Antarctica

南极洲
  • 文章类型: Journal Article
    在南极洲,沿海可以找到无冰区,在山峰上,在麦克默多干燥的山谷里,适应恶劣条件的微生物可以存活和繁殖。代谢分析可以揭示两个沿海地点的南极土壤群落的生存机制,在不同的植物覆盖阶段,以及生长缓慢或休眠的微生物的内部部位,水资源利用率低,盐分积累,有限数量的初级生产者使代谢组学分析变得困难。这里,我们报告,第一次,基于NMR光谱和质谱(MS)的组合,用于南极土壤的提取和代谢谱分析的有效协议。这种方法是建立在维多利亚土地不同地区收获的样品上,在南极洲大陆,没有不同发育的生物结皮或被不同发育的生物结皮覆盖。NMR允许鉴定30种代谢物(主要是糖,氨基酸,和有机酸)以及其中二十多个的定量。UPLC-MS分析鉴定出二十多种其他代谢物,特别是类黄酮,中链和长链脂肪酸,苯甲酸衍生物,蒽,和醌。我们的结果强调了两种分析技术的互补性。此外,我们证明了它们的组合使用代表了对很少探索的样本进行定性和定量分析的“黄金标准”,比如从南极土壤中收集的。
    In Antarctica, ice-free areas can be found along the coast, on mountain peaks, and in the McMurdo Dry Valleys, where microorganisms well-adapted to harsh conditions can survive and reproduce. Metabolic analyses can shed light on the survival mechanisms of Antarctic soil communities from both coastal sites, under different plant coverage stages, and inner sites where slow-growing or dormant microorganisms, low water availability, salt accumulation, and a limited number of primary producers make metabolomic profiling difficult. Here, we report, for the first time, an efficient protocol for the extraction and the metabolic profiling of Antarctic soils based on the combination of NMR spectroscopy and mass spectrometry (MS). This approach was set up on samples harvested along different localities of Victoria Land, in continental Antarctica, devoid of or covered by differently developed biological crusts. NMR allowed for the identification of thirty metabolites (mainly sugars, amino acids, and organic acids) and the quantification of just over twenty of them. UPLC-MS analysis identified more than twenty other metabolites, in particular flavonoids, medium- and long-chain fatty acids, benzoic acid derivatives, anthracenes, and quinones. Our results highlighted the complementarity of the two analytical techniques. Moreover, we demonstrated that their combined use represents the \"gold standard\" for the qualitative and quantitative analysis of little-explored samples, such as those collected from Antarctic soils.
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  • 文章类型: Journal Article
    在确定的时间点收集的XV冬季在Concordia基地(南极考察)的八名参与者的血清样本,包括出发前,构成了特定代谢组学研究的关键底物。为了确定对缺氧的急性变化和慢性适应,使用核磁共振波谱分析血清样品的代谢谱,主成分分析(PCA),然后使用偏最小二乘和正交偏最小二乘判别分析(PLS-DA和OPLS-DA)作为监督分类方法。多变量数据分析清楚地突出了以循环谷氨酰胺和脂质水平增加为特征的适应期。动员来供应身体能量需求。同时,谷氨酸和N-乙酰糖蛋白的循环水平降低,应力状态指标,在核磁共振数据调查中也发现了促炎标志物。随后的通路分析显示代谢过程中可能存在扰动,可能与生理适应有关,主要通过比较基线发现(在海平面,在任务开始之前),基地的到来,和任务结束收集的价值。
    Serum samples from eight participants during the XV winter-over at Concordia base (Antarctic expedition) collected at defined time points, including predeparture, constituted the key substrates for a specific metabolomics study. To ascertain acute changes and chronic adaptation to hypoxia, the metabolic profiles of the serum samples were analyzed using NMR spectroscopy, with principal components analysis (PCA) followed by partial least squares and orthogonal partial least squares discriminant analyses (PLS-DA and OPLS-DA) used as supervised classification methods. Multivariate data analyses clearly highlighted an adaptation period characterized by an increase in the levels of circulating glutamine and lipids, mobilized to supply the body energy needs. At the same time, a reduction in the circulating levels of glutamate and N-acetyl glycoproteins, stress condition indicators, and proinflammatory markers were also found in the NMR data investigation. Subsequent pathway analysis showed possible perturbations in metabolic processes, potentially related to the physiological adaptation, predominantly found by comparing the baseline (at sea level, before mission onset), the base arrival, and the mission ending collected values.
