Antarctic Science最新文献_第10页

Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica 南极洲麦克默多干谷与高相对湿度事件相关的幕式盆地尺度土壤水分异常

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-08-24 DOI: 10.1017/S0954102021000341

J. Levy

{"title":"Episodic basin-scale soil moisture anomalies associated with high relative humidity events in the McMurdo Dry Valleys, Antarctica","authors":"J. Levy","doi":"10.1017/S0954102021000341","DOIUrl":"https://doi.org/10.1017/S0954102021000341","url":null,"abstract":"Abstract Outside of hydrologically wetted active layer soils and humidity-sensitive soil brines, low soil moisture is a limiting factor controlling biogeochemical processes in the McMurdo Dry Valleys. But anecdotal field observations suggest that episodic wetting and darkening of surface soils in the absence of snowmelt occurs during high humidity conditions. Here, I analyse long-term meteorological station data to determine whether soil-darkening episodes are present in the instrumental record and whether they are, in fact, correlated with relative humidity. A strong linear correlation is found between relative humidity and soil reflectance at the Lake Bonney long-term autonomous weather station. Soil reflectance is found to decrease annually by a median of 27.7% in response to high humidity conditions. This magnitude of darkening is consistent with soil moisture rising from typical background values of < 0.5 wt.% to 2–3 wt.%, suggesting that regional atmospheric processes may result in widespread soil moisture generation in otherwise dry surface soils. Temperature and relative humidity conditions under which darkening is observed occur for hundreds of hours per year, but are dominated by episodes occurring between midnight and 07h00 local time, suggesting that wetting events may be common, but are not widely observed during typical diel science operations.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"533 - 547"},"PeriodicalIF":1.6,"publicationDate":"2021-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46741089","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: 5

Lithostratigraphy, age and distribution of Eocene volcanic sequences on eastern King George Island, South Shetland Islands, Antarctica 南极洲南设得兰群岛乔治王岛东部始新世火山层序的岩石地层学、年龄和分布

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-08-01 DOI: 10.1017/S0954102021000213

J. Smellie, R. J. Hunt, W. Mcintosh, R. Esser

{"title":"Lithostratigraphy, age and distribution of Eocene volcanic sequences on eastern King George Island, South Shetland Islands, Antarctica","authors":"J. Smellie, R. J. Hunt, W. Mcintosh, R. Esser","doi":"10.1017/S0954102021000213","DOIUrl":"https://doi.org/10.1017/S0954102021000213","url":null,"abstract":"Abstract New mapping and dating of volcanic outcrops on the east coast of Admiralty Bay, King George Island, has demonstrated that Eocene volcanic sequences are dominant and also crop out extensively elsewhere, particularly on the eastern part of the island. The sequences can be divided into at least three formations (Hennequin, Cape Vauréal and Carruthers Cliff) together with Eocene strata at Warkocz and near Lions Rump that are currently unassigned stratigraphically. New and recently published 40Ar/39Ar ages indicate that all of the formations are Early Eocene in age, mainly Ypresian, extending to Lutetian and possibly even Priabonian time in more easterly outcrops. Compositional contrasts exist between the groups (calc-alkaline vs tholeiitic). The formations are mainly composed of lavas, and many show evidence for contemporary inundation by water. They are interbedded with sedimentary rocks deposited mainly during flooding events as debris flows, debris avalanches, hyperconcentrated flows, from traction currents and in lakes. The common presence of juvenile volcanic detritus suggests that the sediments were probably linked to explosive hydrovolcanic eruptions, some of which were possibly rooted in summit ice caps. Other evidence is also permissive, but the presence of Eocene ice on King George Island is not well established at present.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"373 - 401"},"PeriodicalIF":1.6,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000213","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45187640","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: 8

ANS volume 33 issue 4 Cover and Front matter ANS第33卷第4期封面和封面问题

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-08-01 DOI: 10.1017/s0954102021000365

引用次数: 0

A lithostratigraphical and chronological study of Oligocene-Miocene sequences on eastern King George Island, South Shetland Islands (Antarctica), and correlation of glacial episodes with global isotope events 南设得兰群岛乔治王岛东部渐新世-中新世序列的岩石地层学和年代研究，以及冰川事件与全球同位素事件的相关性

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-07-29 DOI: 10.1017/S095410202100033X

