Base de dados : MEDLINE
Pesquisa : G01.311.977 [Categoria DeCS]
Referências encontradas : 256 [refinar]
Mostrando: 1 .. 10   no formato [Detalhado]

página 1 de 26 ir para página                         

  1 / 256 MEDLINE  
              next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:29023453
[Au] Autor:Anderegg WRL; Wolf A; Arango-Velez A; Choat B; Chmura DJ; Jansen S; Kolb T; Li S; Meinzer F; Pita P; Resco de Dios V; Sperry JS; Wolfe BT; Pacala S
[Ad] Endereço:Department of Biology, University of Utah, Salt Lake City, Utah, United States of America.
[Ti] Título:Plant water potential improves prediction of empirical stomatal models.
[So] Source:PLoS One;12(10):e0185481, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Climate change is expected to lead to increases in drought frequency and severity, with deleterious effects on many ecosystems. Stomatal responses to changing environmental conditions form the backbone of all ecosystem models, but are based on empirical relationships and are not well-tested during drought conditions. Here, we use a dataset of 34 woody plant species spanning global forest biomes to examine the effect of leaf water potential on stomatal conductance and test the predictive accuracy of three major stomatal models and a recently proposed model. We find that current leaf-level empirical models have consistent biases of over-prediction of stomatal conductance during dry conditions, particularly at low soil water potentials. Furthermore, the recently proposed stomatal conductance model yields increases in predictive capability compared to current models, and with particular improvement during drought conditions. Our results reveal that including stomatal sensitivity to declining water potential and consequent impairment of plant water transport will improve predictions during drought conditions and show that many biomes contain a diversity of plant stomatal strategies that range from risky to conservative stomatal regulation during water stress. Such improvements in stomatal simulation are greatly needed to help unravel and predict the response of ecosystems to future climate extremes.
[Mh] Termos MeSH primário: Fotossíntese/fisiologia
Folhas de Planta/fisiologia
Estômatos de Plantas/fisiologia
Transpiração Vegetal/fisiologia
Ciclo Hidrológico
Água/química
[Mh] Termos MeSH secundário: Mudança Climática
Ecossistema
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
059QF0KO0R (Water)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171027
[Lr] Data última revisão:
171027
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:171013
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0185481


  2 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28686667
[Au] Autor:Chen Y; Li J; Ju W; Ruan H; Qin Z; Huang Y; Jeelani N; Padarian J; Propastin P
[Ad] Endereço:Joint Innovation Center for Modern Forestry Studies, College of Biology and Environment, Nanjing Forestry University, Nanjing, China.
[Ti] Título:Quantitative assessments of water-use efficiency in Temperate Eurasian Steppe along an aridity gradient.
[So] Source:PLoS One;12(7):e0179875, 2017.
[Is] ISSN:1932-6203
[Cp] País de publicação:United States
[La] Idioma:eng
[Ab] Resumo:Water-use efficiency (WUE), defined as the ratio of net primary productivity (NPP) to evapotranspiration (ET), is an important indicator to represent the trade-off pattern between vegetation productivity and water consumption. Its dynamics under climate change are important to ecohydrology and ecosystem management, especially in the drylands. In this study, we modified and used a late version of Boreal Ecosystem Productivity Simulator (BEPS), to quantify the WUE in the typical dryland ecosystems, Temperate Eurasian Steppe (TES). The Aridity Index (AI) was used to specify the terrestrial water availability condition. The regional results showed that during the period of 1999-2008, the WUE has a clear decreasing trend in the spatial distribution from arid to humid areas. The highest annual average WUE was in dry and semi-humid sub-region (DSH) with 0.88 gC mm-1 and the lowest was in arid sub-region (AR) with 0.22 gC mm-1. A two-stage pattern of WUE was found in TES. That is, WUE would enhance with lower aridity stress, but decline under the humid environment. Over 65% of the region exhibited increasing WUE. This enhancement, however, could not indicate that the grasslands were getting better because the NPP even slightly decreased. It was mainly attributed to the reduction of ET over 70% of the region, which is closely related to the rainfall decrease. The results also suggested a similar negative spatial correlation between the WUE and the mean annual precipitation (MAP) at the driest and the most humid ends. This regional pattern reflected the different roles of water in regulating the terrestrial ecosystems under different aridity levels. This study could facilitate the understanding of the interactions between terrestrial carbon and water cycles, and thus contribute to a sustainable management of nature resources in the dryland ecosystems.
[Mh] Termos MeSH primário: Ecossistema
Ciclo Hidrológico
Abastecimento de Água
[Mh] Termos MeSH secundário: Animais
Biomassa
Ciclo do Carbono
Dióxido de Carbono/metabolismo
Mudança Climática
Clima Desértico
Pradaria
Seres Humanos
Cazaquistão
Meteorologia
Solo/química
Água/química
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Soil); 059QF0KO0R (Water); 142M471B3J (Carbon Dioxide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171116
[Lr] Data última revisão:
171116
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170708
[St] Status:MEDLINE
[do] DOI:10.1371/journal.pone.0179875