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  • 文章类型: Journal Article
    Variations in the reproductive and survival abilities of individuals within a population are ubiquitous in nature, key to individual fitness, and affect population dynamics, which leads to strong interest in understanding causes and consequences of vital-rate variation. For long-lived species, long-term studies of large samples of known-age individuals are ideal for evaluating vital-rate variation. A population of Weddell seals in Erebus Bay, Antarctica, has been studied each Austral spring since the 1960s. Since 1982, all newborns have been tagged each year and multiple capture-mark-recapture (CMR) surveys have been conducted annually. Over the past 20 years, a series of analyses have built on results of earlier research by taking advantage of steady improvements in the project\'s long-term CMR data and available analytical methods. Here, I summarize progress made on four major topics related to variation in age-specific vital rates for females: early-life survival and age at first reproduction, costs of reproduction, demographic buffering, and demographic senescence. Multistate modelling found that age at first reproduction varies widely (4-14 years of age) and identified contrasting influences of maternal age on survival and recruitment rates of offspring. Subsequent analyses of data for females after recruitment revealed costs of reproduction to both survival and future reproduction and provided strong evidence of demographic buffering. Recent results indicated that important levels of among-individual variation exist in vital rates and revealed contrasting patterns for senescence in reproduction and survival. Sources of variation in vital rates include age, reproductive state, year, and individual. The combination of luck and individual quality results in strong variation in individual fitness outcomes: ~80% of females born in the population produce no offspring, and the remaining 20% vary strongly in lifetime reproductive output (range: 1-23 pups). Further research is needed to identify the specific environmental conditions that lead to annual variation in vital rates and to better understand the origins of individual heterogeneity. Work is also needed to better quantify the relative roles of luck, maternal effects, and environmental conditions on variation in vital rates and to learn the importance of such variation to demographic performance of offspring and on overall population dynamics.
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  • 文章类型: Journal Article
    Diesel acts as a main energy source to complement human activities in Antarctica. However, the increased expedition in Antarctica has threatened the environment as well as its living organisms. While more efforts on the use of renewable energy are being done, most activities in Antarctica still depend heavily on the use of diesel. Diesel contaminants in their natural state are known to be persistent, complex and toxic. The low temperature in Antarctica worsens these issues, making pollutants more significantly toxic to their environment and indigenous organisms. A bibliometric analysis had demonstrated a gradual increase in the number of studies on the microbial hydrocarbon remediation in Antarctica over the year. It was also found that these studies were dominated by those that used bacteria as remediating agents, whereas very little focus was given on fungi and microalgae. This review presents a summary of the collective and past understanding to the current findings of Antarctic microbial enzymatic degradation of hydrocarbons as well as its genotypic adaptation to the extreme low temperature.
