Alice, 5700, South Africa Department of Geography, University of South Africa, Pioneer Avenue, Florida, 1710, South Africa Afromontane Research Unit, Department of Geography, University of the Free State, 205 Nelson Mandela Avenue, Bloemfontein, 9300, South Africa wnel@ufh.ac.za","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44198521","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"The Antarctic ozone hole, ultraviolet radiation and bushfires","authors":"S. Robinson","doi":"10.1017/S0954102023000081","DOIUrl":"https://doi.org/10.1017/S0954102023000081","url":null,"abstract":"In the 1980s, British Antarctic scientists (Farman et al. 1985) discovered the hole in the ozone layer over Antarctica, and we are now familiar with images of springtime ozone depletion extending beyond the continental margins (Fig. 1a). The largest Antarctic ozone hole occurred in 2006 (Fig. 1b), but in recent years recovery has started to become apparent, with the total column ozone predicted to return to 1980 levels by 2066 (WMO 2022). However, there is still reason to be concerned about the timing and extent of ultraviolet (UV) radiation exposure in Antarctica, as well as how ozone recovery may be jeopardized by climate change-mediated events such as wildfires. The ozone layer protects the Earth's surface from damaging UV-B radiation. Recent reports demonstrate that over the period of maximum ozone depletion (1990–2020) the maximum spring UV index at Palmer Station (64°S) has increased by 2.5 times compared to the pre-ozone hole era as measured in the early 1970s. Despite the solar angle being much lower in Antarctica, the maximum UV index at Palmer Station in spring can now sometimes exceed that experienced in summer in subtropical regions (San Diego, CA, 32°N; Bernard et al. 2022; Environmental Effects Assessment Panel in press). Antarctic ozone depletion generally peaks between September and October, when most Antarctic terrestrial vegetation and soil biota will be frozen, dormant and hopefully protected under snow cover. Similarly, much marine life will be protected by sea-ice cover, although some seals and birds might be breeding on the ice at this time. Usually by the time summer arrives the ozone layer has recovered (see white lines in Fig. 1c). However, for the past 3 years ozone depletion has been extensive (Fig. 1b) and long-lasting, extending into early summer (e.g. 2022; see black lines in Fig. 1c). Since 2019, November–December total ozone column depth for latitudes 60–90°S have been the lowest since records began in the 1980s (NASA 2023). From a biologist's perspective, ozone depletion in early December is far more concerning, given that this is closer to the solstice, meaning that all solar radiation is higher, including the UV index. A peak in UV index coincident with snowmelt and the emergence of vegetation as well as during the peak breeding season at the start of the summer is of particular concern, as more biota are likely to be exposed to this higher incident UV-B radiation. For some organisms, such exposure may also occur at a more vulnerable time in their life cycles. The effects of climate change through earlier snowmelt and heatwaves (Robinson et al. 2020, Environmental Effects Assessment Panel in press) is likely to be enhancing the spring and summer UV exposure of Antarctic organisms, as noted in the latest United Nations Environment Program Environmental Effects Assessment Panel report (Barnes et al. 2023; Environmental Effects Assessment Panel in press). The Montreal Protocol is an extremely successful environment","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42978298","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Habitat severity characteristics structure soil communities at regional and local spatial scales along the Antarctica Peninsula","authors":"B. Ball, P. Convey, K. L. Feeser, U. Nielsen, David Van Horn","doi":"10.1017/S0954102023000019","DOIUrl":"https://doi.org/10.1017/S0954102023000019","url":null,"abstract":"Abstract Antarctic soils provide an excellent setting to test biogeographical patterns across spatial and environmental scales given their relatively simple communities and the dominance of physical factors that create strong environmental gradients. Additional urgency is given by the fact that their unique terrestrial communities are the subject of conservation efforts in a rapidly changing environment. We investigated relationships of soil community assembly and alpha and beta diversity with climatic and environmental parameters across regional and local scales in Maritime Antarctica. We sampled from a regional gradient of sites that differ in habitat severity, ranging from relatively