  3 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28447639
[Au] Autor:Taylor CM; Belusic D; Guichard F; Parker DJ; Vischel T; Bock O; Harris PP; Janicot S; Klein C; Panthou G
[Ad] Endereço:Centre for Ecology and Hydrology, Wallingford OX10 8BB, UK.
[Ti] Título:Frequency of extreme Sahelian storms tripled since 1982 in satellite observations.
[So] Source:Nature;544(7651):475-478, 2017 04 26.
[Is] ISSN:1476-4687
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The hydrological cycle is expected to intensify under global warming, with studies reporting more frequent extreme rain events in many regions of the world, and predicting increases in future flood frequency. Such early, predominantly mid-latitude observations are essential because of shortcomings within climate models in their depiction of convective rainfall. A globally important group of intense storms-mesoscale convective systems (MCSs)-poses a particular challenge, because they organize dynamically on spatial scales that cannot be resolved by conventional climate models. Here, we use 35 years of satellite observations from the West African Sahel to reveal a persistent increase in the frequency of the most intense MCSs. Sahelian storms are some of the most powerful on the planet, and rain gauges in this region have recorded a rise in 'extreme' daily rainfall totals. We find that intense MCS frequency is only weakly related to the multidecadal recovery of Sahel annual rainfall, but is highly correlated with global land temperatures. Analysis of trends across Africa reveals that MCS intensification is limited to a narrow band south of the Sahara desert. During this period, wet-season Sahelian temperatures have not risen, ruling out the possibility that rainfall has intensified in response to locally warmer conditions. On the other hand, the meridional temperature gradient spanning the Sahel has increased in recent decades, consistent with anthropogenic forcing driving enhanced Saharan warming. We argue that Saharan warming intensifies convection within Sahelian MCSs through increased wind shear and changes to the Saharan air layer. The meridional gradient is projected to strengthen throughout the twenty-first century, suggesting that the Sahel will experience particularly marked increases in extreme rain. The remarkably rapid intensification of Sahelian MCSs since the 1980s sheds new light on the response of organized tropical convection to global warming, and challenges conventional projections made by general circulation models.
[Mh] Termos MeSH primário: Inundações/estatística & dados numéricos
Chuvas
Imagens de Satélites
[Mh] Termos MeSH secundário: África ao Sul do Saara
África do Norte
Convecção
Aquecimento Global/estatística & dados numéricos
Modelos Teóricos
Estações do Ano
Temperatura Ambiente
Ciclo Hidrológico
Vento
[Pt] Tipo de publicação:JOURNAL ARTICLE; RESEARCH SUPPORT, NON-U.S. GOV'T; RESEARCH SUPPORT, U.S. GOV'T, NON-P.H.S.
[Em] Mês de entrada:1708
[Cu] Atualização por classe:170829
[Lr] Data última revisão:
170829
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170428
[St] Status:MEDLINE
[do] DOI:10.1038/nature22069


