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Galvão JCM, Ayres Neto A, Vieira R, Simões JC. Elemental and mineralogical characterization of marine sediments and their relationship to sedimentary and oceanographic processes in Central Bransfield Basin. AN ACAD BRAS CIENC 2023; 95:e20230990. [PMID: 38126388 DOI: 10.1590/0001-3765202320230990] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Accepted: 11/18/2023] [Indexed: 12/23/2023] Open
Abstract
This work consists of the sedimentological, mineralogical, and geochemical characterization of eight marine sediment cores collected in the Central Bransfield Basin, along a transect between the South Shetland Islands to the Antarctic Peninsula and its correlation to the sedimentary and oceanographic processes of the area. A chemical characterization based on X-ray fluorescence dispersive spectrometry was implemented to obtain geochemical data of the marine sediment while the minerals were identified by X-ray diffraction. The study allowed to classify the cores into three groups according to their sediment source and chemical and mineralogical characteristics. The joint assessment of the geochemical and mineralogical signature of the sediment has confirmed that the elemental ratios Ti/Ca and Fe/Ca can be applied as proxies in the reconstitution of the terrigenous contribution to the Central Bransfield Basin if we consider the sedimentary contribution of the volcanic edifices present in the region. The Fe/K ratio associated with the Chemical Index of Alteration reinforced an increase in the degree of weathering near South Shetland Island, which is also pointed out by other authors in studies on climate change mainly in the subantarctic islands. The trend of temperature increase implies the importance of monitoring the region.
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Affiliation(s)
- Janayna Cynthia M Galvão
- Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Campus da Praia Vermelha, Boa Viagem, 24210-346 Niterói, RJ, Brazil
| | - Arthur Ayres Neto
- Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Campus da Praia Vermelha, Boa Viagem, 24210-346 Niterói, RJ, Brazil
| | - Rosemary Vieira
- Universidade Federal Fluminense, Av. Gal. Milton Tavares de Souza, s/n, Campus da Praia Vermelha, Boa Viagem, 24210-346 Niterói, RJ, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Av. Bento Gonçalves, 9500, Campus do Vale, Caixa Postal 15001, 91501-970 Porto Alegre, RS, Brazil
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Mendes Júnior CW, Arigony Neto J, Hillebrand FL, Freitas MWDDE, Costi J, Simões JC. Spectral Linear Mixing Model application in passive microwave data to analyze Antarctic surface melting dynamics (1978-2018). AN ACAD BRAS CIENC 2023; 95:e20230732. [PMID: 38126385 DOI: 10.1590/0001-3765202320230732] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2023] [Accepted: 11/10/2023] [Indexed: 12/23/2023] Open
Abstract
Several studies have utilized passive microwave imagery for monitoring snowmelt in Antarctica. However, due to the low spatial resolution of these images (25 km), the quantification of snowmelt is not precise. To enhance the accuracy of these estimations, this study proposed a subpixel analysis approach based on a Spectral Linear Mixing Model. This approach was applied to images obtained from channels 18/19 GHz and 37 GHz, both horizontally and vertically polarized, acquired from the Scanning Multichannel Microwave Radiometer (SMMR), Special Sensor Microwave Imager (SSM/I), and Special Sensor Microwave Imager/Sounder (SSM/IS) instruments, spanning the period 1978-2018. The spatiotemporal analysis of the estimated snowmelt fraction images indicated that the most persistent and intensive melt was observed on the Antarctic Peninsula, particularly on the Larsen, Wilkins, George VI, and Wordie ice shelves. The melting period in the Antarctic Peninsula began in late October, with a peak in early January, and ended in late March. Other regions with persistent and intensive snowmelt were Mary Bird Land and Wilkes Land, followed by Dronning Maud Land, Amery Ice Shelf, Filchner-Ronne Ice Shelf, and Ross Ice Shelf. These snowmelt data are valuable for modeling the impacts of snowmelt on glacial systems, local coastal environments, and sea-level rise.
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Affiliation(s)
- Claudio W Mendes Júnior
- Universidade Federal do Rio Grande do Sul (UFRGS), Departamento de Geodésia, Av. Bento Gonçalves, 9500, 91509-900 Porto Alegre, RS, Brazil
| | - Jorge Arigony Neto
- Universidade Federal do Rio Grande (FURG), Instituto de Oceanografia, Avenida Itália s/n, Km 8, 96201-900 Rio Grande, RS, Brazil
| | - Fernando L Hillebrand
- Instituto Federal de Educacão, Ciência e Tecnologia do Rio Grande do Sul (IFRS), Rodovia RS-239, Km 68, 3505, 95700-000 Rolante, RS, Brazil
| | - Marcos W D DE Freitas
- Universidade Federal do Rio Grande do Sul (UFRGS), Departamento de Geografia, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Juliana Costi
- Universidade Federal do Rio Grande (FURG), Instituto de Oceanografia, Avenida Itália s/n, Km 8, 96201-900 Rio Grande, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul (UFRGS), Departamento de Geografia, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
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Rosa KKDA, Perondi C, Lorenz JL, Auger JD, Cazaroto P, Petsch C, Siqueira RG, Simões JC, Vieira R. Glacier fluctuations and a proglacial evolution in King George Bay (King George Island), Antarctica, since 1980 decade. AN ACAD BRAS CIENC 2023; 95:e20230624. [PMID: 38126381 DOI: 10.1590/0001-3765202320230624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2023] [Accepted: 11/18/2023] [Indexed: 12/23/2023] Open
Abstract
This study aims to investigate the glacier shrinkage and recent proglacial environment in King George Bay, Antarctica, since 1988 in response to climate change. Remote sensing data (SPOT, Sentinel, Landsat and Planet Scope images) were applied to glacial landforms and ice-marginal fluctuations mapping. Annual mean near-surface air temperature reanalysis solutions from ERA-Interim were analyzed. Moraines and glaciofluvial landforms were identified. The Ana Northern Glacier has the highest retreat value (3.64 km) (and area loss of 31%) in response to higher depth in frontal ice-margin and reveal ocean-glacier linkages. The Ana South Glacier changed from a tidewater glacier to land-terminating after 1995, and had an outline minimum elevation variation of 89 meters, a shrinkage of 0.63 km, and a new proglacial subaerial sector. The Ana South Glacier foreland had recessional moraines (probably formed between 1995 and 2022), lagoons, and lakes. There are many flutings in low-relief environments. The 1980-1989, 1990-1999, 2000-2009, 2010-2019 anomaly plots concerning to the 1980-2019 average for atmospheric temperature, are shown to be a driver of the local glacial trends.
