Uso de múltiplas metodologias de ensino-aprendizagem em engenharia ambiental por meio de prática de campo integrativa no sul da Amazônia Brasileira

O ensino integrador tem sido uma ferramenta de modernização metodológica, uma vez que as Diretrizes Curriculares Nacionais têm evoluído para valorização de projetos inter-multidisciplinares, harmonizando a absorção de conteúdo de forma contemporânea, tornando os cidadãos independentes e ativos. Este trabalho tem como objetivo aplicar práticas integrativas, metodologias ativas, visando ressignificar a proposta pedagógica do projeto integrador de forma interdisciplinar e transdisciplinar. O projeto integrador sobre a perspectiva do processo educativo, proporciona ao acadêmico, a vivência e experiencia, a capacitação prática sobre a perspectiva da liderança, de trabalhos em grupo, manuseio de equipamentos, tomadas de decisão e planejamento, favorecendo o amadurecimento científico, técnico e humanitário. O uso de metodologias ativas e práticas de extensão, possibilita ampliar as interpretações sobre os processos de ensino aprendizagem, teórico-prático no currículo de Engenharia Ambiental

Variabilidade do índice de área foliar em campos naturais e floresta de transição na região Sul do Amazonas

The Leaf Area Index (LAI) has strong influence on ecosystems’ energy and mass exchange and is fundamental to the understanding of regional climate changes and ecosystem dynamics. The main goal of this work was to establish, based on geostatistical analyses, the variability and spatial dependence of LAI in the natural fields and transitional forest in southern Amazonas State, in Brazil. The LAI was measured in a regular grid with 33 points at each studied area. Field measurements were done using the canopy analyser LAI -2000, which calculates the structure of the vegetation based on the radiation beneath the tree canopy. The average values of LAI varied according to the studied sites: the highest values were found in the transitional forest (4.42 m2m-2), followed by the high (2.03 m2m-2) and low (1.72 m2m-2) natural fields. All studied sites showed spatial dependence according to the kriging methods, but with different degrees of dependence: spatial dependence was moderate at the transition forest and weak at the natural fields. In the more arboreal open fiel d, the maximum limit at which the points are correlated reached a distance of 35.3 m. The kriging maps proved to be very important tools for describing the spatial distribution of LAI in the Amazon. © 2015, Institute for Environmental Research in Hydrographic Basins (IPABHi). All rights reserved

Estimativa do índice de área Foliar (IAF) e biomassa em pastagem no estado de Rondônia, Brasil

Medidas mensais da altura da pastagem, biomassa total, variações de biomassa viva e morta, a área específica foliar (SLA) e o Índice de Área de Folha (IAF) de fevereiro de 1999 a janeiro de 2005 na Fazenda Nossa Senhora (FNS) e em Rolim de Moura (RDM) entre Fevereiro a Março de 1999, Rondônia, Brasil. A pastagem predominante é Urochloa brizantha (Hochst. ex A. Rich) R. D. Webster (99% na FNS e 76% em RDM), com pequenas manchas de Urochloa humidicula (Rendle). A altura média anual da grama foi de ~0,16 m. Com o pastejo, o mínimo mensal foi de 0,09 m (estação seca) e máximo de 0,3 m sem pastejo (estação úmida). O IAF, biomassa total, material morto, vivo e SLA tiveram valores médios de 2,5 m2 m-2 , 2202 kg ha-1, 2916 kg ha-1 e 19 m2 kg-1 respectivamente. A média mensal da biomassa foi 4224 kg ha-1 em 2002 e 6667 kg ha-1 em 2003. Grande variação sazonal do material vivo e morto, sendo mais alto o vivo durante a estação úmida (3229 contra 2529 kg ha-1), sendo o morto maior durante a seca (2542 contra 1894 kg ha-1). O nível de água no solo variou de -3,1 a -6,5 m durante as estações. Em médias anuais os IAF foram de 1,4 em 2000 a 2,8 em 2003 e o SLA entre 16,3 m2 kg-1 em 1999 e 20,4 m2 kg-1 em 2001. As observações do Albedo variaram de 0,18 para 0,16 em relação aos altos valores de IAF

Vulnerability of groundwater to contamination in the municipality of Humaitá, Amazonas

Groundwater has been used intensively throughout Brazil. In southern Amazonas state, the water supplies of some municipalities are derived exclusively from wells. Yet this region generally has no wastewater treatment, leading to potential contamination of the underground water. We classified and mapped the vulnerability of groundwater supplies to contamination in the urban and peri-urban area of Humaitá in southern Amazonas State. We used the GOD method (Groundwater occurrence; Overall Lithology of the unsaturated zone; Depth of the water table) to score vulnerability classes. The results revealed the existence of average and high vulnerability of aquifer contamination in the area, indicating the fragility of the aquifer system that supplies the municipality, and showing the need for public policies aimed at the protection of the region’s groundwater resources