  4 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28408188
[Au] Autor:Brezina E; Prasse C; Meyer J; Mückter H; Ternes TA
[Ad] Endereço:Federal Institute of Hydrology (BfG), Am Mainzer Tor 1, 56068 Koblenz, Germany.
[Ti] Título:Investigation and risk evaluation of the occurrence of carbamazepine, oxcarbazepine, their human metabolites and transformation products in the urban water cycle.
[So] Source:Environ Pollut;225:261-269, 2017 Jun.
[Is] ISSN:1873-6424
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Trace organic contaminants such as pharmaceuticals, personal care products and industrial chemicals are frequently detected in the urban water cycle, including wastewater, surface water and groundwater, as well as drinking water. These also include human metabolites (HMs), which are formed in the human body and then excreted via urine or feces, as well as transformation products (TPs) formed in engineered treatment systems and the aquatic environment. In the current study, the occurrence of HMs as well as their TPs of the anticonvulsants carbamazepine (CBZ) and oxcarbazepine (OXC) were investigated using LC tandem MS in effluents of wastewater treatment plants (WWTPs), surface water and groundwater. Highest concentrations were observed in raw wastewater for 10,11-dihydro-10,11-dihydroxycarbamazepine (DiOHCBZ), 10,11-dihydro-10-hydroxy-cabamazepine (10OHCBZ) and CBZ with concentrations ranging up to 2.7 ± 0.4, 1.7 ± 0.2 and 1.07 ± 0.06 µg L , respectively. Predictions of different toxicity endpoints using a Distributed Structure-Searchable Toxicity (DSSTox) expert system query indicated that several HMs and TPs, in particular 9-carboxy-acridine (9-CA-ADIN) and acridone (ADON), may exhibit an increased genotoxicity compared to the parent compound CBZ. As 9-CA-ADIN was also detected in groundwater, a detailed investigation of the genotoxicity of 9-CA-ADIN is warranted. Investigations of an advanced wastewater treatment plant further revealed that the discharge of the investigated compounds into the aquatic environment could be substantially reduced by ozonation followed by granular activated carbon (GAC) filtration.
[Mh] Termos MeSH primário: Carbamazepina/análise
Poluentes Químicos da Água/análise
[Mh] Termos MeSH secundário: Carbamazepina/análogos & derivados
Carbamazepina/metabolismo
Cromatografia Líquida
Cidades
Filtração
Água Subterrânea
Seres Humanos
Espectrometria de Massas
Medição de Risco
Eliminação de Resíduos Líquidos
Águas Residuais/química
Ciclo Hidrológico
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Waste Water); 0 (Water Pollutants, Chemical); 33CM23913M (Carbamazepine); 35079-97-1 (10,11-dihydro-10,11-dihydroxy-5H-dibenzazepine-5-carboxamide); VZI5B1W380 (oxcarbazepine)
[Em] Mês de entrada:1707
[Cu] Atualização por classe:170728
[Lr] Data última revisão:
170728
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170415
[St] Status:MEDLINE


  5 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28243930
[Au] Autor:Iqbal N; Hossain F; Lee H; Akhter G
[Ad] Endereço:Department of Earth Sciences, Quaid-i-Azam University, Islamabad, Pakistan. naveed_spacian@yahoo.com.
[Ti] Título:Integrated groundwater resource management in Indus Basin using satellite gravimetry and physical modeling tools.
[So] Source:Environ Monit Assess;189(3):128, 2017 Mar.
[Is] ISSN:1573-2959
[Cp] País de publicação:Netherlands
[La] Idioma:eng
[Ab] Resumo:Reliable and frequent information on groundwater behavior and dynamics is very important for effective groundwater resource management at appropriate spatial scales. This information is rarely available in developing countries and thus poses a challenge for groundwater managers. The in situ data and groundwater modeling tools are limited in their ability to cover large domains. Remote sensing technology can now be used to continuously collect information on hydrological cycle in a cost-effective way. This study evaluates the effectiveness of a remote sensing integrated physical modeling approach for groundwater management in Indus Basin. The Gravity Recovery and Climate Experiment Satellite (GRACE)-based gravity anomalies from 2003 to 2010 were processed to generate monthly groundwater storage changes using the Variable Infiltration Capacity (VIC) hydrologic model. The groundwater storage is the key parameter of interest for groundwater resource management. The spatial and temporal patterns in groundwater storage (GWS) are useful for devising the appropriate groundwater management strategies. GRACE-estimated GWS information with large-scale coverage is valuable for basin-scale monitoring and decision making. This frequently available information is found useful for the identification of groundwater recharge areas, groundwater storage depletion, and pinpointing of the areas where groundwater sustainability is at risk. The GWS anomalies were found to favorably agree with groundwater model simulations from Visual MODFLOW and in situ data. Mostly, a moderate to severe GWS depletion is observed causing a vulnerable situation to the sustainability of this groundwater resource. For the sustainable groundwater management, the region needs to implement groundwater policies and adopt water conservation techniques.
[Mh] Termos MeSH primário: Conservação dos Recursos Naturais
Monitoramento Ambiental/métodos
Água Subterrânea
Abastecimento de Água
[Mh] Termos MeSH secundário: Clima
Hidrologia
Modelos Teóricos
Paquistão
Tecnologia de Sensoriamento Remoto
Ciclo Hidrológico
[Pt] Tipo de publicação:EVALUATION STUDIES; JOURNAL ARTICLE
[Em] Mês de entrada:1705
[Cu] Atualização por classe:171020
[Lr] Data última revisão:
171020
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170301
[St] Status:MEDLINE
[do] DOI:10.1007/s10661-017-5846-1


