Gap-filling carbon dioxide, water, energy, and methane fluxes in challenging ecosystems : comparing between methods, drivers, and gap-lengths

Acknowledgements The authors thank the FLUXNET-CH4 research groups for providing the CC-BY-4.0 (Tier one) open-access eddy covariance data (https://fluxnet.org/data/fluxnet-ch4-community-product/) and ERA5 (https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era5) for providing meteorology reanalysis data. They also thank the ReddyProc (https://cran.r-project.org/web/packages/R EddyProc/index.html) team, scikit-learn (https://scikit-learn.org/s table/install.html) team, and Xgboost team (https://xgboost.readthedocs.io/en/stable/python/python_api.html) for the packages that help the implementation and validation for gap-filling approaches. SZ and TH would like to acknowledge funding from Shell to support the PhD studentship. Rothamsted thanks BBSRC grants BBS/E/C/000I0320 and BBS/E/C/000J0100. The Eddy Covariance equipment deployed in this work was funded by CIEL (https://www.cielivestock.co.uk/) and the raw data is available on the Farm Platform Portal (https://nwfp.rothamsted.ac.uk/).Peer reviewedPublisher PD

Variation of non-structural carbohydrates across the fast–slow continuum in Amazon Forest canopy trees

1. Tropical tree species span a range of life-history strategies within a fast–slow continuum. The position of a species within this continuum is thought to reflect a negative relationship between growth and storage, with fast-growing species allocating more carbon to growth and slow-growing species investing more in storage. For tropical species, the relationship between storage and life-history strategies has been largely studied on seedlings and less so in adult trees. 2. We evaluated how stored non-structural carbohydrates (NSC) vary across adult trees spanning the fast–slow continuum in the Peruvian Amazon by: (a) analysing whole-tree NSC in two species of contrasting growth and (b) investigating the relationships with key life-history traits across a broader set of species. 3. Our results are consistent with a growth–storage trade-off. The analysis of whole-tree NSC revealed that the slow-growing Eschweilera coriacea stored about 2.7 times as much NSC as the fast-growing Bixa arborea due to markedly higher storage in woody stems and roots. B. arborea also had higher seasonality in NSC, reflecting its strong seasonality in stem growth. Across a range of species, stem starch was negatively related to species growth rate and positively related to wood density. 4. Given the role of NSC in mediating plants' response to stress, our results suggest that slow-growing species with greater storage reserves may be more resilient to drought than fast-growing species

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

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

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

Non-structural carbohydrates mediate seasonal water stress across Amazon forests

Non-structural carbohydrates (NSC) are major substrates for plant metabolism and have been implicated in mediating drought-induced tree mortality. Despite their significance, NSC dynamics in tropical forests remain little studied. We present leaf and branch NSC data for 82 Amazon canopy tree species in six sites spanning a broad precipitation gradient. During the wet season, total NSC (NSCT) concentrations in both organs were remarkably similar across communities. However, NSCT and its soluble sugar (SS) and starch components varied much more across sites during the dry season. Notably, the proportion of leaf NSCT in the form of SS (SS:NSCT) increased greatly in the dry season in almost all species in the driest sites, implying an important role of SS in mediating water stress in these sites. This adjustment of leaf NSC balance was not observed in tree species less-adapted to water deficit, even under exceptionally dry conditions. Thus, leaf carbon metabolism may help to explain floristic sorting across water availability gradients in Amazonia and enable better prediction of forest responses to future climate change

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

This is the final version. Available on open access from Nature Research via the DOI in this recordData availability: The pan-Amazonian HT dataset (Ψ 50, Ψ dry and HSM50) and branch wood density per species per site, as well as forest dynamic and climate data per plot presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023. Basal area weighted mean LMA is shown in Supplementary Table 2. Species stem wood density data were obtained from Global Wood Density database65,66. Species WDA data were extracted from ref. 45.Code availability: The codes to recreate the main analyses and the main figures presented in this study are available as a ForestPlots.net data package at https://forestplots.net/data-packages/Tavares-et-al-2023.Tropical forests 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, Ψ 50) 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 Ψ 50 and HSM50 vary markedly across the Amazon and are related to average long-term rainfall characteristics. Both Ψ 50 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

Tropical forest lianas have greater non-structural carbohydrate concentrations in the stem xylem than trees

