Navegando por Assunto "Bentos"

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Acesso aberto (Open Access)
Avaliação da qualidade ambiental da baía do Guajará em Belém - PA
(Universidade Federal do Pará, 2018-03-29) SANTOS, Letícia Furtado dos; SOUSA, Adriano Marlisom Leão de; http://lattes.cnpq.br/4371199443425884
Water is a fundamental natural resource for the maintenance of life, so it is of the utmost importance to preserve its quality. However, with the increase of anthropic activities, it has been under severe pressure, something that can affect its quality. Thus, it is necessary to monitor the water bodies, evaluating the physical, chemical and biological factors, in order to know if such activities are causing risks to the quality of this natural resource. The objective of this work was to evaluate the environmental quality of Guajará Bay, through the analysis of water quality, sediment and benthic macroinvertebrates. The collections occur in the year 2015 and 2016, in distinct seasonal periods, rainy and less rainy, characteristic of the Amazon region. The study was performed in 4 points (PT01, PT02, PT03 and PT04). In the water analysis, the physical-chemical and microbiological parameters were evaluated; in the study of the sediment (total and leachate) was quantified the Cr, Cd, Cu and Fe metals, calculating the FC (Contamination Factor), IGeo (Geoacumulation Index) and FE (Enrichment Factor); and in the analysis of the benthic macroinvertebrates the ecological descriptors and the FAB (Bioaccumulation Factor) were evaluated. In the precipitation analysis, the precipitated volume was above the average of the normal climatological in the rainy period, and in the less rainy period it was below the average. In the chemical and microbiological analyzes of the water, the OD (dissolved oxygen) parameter was below that allowed by CONAMA Resolution nº357/05, BOD (biochemical oxygen demand) and thermotolerant coliforms above the reference limit, in addition to high concentrations of COD (chemical oxygen demand) and high CE (electrical conductivity). In the evaluation of the sediment the total sediment Cd presented values above that allowed by PEL and CONAMA nº 454/12, already in the leached phase, all the metals were within the allowed by the legislation. In general, the points presented low to moderate contamination, characterized as an unpolluted environment to a moderately polluted and enriched deficiency. In the analysis of the benthic macroinvertebrates, the most representative phylum found was the Annelida, with most of the species referring to the class Polychaeta and the subclass Oligochaeta (class Clitellata). The Oligochaetas belonging to the Tubificidae family was the most prominent. Such family is characterized as tolerant and opportunistic to situations of hypoxia, being able to inhabit in environments with eutrofizada water. The results of the ecological descriptors showed that the greatest richness, abundance, diversity and better equitability were found in the less rainy period, due to the higher concentration of nutrients and organic matter caused in this period, benthic individuals presented bioaccumulation at all points for metals Cd, Cr, Cu. The results of the matrices analyzed in the study indicated that the accumulation of pollutants in Guajará bay is due to anthropic activities, mainly by the disposal of domestic sewage without pre-treatment that is launched in this region and port activity. Thus, the importance of continuous monitoring is emphasized, given that such contamination, besides causing damages to the aquatic ecosystem, causes harm to the population, since it uses this water body for practices and recreation and fishing.
