A5045245314- Plant Water Relations and Carbon Dynamics
- Atmospheric and Environmental Gas Dynamics
- Tree-ring climate responses
- Geology and Paleoclimatology Research
- Isotope Analysis in Ecology
- Plant responses to elevated CO2
- Hydrology and Watershed Management Studies
- Remote Sensing in Agriculture
- Groundwater and Isotope Geochemistry
- Forest ecology and management
- Soil Carbon and Nitrogen Dynamics
- Species Distribution and Climate Change
- Microbial Community Ecology and Physiology
- Climate variability and models
- Atmospheric chemistry and aerosols
- Mycorrhizal Fungi and Plant Interactions
- Marine and coastal ecosystems
- Horticultural and Viticultural Research
- Peatlands and Wetlands Ecology
- Fire effects on ecosystems
- Lichen and fungal ecology
- Land Use and Ecosystem Services
- Soil and Water Nutrient Dynamics
- Botany and Plant Ecology Studies
- Photosynthetic Processes and Mechanisms
Interactions Sol Plante Atmosphère
2015-2024
École Nationale Supérieure des Sciences Agronomiques de Bordeaux-Aquitaine
2015-2024
Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement
2007-2024
Bipar
2024
Unité de Recherche Œnologie
2007-2022
University of New Hampshire
2020
Louisiana Department of Natural Resources
2020
Ecologie et Ecophysiologie Forestières
2020
Université de Bordeaux
2020
Public and Science
2019
Models of vegetation function are widely used to predict the effects climate change on carbon, water and nutrient cycles terrestrial ecosystems, their feedbacks climate. Stomatal conductance, process that governs plant use carbon uptake, is fundamental such models. In this paper, we reconcile two long-standing theories stomatal conductance. The empirical approach, which most commonly in models, phenomenological, based experimental observations behaviour response environmental conditions....
Abstract Terrestrial ecosystems sequester 2.1 Pg of atmospheric carbon annually. A large amount the terrestrial sink is realized by forests. However, considerable uncertainties remain regarding fate this over both short and long timescales. Relevant data to address these are being collected at many sites around world, but syntheses still sparse. To facilitate future synthesis activities, we have assembled a comprehensive global database for forest ecosystems, which includes budget variables...
Observations on the net carbon exchange of forests in European Mediterranean region, measured recently by eddy covariance method, have revived interest a phenomenon first characterized agricultural and forest soils East Africa 1950s 1960s H. F. Birch now often referred to as "Birch effect." When become dry during summer because lack rain, is common regions with climate, or are dried laboratory controlled conditions, then rewetted precipitation irrigation, there burst decomposition,...
Summary The terrestrial carbon and water cycles are intimately linked: the cycle is driven by photosynthesis, while balance dominated transpiration, both fluxes controlled plant stomatal conductance. ratio between these fluxes, water‐use efficiency (WUE), a useful indicator of vegetation function. WUE can be estimated using several techniques, including leaf gas exchange, stable isotope discrimination, eddy covariance. Here we compare global compilations data for each three techniques. We...
Abstract. For the past decade, observations of carbonyl sulfide (OCS or COS) have been investigated as a proxy for carbon uptake by plants. OCS is destroyed enzymes that interact with CO2 during photosynthesis, namely carbonic anhydrase (CA) and RuBisCO, where CA more important one. The majority sources to atmosphere are geographically separated from this large plant sink, whereas sinks co-located in ecosystems. drawdown can therefore be related without added complication emissions...
Abstract. We investigated plant water sources of an emblematic refugial population Fagus sylvatica (L.) in the Ciron river gorges south-western France using stable isotopes. It is generally assumed that no isotopic fractionation occurs during root uptake, so composition xylem effectively reflects source water. However, this assumption has been called into question by recent studies found that, at least some dates growing season, did not reflect any mixture potential sources. In context,...
A growing number of field studies report isotopic offsets between stem water and its potential sources that prevent the unambiguous identification plant origin using isotopes. We explored causes this offset by conducting a controlled experiment on temperate tree species Fagus sylvatica. measured δ2 H δ18 O soil from potted saplings three substrates subjected to two watering regimes. Regardless substrate, were similar only near permanent wilting point. Under moister conditions, was 11 ± 3‰...
Summary The long‐standing hypothesis that the isotopic composition of plant stem water reflects source is being challenged by studies reporting bulk from woody stems with an cannot be attributed to any potential source. mechanism behind such source–stem offsets still poorly understood. Using a novel technique extract selectively sap xylem conduits, we show that, in cut and potted plants, irrigation water, demonstrating unambiguously no fractionation occurs during root uptake or extraction....
Abstract Soil enzymes are central to ecosystem processes because they mediate numerous reactions that essential in biogeochemical cycles. However, how soil enzyme activities will respond global warming is uncertain. We reviewed the literature on mechanisms linking temperature effects and microbial communities, outlined a conceptual overview these changes may influence carbon fluxes terrestrial ecosystems. At scale, although can have positive effect enzymatic catalytic power short term (i.e....
Abstract. Stable isotope analysis is a powerful tool for assessing plant carbon and water relations their impact on biogeochemical processes at different scales. Our process-based understanding of stable signals, as well technological developments, has progressed significantly, opening new frontiers in ecological interdisciplinary research. This promoted the broad utilisation carbon, oxygen hydrogen applications to gain insight into cycling interaction with atmosphere pedosphere. Here, we...