J. Smellie, W. Mcintosh, R. Whittle, A. Troedson, R. J. Hunt

{"title":"A lithostratigraphical and chronological study of Oligocene-Miocene sequences on eastern King George Island, South Shetland Islands (Antarctica), and correlation of glacial episodes with global isotope events","authors":"J. Smellie, W. Mcintosh, R. Whittle, A. Troedson, R. J. Hunt","doi":"10.1017/S095410202100033X","DOIUrl":"https://doi.org/10.1017/S095410202100033X","url":null,"abstract":"Abstract King George Island (South Shetland Islands, Antarctic Peninsula) is renowned for its terrestrial palaeoenvironmental record, which includes evidence for potentially up to four Cenozoic glacial periods. An advantage of the glacigenic outcrops on the island is that they are associated with volcanic formations that can be isotopically dated. As a result of a new mapping and chronological study, it can now be shown that the published stratigraphy and ages of many geological units on eastern King George Island require major revision. The Polonez Glaciation is dated as c. 26.64 ± 1.43 Ma (Late Oligocene (Chattian Stage)) and includes the outcrops previously considered as evidence for an Eocene glacial ('Krakow Glaciation'). It was succeeded by two important volcanic episodes (Boy Point and Cinder Spur formations) formed during a relatively brief interval (< 2 Ma), which also erupted within the Oligocene Chattian Stage. The Melville Glaciation is dated as c. 21–22 Ma (probably 21.8 Ma; Early Miocene (Aquitanian Stage)), and the Legru Glaciation is probably ≤ c. 10 Ma (Late Miocene or younger). As a result of this study, the Polonez and Melville glaciations can now be correlated with increased confidence with the Oi2b and Mi1a isotope zones, respectively, and thus represent major glacial episodes.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"502 - 532"},"PeriodicalIF":1.6,"publicationDate":"2021-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49460295","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: 6

The limnology and spectral behaviour of a freshwater lake at Harmony Point, Nelson Island, Antarctica 南极洲尼尔森岛和谐角的一个淡水湖的湖沼学和光谱行为

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-07-12 DOI: 10.1017/S0954102021000304

C. N. Rosa, W. Pereira Filho, U. F. Bremer, André Medeiros De Andrade, Gisieli Kramer, F. L. Hillebrand, J. Jesus

{"title":"The limnology and spectral behaviour of a freshwater lake at Harmony Point, Nelson Island, Antarctica","authors":"C. N. Rosa, W. Pereira Filho, U. F. Bremer, André Medeiros De Andrade, Gisieli Kramer, F. L. Hillebrand, J. Jesus","doi":"10.1017/S0954102021000304","DOIUrl":"https://doi.org/10.1017/S0954102021000304","url":null,"abstract":"Abstract The present study investigates the effect of limnology on the spectral reflectance of a freshwater lake, located in an ice-free area in the Antarctic Peninsula. Field-collected samples generated limnological and spectral parameters. This fact indicates that the studied lake has an ultra-oligotrophic/oligotrophic nature based on chlorophyll a (chl a), which registered concentrations below 3 μg l-1 with no total suspended solids, almost neutral pH and transparency equalled by depth. The water spectral behaviour in each sampling station indicates that the benthic characteristics of the lake have a strong influence as the reflectance at the 705 nm wavelength being greater than that at 583 nm signals the presence of soil and/or vegetation at its bottom. Hence, it is believed that the orbital sensors with spectral bands focused on regions between the green and red edge, such as the MultiSpectral Instrument (MSI) sensor, may present better results for distinguishing the different bottom types found in the research area.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"479 - 492"},"PeriodicalIF":1.6,"publicationDate":"2021-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46160730","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

Experimental determination of reflectance spectra of Antarctic krill (Euphausia superba) in the Scotia Sea 斯科舍海南极磷虾反射光谱的实验测定

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-07-12 DOI: 10.1017/S0954102021000262

