Antarctic Science最新文献

Evidence for a floristically diverse rainforest on the Falkland archipelago in the remote South Atlantic during the mid- to late Cenozoic 新生代中晚期偏远南大西洋福克兰群岛上植物多样性雨林的证据

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-09-09 DOI: 10.1017/s0954102024000129

Zoë A. Thomas, Michael Macphail, Haidee Cadd, David J. Cantrill, David K. Hutchinson, Heather A. Haines, Karen Privat, Chris Turney, Stefanie Carter, Paul Brickle

{"title":"Evidence for a floristically diverse rainforest on the Falkland archipelago in the remote South Atlantic during the mid- to late Cenozoic","authors":"Zoë A. Thomas, Michael Macphail, Haidee Cadd, David J. Cantrill, David K. Hutchinson, Heather A. Haines, Karen Privat, Chris Turney, Stefanie Carter, Paul Brickle","doi":"10.1017/s0954102024000129","DOIUrl":"https://doi.org/10.1017/s0954102024000129","url":null,"abstract":"We report the discovery of an ancient forest bed near Stanley, on the Falkland Islands, the second such ancient deposit identified on the South Atlantic island archipelago that is today marked by the absence of native tree species. Fossil pollen, spores and wood fragments preserved in this buried deposit at Tussac House show that the source vegetation was characterized by a floristically diverse rainforest dominated by Nothofagus-Podocarpaceae communities, similar to cool temperate Nothofagus forests/woodlands and Magellanic evergreen Nothofagus rainforests. The age limit of the deposit is inferred from the stratigraphic distribution of fossil pollen species transported by wind, birds or ocean currents from southern Patagonia, as well as similar vegetation types observed across the broader region. The deposit is suggested to be between Late Oligocene and Early Miocene, making it slightly older than the previously analysed Neogene West Point Island forest bed (200 km west of Tussac House). The combined evidence adds to our current knowledge of the role of climate change and transoceanic dispersal of plant propagules in shaping high-latitude ecosystems in the Southern Hemisphere during the late Palaeogene and Neogene.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"17 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142200632","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}

引用次数: 0

Beyond the ice: exploring Antarctic soils research through spatial and scientometrics analysis 冰外：通过空间和科学计量学分析探索南极土壤研究

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-09-09 DOI: 10.1017/s0954102024000166

Ícaro Vieira, Fábio Oliveira, Roberto Ferreira Machado Michel

引用次数: 0

Geochemistry of lake sediments from the South Shetland Islands and James Ross Archipelago, north Antarctic Peninsula 南极半岛北部南设得兰群岛和詹姆斯罗斯群岛湖泊沉积物的地球化学特征

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-05-30 DOI: 10.1017/s0954102024000154

Silvia H. Coria, Soledad Pérez Catán, Andrea I. Pasquini, María Arribere, Rosemary Vieira, Luiz H. Rosa, Juan M. Lirio, Karina L. Lecomte

{"title":"Geochemistry of lake sediments from the South Shetland Islands and James Ross Archipelago, north Antarctic Peninsula","authors":"Silvia H. Coria, Soledad Pérez Catán, Andrea I. Pasquini, María Arribere, Rosemary Vieira, Luiz H. Rosa, Juan M. Lirio, Karina L. Lecomte","doi":"10.1017/s0954102024000154","DOIUrl":"https://doi.org/10.1017/s0954102024000154","url":null,"abstract":"The geochemistry of lake sediments provides valuable information on environmental conditions and geochemical processes in polar regions. To characterize geochemical composition and to analyse weathering and provenance, 26 lakes located in six islands of the South Shetland Islands (SSI) and James Ross Archipelago (JRA) were analysed. Regarding major composition, the studied lake sediments correspond to ferruginous mudstones and to a lesser extent to mudstones. The weathering indices indicate incipient chemical alteration (Chemical Index of Alteration = 52.6; Plagioclase Index of Alteration = 57.6). The La-Th-Sc plot shows different provenance signatures. SSI lake sediments correspond to oceanic island arcs, whereas those of JRA denote a signal of continental arcs with mixed sources. In James Ross Island lake sediments are of continental arcs (inland lakes), oceanic island arcs (coastal lakes) and a middle signature (foreland lakes). Multi-elemental analysis indicates that the sediments are enriched from regional basalts in Ba, Rb, Th, Cs and U (typical of silica-rich rocks) and depleted in Cr and Co due to mafic mineral weathering. The geochemical signals identified by principal component analysis enable us to group the sediments according to the studied islands and their geomorphological characteristics. This study underlines the importance of knowing the geochemical background levels in pristine lake sediments to evaluate potential future anthropogenic effects.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"96 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141191600","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}