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Affiliation(s)
- Kátia K DA Rosa
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Cleiva Perondi
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Júlia L Lorenz
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Jeffrey D Auger
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Pamela Cazaroto
- Universidade de São Paulo, Departamento de Geografia, Av. Professor Lineu Prestes, 338, 05508-000 São Paulo, SP, Brazil
| | - Carina Petsch
- Universidade Federal de Santa Maria, Departamento de Geociências, Av. Roraima, 1000, 97105-900 Santa Maria, RS, Brazil
| | - Rafael G Siqueira
- Universidade Federal de Viçosa, Departamento de Solos, Av. PH Rolfs, s/n, 36570-900 Viçosa, MG, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Rosemary Vieira
- Universidade Federal Fluminense, Departamento de Geografia, Av. Gal. Milton Tavares de Souza, s/n, Campus da Praia Vermelha, Boa Viagem, 24210-346 Niterói, RJ, Brazil
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Portella MBP, Simões JC, Bernardo RT, Ilha JG, Casassa G. Stable-isotope ratios (δ18O and δD) in a firn core from West Antarctica. AN ACAD BRAS CIENC 2023; 95:e20230132. [PMID: 38126378 DOI: 10.1590/0001-3765202320230132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2023] [Accepted: 11/21/2023] [Indexed: 12/23/2023] Open
Abstract
A 22.48 m long ice core (BR-IC-4) was collected in the West Antarctic Ice Sheet (at 83°58'59.4" S, 80°07'01.4" W, 1,295 m above the sea level) during the Austral summer of 2004-2005, as a contribution to the International Trans-Antarctic Expedition program. The isotopic composition (δD and δ18O) of 599 samples, corresponding to the upper 12.98 m of the ice core, was determined by gas source mass spectrometry and cavity ring-down spectroscopy. Relative dating was based on the isotopic ratios and major ions (MS-, Na+, nssSO4 2-) and trace elements (Na, S, Sr) concentrations. The record covers approximately 13 years - from 1990 to 2003. The mean accumulation rate of 0.48 ± 0.09 m water equivalent per year (m eq H2O a1) is relatively high for the geographical area and possibly results from snowdrifting from near areas, as attested by ice glaze surfaces in other sites in the region. The stable isotope δD content varies between -367.90‰ and 256.30‰ (mean -314.42 ± 19.01‰); and δ18O ranges from -44.96‰ to 35.08‰ (mean -39.95 ± 2.05‰). Deuterium excess values (mean 3.70 ± 1.54‰) indicate episodic intense oceanic evaporation and high relative humidity in the moisture sources.
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Affiliation(s)
- Manoela B P Portella
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Climático e Polar, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Climático e Polar, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
- University of Maine, Climate Change Institute, Orono, ME 04469-5790, USA
| | - Ronaldo T Bernardo
- Universidade Federal do Rio Grande do Sul, Centro Climático e Polar, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
| | - João G Ilha
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Climático e Polar, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91540-000 Porto Alegre, RS, Brazil
| | - Gino Casassa
- Universidad de Magallanes, Av. Pdte. Manuel Bulnes 01855, Punta Arenas, Chile
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Fonseca ELDA, Santos ECD, Figueiredo ARDE, Simões JC. The use of sentinel-2 imagery to generate vegetations maps for the Northern Antarctic peninsula and offshore islands. AN ACAD BRAS CIENC 2023; 95:e20230710. [PMID: 38126383 DOI: 10.1590/0001-3765202320230710] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2023] [Accepted: 11/16/2023] [Indexed: 12/23/2023] Open
Abstract
We used Sentinel-2 imagery time series to generate a vegetation map for the Northern part of the Antarctica Peninsula and offshore islands, including the South Shetlands. The vegetation cover was identified in the NDVI maximum value composite image. The NDVI values were associated with the occurrence of algae (0.15 - 0.20), lichens (0.20 - 0.50), and mosses (0.50 - 0.80). The vegetation cover distribution map was validated using the literature information. Generating a vegetation map distribution on an annual basis was not possible due to high cloud cover in the Antarctic region, especially in coastal áreas, so optical images from 2016 to 2021 were necessary to map the vegetation distribution in the entire study área. The final map analyzed in association with the weather data shows the occurrence of a microenvironment over the western islands of the Antarctic Peninsula that provided vegetation growth conditions. The Sentinel-2 images with 10m spatial resolution allow the assembly of accurate vegetation distribution maps for the Antarctica Peninsula and Islands, the Google Earth Engine cloud computing being essential to process a large amount of the satellite images necessary for processing these maps.