A. Belcher, Sophie Fielding, Andrew Gray, L. Biermann, G. Stowasser, P. Fretwell, Louise Ireland, G. Tarling

{"title":"Experimental determination of reflectance spectra of Antarctic krill (Euphausia superba) in the Scotia Sea","authors":"A. Belcher, Sophie Fielding, Andrew Gray, L. Biermann, G. Stowasser, P. Fretwell, Louise Ireland, G. Tarling","doi":"10.1017/S0954102021000262","DOIUrl":"https://doi.org/10.1017/S0954102021000262","url":null,"abstract":"Abstract Antarctic krill are the dominant metazoan in the Southern Ocean in terms of biomass; however, their wide and patchy distribution means that estimates of their biomass are still uncertain. Most currently employed methods do not sample the upper surface layers, yet historical records indicate that large surface swarms can change the water colour. Ocean colour satellites are able to measure the surface ocean synoptically and should theoretically provide a means for detecting and measuring surface krill swarms. Before we can assess the feasibility of remote detection, more must be known about the reflectance spectra of krill. Here, we measure the reflectance spectral signature of Antarctic krill collected in situ from the Scotia Sea and compare it to that of in situ water. Using a spectroradiometer, we measure a strong absorption feature between 500 and 550 nm, which corresponds to the pigment astaxanthin, and high reflectance in the 600–700 nm range due to the krill's red colouration. We find that the spectra of seawater containing krill is significantly different from seawater only. We conclude that it is tractable to detect high-density swarms of krill remotely using platforms such as optical satellites and unmanned aerial vehicles, and further steps to carry out ground-truthing campaigns are now warranted.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"402 - 414"},"PeriodicalIF":1.6,"publicationDate":"2021-07-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000262","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47203993","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: 1

A bathymetric compilation of the Cape Darnley region, East Antarctica 南极洲东部达恩利角地区的测深图

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-07-09 DOI: 10.1017/S0954102021000298

Jodie Smith, Y. Nogi, M. Spinoccia, B. Dorschel, A. Leventer

{"title":"A bathymetric compilation of the Cape Darnley region, East Antarctica","authors":"Jodie Smith, Y. Nogi, M. Spinoccia, B. Dorschel, A. Leventer","doi":"10.1017/S0954102021000298","DOIUrl":"https://doi.org/10.1017/S0954102021000298","url":null,"abstract":"Abstract The Cape Darnley region in East Antarctica has been an area of scientific interest for a variety of disciplines over the last three decades. The recent acquisition of several high-resolution bathymetry datasets enabled the compilation of a detailed regional bathymetry grid. We present a high-resolution bathymetric compilation of the Cape Darnley region in East Antarctica, including areas of the Mac.Robertson Land shelf, slope and adjacent deep sea. A variety of data, single-beam and multibeam swath bathymetry and digitized depths from nautical charts were sourced from numerous institutions. The 100 m-resolution gridded bathymetric dataset improves previous bathymetric representations of the region and enables visualization of the seafloor morphology in unprecedented detail. The bathymetry grid has been constructed using a layered hierarchy approach based on the source of each dataset. This data compilation forms important baseline information for a range of scientific applications and end users including oceanographers, glacial modellers, biologists and geologists. The compilation will aid numerical modelling of ocean circulation, reconstruction of palaeo-ice streams and refinement of ice-sheet models.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"548 - 559"},"PeriodicalIF":1.6,"publicationDate":"2021-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000298","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42654192","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: 3

Ice-free valleys in the Neptune Range of the Pensacola Mountains, Antarctica: glacial geomorphology, geochronology and potential as palaeoenvironmental archives 南极洲彭萨科拉山脉海王星山脉的无冰山谷:冰川地貌、地质年代学和作为古环境档案的潜力

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-07-05 DOI: 10.1017/S0954102021000237

D. Small, M. J. Bentley, D. Evans, A. Hein, S. Freeman

{"title":"Ice-free valleys in the Neptune Range of the Pensacola Mountains, Antarctica: glacial geomorphology, geochronology and potential as palaeoenvironmental archives","authors":"D. Small, M. J. Bentley, D. Evans, A. Hein, S. Freeman","doi":"10.1017/S0954102021000237","DOIUrl":"https://doi.org/10.1017/S0954102021000237","url":null,"abstract":"Abstract We describe the glacial geomorphology and initial geochronology of two ice-free valley systems within the Neptune Range of the Pensacola Mountains, Antarctica. These valleys are characterized by landforms associated with formerly more expanded ice sheet(s) that were at least 200 m thicker than at present. The most conspicuous features are areas of supraglacial debris, discrete debris accumulations separated from modern-day ice and curvilinear ridges and mounds. The landsystem bears similarities to debris-rich cold-based glacial landsystems described elsewhere in Antarctica and the Arctic where buried ice is prevalent. Geochronological data demonstrate multiple phases of ice expansion. The oldest, occurring > 3 Ma, overtopped much of the landscape. Subsequent, less expansive advances into the valleys occurred > 2 Ma and > ~1 Ma. An expansion of some local glaciers occurred < 250 ka. This sequence of glacial stages is similar to that described from the northernmost massif of the Pensacola Mountains (Dufek Massif), suggesting that it represents a regional signal of ice-sheet evolution over the Plio-Pleistocene. The geomorphological record and its evolution over millions of years makes the Neptune Range valleys an area worthy of future research and we highlight potential avenues for this.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"428 - 455"},"PeriodicalIF":1.6,"publicationDate":"2021-07-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000237","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46477239","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: 1

