Distribuição espaço-temporal de Harpacticoida sars, 1903 (Crustacea: Copepoda) nos Cânions São Francisco e Japaratuba na margem continental de Sergipe, Brasil

• Ano de defesa: 2021
• Autor(a) principal: Ribeiro, Viviane Andrade
• Orientador(a): Hirose, Gustavo Luis
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Programa de Pós-Graduação: Pós-Graduação em Ecologia e Conservação
• Palavras-chave em Português: Biodiversidade marinha; Taludes (Mecânica do solo); Mares; Harpacticóides
• Palavras-chave em Inglês: Marine biodiversity; Benthic copepods; Continental slope; South atlantic
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::ECOLOGIA
• Link de acesso: https://ri.ufs.br/jspui/handle/riufs/14823

The order Harpacticoida (Copepoda) is composed of microcrustaceans, generally benthic, with wide distribution, and can be found even in deep-sea regions. In these environments, the presence of undersea canyons that present peculiar characteristics that influence the benthic communities is common. The present work aimed to study the occurrence and spatio-temporal distribution of the harpacticoid community in two submarine canyons on the continental margin of Sergipe, Brazil, relating them to environmental variables. The biotic and abiotic samples came from two oceanographic campaigns carried out in March/April (SED3) and October/November (SED4) 2013, through the project “Environmental Characterization of the Sergipe-Alagoas Basin” (MARSEAL), coordinated by PETROBRAS/ CENPES, on the Sergipe continental slope, in the regions of the São Francisco (C) and Japaratuba (E) canyons, at depths of 400, 700, 1,000, 1,300, 1,900 and 3,000 m. At each station, the sediment samples were collected in triplicate, with the aid of a box corer to carry out the physicochemical and biological analyses. The samples for the study of the fauna were cut into strata of 0-2 and 2-5 cm. In the laboratory, the samples were washed in 300 μm sieves and all retained material was sorted under a stereomicroscope and then identified under an optical microscope. As a result, 40 new occurrences were registered for the continental margin of Sergipe, being 27 of these taxa, new records for the Brazilian coast. The Harpacticoida community was composed of 87 species, 45 genera and 18 families. Argestidae, Pseudotachidiidae, Ameiridae, Aegisthidae and Ectinosomatidae were the most abundant families. Of the 2.968 specimens identified in both canyons, the taxa with the highest total abundance were: Sarsameira sp.1, Pseudotachidius spp., Argestes mollis, Cervinia bradyi, Bradya spp., Anoplosomella sp., Pseudotachidius coronatus, Dactylopusia sp., Keraia longiseta and Bradya scotti. The presence of harpacticoids was significantly more abundant in the 0-2 cm superficial stratum (ANOVA, F=69.40, p=3.44e10), confirming existing records in the literature. Considering the sum of the strata, it was observed that the ecological descriptors of the harpacticoids did not vary significantly between the months sampled. Multivariate permutation analysis detected a significant difference in the composition of the harpacticoid community between the two canyons (PERMANOVA, F=24.31, p=0.001). The São Francisco canyon was represented by 616 adult harpacticoid copepods distributed in 59 taxa, 19 of which were not registered in Japaratuba. In the Japaratuba canyon, 2.352 individuals distributed in 81 taxa were identified, however 41 of these did not occur in the São Francisco canyon region. The abundance, richness and diversity index of harpacticoids were higher at intermediate depths when compared to shallower and deeper regions. Depth, temperature and total carbonate were the environmental variables that most influenced the structuring of the harpacticoid community in both canyons.