  6 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28181733
[Au] Autor:Yan W; Zhong Y; Shangguan Z
[Ad] Endereço:State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Northwest A&F University, Yangling, Shaanxi, 712100, China.
[Ti] Título:Contrasting responses of leaf stomatal characteristics to climate change: a considerable challenge to predict carbon and water cycles.
[So] Source:Glob Chang Biol;23(9):3781-3793, 2017 Sep.
[Is] ISSN:1365-2486
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Stomata control the cycling of water and carbon between plants and the atmosphere; however, no consistent conclusions have been drawn regarding the response of stomatal frequency to climate change. Here, we conducted a meta-analysis of 1854 globally obtained data series to determine the response of stomatal frequency to climate change, which including four plant life forms (over 900 species), at altitudes ranging from 0 to 4500 m and over a time span of more than one hundred thousand years. Stomatal frequency decreased with increasing CO concentration and increased with elevated temperature and drought stress; it was also dependent on the species and experimental conditions. The response of stomatal frequency to climate change showed a trade-off between stomatal control strategies and environmental factors, such as the CO concentration, temperature, and soil water availability. Moreover, threshold effects of elevated CO and temperature on stomatal frequency were detected, indicating that the response of stomatal density to increasing CO concentration will decrease over the next few years. The results also suggested that the stomatal index may be more reliable than stomatal density for determination of the historic CO concentration. Our findings indicate that the contrasting responses of stomata to climate change bring a considerable challenge in predicting future water and carbon cycles.
[Mh] Termos MeSH primário: Carbono/metabolismo
Mudança Climática
Estômatos de Plantas/fisiologia
Ciclo Hidrológico
[Mh] Termos MeSH secundário: Dióxido de Carbono
Folhas de Planta
Água
[Pt] Tipo de publicação:JOURNAL ARTICLE; META-ANALYSIS
[Nm] Nome de substância:
059QF0KO0R (Water); 142M471B3J (Carbon Dioxide); 7440-44-0 (Carbon)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171020
[Lr] Data última revisão:
171020
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170210
[St] Status:MEDLINE
[do] DOI:10.1111/gcb.13654


  7 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:28171808
[Au] Autor:Cai YF; Yang QY; Li SF; Wang JH; Huang W
[Ad] Endereço:Flower Research Institute of Yunnan Academy of Agricultural Sciences, Kunming, Yunnan, China.
[Ti] Título:The water-water cycle is a major electron sink in Camellia species when CO assimilation is restricted.
[So] Source:J Photochem Photobiol B;168:59-66, 2017 Mar.
[Is] ISSN:1873-2682
[Cp] País de publicação:Switzerland
[La] Idioma:eng
[Ab] Resumo:The water-water cycle (WWC) is thought to dissipate excess excitation energy and balance the ATP/NADPH energy budget under some conditions. However, the importance of the WWC in photosynthetic regulation remains controversy. We observed that three Camellia cultivars exhibited high rates of photosynthetic electron flow under high light when photosynthesis was restricted. We thus tested the hypothesis that the WWC is a major electron sink in the three Camellia cultivars when CO assimilation is restricted. Light response curves indicated that the WWC was strongly increased with photorespiration and was positively correlated with extra ATP supplied from other flexible mechanisms excluding linear electron flow, implying that the WWC is an important alternative electron sink to balance ATP/NADPH energy demand for sustaining photorespiration in Camellia cultivars. Interestingly, when photosynthesis was depressed by the decreases in stomatal and mesophyll conductance, the rates of photosynthetic electron flow through photosystem II declined slightly and the rates of WWC was enhanced. Furthermore, the increased electron flow of WWC was positively correlated with the ratio of Rubisco oxygenation to carboxylation, supporting the involvement of alternative electron flow in balancing the ATP/NADPH energy budget. We propose that the WWC is a crucial electron sink to regulate ATP/NADPH energy budget and dissipate excess energy excitation in Camellia species when CO assimilation is restricted.
[Mh] Termos MeSH primário: Camellia/metabolismo
Dióxido de Carbono/metabolismo
Transporte de Elétrons
Ciclo Hidrológico/fisiologia
[Mh] Termos MeSH secundário: Trifosfato de Adenosina/metabolismo
Metabolismo Energético
NADP/metabolismo
Fotossíntese
Complexo de Proteína do Fotossistema II/metabolismo
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Photosystem II Protein Complex); 142M471B3J (Carbon Dioxide); 53-59-8 (NADP); 8L70Q75FXE (Adenosine Triphosphate)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170410
[Lr] Data última revisão:
170410
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:170208
[St] Status:MEDLINE