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)
Comunidades macrobentônicas da Reserva Biológica do Lago Piratuba (Amapá – Brasil)
(Universidade Federal do Pará, 2008) ALMEIDA, Mayk Ferreira de; ROSA FILHO, José Souto; http://lattes.cnpq.br/3223362071251898; ALBERNAZ, Ana Luisa Kerti Mangabeira; http://lattes.cnpq.br/1220240487835422
The structure of the macrobenthic communities was characterized in different climatic periods and areas of the Reserva Biológica do Lago Piratuba (Amapá-Brazil). The samplings occurred on June and November of 2005 (Meridional belt lake - lakes Comprido de cima, Bacia, Lodão, Grande, Comprido de Baixo, Canal Tobaco and estuary of the river Araguari) and of 2006 (eastern belt lake - lakes Piratuba, Jussara, Escara, Trindade, Maresia, Boiado and the Duarte stream and seven places in the coast (areas vegetated and not vegetated). At each site four samples had been collected, with a corer (0.0079 m2) buried 20 cm in the sediment. After collection samples were passed in a 0.3 mm mesh and the retained organisms were fixed in formalin 5%. The structure of the communities varied seasonally, with severe modifications in density, specific composition, richness, eveness and diversity among sampling occasions and environments (lakes/coast). A total of 54 taxa had been identified belonging to phyla: Annelida, Arthropoda, Mollusca and Nemertea. In the rainy seasonal it was recorded 36 taxa, and in the dry seasonal 42 taxa were recorded. Annelida was the most abundant taxon, representing always more than 48% of total organisms. In the lakes Insecta larvae, Mollusca and Oligochaeta were the dominant taxa. In the coast, Polychaeta and Crustacea were dominant. It was recorded 32 taxa in the lakes and mean density of 667 ind.m-2. In the coast 34 taxa were recorded and 1353 ind.m-2. The coastal non-vegetated area was richer and denser and showed the higher eveness. Benthic fauna from the Meridional belt lake and the Eastern belt lake behavioured distinctively among seasons. Three sub-environments had been identified based on the benthic fauna: freshwater environment - majority of the lakes of the Eastern belt, dominated by insects; transition environment (freshwater/coast) with mixed fauna (Polychaeta and Insecta); and coastal environment, with Polychaeta and Crustacea. The environmental characteristics best correlated with spatialtemporal changes in the benthic communities structure were water pH, electric conductivity and turbidity.
Acesso aberto (Open Access)
Predicting biological parameters of estuarine benthic communities using models based on environmental data
(2004-08) ROSA FILHO, José Souto; BEMVENUTI, Carlos Emílio; ELLIOTT, Michael
This study aimed to predict the biological parameters (species composition, abundance, richness, diversity and evenness) of benthic assemblages in southern Brazil estuaries using models based on environmental data (sediment characteristics, salinity, air and water temperature and depth). Samples were collected seasonally from five estuaries between the winter of 1996 and the summer of 1998. At each estuary, samples were taken in unpolluted areas with similar characteristics related to presence or absence of vegetation, depth and distance from the mouth. In order to obtain predictive models, two methods were used, the first one based on Multiple Discriminant Analysis (MDA), and the second based on Multiple Linear Regression (MLR). Models using MDA had better results than those based on linear regression. The best results using MLR were obtained for diversity and richness. It could be concluded that the use predictions models based on environmental data would be very useful in environmental monitoring studies in estuaries.
Acesso aberto (Open Access)
Species composition and abundance of the benthic community of Axiidea
(2012-04) SILVA, Dalila Costa; MARTINELLI-LEMOS, Jussara Moretto
The thalassinideans (Axiidea and Gebiidea) encompasses approximately 615 species with reclusive habits, generally confined to extensive galleries burrowed into the sand or mud and, more rarely, in openings in reefs or the cavities of sessile animals such as sponges and coral. These species use the galleries for shelter, feeding and breeding, except during the pelagic larval stage. They inhabit estuaries, bays, lagoons, beaches, seas and both tropical and temperate oceanic areas throughout the world, distributed predominantly in the intertidal zone (mid-littoral and infralittoral zones). The aim of the present study was to assess the species composition and abundance of thalassinideans, comparing two micro-habitats (consolidated and non-consolidated substrates), and determine whether there is a correlation between abundance of the organisms and time of the year, collection sites or salinity. Twelve monthly samplings were carried out between August 2006 and July 2007 over consolidated and non-consolidated bottoms of the upper and lower portions of the mid-littoral zones, with three sub-samplings, totaling 48 monthly samples and 576 in all. A total of 651 individuals were collected – 114 Lepidophthalmus siriboia Felder & Rodrigues, 1993 and 537 Upogebia vasquezi Ngoc-Ho, 1989. There was correlation between the abundance of both species and salinity, but U. vasquezi was more abundant in the rainy season. Lepidophthalmus siriboia appears to prefer non-consolidated substrates, whereas U. vasquezi prefers consolidated substrates. The recruitment period for the callianassid L. siriboia appears to occur in just two periods of the year and is more intense in the dry season, whereas U. vasquezi is more frequent throughout the year. The smallest and largest sizes (carapace length – CL) recorded for L. siriboia were smaller than those recorded for the species in northeastern region of Brazil. CL values for ovigerous females suggest that U. vasquezi reaches sexual maturity at a smaller size than L. siriboia.