This is the author accepted manuscript. The final version is available on open access from Oxford University Press via the DOI in this recordData availability: The stem non-structural carbohydrate concentration data for trees and lianas are available as data packages via ForestPlots.net (DOI: 10.5521/forestplots.net/2023_3). The inventory data to estimate species growth rate at the study site are from the RAINFOR network, available upon request at ForestPlots.net (Lopez-Gonzalez et al. 2011, ForestPlot.net et al. 2021). Wood density from species occurring in the dry site are from Soares Jancoski et al. (2022), for species in the moist site, we used mean species wood density for the Amazon Basin from Chave et al. (2009), Zanne et al. (2009).Lianas (woody vines) are important components of tropical forests and are known to compete with host trees for resources, decrease tree growth and increase tree mortality. Given the observed increases in liana abundance in some forests and their impacts on forest function, an integrated understanding of carbon dynamics of lianas and liana-infested host trees is critical for improved prediction of tropical forest responses to climate change. Non-structural carbohydrates (NSC) are the main substrate for plant metabolism (e.g., growth, respiration), and have been implicated in enabling tree survival under environmental stress, but little is known of how they vary among life-forms or of how liana infestation impacts host tree NSC. We quantified stem total NSC (NSC) concentrations and its fractions (starch and soluble sugars) in trees without liana infestation, trees with more than 50% of the canopy covered by lianas, and the lianas infesting those trees. We hypothesized that i) liana infestation depletes NSC storage in host trees by reducing carbon assimilation due to competition for resources; ii) trees and lianas, which greatly differ in functional traits related to water transport and carbon uptake, would also have large differences in NSC storage, and that As water availability has a significant role in NSC dynamics of Amazonian tree species, we tested these hypotheses within a moist site in western Amazonia and a drier forest site in southern Amazonia. We did not find any difference in NSC, starch or soluble sugar concentrations between infested and non-infested trees, in either site. This result suggests that negative liana impact on trees may be mediated through mechanisms other than depletion of host tree NSC concentrations. We found lianas have higher stem NSC and starch than trees in both sites. The consistent differences in starch concentrations, a long term NSC reserve, between life forms across sites reflect differences in carbon gain and use of lianas and trees. Soluble sugar concentrations were higher in lianas than in trees in the moist site but indistinguishable between life forms in the dry site. The lack of difference in soluble sugars between trees and lianas in the dry site emphasize the importance of this NSC fraction for plant metabolism of plants occurring in water limited environments. Abstract in Portuguese and Spanish are available in the supplementary material.Natural Environment Research Council (NERC)São Paulo Research FoundationBrazilian National Council for Scientific and Technological Development (CNPq)CAPESEuropean Union Horizon 202

Exame do escarro no manejo clínico dos pacientes com pneumonia adquirida na comunidade Sputum examination in the clinical management of community-acquired pneumonia

OBJETIVO: Este estudo retrospectivo avaliou a freqüência do uso da bacteriologia do escarro no manejo clínico de pacientes com pneumonia adquirida na comunidade (PAC) em um hospital geral, e se a utilização deste método modificou a mortalidade. MÉTODOS: Os prontuários de pacientes internados no Hospital Nossa Senhora da Conceição, em Porto Alegre (RS) Brasil, para tratamento de PAC entre maio e novembro de 2004 foram revisados quanto aos seguintes aspectos: idade; sexo; gravidade da pneumonia (escore de Fine); presença de expectoração; bacteriologia do escarro; história de tratamento; resposta clínica; troca de tratamento; e mortalidade. RESULTADOS: Foram avaliados 274 pacientes com PAC, sendo 134 do sexo masculino. Dentre os 274 pacientes, 79 (28,8%) apresentavam, de acordo com o escore de Fine, classe II; 45 (16,4%), classe III; 97 (35,4%), classe IV; e 53 (19,3%), classe V. Em 92 pacientes (33,6%), uma amostra de escarro foi colhida para exame bacteriológico. Obtivemos amostra válida em 37 casos (13,5%) e diagnóstico etiológico em 26 (9,5%), o que resultou em modificação do tratamento em apenas 9 casos (3,3%). A mortalidade geral foi 18,6%. Idade acima de 65 anos, a gravidade da PAC e a ausência de escarro associaram-se à maior mortalidade. A bacteriologia do escarro não influenciou o desfecho clínico, nem a taxa de mortalidade. CONCLUSÃO: O exame do escarro foi uma ferramenta diagnóstica utilizada na minoria dos pacientes, e não trouxe benefício detectável no manejo clínico dos pacientes com PAC tratados em ambiente hospitalar.<br>OBJECTIVE: To evaluate the frequency of the use of sputum examination in the clinical management of community-acquired pneumonia (CAP) in a general hospital and to determine whether its use has an impact on mortality. METHODS: The medical records of CAP patients treated as inpatients between May and November of 2004 at the Nossa Senhora da Conceição Hospital, located in Porto Alegre, Brazil, were reviewed regarding the following aspects: age; gender; severity of pneumonia (Fine score); presence of sputum; sputum bacteriology; treatment history; change in treatment; and mortality. RESULTS: A total of 274 CAP patients (134 males and 140 females) were evaluated. Using the Fine score to quantify severity, we classified 79 (28.8%) of those 274 patients as class II, 45 (16.4%) as class III, 97 (35.4%) as class IV, and 53 (19.3%) as class V. Sputum examination was carried out in 92 patients (33.6%). A valid sample was obtained in 37 cases (13.5%), and an etiological diagnosis was obtained in 26 (9.5%), resulting in a change of treatment in only 9 cases (3.3%). Overall mortality was 18.6%. Advanced age (above 65), CAP severity, and dry cough were associated with an increase in the mortality rate. Sputum examination did not alter any clinical outcome or have any influence on mortality. CONCLUSION: Sputum examination was used in a minority of patients and was not associated with any noticeable benefit in the clinical management of patients with CAP treated in a hospital setting