Influence of drainage status on soil and water chemistry, litter decomposition and soil respiration in central Amazonian forests on sandy soils

Central Amazonian rainforest landscape supports a mosaic of tall terra firme rainforest and ecotone campinarana, riparian and campina forests, reflecting topography-induced variations in soil, nutrient and drainage conditions. Spatial and temporal variations in litter decomposition, soil and groundwater chemistry and soil CO2 respiration were studied in forests on sandy soils, whereas drought sensitivity of poorly-drained valley soils was investigated in an artificial drainage experiment. Slightly changes in litter decomposition or water chemistry were observed as a consequence of artificial drainage. Riparian plots did experience higher litter decomposition rates than campina forest. In response to a permanent lowering of the groundwater level from 0.1 m to 0.3 m depth in the drainage plot, topsoil carbon and nitrogen contents decreased substantially. Soil CO2 respiration decreased from 3.7±0.6 µmol m-2 s-1 before drainage to 2.5±0.2 and 0.8±0.1 µmol m-2 s-1 eight and 11 months after drainage, respectively. Soil respiration in the control plot remained constant at 3.7±0.6 µmol m-2 s-1. The above suggests that more frequent droughts may affect topsoil carbon and nitrogen content and soil respiration rates in the riparian ecosystem, and may induce a transition to less diverse campinarana or short-statured campina forest that covers areas with strongly-leached sandy soil

Water balance, nutrient and carbon export from a heath forest catchment in central Amazonia, Brazil

Carbon storage values in the Amazon basin have been studied through different approaches in the last decades in order to clarify whether the rainforest ecosystem is likely to act as a sink or source for carbon in the near future. This water balance, dissolved organic carbon (DOC) and nutrient export study were carried out in a micro-scale heath forest (Campina) catchment in central Amazonia, Brazil. For a 1-year study period (18 March 2007 until 19 March 2008), rainfall amounted to 3054mm; of which, 1532mm was evaporated by the forest (4.1mmday-1). Rainfall interception loss amounted to 15.6% of gross rainfall. Surface runoff amounted to 485mm, whereas another 1071mm was discharged as regional groundwater outflow. Accumulated DOC exports in surface runoff amounted to 15.3gm-2year-1, whereas the total carbon exported was 55.9gm-2. This is much higher than that observed for a nearby tall rainforest catchment in central Amazonia (DOC export<20gm-2). As Campina heath forest areas cover a significant proportion of the Amazon Basin, these differences in ecosystem hydrological carbon exports should be taken into account in future studies assessing the carbon budget for the Amazon Basin. Macro-nutrient exports were low, but those of calcium and potassium were higher than those observed for tall rainforest in the Amazon, which may be caused by a lower retention capacity of the heath forest ecosystem. © 2015 John Wiley & Sons, Ltd

Comparative measurements and seasonal variations in energy and carbon exchange over forest and pasture in South West Amazonia

Comparative measurements of radiation flux components and turbulent fluxes of energy and CO2 are made at two sites in South West Amazonia: one in a tropical forest reserve and one in a pasture. The data were collected from February 1999 to September 2002, as part of the Large Scale Biosphere-Atmosphere Experiment in Amazonia (LBA). During the dry seasons, although precipitation and specific humidity are greatly reduced, the soil moisture storage profiles down to 3.4 m indicate that the forest vegetation continues to withdraw water from deep layers in the soil. For this reason, seasonal changes observed in the energy partition and CO2 fluxes in the forest are small, compared to the large reductions in evaporation and photosynthesis observed in the pasture. For the radiation balance, the reflected short wave radiation increases by about 55% when changing from forest to pasture. Combined with an increase of 4.7% in long wave radiation loss, this causes an average reduction of 13.3% in net radiation in the pasture, compared to the forest. In the wet season, the evaporative fraction (λE/Rn) at the pasture is 17% lower than at the forest. This difference increases to 24% during the dry season. Daytime CO2 fluxes are 20-28% lower (in absolute values) in the pasture compared to the forest. The nighttime respiration in the pasture is also reduced compared to the forest, with averages 44% and 57% lower in the wet and dry seasons, respectively. As the reduction in the nocturnal respiration is larger than the reduction in the daytime uptake, the combined effect is a 19-67% higher daily uptake of CO2 in the pasture, compared to the forest. This high uptake of CO2 in the pasture site is not surprising, since the growth of the vegetation is constantly renewed, as the cattle remove the biomass. © Springer-Verlag 2004