Regional and seasonal partitioning of water and temperature controls on global land carbon uptake variability

Global fluctuations in annual land carbon uptake (NEEIAV) depend on water and temperature variability, yet debate remains about local and seasonal controls of the global dependences. Here, we quantify regional and seasonal contributions to the correlations of globally-averaged NEEIAV against terrestrial water storage (TWS) and temperature, and respective uncertainties, using three approaches: atmospheric inversions, process-based vegetation models, and data-driven models. The three approaches agree that the tropics contribute over 63% of the global correlations, but differ on the dominant driver of the global NEEIAV, because they disagree on seasonal temperature effects in the Northern Hemisphere (NH, >25°N). In the NH, inversions and process-based models show inter-seasonal compensation of temperature effects, inducing a global TWS dominance supported by observations. Data-driven models show weaker seasonal compensation, thereby estimating a global temperature dominance. We provide a roadmap to fully understand drivers of global NEEIAV and discuss their implications for future carbon–climate feedbacks

Widespread spring phenology effects on drought recovery of Northern Hemisphere ecosystems

The time required for an ecosystem to recover from severe drought is a key component of ecological resilience. The phenology effects on drought recovery are, however, poorly understood. These effects centre on how phenology variations impact biophysical feedbacks, vegetation growth and, ultimately, recovery itself. Using multiple remotely sensed datasets, we found that more than half of ecosystems in mid- and high-latitudinal Northern Hemisphere failed to recover from extreme droughts within a single growing season. Earlier spring phenology in the drought year slowed drought recovery when extreme droughts occurred in mid-growing season. Delayed spring phenology in the subsequent year slowed drought recovery for all vegetation types (with importance of spring phenology ranging from 46% to 58%). The phenology effects on drought recovery were comparable to or larger than other well-known postdrought climatic factors. These results strongly suggest that the interactions between vegetation phenology and drought must be incorporated into Earth system models to accurately quantify ecosystem resilience.X.W. was financially supported by the National Natural Science Foundation of China (grant nos. 41922001 and 42171050), the Second Tibetan Plateau Scientific Expedition and Research Program (grant no. 2019QZKK0306) and the National Key Research and Development Program of China (grant no. 2022YFF0801800). S.A.K. was supported by the US Department of Energy Environmental System Science program grant no. DE-SC0022052. A.G. is supported by the Ramon y Cajal Program of the Spanish MICINN under grant RyC2020- 030647-I, and by CSIC under grant PIE-20223AT003. W.K.S. and W.Z. were supported by the NASA Carbon Cycle and Ecosystems Program under grant 80NSSC21K1709.Peer reviewe

Timing and Order of Extreme Drought and Wetness Determine Bioclimatic Sensitivity of Tree Growth

© 2022 The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.Tree resistance to extreme droughts and post-drought recovery are sensitive to the drought timing. However, how the bioclimatic sensitivity of tree growth may vary with the timing and order of extreme droughts and wetness is still poorly understood. Here, we quantified the bioclimatic sensitivity of tree growth in the period of 1951–2013 under different seasonal extreme drought/wetness regimes over the extra-tropical Northern Hemisphere, using 1,032 tree ring chronologies from 121 gymnosperm and angiosperm species. We found a negative asymmetry in tree growth under regimes with seasonal extreme droughts. With extreme drought, tree growth in arid and temperate dry regions is more negatively impacted by pre-growing-season (PGS) extreme droughts. Clade-wise, angiosperms are more sensitive to PGS water availability, and gymnosperms to legacy effects of the preceding tree growth conditions in temperate dry and humid regions. Our finding of divergent bioclimatic legacy effects underscores contrasting trends in forest responses to drought across different ecoregions and functional groups in a more extreme climate.This study is financially supported by the National Natural Science Foundation of China (41922001), the Second Tibetan Plateau Scientific Expedition and Research Program (STEP) (2019QZKK0306), the Strategic Priority Research Program of Chinese Academy of Sciences (XDA20100102), and the Swedish Formas (2018-02858).Peer reviewe

Global patterns of daily CO2 emissions reductions in the first year of COVID-19

Day-to-day changes in CO2 emissions from human activities, in particular fossil-fuel combustion and cement production, reflect a complex balance of influences from seasonality, working days, weather and, most recently, the COVID-19 pandemic. Here, we provide a daily CO2 emissions dataset for the whole year of 2020, calculated from inventory and near-real-time activity data. We find a global reduction of 6.3% (2,232 MtCO2) in CO2 emissions compared with 2019. The drop in daily emissions during the first part of the year resulted from reduced global economic activity due to the pandemic lockdowns, including a large decrease in emissions from the transportation sector. However, daily CO2 emissions gradually recovered towards 2019 levels from late April with the partial reopening of economic activity. Subsequent waves of lockdowns in late 2020 continued to cause smaller CO2 reductions, primarily in western countries. The extraordinary fall in emissions during 2020 is similar in magnitude to the sustained annual emissions reductions necessary to limit global warming at 1.5°C. This underscores the magnitude and speed at which the energy transition needs to advance

Increasing immunogenicity of protein antigens of vaccine interest by chemical lipidation