favourable to harsher physicochemical conditions. At the regional scale, bacterial community characteristics and microarthropod abundance varied along this severity gradient, but most measures of fungal communities did not. Microarthropod and microbial communities differed in which soil and climate parameters were most influential, and the specific parameters that influenced each taxon differed across broad and fine spatial scales. This suggests that conservation efforts will need to focus on a large variety of habitat characteristics to successfully encompass diversity across taxa. Because beta diversity was the result of species turnover, conservation efforts also cannot focus on only the most biodiverse sites to effectively preserve all aspects of biodiversity.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47693382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Extreme cold (−69.1°C) in the McMurdo Dry Valleys","authors":"P. Doran, K. Myers, C. Mckay, D. Bromwich","doi":"10.1017/S0954102022000451","DOIUrl":"https://doi.org/10.1017/S0954102022000451","url":null,"abstract":"The McMurdo Dry Valleys in East Antarctica represents the largest ice-free area on the continent. In 1993, the National Science Foundation (NSF) funded the McMurdo Long Term Ecological Research (MCM LTER) site, which built a meteorological network that included a station on the shore of Lake Vida (LVi) in Victoria Valley (VV) installed in 1995 (Doran et al. 1995). This Short Note describes the conditions surrounding the lowest temperature ever recorded in the McMurdo Dry Valleys at LVi and compares them to other nearby meteorological stations.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44338461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Soil environmental DNA metabarcoding in low-biomass regions requires protocol optimization: a case study in Antarctica","authors":"Pamela Olmedo-Rojas, Gert‐Jan Jeunen, M. Lamare, Johanna D. Turnbull, A. Terauds, N. Gemmell, Ceridwen I. Fraser","doi":"10.1017/S0954102022000384","DOIUrl":"https://doi.org/10.1017/S0954102022000384","url":null,"abstract":"Abstract Environmental DNA is a powerful tool for monitoring biodiversity. Although environmental DNA surveys have successfully been implemented in various environments, protocol choice has been shown to affect results and inferences. Thus far, few method comparison studies for soil have been undertaken. Here, we optimized the workflow for soil metabarcoding through a comparative study encompassing variation in sampling strategy (individual and combined samples), DNA extraction (PowerSoil®, NucleoSpin® Soil, PowerSoil® + phosphate buffer and NucleoSpin® Soil + phosphate buffer) and library preparation (one-step and two-step quantitative polymerase chain reaction methods). Using a partial 18S rRNA marker, a total of 309 eukaryotic taxa across 21 phyla were identified from Antarctic soil from one site in the Larsemann Hills. Our optimized workflow was effective with no notable reduction in data quality for a considerable increase in time and cost efficiency. The NucleoSpin® Soil + phosphate buffer was the best-performing extraction method. Compared to similar studies in other regions, we obtained low taxonomic coverage, perhaps because of the paucity of Antarctic terrestrial organisms in genetic reference databases. Our findings provide useful methodological insights for maximizing efficiency in soil metabarcoding studies in Antarctica and other low-biomass environments.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43033253","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"What is the place of science in Antarctica?","authors":"P. Convey","doi":"10.1017/S095410202300007X","DOIUrl":"https://doi.org/10.1017/S095410202300007X","url":null,"abstract":"TheAntarctic Treaty System (ATS) is often paraphrased as providing the means by which Antarctica is protected as a 'continent for peace and science', on the face of it meaning that the primary purpose of humans being present in Antarctica is for the advancement of scientific knowledge. As is well known, some of the earliest expeditions to Antarctica placed scientific discovery and exploration amongst their highest priorities. Scientific research in Antarctica really took off with the International Geophysical Year of 1957/58, illustrating that even then the importance of Antarctica in the global system and for the advancement of science was starting to be appreciated. Even today, the lack of knowledge of parts of the continent and surrounding ocean, and/or within particular disciplines, means that 'discovery science' still has a major role to play. With today's emphasis and focus on the multifaceted field of 