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The 1821 eruption of Bridgeman Island, South Shetland Islands, Antarctica: an observed Capelinhos-style hydrovolcanic event 1821年南极南设得兰群岛布里奇曼岛火山爆发:一次观测到的Capelinhos型水火山事件
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-07-12 DOI: 10.1017/s0954102023000111
J. Smellie, S. Kraus, K. Williams
The first recorded volcanic eruption in Antarctica occurred on Bridgeman Island (South Shetland Islands) in early 1821, < 2 years after Antarctica was discovered. However, the observations were disputed owing to a lack of physical evidence. A consensus arose that they probably referred to Penguin Island, a young volcano with a well-formed volcanic cone situated just 60 km to the west. However, a recent re-examination of the historical reports demonstrated that the event was undoubtedly located at Bridgeman Island. Our new study demonstrates that the eruption was explosive and lasted throughout 1821. The vent was situated in the sea ~500 m to the west of Bridgeman Island and the eruption was hydrovolcanic (Surtseyan). The new volcano constructed a tuff ring composed of unconsolidated lapilli and ash, which rapidly coalesced with nearby Bridgeman Island, similar to how the Capelinhos volcano joined with neighbouring Faial (Azores) in 1957–1958. The tuff ring had a very low profile and was rapidly removed by marine erosion. However, fumarolic activity persisted for a few decades. Because the eruption is only 200 years old, the underlying volcanic construct (Bridgeman Rise) should be regarded as dormant rather than extinct.
1821年初,南极洲首次有记录的火山喷发发生在布里奇曼岛(南设得兰群岛),距离南极洲被发现不到2年。然而,由于缺乏实物证据,这些意见存在争议。人们一致认为,他们可能指的是企鹅岛,这是一座年轻的火山,西面60公里处有一个形成良好的火山锥。然而,最近对历史报道的重新审查表明,该事件无疑发生在布里奇曼岛。我们的新研究表明,这次喷发具有爆炸性,并持续了整个1821年。该火山口位于布里奇曼岛以西约500米的海域,火山喷发为水火山喷发(Surtseyan)。新火山建造了一个由松散的火山灰和火山灰组成的凝灰岩环,这些凝灰岩环与附近的布里奇曼岛迅速融合,类似于1957年至1958年卡佩利尼奥斯火山与邻近的法亚尔(亚速尔群岛)的结合。凝灰岩环的剖面非常低,并被海洋侵蚀迅速清除。然而,延胡索酸活性持续了几十年。因为这次火山喷发只有200年的历史,所以下面的火山构造(布里奇曼隆起)应该被视为休眠而不是灭绝。
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引用次数: 1
Prioritization of alien plant targets for biological control in South Africa's offshore sub-Antarctic islands 南非近海亚南极岛屿生物控制外来植物目标的优先次序
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-07-12 DOI: 10.1017/s0954102023000135
K. Canavan, I. Paterson
Invasive alien plants (IAPs) are a significant threat to the biodiversity and ecological functioning of the sub-Antarctic Prince Edward Islands (PEIs); however, weed biological control has not yet been implemented as a management tool. The PEIs have had 23 alien plants recorded, of which several are considered beyond eradication and therefore could benefit from the release of safe and effective biocontrol agents. We used the South African Biological Control Target Selection (BCTS) system to provide a ranked list of the target species in order of priority for further biocontrol research. The highest-scoring species, and therefore those that should be considered first to be targeted, were Sagina procumbens and Cerastium fontanum. No biocontrol agents for IAPs have been released in any climate with as consistent low temperatures as in the PEIs, so the climatic compatibility of agents will be essential prior to any decision to release. However, with very few native species present on the PEIs, the programmes would involve limited host specificity testing, which would improve the feasibility and speed with which new biocontrol agents could be developed. Biocontrol may offer an environmentally safe and sustainable method of reducing the negative impacts of these priority species and thus warrants further investigation.