First de novo transcriptome analysis of the Antarctic springtail Cryptopygus terranovus (Collembola: Isotomidae) following mid-term heat exposure 中期高温暴露后南极跳尾隐锥虫的首次从头转录组分析

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-06-08 DOI: 10.1017/S0954102021000195

Claudio Cucini, Chiara Leo, F. Nardi, Samuele Greco, C. Manfrin, P. Giulianini, A. Carapelli

{"title":"First de novo transcriptome analysis of the Antarctic springtail Cryptopygus terranovus (Collembola: Isotomidae) following mid-term heat exposure","authors":"Claudio Cucini, Chiara Leo, F. Nardi, Samuele Greco, C. Manfrin, P. Giulianini, A. Carapelli","doi":"10.1017/S0954102021000195","DOIUrl":"https://doi.org/10.1017/S0954102021000195","url":null,"abstract":"Abstract Global human activities, such as greenhouse emissions and pollution, are promoting global warming, environmental changes and biodiversity reduction. Pristine environments such as those of Antarctica are not immune to these phenomena, as is noticeable from the increasing pace of the temperature shift registered within the continent in recent decades. In this study, we describe the first de novo transcriptome analysis of the endemic Antarctic springtail (= collembolan) Cryptopygus terranovus and we evaluate its global gene expression response following a mid-term exposure of 20 days to 18°C. Expression data are compared with wild specimens sampled from their native environment to outline the molecular mechanisms triggered by the thermal exposure. Although individual plasticity in transcript modulation is assessed, several pathways appear to be differentially modulated in springtails subjected to the heat treatment vs wild specimens. Through enrichment analysis, we show that protein catabolism, fatty acid metabolism and a sexual response characterized by spermatid development are induced, while carbohydrate consumption, lipid catabolism and tissue development are downregulated in treated samples compared to controls.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"459 - 468"},"PeriodicalIF":1.6,"publicationDate":"2021-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000195","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47708115","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: 2

First glaciological investigations at Ridge B, central East Antarctica 南极东部中部山脊B的首次冰川学调查

IF 1.6 4区地球科学

Antarctic Science Pub Date : 2021-06-08 DOI: 10.1017/S0954102021000171

A. Ekaykin, A. Bolshunov, V. Lipenkov, M. Scheinert, L. Eberlein, Evgeniy Brovkov, S. Popov, A. Turkeev

{"title":"First glaciological investigations at Ridge B, central East Antarctica","authors":"A. Ekaykin, A. Bolshunov, V. Lipenkov, M. Scheinert, L. Eberlein, Evgeniy Brovkov, S. Popov, A. Turkeev","doi":"10.1017/S0954102021000171","DOIUrl":"https://doi.org/10.1017/S0954102021000171","url":null,"abstract":"Abstract The region of Ridge B in central East Antarctica is one of the last unexplored parts of the continent and, at the same time, ranks among the most promising places to search for Earth's oldest ice. In January 2020, we carried out the first scientific traverse from Russia's Vostok Station to the topographical dome of Ridge B (Dome B, 3807 m above sea level, 79.02°S, 93.69°E). The glaciological programme included continuous snow-radar profiling and geodetic positioning along the traverse's route, installation of snow stakes, measurements of snow density, collection of samples for stable water isotope and chemical analyses and drilling of a 20 m firn core. The first results of the traverse show that the surface mass balance at Dome B (2.28 g cm−2 year−1) is among the lowest in Antarctica. The firn temperature below the layer of annual variations is −58.1 ± 0.2°C. A very low value of heavy water stable isotope content (-58.2‰ for oxygen-18) was discovered at a distance of 170 km from Vostok Station. This work is the first step towards a comprehensive reconnaissance study of the Ridge B area aimed at locating the best site for future deep drilling for the oldest Antarctic ice.","PeriodicalId":50972,"journal":{"name":"Antarctic Science","volume":"33 1","pages":"418 - 427"},"PeriodicalIF":1.6,"publicationDate":"2021-06-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.1017/S0954102021000171","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47320063","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: 3