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Estrutura termohalina e massas de água ao norte da Península Antártica revelada a partir de dados in situ coletados por elefantes-marinhos do sul (Mirounga leonina)

Thermohaline structure and water masses in the north of Antarctic Peninsula from data collected in situ by southern elephant seals (Mirounga leonina)

Resumos

A Península Antártica Oeste é uma das regiões do planeta que está se aquecendo rapidamente e apresenta alta diversidade animal principalmente ao longo de sua plataforma continental. Esta região também é de grande importância devido à mistura causada pela interação de águas do Mar de Weddell (MW), do Estreito de Bransfield (EB) e da Corrente Circumpolar Antártica (CCA) que transmitem características termohalinas e nutrientes de diferentes locais de formação e mais tarde se conectam com todos os oceanos do planeta. Entretanto, estudos sobre a variabilidade temporal das condições oceanográficas desta região que consequentemente determinam a formação de massas d'água, são escassos em função das dificuldades logísticas envolvidas em levantamentos oceanográficos e monitoramentos tradicionais durante os meses de inverno. Para esse trabalho, variações da estrutura termohalina e das massas d'água nas proximidades e abaixo do gelo marinho na região norte da Península Antártica (PA) e Mar da Escócia (ME) foram registradas entre os meses de fevereiro e novembro de 2008 por duas fêmeas de elefante-marinho do sul (EMS, Mirounga leonina) instrumentadas com Conductivity - Temperature - Depth/Satellite-Relay Data Logger (CTD - SRDL). 1330 perfis verticais de temperatura e salinidade foram coletados por estes indivíduos que foram instrumentados pelo Projeto MEOP-BR na Ilha Elefante, Shetlands do Sul. Esses perfis, juntamente com diagramas de estado espalhado permitiram a identificação de massas d'água e suas alterações na estrutura vertical oceânica. Dentre as massas d'água identificadas citamos: Água de Superfície Antártica (AASW), Água de Inverno (WW), Água Cálida Profunda (WDW), Água Cálida Profunda Modificada (MWDW), Água Circumpolar Profunda (CDW), Água Profunda Circumpolar Superior (UCDW), Água Profunda Circumpolar Inferior (LCDW) e Água de Plataforma de Gelo (ISW). Nossos resultados mostram que a estrutura vertical oceânica sofre alterações que tradicionalmente não podem ser monitoradas, principalmente durante o inverno austral, e que os EMS são importantes e modernas plataformas para coleta de dados oceanográficos, permitindo um aumento em nosso conhecimento dos processos oceanográficos na região antártica.

Estrutura termohalina; massas de água; península Antártica; elefante-marinho do sul; oceano austral


The Western Antarctic Peninsula is rapidly warming and exhibits high indices of biodiversity concentrated mostly along its continental shelf. This region has great importance due to the the mixing caused by the interaction of waters from Weddell Sea (MW), Bransfield Strait (EB) and the Antarctic Circumpolar Current (CCA) transmits thermohaline characteristics and nutrients of different sites and finally connects with all the world's oceans. However, studies focusing on the temporal variability of the region's oceanographic conditions that finally determine the water mass formation are sparse due to the logistical difficulties of conducting oceanographic surveys and traditional monitoring during the winter. For this study, variations of the thermohaline structure and water masses in the vicinity and below the sea ice in the North of the Antarctic Peninsula (AP) and Scotia Sea (SS) were recorded between February and November 2008 by two female southern elephant seals (SES, Mirounga leonina) tagged with Conductivity - Temperature - Depth/Satellite-Relay Data Logger (CTD - SRDL). One thousand three hundred and thirty vertical profiles of temperature and salinity were collected by seals which were tagged by the MEOP-BR Project team at the Elephant Island, South Shetlands. These profiles, together with spread state diagrams allowed the identification of water masses and their variances in the ocean's vertical structure. Among the set of identified water masses we cite: Antarctic Surface Water (AASW), Winter Water (WW), Warm Deep Water (WDW), Modified Warm Deep Water (MWDW), Circumpolar Deep Water (CDW), Upper Circumpolar Deep Water (UCDW), Lower Circumpolar Deep Water (LCDW) and Ice Shelf Water (ISW). Our results show that the oceanic vertical structure undergoes changes that cannot be traditionally monitored, particularly during the Austral winter and that SES are important and modern oceanographic data collection platforms allowing for the improvement of our knowledge of oceanographic processes in the Antarctic region.

Thermohaline structure; water masses; Antarctic peninsula; southern elephant seal; austral ocean


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Datas de Publicação

  • Publicação nesta coleção
    08 Out 2013
  • Data do Fascículo
    Abr 2013
Instituto de Pesquisas Ambientais em Bacias Hidrográficas Instituto de Pesquisas Ambientais em Bacias Hidrográficas (IPABHi), Estrada Mun. Dr. José Luis Cembranelli, 5000, Taubaté, SP, Brasil, CEP 12081-010 - Taubaté - SP - Brazil
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