外来入侵植物对亚南极爱德华王子群岛的生物多样性和生态功能构成重大威胁;然而,杂草生物防治尚未作为一种管理工具得到实施。PEI记录了23种外来植物,其中一些被认为是无法根除的,因此可以从安全有效的生物防治剂的释放中受益。我们使用南非生物控制目标选择(BCTS)系统,按照优先顺序提供了目标物种的排名列表,以供进一步的生物控制研究。得分最高的物种,也就是那些应该首先被视为目标的物种,是前伞骨和方角角Cerastium fontanum。IAP的生物控制剂在任何气候下都没有像PEI中那样持续低温释放,因此在决定释放之前,制剂的气候兼容性至关重要。然而,由于PEI上的本土物种非常少,这些计划将涉及有限的宿主特异性测试,这将提高开发新生物防治剂的可行性和速度。生物防治可以提供一种环境安全和可持续的方法来减少这些优先物种的负面影响,因此值得进一步研究。
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引用次数: 0
Unravelling the complex sub-ice geology of the Wilkes Subglacial Basin region of East Antarctica from marine sediment provenance analyses 从海洋沉积物物源分析揭示南极洲东部威尔克斯冰下盆地复杂的冰下地质
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-06-01 DOI: 10.1017/S0954102023000123
M. Pandey, N. Pant, Devsamridhi Arora, F. Ferraccioli, Rashmi Gupta, S. Joshi
Abstract Deciphering the sub-ice geology in the Wilkes Subglacial Basin region is important for understanding solid earth-ice sheet evolution and for assessing geological ties between East Antarctica and formerly contiguous Australia. We analyse marine sediment samples derived from drill site U1359 of Integrated Oceanic Drilling Program Expedition 318. Our study reports for the first time that the inland sediment source area comprises a complex mafic igneous terrain and a metamorphosed Precambrian subglacial basement. Pyroxene geochemical analyses confirm the presence of tholeiitic to calc-alkaline basalts. The high-grade part of the subglacial terrain contains upper amphibolite to granulite facies rocks that are comparable to Archaean to Palaeoproterozoic rocks exposed in the Terre Adélie Craton and the formerly adjacent Gawler Craton in Australia. Chemical Th-U-total Pb isochron method (CHIME) ages extracted from a subhedral monazite grain associated with the low-grade biotite-muscovite schist rock fragment provide a unimodal age of 799 ± 13 Ma. Rare occurrences of 800 Ma age in the Terre Adélie Craton and/or George V Coast provide evidence for the presence of at least one late Neoproterozoic magmato-metamorphic event in the interior of Wilkes Land. The affinity of the unexposed geological domains of Wilkes Land, East Antarctica, with their Australian counterparts is discussed in the context of the Rodinia supercontinent.
破译威尔克斯冰下盆地地区的冰下地质对于理解固体地球冰盖演化以及评估东南极洲与以前毗邻的澳大利亚之间的地质联系具有重要意义。我们分析了来自综合海洋钻探计划远征318的U1359钻探点的海洋沉积物样本。我们的研究首次报道了内陆沉积物源区由一个复杂的基性火成岩地形和一个变质的前寒武纪冰下基底组成。辉石地球化学分析证实了拉斑岩到钙碱性玄武岩的存在。冰下地形的高等级部分包含上部角闪岩至麻粒岩相岩,与澳大利亚Terre ad克拉通和以前相邻的Gawler克拉通中暴露的太古宙至古元古代岩石相当。化学Th-U-total Pb等时线法(CHIME)测定了与低品位黑云母-白云母片岩碎片相关的半面体单脱石颗粒的年龄,得到了799±13 Ma的单峰年龄。在Terre ad克拉通和/或乔治五世海岸罕见出现的800 Ma岩浆,为威尔克斯大陆内部至少存在一次晚新元古代岩浆变质事件提供了证据。在罗丁尼亚超大陆的背景下,讨论了东南极洲威尔克斯地未暴露的地质域与澳大利亚对应地质域的亲缘关系。
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引用次数: 1
Storytelling, exploration and science at the end of the world 讲故事,探索和科学在世界的尽头
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-06-01 DOI: 10.1017/s0954102023000184
Katharine Hendry, N. Hewit
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引用次数: 0
Suspended particulate organic carbon and its carbon isotopic composition in the surface water around the Antarctic Peninsula during summer 2017–2018 2017-2018年夏季南极半岛周边地表水中悬浮颗粒有机碳及其碳同位素组成
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-05-12 DOI: 10.1017/S0954102023000093
Yunpeng Lin, Y. Li, Yuanhui Huang, Zhihua Chen, Liang Wang, Dong-yi Li, S. Tao
Abstract The concentration of suspended particulate organic carbon (POC) and its carbon isotopic composition (δ13CPOC) were analysed in this study with the aim of exploring the sources and factors influencing levels of POC in the surface water around the Antarctic Peninsula. The scanning electron microscopy results suggest that diatom particles formed the main component of suspended particulate matter, indicating that POC was mainly from in situ primary production. The high concentrations of chlorophyll a and POC in sea water mainly occurred in nearshore and sea-ice edge regions, which might be controlled by nutrient and reactive iron inputs stemming from sea-ice melting. The δ13CPOC in the study area is significantly lower than that in low-latitude waters, with a range of -31.8‰ to -22.8‰ (mean -28.9‰), which was controlled by the high CO2 concentration in the Southern Ocean and might be influenced by phytoplankton growth rates and assemblages. This study helps us to understand material cycling in the Antarctic region under the conditions of global climate change.