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Affiliation(s)
- Eliana L DA Fonseca
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Departament of Geography, Av. Bento Gonçalves, 9500, Bairro Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Edvan C Dos Santos
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Bairro Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Anderson R DE Figueiredo
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Bairro Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Departament of Geography, Av. Bento Gonçalves, 9500, Bairro Agronomia, 91501-970 Porto Alegre, RS, Brazil
- University of Maine, Climate Change Institute, 04469-5790, Orono, ME, USA
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Andrade AMDE, Michel RFM, Bremer UF, Lima Neto EDE, Vieira GBTG, Schaefer CEGR, Simões JC. Thermal variations of the active layer in Fildes Peninsula, King George Island, Maritime Antarctica. AN ACAD BRAS CIENC 2023; 95:e20230181. [PMID: 38126379 DOI: 10.1590/0001-3765202320230181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 11/06/2023] [Indexed: 12/23/2023] Open
Abstract
This work aimed to characterize the variation in the thermal regime of the active layer in a permafrost area on Fildes Peninsula, Antarctica, and relate this variability with meteorological data between 2014 and 2016. The monitoring site was installed to continuously monitor the temperature and moisture of the active layer, radiation flow on the surface, and air temperature. We used data collected to generate the indexes freezing degree-days, thawing degree-days, frost number, n-factor, apparent thermal diffusivity, and active layer thickness. The temperature of the active layer is not homogeneous, varying with depth and position in the transect, with the greatest variations in soil with better drainage and lower moisture content. Among the evaluated factors, air and soil surface temperature are the ones that most influence the thermal gradient of the active layer. We identified that near the surface there is a greater influence of albedo and cloudiness and at -35 cm depth there is a greater influence of net radiation and soil moisture. The average depth of the active layer in 2014 was -44.3 cm and in 2015 -47.7 cm and the frost number index indicates that there was a predominance of continuous permafrost in the transect during the monitoring.
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Affiliation(s)
- André M DE Andrade
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Avenida Universitária, 1000, 38620-870 Unaí, MG, Brazil
| | - Roberto F M Michel
- Universidade Estadual de Santa Cruz, Rodovia Jorge Amado, Km 16, 45662-900 Ilhéus, BA, Brazil
| | - Ulisses Franz Bremer
- Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Elias DE Lima Neto
- Universidade de São Paulo, Avenida Trabalhador São-carlense, 400, 13566-590 São Carlos, SP, Brazil
| | | | | | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
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Simões JC, Alder V, Sayão JM. Forty years of Brazilian Antarctic research: A second volume. AN ACAD BRAS CIENC 2023; 95:e20231270. [PMID: 38088644 DOI: 10.1590/0001-3765202320231270] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2023] [Accepted: 11/18/2023] [Indexed: 12/18/2023] Open
Affiliation(s)
- Jefferson C Simões
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Av. Bento Gonçalves, 9500, 90650-001 Porto Alegre, RS, Brazil
- University of Maine, Climate Change Institute, 04469, Orono, ME, USA
| | - Viviana Alder
- UBA, Facultad de Ciencias Exactas y Naturales, Dpto. de Ecología, Genética y Evolución e Inst. de Ecología, Genética y Evolución de Buenos Aires (UBA-CONICET), Pabellón II, 4° Piso, Lab. Ecología Marina Microbiana, Intendente Güiraldes 2620, Ciudad Universitaria, C1428EHA, Ciudad Autónoma de Buenos Aires, Argentina
- Universidad Nacional de San Martín (UNSAM), Instituto Antártico Argentino, Av. 25 de Mayo 1143, Campus Miguelete, 1650, San Martín, Provincia de Buenos Aires, Argentina
| | - Juliana M Sayão
- Universidade Federal do Rio de Janeiro, Laboratório de Paleobiologia e Paleogeografia Antártica, Museu Nacional, Quinta da Boa Vista, s/n, 29040-040 Rio de Janeiro, RJ, Brazil
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Lorenz JL, Rosa KKDA, Petsch C, Perondi C, Idalino FD, Auger JD, Vieira R, Simões JC. Short-term glacier area changes, glacier geometry dependence, and regional climatic variations forcing, King George Island, Antarctica. AN ACAD BRAS CIENC 2023; 95:e20211627. [PMID: 38055509 DOI: 10.1590/0001-3765202320211627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2021] [Accepted: 09/04/2022] [Indexed: 12/08/2023] Open
Abstract
This study investigates the transient snowline (TSL) altitude for summer 2020, as well as glacial area loss in King George Island Icefields since 1988 using Sentinel-1 and 2 and Landsat Thematic Mapper (TM) imagery. Trends and anomalies in atmospheric temperature, U-wind, and V-wind were examined using ERA5 solutions. Results show the wet-snow zone corresponds to values of ≤ -13dB, and 44.3% of the glacial area is located above the TSL (≥ 300 m). Glacial area for 2020 is 999.95 km², and losses in the period represent 104.9 km² (error <1%) - a retreat of 3.17 km² / year. Glaciers in Keller Peninsula and Bellingshausen Dome lost the most area (28% and 17%, respectively) and did not have a TSL in 2020; followed by Warszawa (15%), Kraków (13%), and Eastern (10%), where the TSL was verified. Percentage area loss values increased with decreases in dimensions, area above TSL, and maximum elevation. Calving glaciers with ice-flow toward deeper and steeper submarine sectors (Bransfield Strait) exhibited greater glacier variations. The trend in warming atmospheric temperature was greater in the Bransfield Strait than in the Drake Passage. TSL and retreat difference between glaciers were influenced by climatic and ocean input, as well as multiple environmental factors.