引用次数: 0

Mosses of Cockburn Island plateau, Antarctica 南极科伯恩岛高原的苔藓

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-05-10 DOI: 10.1017/s0954102024000014

Agustina Celeste Cottet, María Inés Messuti, Martín Ansaldo, Laura Patricia Dopchiz

引用次数: 0

Fine-scale phylogenetic diversity gradients support the Antarctic geothermal refugia hypothesis 精细尺度的系统发育多样性梯度支持南极地热避难所假说

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-05-07 DOI: 10.1017/s0954102024000099

William S. Pearman, Clare I.M. Adams, Maria Monteiro, Antonio Quesada, Ceridwen I. Fraser

{"title":"Fine-scale phylogenetic diversity gradients support the Antarctic geothermal refugia hypothesis","authors":"William S. Pearman, Clare I.M. Adams, Maria Monteiro, Antonio Quesada, Ceridwen I. Fraser","doi":"10.1017/s0954102024000099","DOIUrl":"https://doi.org/10.1017/s0954102024000099","url":null,"abstract":"The possible role of geothermal areas, such as volcanoes, in fostering biodiversity in Antarctica has received considerable recent attention. Under a geothermal refugia hypothesis, diverse life could be supported near or at geothermal sites, and we should see decreasing diversity and/or patterns of nestedness moving away from ‘hotspots’. Although there is evidence that geothermal areas have played a role in the persistence of some terrestrial species through glacial periods in Antarctica, the spatial scales at which such refugia operate is not clear. We sampled sediment from a range of locations across volcanic Deception Island in the Maritime Antarctic and used eDNA metabarcoding approaches (targeting a region of the 28S marker) to assess patterns of diversity in relation to thermal gradients. We found that although colder sites harboured significantly greater taxonomic richness than warmer sites, phylogenetic diversity was lower at colder sites (i.e. taxa at colder sites tend to be more evolutionary close to each other). We infer that increased selective processes in low-temperature environments have reduced phylogenetic diversity, supporting a hypothesis of geothermal locations acting as refugia for diverse taxa, even on fine spatial scales, in cold-climate regions such as Antarctica.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"4 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-05-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140886329","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}

引用次数: 0

McMurdo Dry Valley lake edge ‘moats’: the ecological intersection between terrestrial and aquatic polar desert habitats 麦克默多干谷湖边 "护城河"：陆生和水生极地沙漠栖息地之间的生态交叉点

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-04-19 DOI: 10.1017/s0954102024000087

Michael S. Stone, Shawn P. Devlin, Ian Hawes, Kathleen A. Welch, Michael N. Gooseff, Cristina Takacs-Vesbach, Rachael Morgan-Kiss, Byron J. Adams, J.E. Barrett, John C. Priscu, Peter T. Doran

{"title":"McMurdo Dry Valley lake edge ‘moats’: the ecological intersection between terrestrial and aquatic polar desert habitats","authors":"Michael S. Stone, Shawn P. Devlin, Ian Hawes, Kathleen A. Welch, Michael N. Gooseff, Cristina Takacs-Vesbach, Rachael Morgan-Kiss, Byron J. Adams, J.E. Barrett, John C. Priscu, Peter T. Doran","doi":"10.1017/s0954102024000087","DOIUrl":"https://doi.org/10.1017/s0954102024000087","url":null,"abstract":"Aquatic ecosystems - lakes, ponds and streams - are hotspots of biodiversity in the cold and arid environment of Continental Antarctica. Environmental change is expected to increasingly alter Antarctic aquatic ecosystems and modify the physical characteristics and interactions within the habitats that they support. Here, we describe physical and biological features of the peripheral ‘moat’ of a closed-basin Antarctic lake. These moats mediate connectivity amongst streams, lake and soils. We highlight the cyclical moat transition from a frozen winter state to an active open-water summer system, through refreeze as winter returns. Summer melting begins at the lakebed, initially creating an ice-constrained lens of liquid water in November, which swiftly progresses upwards, creating open water in December. Conversely, freezing progresses slowly from the water surface downwards, with water at 1 m bottom depth remaining liquid until May. Moats support productive, diverse benthic communities that are taxonomically distinct from those under the adjacent permanent lake ice. We show how ion ratios suggest that summer exchange occurs amongst moats, streams, soils and sub-ice lake water, perhaps facilitated by within-moat density-driven convection. Moats occupy a small but dynamic area of lake habitat, are disproportionately affected by recent lake-level rises and may thus be particularly vulnerable to hydrological change.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"21 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-04-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140627500","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}