Commentary p309
Abstract Rising atmospheric [CO 2 ], c a , is expected to affect stomatal regulation of leaf gas‐exchange woody plants, thus influencing energy fluxes as well carbon (C), water, and nutrient cycling forests. Researchers have proposed various strategies for that include maintaining constant internal i drawdown in CO ( − ), / . These can result drastically different consequences gas‐exchange. The accuracy Earth systems models depends part on assumptions about generalizable patterns responses...
Abstract. Plant phenological development is orchestrated through subtle changes in photoperiod, temperature, soil moisture and nutrient availability. Presently, the exact timing of plant stages their response to climate management practices are crudely represented land surface models. As visual observations phenology laborious, there a need supplement long-term with automated techniques such as those provided by digital repeat photography at high temporal spatial resolution. We present first...
Summary We compiled hydrogen and oxygen stable isotope compositions (δ 2 H δ 18 O) of leaf water from multiple biomes to examine variations with environmental drivers. Leaf was more closely correlated xylem or atmospheric vapour, whereas O air relative humidity. This resulted the larger proportional range for meteoric waters extent evaporative enrichment compared O. next expressed as isotopic above (Δ Δ remove impact variation. For H, still showed no such correlation. explained by covariance...
ABSTRACT We report diurnal variations in 13 C discrimination ( Δ) of Picea sitchensis (Bong.) Carr. branches measured the field using a branch chamber technique. The observations were compared to predicted Δ based on concurrent measurements gas exchange. Observed values described well by classical model including isotope effects during photorespiration, day respiration and CO 2 transfer through series resistances sites carboxylation. A simplified linear did not capture observed variability....
The carbon and oxygen stable isotope composition of wood cellulose (delta(13)C(cellulose) delta(18)O(cellulose), respectively) reveal well-defined seasonal variations that contain valuable records past climate, leaf gas exchange allocation dynamics within the trees. Here, we present a single-substrate model for growth to interpret isotopic signals collected in an even-aged maritime pine plantation growing South-west France, where soil flux variables were also monitored. Observed patterns...
Corrigendum for Medlyn et al. 2011, Global Change Biology 17: 2134–2144. A factor of 1.6 (converting from conductance to CO2 water vapour) was inadvertently missed in the derivation model (see revised Appendix). The as derived therefore applies stomatal rather than vapour. parameter values presented paper were incorrectly by fitting obtained Eqn (11) data (Table 2) should read: g1 listed caption Figure 3 (obtained 11 without intercept g0) Sitka A, 1.7; B, 1.8; Duke Pine, 2.6; Fagus, 2.8;...
Improved global estimates of terrestrial photosynthesis and respiration are critical for predicting the rate change in atmospheric CO(2). The oxygen isotopic composition CO(2) can be used to estimate these fluxes because exchange between water creates distinct flux signatures. enzyme carbonic anhydrase (CA) is known accelerate this leaves, but possibility CA activity soils commonly neglected. Here, we report widespread accelerated soil hydration. Exchange was 10-300 times faster than...
Abstract. Estimates of photosynthetic and respiratory fluxes at large scales are needed to improve our predictions the current future global CO2 cycle. Carbonyl sulfide (OCS) is most abundant sulfur gas in atmosphere has been proposed as a new tracer gross primary productivity (GPP), uptake OCS from dominated by activity carbonic anhydrase (CA), an enzyme leaves that also catalyses hydration during photosynthesis. However soils exchange with atmosphere, which complicates retrieval GPP...
Abstract Drought‐related tree mortality had become a widespread phenomenon in forests around the globe. This process leading to these events and its complexity is not fully understood. Trees dry timberline are exposed ongoing drought, available water for transpiration soil can determine their survival chances. Recent drought years led 5%–10% semi‐arid pine forest of Yatir (Israel). The distribution dead trees was, however, highly heterogeneous with parts showing >80% (D plots) others...
Climate-smart forestry (CSF) is an emerging branch of sustainable adaptive forest management aimed at enhancing the potential forests to adapt and mitigate climate change. It relies on much higher data requirements than traditional forestry. These can be met by new devices that support continuous, in situ monitoring conditions real time. We propose a comprehensive network sensors, i.e., wireless sensor (WSN), part worldwide interconnected uniquely addressable objects, Internet Things (IoT),...
Abstract. Isotope-based approaches to study plant water sources rely on the assumption that root uptake and within-plant transport are non-fractionating processes. However, a growing number of studies have reported offsets between source stable isotope composition for wide range ecosystems. These isotopic can result in erroneous attribution used by plants potential overestimations groundwater vegetation. We conducted global meta-analysis quantify magnitude these explored whether their...
Abstract. For the past decade, observations of carbonyl sulfide (OCS or COS) have been investigated as a proxy for carbon uptake by plants. OCS is destroyed enzymes that interact with CO2 during photosynthesis, namely carbonic anhydrase (CA) and RuBisCO, where CA more important. The majority sources to atmosphere are geographically separated from this large plant sink, whereas sinks co-located in ecosystems. drawdown can therefore be related without added complication emissions comparable...