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Affiliation(s)
- Júlia L Lorenz
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
| | - Kátia K DA Rosa
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
| | - Carina Petsch
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
- Universidade Federal de Santa Maria, Programa de Pós-graduação em Geografia, Avenida Roraima 1000, 97105-900 Santa Maria, RS, Brazil
| | - Cleiva Perondi
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
| | - Filipe D Idalino
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
| | - Jeffrey Daniel Auger
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
| | - Rosemary Vieira
- Universidade Federal Fluminense, Laboratório de Processos Sedimentares e Ambientais, Departamento de Geografia, Campus da Praia Vermelha, Avenida General Milton Tavares de Souza, s/n, 24210-346 Niterói, RJ, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Avenida Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brasil
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Ilha JG, Simões JC, Portella MBP, Bernardo RT, Thoen IU, Casassa G. Ionic and stable isotopic content in two Antarctic firn cores under different environment settings. AN ACAD BRAS CIENC 2023; 95:e20220158. [PMID: 38055510 DOI: 10.1590/0001-37652023202201] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 02/25/2023] [Indexed: 12/08/2023] Open
Abstract
This article compares isotopic, ionic and climatic data from two firn cores from the West Antarctic Ice Sheet (WAIS). The IC-02 (88°01'21.3"S , 82°04'21.7"W) and the IC-05 (82°30'30.8"S , 79°28'02.7"W) closer to the coast. The IC-02 had 488 samples analyzed covering 14.58 meters depth while the IC-05 had 602 samples analyzed covering 19.73 meters depth. The time interval for both ice cores is 25 years ranging from 1978 to 2003. Sodium, sulfate and chloride were analyzed via ion chromatography using three DionexTM ionic chromatographers at the laboratories of Centro Polar e Climático (CPC) and at the Climate Change Institute. Stable isotope data was determined using cavity ring-down spectroscopy in a Picarro® spectrometer at the CPC. Annual accumulation was greater at IC-05 with an average of 0.35 m.eq.w.a-1 compared to 0.25 m.eq.w.a-1 at the IC-02. Stable isotope data was approximately 1.3 times more negative at the IC-02 which also presented higher d values. Na+ and Cl- were in higher concentrations at the IC-05 however Cl/Na was greater in the IC-02. The Cl excess was found to be derived from fractionation of sea salt aerosols and not related to volcanism. This work presents new insights regarding the chemical differences between ice cores.
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Affiliation(s)
- João G Ilha
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, Agronomia, 91501-970 Porto Alegre, RS, Brazil
- University of Maine, Climate Change Institute, 5764 Sawyer Environmental Research Ctr Orono, ME 04469, USA
| | - Manoela B P Portella
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geociências, Av. Bento Gonçalves, 9500, Agronomia, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Ronaldo T Bernardo
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Isaías U Thoen
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, Agronomia, 91501-970 Porto Alegre, RS, Brazil
| | - Gino Casassa
- Universidad de Magallanes. Av. Pdte. Manuel Bulnes 01855, Punta Arenas, Chile
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Hillebrand FL, Freitas MWDDE, Bremer UF, Abrantes TC, Simões JC, Mendes Júnior CW, Schardong F, Arigony-Neto J. Concentration and thickness of sea ice in the Weddell Sea from SSM/I passive microwave radiometer data. AN ACAD BRAS CIENC 2023; 95:e20230342. [PMID: 37937658 DOI: 10.1590/0001-3765202320230342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Accepted: 08/27/2023] [Indexed: 11/09/2023] Open
Abstract
This study evaluated feasibility statistically and analyzed, during the freezing period, the relationship between brightness temperature (Tb) data of the 37V polarisation and the GR3719 (Gradient Ratio 37V and 19V) obtained by Special Sensor Microwave/Imager from F11 and F13 satellites with sea ice thickness (SIT) data obtained in the Weddell Sea through Antarctic Sea Ice Processes and Climate program. The multiple linear regression (MLR) was applied at 1,520 points, with 70% of these points being randomly separated to generate the MLR and 30% to carry out the validation. To perform the temporal mapping, the MLR was applied only to pixels with sea ice concentration (SIC) ≥ 90%, obtained through the fraction image calculated from the spectral linear mixing model (SLMM) using the Tb in the channels and polarizations 19H, 19V and 37V. The results of the SLMM validation process for estimating the SIC were σ = 10.5%, RMSE = 11.0%, and bias = -2.8%, and the SIT based on the MLR, the results were R² = 0.57, RMSE = 0.268 m, and bias = 0.103 m. In the SIT mapping, we highlight the trend of thickness reduction on the east coast of the Antarctic Peninsula during the period 1992-2009.
