Navegando por Assunto "Meiofauna"

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Acesso aberto (Open Access)
Análise ecológica da ostracofauna (crustacea) e meiofauna bentônica associada como bioindicadores ambientais na ilha de Cotijuba, Belém (PA), Amazônia
(Universidade Federal do Pará, 2025-02-27) BRITO, Maurício de Souza; PEREIRA, Ana Paula Linhares; http://lattes.cnpq.br/8369046011837903
The uncontrolled occupation of environmental protection areas (APA) in Belém-PA and candidates for APA, such as Cotijuba Island, has intensified the environmental impacts in the region. To mitigate these effects, Conservation Paleobiology integrates historical data on the distribution of fauna and flora, connecting past, present, and future. In turn, ostracods, small crustaceans sensitive to environmental variations, which are part of the benthic meiofauna, provide information about changes in ecosystems through the analysis of their communities and shells, formed from the calcium carbonate in the water. In this way, the survey of the ostracofauna and associated meiofauna on the island of Cotijuba allowed the use of these groups as bioindicators. The research was conducted during the rainy, transitional, and less rainy seasons, at two beaches: Flexeira, less impacted, and Farol, more influenced by human activities. During the campaigns, surface samples were collected in the inframarine, intertidal and supramarine zones, as well as sediment cores, physico-chemical water measurements, and beach profiles. The results showed Farol beach as reflective and Flexeira beach as dissipative, in addition to physical-chemical parameters with low influence on the organisms. The benthic meiofauna recorded 10 distinct classes: Oligochaeta, Polychaeta, Insecta (Diptera and Trichoptera), Malacostraca (Amphipoda), Arachnida, Ostracoda, Hydrozoa, Gastropoda, Bivalvia, and Rhabditophora. Approximately 84% of the specimens are from Flexeira beach, with this proportion being higher when only ostracods are analyzed (89%). Despite the lower abundance at Farol beach, a large number of cocoons of Trichoptera pupae were observed, known for their sensitivity to pollution and environmental changes, indicating a relatively healthy environment. However, a low abundance of ostracods was observed, which may be related to abiotic factors, such as the type of beach and coarse sediments. Moreover, the overall abundance of meiofauna in Cotijuba was also considered low, even without indications of significant anthropogenic intervention, which suggests a relationship between the low number of specimens and hydrodynamic conditions that intensify erosive and depositional processes. The record of a new species is highlighted: Cyprideis cotijubensis sp. nov., as a potential bioindicator of recent ostracofauna in river estuaries in the Amazon. The project also resulted in the digital book “Cartilha Digital Preserva Amazônia”, aimed at raising awareness about the conservation of the Amazon.
Acesso aberto (Open Access)
Composição e variabilidade espaço-temporal da meiofauna de uma praia arenosa na região amazônica (Ajuruteua, Pará)
(2009-06) GOMES, Tatianne Pereira; ROSA FILHO, José Souto
The present study investigates the spatio-temporal changes in the meiofauna community along the intertidal zone of Ajuruteua Beach, State of Pará, Brazil. Samples were collected during spring tides at different levels of the beach face every two months from April 2003 to February 2004. The material was sampled using a cylindrical corer (3.14 cm2) and fixed with 5% saline formalin. In the laboratory, samples were sieved through a 0.063 mm mesh screen and the retained organisms were identified at higher taxonomic levels, counted and preserved in ethanol 70%. Meiofauna was composed of eight groups: Turbellaria, Nematoda, Tardigrada, Polychaeta, Oligochaeta, Acari, Copepoda and nauplius (Copepoda). Nematoda was the dominant group, representing 74% of total organisms, followed by Copepoda (19%). A clear faunal zonation was observed on three lines parallel to the shoreline, which showed significant differences in abundance, richness and density of the main taxonomic groups. The mean density was lowest in April and highest in December. The highest densities and richness were recorded in the mid intertidal zone, while the lowest values were recorded in the upper and lower intertidal zones. Meiofauna community was most rich and abundant during the dry months, although differences were not significant between climatic periods. The main factors
Acesso aberto (Open Access)
Comunidade de meiofauna e associações de nematoda em praias arenosas Amazônicas de macromaré: variações espaciais e sazonais
(Universidade Federal do Pará, 2016-10-27) MELO, Tatianne Pereira Gomes de; VENEKEY, Virág; http://lattes.cnpq.br/1106411624280455
Considering benthic communities few studies are related to meiobenthic communities of tropical regions with macrotidal regime. This thesis is divided in two chapters. In chaper 1 the space temporal variations of meiofauna structure and Nematoda associations were analysed in beaches with different hydrodynamics at Algodoal Island. (Para). The samplings were made during one year (September/2011, December 2011, March/2012 and June/2012) in three beaches of the island: Caixa d’Agua, Farol and Princesa. The meiofauna was composed by 14 taxons, with Nematoda and Tardigrada as dominant groups. The mean density of meiofauna at Princesa beach was significantly different from Farol beach. The result was attributed to the higher disponibility of food in the intermediate beach (Farol) and the lower disponibility of food and higher waves action in the oceanic dissipative beach (Princesa). All Nematoda descripts (density, richness, eveness and diversity) presented higher values in the protected estuarine beach Caixa d’Agua and lower in the oceanic beach. Considering stations in the beaches, higher densities occured in the middle intertidal zone and lower values in the upper intertidal zone, however richness, eveness and diversity presented maximum values on the lower intertidal zone. 131 Nematoda genera were identified. The nematofauna was significantly different between months and stations in all beaches. Water content, subtrate temperature and proportion of sand were the enviromental variables more related to Nematoda genera. In chapter 2 was verified a taxonomic review and analysys were done to identify the diversity patterns of meiofauna and Nematoda from macrotidal sandy beaches, considering different morphodynamic states and different latitudes: a literature review. Until now 46 Nematoda genera were identified in dissipative beaches, 103 in beach dominated by semi-exposted tide, 82 in protected beach, 80 in beach modified by tide and 82 in ultradissipative beaches. Concerning latitudes, 139 genera were recorded in tropical region and 107 in temperate region.