摘要本研究分析了南极半岛周围地表水中悬浮颗粒有机碳(POC)的浓度及其碳同位素组成(δ13CPOC),旨在探讨POC的来源和影响POC水平的因素。扫描电子显微镜结果表明,硅藻颗粒是悬浮颗粒物的主要成分,表明POC主要来自原位初级生产。海水中叶绿素a和POC的高浓度主要发生在近岸和海冰边缘区域,这可能受到海冰融化产生的营养和活性铁输入的控制。研究区的δ13CPOC明显低于低纬度水域,范围为-31.8‰至-22.8‰(平均-28.9‰),这是受南大洋高CO2浓度的控制,可能受浮游植物生长速率和组合的影响。这项研究有助于我们了解全球气候变化条件下南极地区的物质循环。
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引用次数: 0
The history of a cluster of large icebergs on leaving the Weddell Sea pack ice and their impact on the ocean 一群大型冰山离开威德尔海浮冰的历史及其对海洋的影响
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-04-24 DOI: 10.1017/S0954102022000517
G. Bigg, R. Marsh
Abstract The life history and oceanic impact of three very large icebergs that escaped together from the Weddell Sea sea ice, near the tip of the Antarctic Peninsula, are traced from March 2014. Despite the initial proximity of these three icebergs, they followed very different trajectories across the South Atlantic until their eventual break-up and melting 1 year later. The largest, giant iceberg, B17a, spent extensive periods grounded near two different islands. The triplet's gradual melting is examined through the impact on the icebergs' dimensions, but also the meltwater's oceanic influence on the local salinity and primary productivity. It is found that there was generally a significant local surface and mixed-layer freshening of a few tenths of a practical salinity unit, up to several hundred kilometres away from the 10–20 km-sized icebergs. In contrast, the chlorophyll impact was highly temporally variable, although it tended to be larger in the summer. Break-up of these large icebergs did not occur until near the end of their life. We also show that modelling the trajectories of individual very large icebergs can be reasonable for up to 2 weeks if the characteristics of the iceberg and the local ocean and atmospheric forcing are well known.
从2014年3月开始,研究人员追踪了从南极半岛尖端附近的威德尔海海冰中一起逃逸的三座超大型冰山的生活史和海洋影响。尽管这三座冰山最初很接近,但它们在南大西洋上的轨迹却截然不同,直到一年后它们最终破裂并融化。最大的巨型冰山B17a在两个不同的岛屿附近搁浅了很长时间。通过对冰山尺寸的影响,以及融水对当地盐度和初级生产力的海洋影响,研究了三重体的逐渐融化。研究发现,在距离10-20公里大小的冰山几百公里的地方,通常有一个显著的局部表面和混合层的盐度单位的十分之一的更新。相比之下,叶绿素的影响在时间上变化很大,尽管它在夏季往往更大。这些巨大的冰山直到它们生命的末期才开始破裂。我们还表明,如果冰山和当地海洋和大气强迫的特征是众所周知的,那么在长达2周的时间内,对单个超大型冰山的轨迹进行建模是合理的。
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引用次数: 1
Revisiting the bipolarity of Roaldia revoluta (Mitt.) P.E.A.S. Câmara & Carv.-Silva (Bryophyta, Pylaisiaceae) 重温罗阿尔迪亚·雷沃卢塔(米特)P.E.A.S.Câmara&Carv的两极性-席尔瓦(苔藓植物门,Pylaiceae)
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-04-04 DOI: 10.1017/S0954102023000044
Paulo Eduardo Aguiar Saraiva Câmara, Micheline Carvalho-Silva, Daiane Valente Valente, Diego Knop Henriques, Eduardo Toledo De Amorim, Wellington Santos Fava, Hans (J.D.) Kruijer, Michael Stech
Abstract The occurrence of species in both polar regions (bipolarity) is a common phenomenon in the Antarctic flora. Considering the high morphological variation in polar regions due to extreme conditions, the use of molecular tools is indispensable for testing whether Arctic and Antarctic populations indeed belong to the same species. However, few phylogeographic studies of bipolar bryophytes have been conducted so far, especially when comparing molecular and morphological variation. Here, we assess the bipolarity and intraspecific variation of Roaldia revoluta, a strictly bipolar species of pleurocarpous mosses. Phylogenetic analyses based on ITS sequences clearly resolve R. revoluta as monophyletic and confirm its bipolar distribution pattern. Low intraspecific molecular variation in the markers ITS/26S and rpl16 was observed, and most specimens from both polar regions belong to a single haplotype, making it difficult to infer the origin and dispersal routes between both polar regions of R. revoluta. Morphometric analysis furthermore suggests that there are no significant morphological differences among populations from both polar regions and that morphological variation is mainly influenced by local environmental conditions. Our data do not unequivocally support the recent separation of the former intraspecific taxon Hypnum revolutum var. dolomiticum at the species level as Roaldia dolomitica.