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Affiliation(s)
- Fernando Luis Hillebrand
- Instituto Federal de Educacão, Ciência e Tecnologia do Rio Grande do Sul/IFRS, Rodovia RS-239, Km 68, 3505, 95700-000 Rolante, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, 91501-970 Porto Alegre, RS, Brazil
| | - Marcos W D DE Freitas
- Universidade Federal do Rio Grande do Sul/UFRGS, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Programa de Pós-Graduação em Sensoriamento Remoto, Av. Bento Gonçalves, 9500, Prédio 44202, Setor 5, 90501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Av. Bento Gonçalves, 9500, 90501-970 Porto Alegre, RS, Brazil
| | - Ulisses F Bremer
- Universidade Federal do Rio Grande do Sul/UFRGS, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Programa de Pós-Graduação em Sensoriamento Remoto, Av. Bento Gonçalves, 9500, Prédio 44202, Setor 5, 90501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Av. Bento Gonçalves, 9500, 90501-970 Porto Alegre, RS, Brazil
| | - Tales C Abrantes
- Universidade Federal do Rio Grande do Sul/UFRGS, Programa de Pós-Graduação em Sensoriamento Remoto, Av. Bento Gonçalves, 9500, Prédio 44202, Setor 5, 90501-970 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul/UFRGS, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Av. Bento Gonçalves, 9500, 90501-970 Porto Alegre, RS, Brazil
| | - Cláudio W Mendes Júnior
- Universidade Federal do Rio Grande do Sul/UFRGS, Centro Polar e Climático, Av. Bento Gonçalves, 9500, Prédio 43136, Salas 208 e 210, 91501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Programa de Pós-Graduação em Sensoriamento Remoto, Av. Bento Gonçalves, 9500, Prédio 44202, Setor 5, 90501-970 Porto Alegre, RS, Brazil
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Av. Bento Gonçalves, 9500, 90501-970 Porto Alegre, RS, Brazil
| | - Frederico Schardong
- Instituto Federal de Educacão, Ciência e Tecnologia do Rio Grande do Sul/IFRS, Rodovia RS-239, Km 68, 3505, 95700-000 Rolante, RS, Brazil
| | - Jorge Arigony-Neto
- Universidade Federal do Rio Grande/FURG, Instituto de Oceanografia, Av. Itália, s/n, Km 8, 96201-900 Rio Grande, RS, Brazil
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11
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Simões JC, Cartes ML, Sayão JM. Forty years of Brazilian Antarctic research: A tribute to Professor Antonio Carlos Rocha-Campos. AN ACAD BRAS CIENC 2022; 94:e20220493. [PMID: 35766620 DOI: 10.1590/0001-3765202220220493] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Accepted: 06/09/2022] [Indexed: 11/22/2022] Open
Affiliation(s)
- Jefferson C Simões
- Universidade Federal do Rio Grande do Sul/UFRGS, Instituto de Geociências, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 90650-001 Porto Alegre, RS, Brazil.,Climate Change Institute, University of Maine, 04469, Orono, ME, USA
| | | | - Juliana M Sayão
- Universidade Federal do Rio de Janeiro, Laboratório de Paleobiologia e Paleogeografia Antártica, Museu Nacional, Quinta da Boa Vista, s/n, 29040-040 Rio de Janeiro, RJ, Brazil
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Perondi C, Rosa KKDA, Vieira R, Magrani FJG, Ayres Neto A, Simões JC. Geomorphology of Martel inlet, King George Island, Antarctica: a new interpretation based on multi-resolution topo-bathymetric data. AN ACAD BRAS CIENC 2022; 94:e20210482. [PMID: 35648991 DOI: 10.1590/0001-3765202220210482] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Accepted: 01/22/2022] [Indexed: 11/22/2022] Open
Abstract
This study investigated the terrestrial and submarine geomorphology and glacial landform records in the Martel inlet (King George Island) using a multi-resolution topobathymetric data based on seismic, multibeam surveys and terrestrial satellite datasets (REMA DEM). Geomorphometric analysis provided glacial landforms and sedimentary processes interpretation. The submarine sector has a mean depth of 143 m, a maximum depth of 398 m, and most of it has a low slope (0°-16°). Steep slopes (>30°) are found along the mid-outer sectors transition area. The continental shelf was divided into inner fjord (49 m depth), middle fjord (119 m), and outer fjord (259 m), based on depth, elevation and slope. The topobathymetric digital model provides evidence of geomorphological contrasts between these zones in the fjord's seafloor and subaerial environments. A prominent morainal bank in the transition between the inner and middle parts marks the limit of a past stationary stage of the Dobrowolski-Goetel ice margin. Streamlined glacial lineations demonstrate an NE-SW past ice flow direction and a wet-based thermal regime. The combined analysis of submarine and subaerial landforms enable the understanding of the former glacier configuration and its deglaciation history.