引用次数: 0

Extremophile hypolithic communities in the Vestfold Hills, East Antarctica 南极洲东部维斯特福尔丘陵的极端嗜下石群落

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-03-25 DOI: 10.1017/s0954102023000408

Laurence J. Clarke, Eric J. Raes, Toby Travers, Patti Virtue, Dana M. Bergstrom

{"title":"Extremophile hypolithic communities in the Vestfold Hills, East Antarctica","authors":"Laurence J. Clarke, Eric J. Raes, Toby Travers, Patti Virtue, Dana M. Bergstrom","doi":"10.1017/s0954102023000408","DOIUrl":"https://doi.org/10.1017/s0954102023000408","url":null,"abstract":"The Vestfold Hills are a 400 km2, isolated ice-free oasis in eastern Antarctica featuring large areas with translucent quartz rocks that provide habitat for hypolithic microbial communities underneath. We used high-throughput DNA sequencing of 16S and 18S ribosomal RNA amplicons to characterize bacterial and eukaryotic hypolithic communities across the Vestfold Hills. We found high-level, local heterogeneity in community structure consistent with limited dispersal between hypoliths. Hypolithic communities were dominated by heterotrophic Bacteroidetes (mean bacterial relative read abundance: 56%) as well as Cyanobacteria (35%), with the eukaryote component often dominated by Chlorophyta (43%). Small but significant proportions of the variation in microbial community composition and function were explained by soil salinity (5–7%) and water availability (8–11%), with distinct taxa associated with different salinities and water availabilities. Furthermore, many inferred bacterial metabolic pathways were enriched in hypolithic communities from either dry or high-salinity sites. Vestfold Hills hypolithic habitats are likely to be local refuges for bacterial and eukaryotic diversity. Gradients in soil salinity and water availability across the Vestfold Hills, in addition to the number and diversity of lake types and fjords as potential source populations, may contribute to the observed variation in the extremophile, hypolithic microbial community composition.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"47 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140299584","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}

引用次数: 0

Varying population size of the Cape Royds Adélie penguin colony, 1955–2020: a synthesis 1955-2020 年罗伊兹角阿德利企鹅群数量变化：综述

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-03-18 DOI: 10.1017/s0954102024000051

David G. Ainley, Virginia Morandini, Kerry Barton, Phil O'B. Lyver, Megan Elrod, Michelle A. Larue, Jean Pennycook

{"title":"Varying population size of the Cape Royds Adélie penguin colony, 1955–2020: a synthesis","authors":"David G. Ainley, Virginia Morandini, Kerry Barton, Phil O'B. Lyver, Megan Elrod, Michelle A. Larue, Jean Pennycook","doi":"10.1017/s0954102024000051","DOIUrl":"https://doi.org/10.1017/s0954102024000051","url":null,"abstract":"Among the longest Antarctic biological time series is that of Adélie penguin Pygoscelis adeliae population size at Cape Royds, 1955 to the present. Demographic trends over the 66 years fall into five periods: 1) decrease then recovery due to control of tourism from McMurdo Station/Scott Base; 2) further increase responding to the removal of > 20 000 trophically competing Antarctic minke whales Balaenoptera bonaerensis from the colony's wintering area; 3) stabilization but not decrease upon the ban of whaling in 1982, and whale recovery, owing to increased winds facilitating McMurdo Sound Polynya presence (easier ocean access during nesting); 4) decrease in 2001–2005 when two mega-icebergs, B15A/C16, opposed the wind effect by increasing sea-ice cover, thus limiting ocean access; and 5) after iceberg departure, minimal recovery due to the increased velocity of the wind-generated Ross Gyre reducing penguin breeding probability. A multivariant model using 1998–2018 data confirmed the roles of gyre speed (negative) and open water (positive) in colony growth. Additional negative influence came from high nest predation by south polar skuas Stercorarius maccormicki, reducing chick production, as well as perhaps increased trophic competition from nearby Weddell seals Leptonychotes weddellii. Clearly, long time series increase our understanding of penguin population dynamics responding to a complexity of factors.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"16 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149148","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}