摘要物种在两极地区的出现(两极性)是南极植物群中的一种常见现象。考虑到极地由于极端条件造成的高度形态变异,使用分子工具对于测试北极和南极种群是否真的属于同一物种是必不可少的。然而,迄今为止,很少对两极苔藓植物进行系统地理学研究,尤其是在比较分子和形态变异时。在这里,我们评估了Roaldia revoluta的双极性和种内变异,Roaldia revoluta是一种严格的双极性胸膜苔藓物种。基于ITS序列的系统发育分析清楚地确定了R.revoluta为单系,并证实了其双极分布模式。在标记ITS/26S和rpl16中观察到低的种内分子变异,并且来自两个极地的大多数标本属于单一的单倍型,这使得很难推断R.revoluta的两个极地之间的起源和传播途径。形态计量学分析进一步表明,来自两极地区的种群之间没有显著的形态差异,形态变异主要受当地环境条件的影响。我们的数据并不明确支持最近在物种水平上将前种内分类单元Hypnum revolutum var.白云石分离为Roaldia白云石。
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引用次数: 0
Prediction of subglacial lake melt source regions from site characteristics 基于场地特征的冰下湖融水源区预测
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-04-01 DOI: 10.1017/S0954102023000032
S. Willcocks, D. Hasterok
Abstract Subglacial melt has important implications for ice-sheet dynamics. Locating and identifying subglacial lakes are expensive and time-consuming, requiring radar surveys or satellite methods. We explore three methods to identify source regions for lakes using seven continent-wide environmental characteristics that are sensitive to or influenced by ice-sheet temperature. A simple comparison of environmental properties at lake locations with their continent-wide distributions suggests a statistical relationship (high Kolmogorov-Smirnov statistic) between stable lake locations and ice thickness and surface temperatures, indicating melting under passive conditions. Active lakes, in contrast, show little correlation with direct thermally influenced parameters, instead exhibiting large statistical differences with horizontal velocity and bedrock elevation. More sophisticated techniques, including principal component analysis (PCA) and machine learning (ML) classification, provide better spatial identification of lake types. Positive PCA scores derived from the environmental characteristics correlate with stable lakes, whereas negative values correspond to active lakes. ML methods can also identify regions where subglacial lake melt sources are probable. While ML provides the most accurate classification maps, the combination of approaches adds deeper knowledge of the primary controls on lake formation and the environmental settings in which they are likely to be found.
冰下融化对冰盖动力学具有重要意义。定位和识别冰下湖泊既昂贵又耗时,需要雷达测量或卫星方法。我们利用七个对冰盖温度敏感或受其影响的全大陆环境特征,探索了三种确定湖泊源区的方法。将湖泊位置的环境特性与其整个大陆的分布进行简单的比较表明,稳定的湖泊位置与冰厚和表面温度之间存在统计关系(高Kolmogorov-Smirnov统计量),表明在被动条件下融化。相比之下,活动湖泊与直接热影响参数的相关性很小,而与水平速度和基岩高程的统计差异很大。更复杂的技术,包括主成分分析(PCA)和机器学习(ML)分类,提供了更好的湖泊类型空间识别。由环境特征得出的正PCA值与稳定湖泊相关,而负值对应于活跃湖泊。ML方法还可以识别可能存在冰下湖融水源的区域。虽然机器学习提供了最准确的分类地图,但这些方法的结合增加了对湖泊形成的主要控制因素和可能发现它们的环境设置的更深入的了解。
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引用次数: 0
Researchers on ice? How the COVID-19 pandemic has impacted Antarctic researchers 研究人员在冰上?新冠肺炎大流行对南极研究人员的影响
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-04-01 DOI: 10.1017/S0954102023000020
D. Liggett, Andrea Herbert, R. Badhe, G. E. Charnley, Kelly P. Hudson, I. Kelman, Won Sang Lee, C. Lorenzo, Pedro Marques-Quinteiro, M. Nash, J. Pickett, Yelena Yermakova
Abstract The COVID-19 pandemic and pandemic-related measures have impacted the lives and work-related activities of Antarctic researchers. To explore these impacts, we designed, piloted and disseminated an online survey in English, Russian, Spanish and Chinese in late 2020 and early 2021. The survey explored how the pandemic affected the productivity of Antarctic researchers, their career prospects and their mental wellbeing. Findings exposed patterns of inequities. For instance, of the 406 unique responses to the survey, women appeared to have been affected more adversely than men, especially in relation to mental health, and early-career researchers were disadvantaged more than their mid- or late-career colleagues. Overall, a third of the research participants reported at least one major negative impact from the pandemic on their mental health. Approximately half of the participants also mentioned that the COVID-19 pandemic had some positive effects, especially in terms of the advantages that working from home brought and opportunities to attend events, network or benefit from training workshops online. We conclude with a series of recommendations for science administrators and policymakers to mitigate the most serious adverse impacts of the pandemic on Antarctic research communities, with implications for other contexts where scientific activities are conducted under extreme circumstances.