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Affiliation(s)
- Cleiva Perondi
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geografia, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Kátia Kellem DA Rosa
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Rosemary Vieira
- Universidade Federal Fluminense, Instituto de Geociências, Departamento de Geografia, Av. Gal. Milton Tavares de Souza, s/n, 24210-346 Niterói, RJ, Brazil
| | - Fabio José Guedes Magrani
- Universität Bern, Oeschger Centre for Climate Change Research & Institut für Geologie. Baltzerstrasse 1+3, 3012 Bern, Switzerland
| | - Arthur Ayres Neto
- Universidade Federal Fluminense, Departamento de Geologia e Geofísica, Av. Gal. Milton Tavares de Souza, s/n, 24210-346 Niterói, RJ, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Programa de Pós-graduação em Geografia, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,University of Maine, Climate Change Institute, 168 College Ave, Orono, ME, USA
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13
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Marcher A, Bernardo RT, Simões JC, Auger J. Water stable isotopes in snow along a traverse of the West Antarctic Ice Sheet: insights into moisture origins, air-masses distillation history, and climatic value. AN ACAD BRAS CIENC 2022; 94:e20210353. [PMID: 35648989 DOI: 10.1590/0001-3765202220210353] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 01/04/2022] [Indexed: 11/22/2022] Open
Abstract
This study investigated the water isotopic content (δ18O, δD, d-excess) of the surface snow along a 995 km traverse over the West Antarctic Ice Sheet from the Möller Ice Stream - Institute Ice Stream to the upper reaches of the Pine Island Glacier drainage basin. The purpose of this study was to evaluate the climatic record preserved in the snow. We analyzed 92 surface samples (~0.15-0.20 m deep), retrieved during 2014/2015 austral summer from every ~10 km along the traverse route, using the laser spectroscopy technique. We computed the isotopic-geographical characteristics and spatial co-isotopic empirical relationships and compared the isotopic results with the tropospheric mean annual temperature and air mass trajectories. Our isotopic results were sensitive to capturing the well-known climatic asymmetry between the Amundsen-Bellingshausen Sea (ABS; which receives more influence from warmer (oceanic) air masses) and Weddell Sea (WS; more influenced by colder (continental) air masses) sectors. Further, the spatial distribution of δs and d-excess and the co-isotopic relationships reflect two preferential fractionation paths: one from the coast of the ABS sector to the WS sector, and another from the coast of the WS sector to the inland. The Pacific Ocean is confirmed as the primary source of moisture.
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Affiliation(s)
- Andressa Marcher
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Ronaldo T Bernardo
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Climate Change Institute, University of Maine, Orono, ME 04469-5790, USA
| | - Jeffrey Auger
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Instituto de Geociências, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Climate Change Institute, University of Maine, Orono, ME 04469-5790, USA
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14
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Travassos JM, Martins SS, Simões JC. A firn dielectric log depth-tied to an ice core on the West Antarctica Ice Sheet. AN ACAD BRAS CIENC 2022; 94:e20210815. [PMID: 35648996 DOI: 10.1590/0001-3765202220210815] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 12/08/2021] [Indexed: 11/21/2022] Open
Abstract
We have estimated a 1-D permittivity model from a 100m long variable offset GPR in the West Antarctic ice sheet. That model inherits the inaccuracies in depth from the velocity model, which should be corrected before attempting to correlate it with the density log from a close-by borehole. We performed that correction by aligning a synthetic ice density derived from a Maxwell Garnett two-phase mixture model to the ice core density measurements through dynamic time warping. The shifts to bring the permittivity estimates to their proper depths suggest a direct correlation of radar-derived data to borehole depths may suffer from noise to an unknown degree. The present methodology is within reach of a standard GPR survey, having at least one variable offset gather.
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Affiliation(s)
- Jandyr M Travassos
- Universidade Federal do Rio de Janeiro (UFRJ), Laboratório de Métodos de Modelagem e Geofísica Computacional - COPPE, Av. Pedro Calmon, s/n, Cidade Universitária, 21941-596 Rio de Janeiro, RJ, Brazil
| | - Saulo S Martins
- Universidade Federal do Pará (UFPA), Faculdade de Geofísica, Rua Augusto Corrêa, 01, 66075-110 Belém, PA, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul (UFRGS), Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,Climate Change Institute, University of Maine, Orono, ME 04469-5790, EUA
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15
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Fonseca EL, Santos ECD, Figueiredo ARDE, Simões JC. Antarctic biological soil crusts surface reflectance patterns from landsat and sentinel-2 images. AN ACAD BRAS CIENC 2022; 94:e20210596. [PMID: 35544838 DOI: 10.1590/0001-3765202220210596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Accepted: 11/10/2021] [Indexed: 11/21/2022] Open
Abstract
The remote sensing techniques must be used to obtain long-term information in remote areas, like the Antarctic continent, to monitor the environmental productivity and its changes. The aim of this work was to analyze the surface reflectance profile patterns for the Antarctic biological soil crusts (algae, lichens, and mosses) in an area of Nelson Island (South Shetland Islands, maritime Antarctic), calculated from Landsat and Sentinel-2 images to identify its similarities and differences due to targets, sensors and acquired date. The surface reflectance values for Antarctic biological soil crusts are similar for those observed for biological soil crusts in other Earth extreme environments, like deserts. In Landsat images, the differences among biological soil crusts surface reflectance were identified at visible and near-infrared wavelengths and for Sentinel-2 images, the differences occur at visible, red-edge and shortwave infrared wavelengths, showing the feasibility of using surface reflectance products to identify these different crusts, despite its inherent pixel spectral mixture. Long-term biophysical parameters from such crusts as retrieved from orbital data is not possible due to very low cloud-free images over the Antarctic, which prevents building a consistent surface reflectance time-series which covers all biological soil crusts growth season.
