AVALIAÇÃO DOS IMPACTOS SOCIOAMBIENTAIS URBANOS: O DESCARTE INCORRETO DOS RESÍDUOS E ATIVIDADE DE CONSCIENTIZAÇÃO AMBIENTAL NA CIDADE DE APODI-RN

O surgimento de novas tecnologias resulta no crescimento do número de indústrias e aumento populacional nos centros urbanos. Atrelado a esse crescimento surge a problemática dos resíduos, estes que se transformaram em graves problemas urbanos, muitas vezes, com um gerenciamento oneroso e complexo. Devido à escassez de áreas para deposição, os resíduos estão ligados diretamente à qualidade de vida de uma sociedade.  A quantidade de resíduos produzida por uma população depende de uma série de fatores, como renda, época do ano, modo de vida. Mesmo considerada uma cidade de pequeno porte, Apodi apresenta um crescimento significativo em sua produção de resíduos domésticos e, não havendo um destino correto para os mesmos, surge uma série de problemas socioambientais, tais como: estéticos, saúde e ambiental na cidade. As discussões sobre essa problemática procura responder quais os possíveis impactos socioambientais causados por esses resíduos domésticos e deficiências de instrumentos de saneamento ambiental na população afetada.  Contudo, o presente trabalho tem como objetivo principal propor estudos de conscientização dos impactos socioambientais oriundos do descarte incorreto dos resíduos domésticos na cidade de Apodi – RN, através de pesquisas realizadas e a identificação dos problemas enfrentados pela população da cidade

Índices de eficiência do nitrogênio para avaliação da absorção e da utilização de nitrogênio no sistema radicular e no tanque de bromélias ornamentais

The objective of this work was to evaluate if nitrogen use efficiency (NUE) indexes can elucidate functional differences in nutrient uptake between the root system and tank of epiphytic bromeliads. The bromeliads Guzmania lingulata and Vriesea 'Harmony' received fertilizers in their tanks or through their roots using modified Hoagland & Arnon solution, with 0.00, 2.62, or 5.34 mmol L-1 nitrogen, as urea. After 90 days, nitrogen contents in leaves and plant biomass were evaluated, and NUE indexes were calculated. Guzmania lingulata and V. 'Harmony' fertilized in their tanks with 5.34 mmol L-1 had the highest averages of nitrogen uptake efficiency and recovery efficiency; those fertilized with 2.62 mmol L-1 through their roots showed the highest averages of NUE, nitrogen utilization efficiency, nitrogen physiological efficiency, and biomass conversion efficiency. The NUE indexes, besides being an effective tool to assess the nutritional status of ornamental bromeliads, reveal that the root system of epiphytic bromeliads is functional for nitrogen uptake and use.O objetivo deste trabalho foi avaliar se os índices de eficiência de uso do nitrogênio (EUN) podem elucidar diferenças funcionais na absorção de nutrientes entre o sistema radicular e o tanque de bromélias epifíticas. As bromélias Guzmania lingulata e Vriesea 'Harmony' receberam fertilizantes nos seus tanques ou pelas raízes com solução de Hoagland & Arnon modificada, com 0,00, 2,62 ou 5,34 mmol L-1 de nitrogênio na forma de ureia. Após 90 dias, o conteúdo de nitrogênio nas folhas e a biomassa das plantas foram avaliados, e os índices de EUN calculados. Guzmania lingulata e V. 'Harmony' adubadas no tanque com 5,34 mmol L-1 apresentaram maiores médias de eficiência de absorção de nitrogênio e de eficiência de recuperação; as adubadas nas raízes, com 2,62 mmol L-1, apresentaram as maiores médias de EUN, eficiência de utilização de nitrogênio, eficiência fisiológica de nitrogênio e índice de eficiência de conversão de biomassa. Os índices de EUN, além de serem importantes ferramentas para avaliação do status nutricional das bromélias, revelam que o sistema radicular das bromélias epífitas é funcional para absorção e utilização de nitrogênio

Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

ests face increasing climate risk, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk, little is known about how these vary across Earth’s largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth–mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon, with strong implications for the Amazon carbon sink

Basin-wide variation in tree hydraulic safety margins predicts the carbon balance of Amazon forests