'global climate change', it is often easy to forget that little more than 30 years ago the concept was barely mentioned or its importance widely appreciated. So, what were the major drivers of the rapid development of Antarctic science in the midto late-20 Century, before 'climate fever' took over, and to what extent do these still apply? Perhaps more provocatively, does science itself really drive the actions and plans of those nations operating in Antarctica, or is it more accurate to see 'the tail wagging the dog', with scientific priorities and cooperation trailing behind geopolitical manoeuvring and the maximising of national prestige within the ATS? Antarctica has always fascinated humans, whether scientists or not. From both scientific and personal perspectives, it provides some of the planet's extremes and superlatives. With most of the world's ice, lowest temperatures, importance as an upper atmospheric and space observatory and surrounded by the most powerful ocean current, it has long been central to glaciological, geological, tectonic, atmospheric and oceanographic studies. Its extreme environments quickly catalysed research into the evolution and exceptional survival abilities of its resident biota – remarkably diverse in the surrounding ocean and equally remarkably sparse on land, but both sharing very long-term histories in the region. There is still much to learn in all these fields, especially at the boundaries between traditionally distinct disciplines, in what used to be known as 'pure' research, or philosophical recognition of the value of knowledge itself. In today's world, Antarctica and the Southern Ocean play key roles as 'sentinels' for change across the globe, not only relating to climate, but also areas like pollution, erosion of biogeography, space weather and the importance of wilderness values. Their roles as the 'engine' for the global ocean circulation system and a key driver of global climate now take prominence. However, it could be suggested that researchers who cannot connect what they do in someway to 'cli","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46552589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Antarctic science in Chile: a bibliometric analysis of scientific productivity during the 2009–2019 period","authors":"M. González-Aravena, L. Krüger, L. Rebolledo, R. Jaña, A. Aguayo‐Lobo, Marcelo A. Leppe, R. Rondón, F. Santa-Cruz, Carla Salinas, C. Trevisan, C. A. Cárdenas","doi":"10.1017/S0954102022000487","DOIUrl":"https://doi.org/10.1017/S0954102022000487","url":null,"abstract":"Abstract The changes implemented in 2005 in the development strategies of Antarctic science carried out by Chile have had a positive impact on the scientific productivity of the Chilean Antarctic Science Program (PROCIEN). We analysed scientometric indicators from between 2009 and 2019. The bibliographic data were extracted from the Web of Science database using search query keywords. We used multiple correspondence analysis to identify specific trends and also network analyses of international collaboration in VOSviewer. The number of Antarctic science publications in Chile has gradually increased from 21 in 2009 to 95 in 2019. The rise in the number of articles was higher in journals for the first impact factor quartile. Research lines showing increased first-quartile impact factor papers corresponded to Antarctic ecosystems, biotechnology and geosciences. The main geographical domains in which such research activities have been carried out corresponded to in the South Shetland Islands and the Antarctic Peninsula. Fieldwork data are the main sources for the production of scientific articles, and there are three science platforms within which most of these papers concentrate. The diversification of funding sources, the implementation of improvements in the selection process and Chile's alignment with Scientific Committee on Antarctic Research programmes have contributed to improving the science that Chile has developed in Antarctica.