Les protéines lipidées purifiées à partir d’extraits de pathogènes ou produites de façon recombinante ont démontré leur pouvoir immunogène. Malheureusement, ce type de protéines est généralement difficile à purifier et/ou à produire. Afin de résoudre ces difficultés, l’objectif de cette thèse a été de mettre au point un procédé de lipidation chimique d’antigènes protéiques d’intérêt vaccinal, présents naturellement sous forme lipidée mais produits de façon recombinante sous forme non lipidée. La lipidation chimique a ainsi été réalisée sur 2 protéines, à savoir rTbpB-dl provenant de N. meningitidis et rNWMN_A issue de S. aureus, par des lipopeptides synthétiques de structure minimale, Pam2CAG et Pam3CAG, ciblant respectivement les récepteurs TLR2/6 et TLR2/1. Ces lipopeptides ont été préalablement fonctionnalisés par des groupes réactifs aux fonctions thiols (maléimide ou bromoacétyle) afin de réaliser le couplage chimique. Des analyses physico-chimiques et biochimiques ont démontré que la modification des protéines antigéniques a bien été réalisée. La lipidation de rTbpB-dl et rNWMN_A par les lipopeptides a induit in vitro l’activation des cellules immunitaires murines et humaines via TLR2 et a également augmenté in vivo l’immunogénicité de ces protéines recombinantes, en présence ou non d’un adjuvant. De plus, ces protéines lipidées ont joué in vivo le rôle d’adjuvant en augmentant l’immunogénicité d'une protéine antigénique co-administrée. Notre procédé de lipidation chimique a été simple, rapide, de faible coût et répétable. Au final, ce procédé pourrait s’appliquer sur des antigènes protéiques d’intérêt vaccinal et de faible immunogénicité provenant de différents pathogènes et/ou sur des antigènes lipoprotéiques rencontrant des problèmes de production/purification. Il pourraitreprésenter un choix pertinent dans la mise au point et dans le développement de candidatsvaccins, en présence ou non d’adjuvant(s) et/ou d’autre(s) antigène(s) d’intérêt.Lipidated proteins, purified from pathogens extracts or produced recombinantly, have demonstrated their immunogenic power. Unfortunately, this type of proteins is generally difficult to purify and/or to produce. To solve these difficulties, the objective of this thesis was to develop a process of chemical lipidation of protein antigens of vaccine interest, which are present naturally inlipidated form but produced recombinantly in non-lipidated form. The chemical lipidation was carried out on two proteins, namely rTbpB-dl from N. meningitidis and rNWMN_A from S. aureus, by minimum structure synthetic lipopeptides, Pam2CAG and Pam3CAG targeting receptors TLR2/6 and TLR2/1 respectively. These lipopeptides have been functionalized beforehand with thiolreactive groups (maleimide or bromoacetyl) for performing chemical coupling. Physicochemical and biochemical analysis have shown that the modification of the antigenic proteins has been achieved. The lipidation of rTbpB-dl and rNWMN_A by these lipopeptides induced in vitro activation of murine and human immune cells through TLR2. This lipidation also increased in vivo immunogenicity (mainly humoral) of the recombinant protein, in the presence or absence of an adjuvant. Furthermore, these lipidated proteins acted in vivo as an adjuvant by increasing immunogenicity of a co-administered antigen protein. Our process of chemical lipidation was simple, rapid, low-cost and repeatable. Taken together, this process could apply to antigens of protein nature, of vaccine interest and poorly immunogenic from different pathogens and/or to lipoprotein antigens encountering production/purification problems. It could be a relevant choice for the development of candidate vaccines, in the presence or absence of adjuvant(s) and/or other antigen(s) of interest

Développement de formulations vaccinales synthétiques à base de liposomes contre Pseudomonas aeruginosa

STRASBOURG ILLKIRCH-Pharmacie (672182101) / SudocSudocFranceF

Modification of land-atmosphere interactions by CO 2 effects: Implications for summer dryness and heat wave amplitude

International audienc

Observed strong atmospheric water constraints on forest photosynthesis using eddy covariance and satellite-based data across the Northern Hemisphere

International audienc

Design of a Liposomal Candidate Vaccine Against Pseudomonas aeruginosa and its Evaluation in Triggering Systemic and Lung Mucosal Immunity

International audienc

Reliance on fossil fuels increases during extreme temperature events in the continental United States

International audienceIncreasing extreme climate events driven by climate change raise the question of their impacts on the power production system, and implications for renewable versus fossil power supply. Here, using climate reanalysis data and daily electricity generation (2018-2023), we systematically quantify the impact of extreme climate events, specifically extreme cold events and extreme hot events on United States state-level carbon emissions and on the carbon intensity of electricity. We find that extreme climate events increase the carbon intensity of the energy production, increasing the reliance on fossil-based sources of energy and reducing the capacity of renewables. The states with more renewable electricity generation were also more affected by extreme temperatures. Our results reveal the extent to which the reliability and resilience of the current United States electricity system depends on fossil energy during extreme climate events, and suggest a need for adaptation measures as the country will transition to higher shares of renewable energy while extreme events will become more frequent