  8 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27810539
[Au] Autor:Zhu X; Jin L; Yang J; Wu J; Zhang B; Zhang X; Yu N; Wei S; Wu J; Yu H
[Ad] Endereço:MOE Key Laboratory of Surficial Geochemistry, Department of Hydrosciences, School of Earth Sciences and Engineering, Nanjing University, Nanjing, People's Republic of China.
[Ti] Título:Perfluoroalkyl acids in the water cycle from a freshwater river basin to coastal waters in eastern China.
[So] Source:Chemosphere;168:390-398, 2017 Feb.
[Is] ISSN:1879-1298
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:The distribution of perfluoroalkyl acids (PFAAs), one class of persistent organic pollutants, in groundwater, especially in confined aquifers remains poorly understood. In this study, we investigated the occurrence of 12 PFAAs through a water cycle from the Huai River Basin to the Yellow Sea, including confined aquifers, unconfined aquifers, rivers, and coastal waters. We found the ubiquity of PFAAs in all types of samples, including those from confined aquifers (2.7-6.8 ng/L). Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) were the major PFAAs in all samples, accounting for an average of 49.1% (0.8-84.8%) and 33.3% (6.3-92.2%) of total PFAAs, respectively. Comparing the concentration of PFOA with that of PFOS, we found a higher concentration of PFOA in rivers and a higher concentration of PFOS in confined aquifers. Short-chain perfluoropentanoic acid accounted for an average of 10.3% (1.9-24.6%) of total PFAAs in rivers and coastal waters. Branched isomers of both PFOA and PFOS were detected in most samples (36/42 and 39/42, respectively). One-way analysis of variance indicated a significant difference in the profiles of PFAAs among the different types of water samples. Principal component analysis suggested that rainwater and recent uses of PFAAs could be the major sources of PFAAs in confined aquifers, while recent and current uses of PFAAs could be the major source of PFAAs in unconfined aquifers, rivers and coastal waters. The risk quotients of PFOA and PFOS in groundwater and rivers were 2-3 orders of magnitude lower than unity, indicating no immediate risks via drinking water consumption.
[Mh] Termos MeSH primário: Ácidos Alcanossulfônicos/análise
Monitoramento Ambiental/métodos
Fluorcarbonetos/análise
Água Subterrânea/análise
Rios
Ciclo Hidrológico
Poluentes Químicos da Água/análise
[Mh] Termos MeSH secundário: Caprilatos/análise
China
Água Doce/análise
Geografia
Medição de Risco
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
0 (Alkanesulfonic Acids); 0 (Caprylates); 0 (Fluorocarbons); 0 (Water Pollutants, Chemical); 947VD76D3L (perfluorooctanoic acid); 9H2MAI21CL (perfluorooctane sulfonic acid)
[Em] Mês de entrada:1704
[Cu] Atualização por classe:170817
[Lr] Data última revisão:
170817
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:161105
[St] Status:MEDLINE