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Affiliation(s)
- Eliana L Fonseca
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Departament of Geography, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Edvan C Dos Santos
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Anderson R DE Figueiredo
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil
| | - Jefferson C Simões
- Universidade Federal do Rio Grande do Sul, Centro Polar e Climático, Departament of Geography, Av. Bento Gonçalves, 9500, 91501-970 Porto Alegre, RS, Brazil.,University of Maine, Climate Change Institute, Bryand Global Sciences Building, 04469-5790, Orono, ME, USA
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16
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de Menezes GC, Amorim SS, Gonçalves VN, Godinho VM, Simões JC, Rosa CA, Rosa LH. Diversity, Distribution, and Ecology of Fungi in the Seasonal Snow of Antarctica. Microorganisms 2019; 7:E445. [PMID: 31614720 PMCID: PMC6843862 DOI: 10.3390/microorganisms7100445] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/04/2019] [Accepted: 10/08/2019] [Indexed: 11/27/2022] Open
Abstract
We characterized the fungal community found in the winter seasonal snow of the Antarctic Peninsula. From the samples of snow, 234 fungal isolates were obtained and could be assigned to 51 taxa of 26 genera. Eleven yeast species displayed the highest densities; among them, Phenoliferia glacialis showed a broad distribution and was detected at all sites that were sampled. Fungi known to be opportunistic in humans were subjected to antifungal minimal inhibition concentration. Debaryomyces hansenii, Rhodotorula mucilaginosa, Penicillium chrysogenum, Penicillium sp. 3, and Penicillium sp. 4 displayed resistance against the antifungals benomyl and fluconazole. Among them, R. mucilaginosa isolates were able to grow at 37 °C. Our results show that the winter seasonal snow of the Antarctic Peninsula contains a diverse fungal community dominated by cosmopolitan ubiquitous fungal species previously found in tropical, temperate, and polar ecosystems. The high densities of these cosmopolitan fungi suggest that they could be present in the air that arrives at the Antarctic Peninsula by air masses from outside Antarctica. Additionally, we detected environmental fungal isolates that were resistant to agricultural and clinical antifungals and able to grow at 37 °C. Further studies will be needed to characterize the virulence potential of these fungi in humans and animals.
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Affiliation(s)
- Graciéle C.A. de Menezes
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
| | - Soraya S. Amorim
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
| | - Vívian N. Gonçalves
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
| | - Valéria M. Godinho
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
| | - Jefferson C. Simões
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Porto Alegre 91201-970, Brazil;
| | - Carlos A. Rosa
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
| | - Luiz H. Rosa
- Departamento de Microbiologia, Instituto de Ciências Biológicas, Universidade Federal de Minas Gerais, Belo Horizonte 31270-901, Brazil (S.S.A.); (V.N.G.); (V.M.G.); (C.A.R.)
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Pessi IS, Osorio-Forero C, Gálvez EJC, Simões FL, Simões JC, Junca H, Macedo AJ. Distinct composition signatures of archaeal and bacterial phylotypes in the Wanda Glacier forefield, Antarctic Peninsula. FEMS Microbiol Ecol 2014; 91:1-10. [PMID: 25764530 DOI: 10.1093/femsec/fiu005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Several studies have shown that microbial communities in Antarctic environments are highly diverse. However, considering that the Antarctic Peninsula is among the regions with the fastest warming rates, and that regional climate change has been linked to an increase in the mean rate of glacier retreat, the microbial diversity in Antarctic soil is still poorly understood. In this study, we analysed more than 40 000 sequences of the V5-V6 hypervariable region of the 16S rRNA gene obtained by 454 pyrosequencing from four soil samples from the Wanda Glacier forefield, King George Island, Antarctic Peninsula. Phylotype diversity and richness were surprisingly high, and taxonomic assignment of sequences revealed that communities are dominated by Proteobacteria, Bacteroidetes and Euryarchaeota, with a high frequency of archaeal and bacterial phylotypes unclassified at the genus level and without cultured representative strains, representing a distinct microbial community signature. Several phylotypes were related to marine microorganisms, indicating the importance of the marine environment as a source of colonizers for this recently deglaciated environment. Finally, dominant phylotypes were related to different microorganisms possessing a large array of metabolic strategies, indicating that early successional communities in Antarctic glacier forefield can be also functionally diverse.
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Affiliation(s)
- Igor S Pessi
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500 - Agronomia, Porto Alegre - RS, 91501-970, Brazil
| | - César Osorio-Forero
- Research Group Microbial Ecology: Metabolism, Genomics and Evolution of Communities of Environmental Microorganisms, CorpoGen, Carrera 5 66A-34, 110231, Bogotá, DC, Colombia
| | - Eric J C Gálvez
- Research Group Microbial Ecology: Metabolism, Genomics and Evolution of Communities of Environmental Microorganisms, CorpoGen, Carrera 5 66A-34, 110231, Bogotá, DC, Colombia
| | - Felipe L Simões
- Instituto de Biociências, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500 - Agronomia, Porto Alegre - RS, 91501-970, Brazil
| | - Jefferson C Simões
- Centro Polar e Climático, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500 - Agronomia, Porto Alegre - RS, 91501-970, Brazil
| | - Howard Junca
- Research Group Microbial Ecology: Metabolism, Genomics and Evolution of Communities of Environmental Microorganisms, CorpoGen, Carrera 5 66A-34, 110231, Bogotá, DC, Colombia
| | - Alexandre J Macedo
- Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul, Avenida Bento Gonçalves, 9500 - Agronomia, Porto Alegre - RS, 91501-970, Brazil Faculdade de Farmácia, Universidade Federal do Rio Grande do Sul, Avenida Ipiranga, 2752 - Azenha, Porto Alegre - RS, 90610-000, Brazil
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Teive HAG, Munhoz RP, Simões JC. Charcot's son, commander Jean-Baptiste Charcot: from neurology to "Pourquoi Pas?". Arq Neuropsiquiatr 2012; 70:305-7. [PMID: 22510742 DOI: 10.1590/s0004-282x2012000400016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/22/2011] [Accepted: 11/17/2011] [Indexed: 11/21/2022]
Abstract
Charcot name became very famous around the world, firstly because of the work of Professor Jean-Martin Charcot, the founder of Clinical Neurology, and, secondly, because of his son, Jean-Baptiste, the world famous maritime explorer.