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  • 文章类型: Journal Article
    高分辨率XRF扫描记录了亚南极冰缘湖的年际古生物学变化,在乔治王岛百年冰川撤退的过程中,南极洲。从元素的综合分析中推断了两个主要的古环境阶段,分子和同位素生物标志物,边界或过渡集约为3200yrBP。第一阶段的特点是异源有机物含量相对较低,降低生产率和氮水平。这种古环境条件被解释为受冰缘影响的陆地系统,材料流入与融水排放的侵蚀过程有关,因为靠近柯林斯冰川冰盖.在全新世主要冰川提前期大约3500年BP之后,冰盖撤退导致了乌拉圭湖的形成,这涉及导致冰冰冰沉积的填充过程,冰原融水通道,和陆地冰川旁边的湖泊。在第二阶段,随着当前暖期的开始,在1900CE之前,层状沉积物中Zr/Rb比率的稳定记录了湖相沉积系统的起源,随着沉降速率和生物量含量(总氮和有机碳)的增加。时间序列分析显示,湖泊显示出与厄尔尼诺南方涛动(ENSO)有关的变化周期,正如晶粒尺寸的高分辨率沉积学代理所反映的那样,风化,来自分水岭的外来投入,生物量和生产力的增加,和氧化还原条件的变化,所有这些都显示出相似的振荡周期,从2年到6年。在这个冰周衰退和相关的富营养化过程中,从初步选定的古代DNA分析中推断,我们发现细菌特异性丰富度和多样性都出现了惊人的损失。因此,导致冰川枯竭的南极变暖情景似乎对亚南极微生物网产生了恶化的后果。
    High resolution XRF scanning documented inter-annual paleolimnological changes of a Subantarctic periglacial lake, during a process of centennial glacier retreat in King George Island, Antarctica. Two major paleoenvironmental stages were inferred from the combined analysis of elemental, molecular and isotopic biomarkers, with a boundary or transition set at about 3200 yr BP. The first stage was characterized by a relatively low allochthonous organic content, reduced productivity and nitrogen levels. Such paleoenvironmental conditions are interpreted as a terrestrial system under periglacial influence, where material influx was related to erosion process from the melt water discharge, because of the proximity to the Collins Glacier ice cap. After the major Holocene glacier advance dated at about 3500 yr BP, the ice cap retreat led to the formation of Lake Uruguay, which involved in filling processes leading to moraine deposits, proglacial meltwater channels, and lakes next to the land glacier. During the second stage, with the onset of the Current Warm Period, prior to 1900 CE the stabilization of the Zr/Rb ratio within the laminated sediments documented the origin of the lacustrine sedimentation system, with subsequent increases in the sedimentation rate and biomass content (total nitrogen and organic carbon). Time series analyses revealed that the lake displayed variability cycles related to El Niño Southern Oscillation (ENSO), as reflected by high resolution sedimentological proxies for grain size, weathering, allochthonous inputs from the watershed, increase of biomass and productivity, and changes in redox conditions, all of which displayed similar oscillation cycles from 2 to 6 yr. During this periglacial recession and associated eutrophication process, we detected a striking loss in both bacterial specific richness and diversity as inferred from preliminary selected ancient DNA analyses. Thus, the Antarctic warming scenario leading to glacier depletion appears to exert deterioration consequences on the Subantarctic microbial web.
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  • 文章类型: Journal Article
    干扰是大多数自然环境中的关键因素,全球,扰动机制正在改变,在人为影响增加的驱动下,包括气候变化。有,然而,仍然缺乏对干扰如何与物种扩散能力相互作用以形成海洋组合结构的理解。我们通过对比两个具有不同扩散能力的群体的响应,研究了冰冲刷扰动历史(2009-2016年)对南极半岛西部高度扰动地区近岸海底的影响:一个群体由高扩散物种组成(与上层幼虫一起移动)和一种低扩散物种(与底栖幼虫无柄)。构建了分段结构方程模型来检验潜在机制的多因素预测,基于两组对干扰的假设反应。至少有两个或三个干扰因素,作用于不同的空间尺度,驱动组合组成。高分散和低分散模型之间的比较表明,这些机制是分散依赖性的。扰动不应视为单一度量,但是应该考虑到分类群的扩散和干扰遗留,将远程和直接的干扰事件纳入其中。这些建模方法可以提供对扰动形状如何在其他扰动状态下组合的见解,如易发生火灾的森林和拖网渔业。
    Disturbance is a key factor in most natural environments and, globally, disturbance regimes are changing, driven by increased anthropogenic influences, including climate change. There is, however, still a lack of understanding about how disturbance interacts with species dispersal capacity to shape marine assemblage structure. We examined the impact of ice scour disturbance history (2009-2016) on the nearshore seafloor in a highly disturbed region of the Western Antarctic Peninsula by contrasting the response of two groups with different dispersal capacities: one consisting of high-dispersal species (mobile with pelagic larvae) and one of low-dispersal species (sessile with benthic larvae). Piecewise Structural Equation Models were constructed to test multi-factorial predictions of the underlying mechanisms, based on hypothesised responses to disturbance for the two groups. At least two or three disturbance factors, acting at different spatial scales, drove assemblage composition. A comparison between both high- and low-dispersal models demonstrated that these mechanisms are dispersal dependent. Disturbance should not be treated as a single metric, but should incorporate remote and direct disturbance events with consideration of taxa-dispersal and disturbance legacy. These modelling approaches can provide insights into how disturbance shapes assemblages in other disturbance regimes, such as fire-prone forests and trawl fisheries.