新冠肺炎疫情及其相关措施对南极科研人员的生活和工作活动造成了影响。为了探索这些影响,我们在2020年底和2021年初设计、试点和传播了一项在线调查,使用英语、俄语、西班牙语和中文。这项调查探讨了疫情如何影响南极研究人员的生产力、他们的职业前景和心理健康。调查结果揭示了不平等的模式。例如,在调查的406个独特回复中,女性似乎比男性受到更不利的影响,特别是在心理健康方面,早期职业研究人员比他们的中后期同事更处于不利地位。总体而言,三分之一的研究参与者报告说,疫情对他们的心理健康至少产生了一项重大负面影响。大约一半的参与者还提到,COVID-19大流行产生了一些积极影响,特别是在在家工作带来的优势以及参加活动、建立网络或从在线培训研讨会中受益的机会方面。最后,我们向科学管理人员和决策者提出了一系列建议,以减轻这一流行病对南极研究界的最严重不利影响,并对在极端情况下开展科学活动的其他情况产生影响。
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引用次数: 1
The need for increased protection of Antarctica's inland waters 需要加强对南极洲内陆水域的保护
IF 1.6 4区 地球科学 Q2 Earth and Planetary Sciences Pub Date : 2023-04-01 DOI: 10.1017/S0954102022000463
I. Hawes, C. Howard-Williams, Neil Gilbert, K. Hughes, P. Convey, A. Quesada
Abstract Protection of Antarctica's biodiversity and ecosystem values is enshrined in the Protocol on Environmental Protection to the Antarctic Treaty, which provides for the designation of Antarctic Specially Protected Areas (ASPAs) to areas with outstanding values. Concern has been raised that existing ASPAs fail to prioritize areas to maximize the likelihood of ensuring the long-term conservation of Antarctic ecosystems and biodiversity. The absence of systematic and representative protection is particularly acute for inland aquatic ecosystems, which support a disproportionate amount of inland biodiversity. This paper promotes the case for overt inclusion of inland waters as a critical component of a representative protected area framework for Antarctica, thereby addressing their current underrepresentation. We set out a structured approach to enable the selection of representative freshwater systems for inclusion in the ASPA framework that, with modification, could also be applied across other Antarctic habitats. We acknowledge an overall lack of information on the biogeography of inland aquatic diversity and recommend increased use of remote data collection along with classification tools to mitigate this, as well as the need for the consideration of catchment-scale processes. Changes that accompany contemporary and anticipated climate change make the need for the conservation of representative biodiversity increasingly urgent.
摘要保护南极洲的生物多样性和生态系统价值载于《南极条约环境保护议定书》,该议定书规定将南极特别保护区指定为具有突出价值的地区。有人担心,现有的ASPA未能优先考虑区域,以最大限度地确保南极生态系统和生物多样性的长期保护。缺乏系统和有代表性的保护对内陆水生生态系统来说尤其严重,因为它们支持着不成比例的内陆生物多样性。本文提倡将内陆水域作为南极洲代表性保护区框架的关键组成部分,从而解决目前内陆水域代表性不足的问题。我们制定了一种结构化的方法,以选择具有代表性的淡水系统,纳入ASPA框架,经过修改,也可以应用于其他南极栖息地。我们承认总体上缺乏关于内陆水生生物多样性生物地理学的信息,并建议更多地使用远程数据收集和分类工具来缓解这种情况,同时需要考虑集水区规模的过程。伴随着当代和预期的气候变化而来的变化,使保护具有代表性的生物多样性的必要性变得越来越迫切。
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引用次数: 4
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Antarctic Science
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