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Affiliation(s)
- Hélio A G Teive
- Movement Disorders Unit, Neurology Service, Internal Medicine Department, Hospital de Clínicas, Federal University of Paraná, Curitiba PR, Brazil.
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19
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McConnell JR, Aristarain AJ, Banta JR, Edwards PR, Simões JC. 20th-Century doubling in dust archived in an Antarctic Peninsula ice core parallels climate change and desertification in South America. Proc Natl Acad Sci U S A 2007; 104:5743-8. [PMID: 17389397 PMCID: PMC1851562 DOI: 10.1073/pnas.0607657104] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Crustal dust in the atmosphere impacts Earth's radiative forcing directly by modifying the radiation budget and affecting cloud nucleation and optical properties, and indirectly through ocean fertilization, which alters carbon sequestration. Increased dust in the atmosphere has been linked to decreased global air temperature in past ice core studies of glacial to interglacial transitions. We present a continuous ice core record of aluminum deposition during recent centuries in the northern Antarctic Peninsula, the most rapidly warming region of the Southern Hemisphere; such a record has not been reported previously. This record shows that aluminosilicate dust deposition more than doubled during the 20th century, coincident with the approximately 1 degrees C Southern Hemisphere warming: a pattern in parallel with increasing air temperatures, decreasing relative humidity, and widespread desertification in Patagonia and northern Argentina. These results have far-reaching implications for understanding the forces driving dust generation and impacts of changing dust levels on climate both in the recent past and future.
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Affiliation(s)
- Joseph R McConnell
- Desert Research Institute, Nevada System of Higher Education, Reno, NV 89512, USA.
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Liu L, Kang J, Petit JR, Simões JC, De Angelis M. The 4700 aB.P. volcanic signal detected in Vostok BH8 ice core, Antarctica. Chin Sci Bull 2005. [DOI: 10.1007/bf03183662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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21
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da Cunha KD, Evangelista H, Dalia KC, Simões JC, Barros Leite CV. Application of 252Cf-PDMS to characterize airborne particles deposited in an Antarctic glacier. Sci Total Environ 2004; 323:123-135. [PMID: 15081722 DOI: 10.1016/j.scitotenv.2003.10.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2003] [Revised: 08/27/2003] [Accepted: 10/04/2003] [Indexed: 05/24/2023]
Abstract
The aim of this study is to apply the (252)Cf-PDMS (plasma desorption mass spectrometry) technique to characterize particles deposited in ice samples. This technique allows identification of molecular ions, even large molecules, desorbed from the sample surface, in contrast with PIXE (particle induced X-ray emission) or EDS (energy dispersive spectrometry). Two shallow snow cores obtained from different glacial drainage basins on King George Island ice cap, South Shetland Islands (Antarctica), were analyzed by PDMS. The chemical compounds identified in the ice mass spectra show that the particle contents of both samples were statistically different, indicating a non-homogeneous spatial deposition distribution for the deposited particles. The analysis of the ice mass spectra suggests some possible sources for the airborne particles. The mass spectra of ice samples collected at a site exposed directly to air masses coming from the Drake Passage show a significant contribution of particles from crustal and anthropogenic sources. However, the mass spectra of ice samples taken from a site on a slope towards a local inlet point out a high influence of marine aerosol. Therefore, it was concluded that particles deposited onto the ice cap were attributable to different aerosol sources, besides long-range atmospheric transport. The (252)Cf-PDMS technique can be considered a powerful tool for studies of snow and ice samples, providing important information for understanding the global atmospheric transport and deposition of airborne particles.
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Affiliation(s)
- K Dias da Cunha
- Instituto de Radioproteção e Dosimetria-(IRD/CNEN), Av. Salvador Allende s/n, Jacarepaguá, Rio de Janeiro, RJ CEP 22 780-160, Brazil.
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Simões JC, Pudles E, Filho RS, de Lourdes Biondo M, Smaka RS. [A needle for percutaneous bone biopsy]. AMB Rev Assoc Med Bras 1982; 28:33-4. [PMID: 6984909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Simões JC, Abrão AT, Gulin D, Neiva JB. [Epidermoid carcinoma of the scalp with disseminated bone metastases]. AMB Rev Assoc Med Bras 1979; 25:111-2. [PMID: 315585] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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Castelfranchi PL, Simões JC. [A needle for percutaneous biopsy of the lung]. AMB Rev Assoc Med Bras 1977; 23:399-400. [PMID: 305586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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