引用次数: 0

Assessment of trophic segregation amongst gentoo penguin (Pygoscelis papua) individuals in Antarctica using a non-invasive methodology 利用非侵入式方法评估南极洲巴布亚企鹅个体之间的营养隔离情况

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-03-15 DOI: 10.1017/s0954102024000026

Lucía Rabinovich-Larrechea, Daniel E. Naya, Mariana Cosse, Nadia Bou, Valentina Franco-Trecu

{"title":"Assessment of trophic segregation amongst gentoo penguin (Pygoscelis papua) individuals in Antarctica using a non-invasive methodology","authors":"Lucía Rabinovich-Larrechea, Daniel E. Naya, Mariana Cosse, Nadia Bou, Valentina Franco-Trecu","doi":"10.1017/s0954102024000026","DOIUrl":"https://doi.org/10.1017/s0954102024000026","url":null,"abstract":"Individual trophic specialization (ITS) refers to the trophic diversification amongst individuals within a population. The gentoo penguin (Pygoscelis papua) is considered a trophic generalist at the population level, but little is known about its individual trophic differentiation. We assessed the degree of ITS at one of its main breeding colonies: Ardley Island, South Shetland Islands. We used skin from 19 dead individuals to determine species and sex by molecular methods and a nail for stable isotope analysis of δ15N and δ13C. Isotopic niche metrics and ITS were estimated for the population and for each sex. We found a moderately high degree of ITS associated with the trophic position of the resources consumed (δ15N) for the population and both sexes, as well as a moderate degree of ITS in the foraging habitat (δ13C) for the population and females. Females showed a higher exclusive niche area, suggesting that they use resources and foraging areas that males do not, probably related to reproductive energy demands. Given the high population density of this species, ITS could function as a mechanism to decrease intraspecific competition. This combination of genetic and isotopic tools allowed us to provide relevant information on the trophic ecology of the gentoo penguin without manipulating animals or using invasive methods.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"30 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-03-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140149482","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}

引用次数: 0

Mapping of morainic complexes and reconstruction of glacier dynamics north-east of Cook Ice Cap, Kerguelen Archipelago (49°S) 绘制凯尔盖朗群岛（南纬 49 度）库克冰帽东北部冰碛复合体地图并重建冰川动力学

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2024-02-26 DOI: 10.1017/s0954102023000378

Philip Deline, Henriette Linge, Ludovic Ravanel, Talin Tuestad, Romain Lafite, Fabien Arnaud, Jostein Bakke

{"title":"Mapping of morainic complexes and reconstruction of glacier dynamics north-east of Cook Ice Cap, Kerguelen Archipelago (49°S)","authors":"Philip Deline, Henriette Linge, Ludovic Ravanel, Talin Tuestad, Romain Lafite, Fabien Arnaud, Jostein Bakke","doi":"10.1017/s0954102023000378","DOIUrl":"https://doi.org/10.1017/s0954102023000378","url":null,"abstract":"Due to the limited landmasses in the Southern Hemisphere, we must rely on data from sub-Antarctic islands within the Southern Ocean to record historical climate patterns. Over the past few decades, glaciers throughout the Southern Ocean region have experienced a noticeable retreat, especially in the Kerguelen Archipelago, whose glacial landforms offer valuable insights into long-term climate fluctuations. Our comprehensive glacial geomorphological study conducted in its remote north-western region meticulously examines morainic complexes from smaller cirque glaciers and larger outlet glaciers stemming from the Cook Ice Cap. We mapped these landforms to reconstruct historical glacier extents during the Holocene. The surface area of the three main glaciers had decreased in 1962–1964 by only 35% compared to their maximum extents, whereas surface area changes across 12 time intervals spanning from 1962 to 2019 from aerial and satellite imagery reveal a cumulative reduction of 43.5%. Additionally, we modelled changes in glacier thickness and equilibrium-line altitude for the key glaciers at three distinct stages: 1) their maximum extent before 1962, 2) the early 1960s and 3) 2019. This multifaceted analysis contributes valuable insights into the dynamics of Kerguelen's glaciers and the broader implications for understanding past and ongoing climate dynamics in the Southern Hemisphere.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"15 1","pages":""},"PeriodicalIF":1.6,"publicationDate":"2024-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139968874","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}

引用次数: 0