Composição das assembleias de nemátodas associadas a carcaças de baleia no Oceano Atlântico Sudoeste
Data
2021-02-24
Autores
Ávila, Ana Karoline Frutuoso de 
Orientadores
Gallucci, Fabiane
Tipo
Trabalho de conclusão de curso
Título da Revista
ISSN da Revista
Título de Volume
Resumo
As carcaças de baleia proporcionam enriquecimento orgânico essencial para o ecossistema de mar profundo, suportando uma densa comunidade de organismos oportunistas e especialistas neste tipo de ambiente. A carcaça pode passar por pelo menos três estágios sucessionais denominados de necrófagos móveis, estágio de enriquecimento oportunista e estágio sulfofílico. A grande disponibilidade de alimento proporcionada pela carcaça suporta o desenvolvimento de condições redutoras de modo que a fauna colonizadora durante o estágio sulfofílico da carcaça se assemelha a fauna de outros ambientes quimiossintetizantes de mar profundo. O objetivo deste estudo foi descrever a composição das assembleias de nemátodas marinhos de vida livre associadas a ossos de baleia implementados experimentalmente a 1500 metros e 3300 metros de profundidade no oceano Atlântico Sudoeste, e compará-las a outros ambientes de mar profundo, incluindo ambientes redutores e sedimento adjacente à área de estudo. As assembléias de carcaças implantadas a 1500 metros de profundidade foram dominadas pelo gênero Halomonhystera, que representou mais de 90% da abundância total. Já os pontos mais profundos, tiveram contribuição expressiva do gênero Paranticoma, à exceção do ponto SP-3300, que de modo similar às estações mais rasas foi dominada pelo gênero Halomonhystera. Essa variação entre os pontos de implementação das carcaças foi associada a processos oceanográficos, representados por duas massas de água no local: a Água Profunda do Atlântico Norte, que flui em direção ao Sul na região rasa (1500 metros) e a Água de Fundo Antártica, que flui em direção ao Norte na região mais profunda (3300 metros). O estudo ainda apontou que as assembleias das carcaças são bem diferentes daquelas presentes nos sedimentos adjacentes e demais ambientes de mar profundo. Porém, as assembleias de nemátodas presentes nas carcaças de baleia apresentaram grande similaridade com ambientes redutores, como exsudações frias e fontes hidrotermais, suportando a hipótese de que carcaças de baleia podem servir como ambientes intermediários para fins de dispersão da fauna dependente de ambientes de quimiossíntese, destacando a importância de ilhas orgânicas para a compreensão da conectividade e filogenia de organismos no mar profundo.
Whale carcasses promote organic enrichment essential to the deep-sea ecosystem, therefore supporting a dense community of opportunistic organisms that are specialists in this type of environment. The communities of the carcass pass three successional stages denominated mobile scavenger, enrichment opportunist, and sulfophilic stage. The high availability of food resources provided by the carcass supports the development of reductive conditions so that the colonizing fauna resembles those from other chemosynthetic deep-sea environments. The aim of this study is to describe the composition of free-living marine nematode assemblages associated with experimentally deployed whalebones at 1500 meters and 3300 meters depth in the Southwest Atlantic Ocean and to compare them to other deep-sea environments, including reduced environments and sediments adjacent to the study area. Assemblages from carcasses deployed at 1500 meters were dominated by the genus Halomonhystera, which represented more than 90 % from total abundances. Deeper sites, on the other hand, had a significant contribution o the genus Paranticoma, with the exception of the site SP-3300 which like the shallower sites was dominated by Halomonhystera. This variation between sites where the carcasses were deployed was associated with oceanographic processes, represented by two water masses: the North Atlantic Deep Water, which flows southward in the shallow region (1500 meters), and the Antarctic Bottom Water that flows northward in the deepest region (3300 meters). The study also pointed out that the carcass assemblages differed from those of adjacent sediments as well as other deep-sea environments. However, they were highly similar to those from reductive environments, like cold seeps and vents, giving support to the hypothesis that whale carcasses may serve as intermediate environments for the dispersal of the fauna dependent on chemosynthesis environments, highlighting the importance of organic islands for understanding the connectivity and phylogeny of organisms in the deep sea.
Whale carcasses promote organic enrichment essential to the deep-sea ecosystem, therefore supporting a dense community of opportunistic organisms that are specialists in this type of environment. The communities of the carcass pass three successional stages denominated mobile scavenger, enrichment opportunist, and sulfophilic stage. The high availability of food resources provided by the carcass supports the development of reductive conditions so that the colonizing fauna resembles those from other chemosynthetic deep-sea environments. The aim of this study is to describe the composition of free-living marine nematode assemblages associated with experimentally deployed whalebones at 1500 meters and 3300 meters depth in the Southwest Atlantic Ocean and to compare them to other deep-sea environments, including reduced environments and sediments adjacent to the study area. Assemblages from carcasses deployed at 1500 meters were dominated by the genus Halomonhystera, which represented more than 90 % from total abundances. Deeper sites, on the other hand, had a significant contribution o the genus Paranticoma, with the exception of the site SP-3300 which like the shallower sites was dominated by Halomonhystera. This variation between sites where the carcasses were deployed was associated with oceanographic processes, represented by two water masses: the North Atlantic Deep Water, which flows southward in the shallow region (1500 meters), and the Antarctic Bottom Water that flows northward in the deepest region (3300 meters). The study also pointed out that the carcass assemblages differed from those of adjacent sediments as well as other deep-sea environments. However, they were highly similar to those from reductive environments, like cold seeps and vents, giving support to the hypothesis that whale carcasses may serve as intermediate environments for the dispersal of the fauna dependent on chemosynthesis environments, highlighting the importance of organic islands for understanding the connectivity and phylogeny of organisms in the deep sea.
Descrição
Citação
ÁVILA, Ana Karoline Frutuoso de. Composição das assembleias de nemátodas associadas a carcaças de baleia no Oceano Atlântico Sudoeste. 2021. 25 f. Trabalho de conclusão de curso de graduação (Bacharelado Interdisciplinar em Ciência e Tecnologia do Mar) - Instituto do Mar, Universidade Federal de São Paulo, Santos, 2021.