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47664750","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Time-lapse recording of yearly activity of the sea star Odontaster validus and the sea urchin Sterechinus neumayeri in Tethys Bay (Ross Sea, Antarctica)","authors":"A. Peirano, A. Bordone, L. Corgnati, S. Marini","doi":"10.1017/S0954102022000529","DOIUrl":"https://doi.org/10.1017/S0954102022000529","url":null,"abstract":"Abstract One-year time-lapse images acquired via an autonomous photo imaging device positioned at a depth of 20 m in Tethys Bay (Ross Sea, Antarctica) on a rocky bottom colonized by the sponge Mycale (Oxymycale) acerata were analysed. Monthly changes in the abundance and activity of the sea star Odontaster validus and sea urchin Sterechinus neumayeri on the sponge and nearby rocky bottom were compared with respect to environmental variables such as pack-ice presence/absence, temperature, salinity and photosynthetically active radiation. Sea urchins were more abundant on the rocky bottom and sponge during the summer and winter, respectively. Sea stars showed a decrease in the number of individuals on the sponge from January to December. The grazing activity of both species reached its maximum in January–April, when increased sunlight contributed to the phytoplankton bloom. The winter months were critical both for O. validus and S. neumayeri; although the red sea star maintained its pattern of activity on the rocky bottoms in terms of searching for food, the sea urchin reduced its activity. Time-lapse monitoring systems coupled with physicochemical sensors showed potential for revealing species behaviour in polar environments, contributing to the elucidation of future changes in coastal communities facing climate change.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43927915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Microsatellite locus development in the seaweed Plocamium sp.","authors":"S. Heiser, C. Amsler, S. A. Krueger‐Hadfield","doi":"10.1017/S0954102022000475","DOIUrl":"https://doi.org/10.1017/S0954102022000475","url":null,"abstract":"Macroalgae cover up to 80% of the benthos along the western Antarctic Peninsula (WAP; Wiencke & Amsler 2012). One of the most common and widespread members of the understory community is the red macroalga Plocamium sp. (Heiser et al. 2020). It supports among the highest amphipod and gastropod densities and is protected from predation through highly diverse chemical defences (Heiser et al. 2020). Haplotypic diversity, based on the mitochondrial cox1 barcode, showed some evidence of geographical structure as well as correlation with specific chemical defences (Shilling et al. 2021). These coarse patterns of genetic diversity are insufficient to understand the processes structuring populations of Plocamium sp. along the WAP, necessitating the use of more polymorphic, nuclear loci, such as microsatellites. Microsatellites have enabled the empirical quantification of the relative rates of selfing (i.e. self-fertilization) vs outcrossing (e.g. Winn et al. 2011) and sexual vs asexual reproduction (e.g. Vallejo-Marín et al. 2010), but studies have been restricted largely to angiosperms or animals, with far fewer investigations in macroalgae (KruegerHadfield et al. 2021). Plocamium sp., like many macroalgae, has a haploid-diploid life cycle, with free-living diploid tetrasporophytes and free-living haploid gametophytes, which are morphologically indistinguishable unless they are reproductive (Fig. S1; Heiser et al. 2020). Meiosis occurs on the tetrasporophytes, resulting in the release of haploid tetraspores. Tetraspores germinate and develop into male and female gametophytes. Gametes are mitotically produced by the gametophytes, but, following fertilization, the zygote is retained on the female gametophyte, where the carposporophyte develops. Each diploid carpospore can germinate into a tetrasporophyte. In natural populations, many thalli are vegetative, rendering it difficult to distinguish the stages. This life cycle results in unique eco-evolutionary consequences that challenge traditional understanding and the utility of common proxies to describe patterns of reproductive system variation (Krueger-Hadfield et al. 2021). For example, Plocamium sp. has separate sexes, but this does not preclude selfing (intergametophytic selfing; see Klekowski 1969). Separate sexes, therefore, cannot be used as a proxy to deduce outcrossing in natural populations. Instead, we must use population genetic tools to empirically quantify the relative rates of selfing, outcrossing and asexual reproduction in natural populations. We developed microsatellites to quantify patterns of genetic diversity and gene flow in Plocamium sp. (Heiser 2022). We chose microsatellites over other approaches for several reasons: 1) microsatellites facilitate the iterative addition of new samples to a dataset, something that is not possible in most genotyping by sequencing (GBS) approaches to identify single nucleotide polymorphisms; 2) microsatellites are an appropriate tool when existing data","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":null,"pages":null},"PeriodicalIF":1.6,"publicationDate":"2023-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43499914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"地球科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}