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  • 文章类型: Journal Article
    Pollution threats Antarctica and scientists blame xenobiotics and anthropic activities. Yet little is known about their effect on Antarctic ichthyofauna. Accordingly, we investigated the endocrine system of male fish Notothenia rossii and N. coriiceps (Perciformes, Nototheniidae) collected during Austral summer. For N. rossii, hormone levels of estradiol, testosterone, and 11-ketotestosterone were higher in fish collected during March than those of January; whereas for N. coriiceps estradiol and androgens levels were higher and lower in March, respectively. Histological analysis of the testes showed an unrestricted lobular type with no pathological alterations. However, detection of vitellogenin-like in plasma and skin mucus were seen in 75% of N. coriiceps males and 7% of N. rossii males. This is the first report of mucus vitellogenin-like detection as a non-invasive biomarker of endocrine disruption in notothenioid males and settles a baseline for future studies of reproductive biology and endocrine disruption in Antarctic fishes.
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  • 文章类型: Journal Article
    背景:pallenopsispatagonica(Hoek,1881)是一种形态和遗传可变的海蜘蛛物种,其分类学分类具有挑战性。目前,它被认为是一个物种复合体,包括几个遗传谱系,其中许多尚未被正式描述为物种。该物种群的成员出现在巴塔哥尼亚和南极大陆架以及南极亚岛屿周围。这些栖息地受到历史大规模冰川的强烈影响,先前的研究表明,在冰川最大时期,社区仅限于很少的避难所。因此,这些独立避难所中的同种异体物种形成被认为是导致高纬度南半球海洋底栖类群生物多样性高的常见机制。然而,其他机制,如生态物种形成很少被考虑或测试。因此,我们进行了综合形态和遗传研究巴塔哥尼察物种复合体,以i)解决物种多样性使用目标杂交富集方法,以获得多个基因组标记,ii)找到形态特征并分析形态测量以区分物种,和iii)研究导致物种复合体内多个谱系的物种形成过程。
    结果:系统基因组结果支持巴氏疟原虫物种复合体中大多数先前报道的谱系,形态学数据表明,几个谱系是具有诊断特征的不同物种。提出了两个谱系作为新物种,P.aulaeturcarumsp.11月。Dömel&Melzer,2019年和P。11月。Dömel,2019年,分别。然而,并非所有谱系都可以在形态上区分,因此可能代表只能用遗传工具鉴定的隐秘物种。Further,135次测量的形态计量学数据显示,物种内部和物种之间存在很大的变异性,而没有明显的自适应性差异支持。
    结论:我们使用目标杂交富集方法为巴塔哥尼卡海蜘蛛物种复合体的成员生成了前所未有的分子数据集,我们结合广泛的形态学和形态学分析来研究分类学,该组的系统发育和生物地理学。广泛的数据集使我们能够划定物种边界,在此基础上,我们正式描述了两个新物种。没有发现阳性选择的一致证据,在同种冰川避难所中呈现物种形成,作为最有可能的物种形成模型。
    BACKGROUND: Pallenopsis patagonica (Hoek, 1881) is a morphologically and genetically variable sea spider species whose taxonomic classification is challenging. Currently, it is considered as a species complex including several genetic lineages, many of which have not been formally described as species. Members of this species complex occur on the Patagonian and Antarctic continental shelves as well as around sub-Antarctic islands. These habitats have been strongly influenced by historical large-scale glaciations and previous studies suggested that communities were limited to very few refugia during glacial maxima. Therefore, allopatric speciation in these independent refugia is regarded as a common mechanism leading to high biodiversity of marine benthic taxa in the high-latitude Southern Hemisphere. However, other mechanisms such as ecological speciation have rarely been considered or tested. Therefore, we conducted an integrative morphological and genetic study on the P. patagonica species complex to i) resolve species diversity using a target hybrid enrichment approach to obtain multiple genomic markers, ii) find morphological characters and analyze morphometric measurements to distinguish species, and iii) investigate the speciation processes that led to multiple lineages within the species complex.