  9 / 256 MEDLINE  
              first record previous record next record last record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27633752
[Au] Autor:Knapp AK; Avolio ML; Beier C; Carroll CJ; Collins SL; Dukes JS; Fraser LH; Griffin-Nolan RJ; Hoover DL; Jentsch A; Loik ME; Phillips RP; Post AK; Sala OE; Slette IJ; Yahdjian L; Smith MD
[Ad] Endereço:Department of Biology and Graduate Degree Program in Ecology, Colorado State University, Fort Collins, CO, 80523, USA.
[Ti] Título:Pushing precipitation to the extremes in distributed experiments: recommendations for simulating wet and dry years.
[So] Source:Glob Chang Biol;23(5):1774-1782, 2017 May.
[Is] ISSN:1365-2486
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Intensification of the global hydrological cycle, ranging from larger individual precipitation events to more extreme multiyear droughts, has the potential to cause widespread alterations in ecosystem structure and function. With evidence that the incidence of extreme precipitation years (defined statistically from historical precipitation records) is increasing, there is a clear need to identify ecosystems that are most vulnerable to these changes and understand why some ecosystems are more sensitive to extremes than others. To date, opportunistic studies of naturally occurring extreme precipitation years, combined with results from a relatively small number of experiments, have provided limited mechanistic understanding of differences in ecosystem sensitivity, suggesting that new approaches are needed. Coordinated distributed experiments (CDEs) arrayed across multiple ecosystem types and focused on water can enhance our understanding of differential ecosystem sensitivity to precipitation extremes, but there are many design challenges to overcome (e.g., cost, comparability, standardization). Here, we evaluate contemporary experimental approaches for manipulating precipitation under field conditions to inform the design of 'Drought-Net', a relatively low-cost CDE that simulates extreme precipitation years. A common method for imposing both dry and wet years is to alter each ambient precipitation event. We endorse this approach for imposing extreme precipitation years because it simultaneously alters other precipitation characteristics (i.e., event size) consistent with natural precipitation patterns. However, we do not advocate applying identical treatment levels at all sites - a common approach to standardization in CDEs. This is because precipitation variability varies >fivefold globally resulting in a wide range of ecosystem-specific thresholds for defining extreme precipitation years. For CDEs focused on precipitation extremes, treatments should be based on each site's past climatic characteristics. This approach, though not often used by ecologists, allows ecological responses to be directly compared across disparate ecosystems and climates, facilitating process-level understanding of ecosystem sensitivity to precipitation extremes.
[Mh] Termos MeSH primário: Secas
Ecossistema
Ciclo Hidrológico
[Mh] Termos MeSH secundário: Ecologia
Chuvas
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171023
[Lr] Data última revisão:
171023
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160917
[St] Status:MEDLINE
[do] DOI:10.1111/gcb.13504


  10 / 256 MEDLINE  
              first record previous record
seleciona
para imprimir
Fotocópia
Texto completo
[PMID]:27435666
[Au] Autor:Rigden AJ; Salvucci GD
[Ad] Endereço:Department of Earth and Environment, Boston University, 675 Commonwealth Ave., Boston, MA, 02215, USA.
[Ti] Título:Stomatal response to humidity and CO implicated in recent decline in US evaporation.
[So] Source:Glob Chang Biol;23(3):1140-1151, 2017 Mar.
[Is] ISSN:1365-2486
[Cp] País de publicação:England
[La] Idioma:eng
[Ab] Resumo:Evapotranspiration, defined as the total flux of water from the land surface to the atmosphere, is a major component of the hydrologic cycle and surface energy balance. Although evapotranspiration is expected to intensify with increasing temperatures, long-term, regional trends in evapotranspiration remain uncertain due to spatially and temporally limited direct measurements. In this study, we utilize an emergent relation between the land surface and atmospheric boundary layer to infer daily evapotranspiration from historical meteorological data collected at 236 weather stations across the United States. Our results suggest a statistically significant (α = 0.05) decrease in evapotranspiration of approximately 6% from 1961 to 2014, with a significant (α = 0.05) sharp decline of 13% from 1998 to 2014. We attribute the decrease in evapotranspiration mostly to declines in surface conductance, but also to offsetting changes in longwave radiation, wind speed, and incoming solar radiation. Using an established stomatal conductance model, we explain the changes in inferred surface conductance as a response to increases in carbon dioxide and, more recently, to an abrupt decrease in atmospheric humidity.
[Mh] Termos MeSH primário: Dióxido de Carbono
Umidade
Ciclo Hidrológico
[Mh] Termos MeSH secundário: Estados Unidos
Água
Tempo (Meteorologia)
[Pt] Tipo de publicação:JOURNAL ARTICLE
[Nm] Nome de substância:
059QF0KO0R (Water); 142M471B3J (Carbon Dioxide)
[Em] Mês de entrada:1710
[Cu] Atualização por classe:171023
[Lr] Data última revisão:
171023
[Sb] Subgrupo de revista:IM
[Da] Data de entrada para processamento:160721
[St] Status:MEDLINE
[do] DOI:10.1111/gcb.13439



página 1 de 26 ir para página                         
   


Refinar a pesquisa
  Base de dados : MEDLINE Formulário avançado   

    Pesquisar no campo  
1  
2
3
 
           



Search engine: iAH v2.6 powered by WWWISIS

BIREME/OPAS/OMS - Centro Latino-Americano e do Caribe de Informação em Ciências da Saúde