Funding: Data collection was largely funded by the UK Natural Environment Research Council (NERC) project TREMOR (NE/N004655/1) to D.G., E.G. and O.P., with further funds from Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES, finance code 001) to J.V.T. and a University of Leeds Climate Research Bursary Fund to J.V.T. D.G., E.G. and O.P. acknowledge further support from a NERC-funded consortium award (ARBOLES, NE/S011811/1). This paper is an outcome of J.V.T.’s doctoral thesis, which was sponsored by CAPES (GDE 99999.001293/2015-00). J.V.T. was previously supported by the NERC-funded ARBOLES project (NE/S011811/1) and is supported at present by the Swedish Research Council Vetenskapsrådet (grant no. 2019-03758 to R.M.). E.G., O.P. and D.G. acknowledge support from NERC-funded BIORED grant (NE/N012542/1). O.P. acknowledges support from an ERC Advanced Grant and a Royal Society Wolfson Research Merit Award. R.S.O. was supported by a CNPq productivity scholarship, the São Paulo Research Foundation (FAPESP-Microsoft 11/52072-0) and the US Department of Energy, project GoAmazon (FAPESP 2013/50531-2). M.M. acknowledges support from MINECO FUN2FUN (CGL2013-46808-R) and DRESS (CGL2017-89149-C2-1-R). C.S.-M., F.B.V. and P.R.L.B. were financed by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior—Brasil (CAPES, finance code 001). C.S.-M. received a scholarship from the Brazilian National Council for Scientific and Technological Development (CNPq 140353/2017-8) and CAPES (science without borders 88881.135316/2016-01). Y.M. acknowledges the Gordon and Betty Moore Foundation and ERC Advanced Investigator Grant (GEM-TRAITS, 321131) for supporting the Global Ecosystems Monitoring (GEM) network (gem.tropicalforests.ox.ac.uk), within which some of the field sites (KEN, TAM and ALP) are nested. The authors thank Brazil–USA Collaborative Research GoAmazon DOE-FAPESP-FAPEAM (FAPESP 2013/50533-5 to L.A.) and National Science Foundation (award DEB-1753973 to L. Alves). They thank Serrapilheira Serra-1709-18983 (to M.H.) and CNPq-PELD/POPA-441443/2016-8 (to L.G.) (P.I. Albertina Lima). They thank all the colleagues and grants mentioned elsewhere [8,36] that established, identified and measured the Amazon forest plots in the RAINFOR network analysed here. The authors particularly thank J. Lyod, S. Almeida, F. Brown, B. Vicenti, N. Silva and L. Alves. This work is an outcome approved Research Project no. 19 from ForestPlots.net, a collaborative initiative developed at the University of Leeds that unites researchers and the monitoring of their permanent plots from the world’s tropical forests [61]. The authros thank A. Levesley, K. Melgaço Ladvocat and G. Pickavance for ForestPlots.net management. They thank Y. Wang and J. Baker, respectively, for their help with the map and with the climatic data. The authors acknowledge the invaluable help of M. Brum for kindly providing the comparison of vulnerability curves based on PAD and on PLC shown in this manuscript. They thank J. Martinez-Vilalta for his comments on an early version of this manuscript. The authors also thank V. Hilares and the Asociación para la Investigación y Desarrollo Integral (AIDER, Puerto Maldonado, Peru); V. Saldaña and Instituto de Investigaciones de la Amazonía Peruana (IIAP) for local field campaign support in Peru; E. Chavez and Noel Kempff Natural History Museum for local field campaign support in Bolivia; ICMBio, INPA/NAPPA/LBA COOMFLONA (Cooperativa mista da Flona Tapajós) and T. I. Bragança-Marituba for the research support.Tropical forests face increasing climate risk1,2, yet our ability to predict their response to climate change is limited by poor understanding of their resistance to water stress. Although xylem embolism resistance thresholds (for example, Ψ50) and hydraulic safety margins (for example, HSM50) are important predictors of drought-induced mortality risk3-5, little is known about how these vary across Earth's largest tropical forest. Here, we present a pan-Amazon, fully standardized hydraulic traits dataset and use it to assess regional variation in drought sensitivity and hydraulic trait ability to predict species distributions and long-term forest biomass accumulation. Parameters Ψ50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ50 and HSM50 influence the biogeographical distribution of Amazon tree species. However, HSM50 was the only significant predictor of observed decadal-scale changes in forest biomass. Old-growth forests with wide HSM50 are gaining more biomass than are low HSM50 forests. We propose that this may be associated with a growth-mortality trade-off whereby trees in forests consisting of fast-growing species take greater hydraulic risks and face greater mortality risk. Moreover, in regions of more pronounced climatic change, we find evidence that forests are losing biomass, suggesting that species in these regions may be operating beyond their hydraulic limits. Continued climate change is likely to further reduce HSM50 in the Amazon6,7, with strong implications for the Amazon carbon sink.Publisher PDFPeer reviewe

Biogeochemical diversity, O2-supersaturation and hot moments of GHG emissions from shallow alkaline lakes in the Pantanal of Nhecolândia, Brazil

International audienceNhecolândia is a vast sub-region of the Pantanal wetland in Brazil with great diversity in surface water chemistry evolving in a sodic alkaline pathway under the influence of evaporation. In this region, more than 15,000 shallow lakes are likely to contribute an enormous quantity of greenhouse gas to the atmosphere, but the diversity of the biogeochemical scenarios and their variability in time and space is a major challenge to estimate the regional contribution. From 4 selected alkaline lakes, we compiled measurements of the physico-chemical characteristics of water and sediments, gas fluxes in floating chambers, and sedimentation rates to illustrate this diversity. Although these lakes have a similar chemical composition, the results confirm a difference between the black-water and green-water alkaline lakes, corresponding to distinct biogeochemical functioning. This difference does not appear to affect lake sedimentation rates, but is reflected in gas emissions. Black-water lakes are CO2 and CH4 sources, with fairly constant emissions throughout the seasons. Annual carbon dioxide and methane emissions approach 0.86 mol m-2 y-1 and 0.07 mol m-2 y-1 , respectively, and no clear trend towards N2O capture or emission was observed. By contrast, green-water lakes are CO2 and N2O sinks but important CH4 sources with fluxes varying significantly throughout the seasons, depending on the magnitude of the phytoplankton bloom. The results highlight important daily and seasonal variations in gas fluxes, and in particular a hot moments for methane emissions, when the O2-supersaturation is reached during the afternoon under extreme bloom and sunny weather conditions, provoking an abrupt O2 purging of the lakes. Taking into account the seasonal variability, annual methane emissions are around 10.2 mol m-2 y-1 , i.e., much higher than reported in previous studies for alkaline lakes in Nhecolândia. Carbon dioxide and nitrous oxide consumption is estimated about 1.9 mol m-2 y-1 and 0.73 mmol m-2 y-1 , respectively. However, these balances must be better constrained with systematic and targeted measurements throughout the seasons