    RESULTS: Phylogenomic results support most of the previously reported lineages within the P. patagonica species complex and morphological data show that several lineages are distinct species with diagnostic characters. Two lineages are proposed as new species, P. aulaeturcarum sp. nov. Dömel & Melzer, 2019 and P. obstaculumsuperavit sp. nov. Dömel, 2019, respectively. However, not all lineages could be distinguished morphologically and thus likely represent cryptic species that can only be identified with genetic tools. Further, morphometric data of 135 measurements showed a high amount of variability within and between species without clear support of adaptive divergence in sympatry.
    CONCLUSIONS: We generated an unprecedented molecular data set for members of the P. patagonica sea spider species complex with a target hybrid enrichment approach, which we combined with extensive morphological and morphometric analyses to investigate the taxonomy, phylogeny and biogeography of this group. The extensive data set enabled us to delineate species boundaries, on the basis of which we formally described two new species. No consistent evidence for positive selection was found, rendering speciation in allopatric glacial refugia as the most likely model of speciation.
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  • 文章类型: Journal Article
    This article presents a review of information related to the influence of potential permafrost degradation on the environmental fate of chemical species which are released and stored, classified as potential influence in future Antarctic environment. Considering all data regarding climate change prediction, this topic may prove important issue for the future state of the Antarctic environment. A detailed survey on soil and permafrost data permitted the assumption that this medium may constitute a sink for organic and inorganic pollution (especially for persistent organic pollution, POPs, and heavy metals). The analysis of the environmental fate and potential consequences of the presence of pollutants for the existence of the Antarctic fauna leads to a conclusion that they may cause numerous negative effects (e.g. Endocrine disruptions, DNA damage, cancerogenicity). In the case of temperature increase and enhanced remobilisation processes, this effect may be even stronger, and may disturb natural balance in the environment. Therefore, regular research on the environmental fate of pollution is required, especially in terms of processes of remobilisation from the permafrost reserves.
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  • 文章类型: Journal Article
    南极洲是科学探索的标志性区域,因为它偏远,是全球气候系统的重要组成部分。最近的气候变化导致南极洲的冰急剧减少,并对其沿海生态系统产生影响。这些人为影响有可能增加南极潮间带组合的栖息地可用性。评估这些变化的程度和生态后果需要我们开发准确的生物基线和定量预测工具。在这项研究中,我们证明了基于卫星的遥感,当与原位地面实况和机器学习算法结合使用时,提供了一个强大的工具来预测潮间带大型藻类的覆盖率和丰富度。显着的发现是,基于Sentinel的遥感描述了南极大型藻类的覆盖率和丰富度的显着变化。性能最高的模型是巨藻丰富度和绿藻覆盖率,而不是棕色和红色藻类覆盖率模型。当扩大地面真相的地理范围时,甚至只涉及几个样本点,有可能绘制其他南极潮间带大型藻类栖息地并监测其动态。这是一个重要的里程碑,因为后勤限制是南极探险不可或缺的一部分。该方法在其他偏远沿海地区也具有潜力,在这些地区无法进行广泛的原位制图。
    Antarctica is an iconic region for scientific explorations as it is remote and a critical component of the global climate system. Recent climate change causes a dramatic retreat of ice in Antarctica with associated impacts to its coastal ecosystem. These anthropogenic impacts have a potential to increase habitat availability for Antarctic intertidal assemblages. Assessing the extent and ecological consequences of these changes requires us to develop accurate biotic baselines and quantitative predictive tools. In this study, we demonstrated that satellite-based remote sensing, when used jointly with in situ ground-truthing and machine learning algorithms, provides a powerful tool to predict the cover and richness of intertidal macroalgae. The salient finding was that the Sentinel-based remote sensing described a significant proportion of variability in the cover and richness of Antarctic macroalgae. The highest performing models were for macroalgal richness and the cover of green algae as opposed to the model of brown and red algal cover. When expanding the geographical range of the ground-truthing, even involving only a few sample points, it becomes possible to potentially map other Antarctic intertidal macroalgal habitats and monitor their dynamics. This is a significant milestone as logistical constraints are an integral part of the Antarctic expeditions. The method has also a potential in other remote coastal areas where extensive in situ mapping is not feasible.
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