Força muscular respiratória e capacidade funcional na insuficiência renal terminal

OBJETIVO: Verificar a associação da força muscular respiratória com a capacidade funcional, força proximal de membros inferiores e variáveis bioquímicas em pacientes em hemodiálise (HD). MÉTODOS: Participaram deste estudo 30 indivíduos (18 homens), com 53,4 ± 12,9 anos e tempo de HD de 41,1 ± 55,7 meses. Foram avaliados pressão inspiratória máxima (PImax), pressão expiratória máxima (PEmax), distância percorrida no teste de caminhada de seis minutos (6MWT), número de repetições no teste de sentar-e-levantar em 30 segundos (TSL) e registrados os exames bioquímicos de rotina no serviço. RESULTADOS: Houve diminuição da PEmax em relação aos valores preditos (p = 0,015) e redução na distância percorrida no 6MWT quando comparados com equações de predição (p < 0,001). O logPImax e o logPEmax correlacionaram-se com o número de repetições no TSL (r = 0,476, p = 0,008; r = 0,540, p = 0,002, respectivamente), e com os níveis séricos de fósforo (r = 0,422, p = 0,020; r = 0,639, p < 0,001, respectivamente). A distância no 6MWT correlacionou-se com o logPEmax (r = 0,511; p = 0,004) e com o número de repetições no TSL (r = 0,561; p = 0,001). CONCLUSÃO: A redução da PEmax em pacientes com IRT em HD está associada à capacidade funcional, força proximal de membros inferiores e níveis de fósforo sérico, podendo representar, pelo menos em parte, o baixo desempenho físico-funcional desses pacientes.OBJECTIVE: to evaluate the association of respiratory muscle strength with functional capacity, lower limb strength and biochemical variables in hemodialysis (HD) patients. METHODS: a cross-sectional study involving 30 patients (18 male), 53.4 ± 12.9 years, 41.1 ± 55.7 months on HD therapy. Maximal inspiratory pressure (PImax),maximal expiratory pressure (PEmax),distance completed in a six-minute walk test (6MWT) and number of repetitions in sit-and-stand test (STST) were evaluated. The biochemical variables were recorded in the database routine work service. RESULTS: LogEPmax and 6MWT values were significantly lower than the predicted values (p = 0.015; p < 0.001, respectively). logPImax and logPEmax were correlated with number of repetitions in STST (r = 0.476, p = 0.008; r = 0.540, p = 0.002, respectively) and with phosphorus blood levels (r = 0.422, p = 0.020; r = 0.639, p < 0.001, respectively). 6MWT was correlated with logPEmax (r = 0.511; p = 0.004) and with number of repetitions in STST (r = 0.561; p = 0.001). CONCLUSION: PEmax reduction in patients with ESRD on HD is associated with functional capacity, lower limb strength and phosphorus blood levels, and may at least partly represent the low physical and functional performance of these patients