Adrien Jacotot

This study provides a multi‐year (2017–2022) Net Ecosystem Carbon Balance (NECB) of a Pyrenean mountainous peatland through the integration of field data, satellite imagery, and statistical modeling. Fluvial organic carbon export was measured at 30 min frequency, while gaseous (CO2 and CH4) exchanges were measured monthly using closed chambers. The...

Despite covering only 3% of the global land surface, peatlands are an active part of the Critical Zone (CZ) exchanging large water and greenhouse gas (GHG) fluxes with the surrounding aquifers, surface waters, and the atmosphere. While ecosystem services of peatlands (carbon and water storage, buffering of local climate) are essential to address 21...

The year 2022 saw record breaking temperatures in Europe during both summer and fall. Similar to the recent 2018 drought, close to 30% (3.0 million km²) of the European continent was under severe summer drought. In 2022, the drought was located in central and southeastern Europe, contrasting the Northern-centered 2018 drought. We show, using multip...

Simulating the carbon-water fluxes at more widely distributed meteorological stations based on the sparsely and unevenly distributed eddy covariance flux stations is needed to accurately understand the carbon-water cycle of terrestrial ecosystems. We established a new framework consisting of machine learning, determination coefficient (R²), Euclide...

Mangrove forests are potentially large biogenic sources of atmospheric hydrogen sulphide (H2S), featuring among the carbon-richest ecosystems in the world associated with strong soil anoxia and large quantities of sulphates brought by tides. H2S is highly toxic and acts as a precursor for atmospheric sulphur compounds and sulphate aerosols, which c...

Peatlands cover only 3 % of emerged lands, but their carbon stock represents about 30 % of the global soil organic carbon. Climate change and local anthropogenic disturbances deeply affect the hydrological functioning of peatlands. This may trigger carbon fluxes to surface waters and the atmosphere, thus leading to a positive feedback for global wa...

The continuous measurement of CO2 fluxes at the open-top chamber experiment in the ombrotrophic peatland (located in the middle taiga zone, West Siberia, Russia) has been provided during the warm season of 2022 (beginning of June to beginning of October). The R eco, NEE and GPP were calculated for this period; abiotic factors related to CO2 emissio...

Wetlands are the largest natural source of methane (CH4 ) to the atmosphere. The eddy covariance method provides robust measurements of net ecosystem exchange of CH4 , but interpreting its spatio-temporal variations is challenging due to the co-occurrence of CH4 production, oxidation, and transport dynamics. Here we estimate these three processes u...

To understand the variability of methane (CH4) fluxes between a temperate mid-altitude Sphagnum-dominated peatland and the atmosphere, we monitored simultaneously eddy covariance, hydrometeorological and physical parameters between April 2019 and December 2021. The site was a CH4 source for the atmosphere, with a cumulative emission of 23.9 ± 0.6 g...

Increasing awareness of the significance of coastal wetlands in global carbon budgets combined with recently developed approaches such as in-situ gas analyzers connected to flux chambers, has led to the wide interests in quantifying greenhouse gas exchange in these ecosystems, for which less attention was paid to than terrestrial ecosystems. Consid...

Time series of wetland methane fluxes measured by eddy covariance require gap-filling to estimate daily, seasonal , and annual emissions. Gap-filling methane fluxes is challenging because of high variability and complex responses to multiple drivers. To date, there is no widely established gap-filling standard for wetland methane fluxes, with regar...

Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions due to quasi-co...

Mangrove sediments from New Caledonia were screened for xylanase sequences. One enzyme was selected and characterized both biochemically and for its industrial potential. Using a specific cDNA amplification method coupled with a MiSeq sequencing approach, the diversity of expressed genes encoding GH11 xylanases was investigated beneath Avicenia mar...

The mechanisms behind the plant litter mixture effect on decomposition are still difficult to disentangle. To tackle this issue, we used a model that specifically addresses the role of the litter moisture content. Our model predicts that when two litters interact in terms of water flow, the difference of evaporation rate between two litters can tri...

Mitigating and adapting to global changes requires a better understanding of the response of the Biosphere to these environmental variations. Human disturbances and their effects act in the long term (decades to centuries) and consequently, a similar time frame is needed to fully understand the hydrological and biogeochemical functioning of a natur...

Carbon fractionation (Δ13C) is well documented for various plants functional types. Yet, specific studies on Δ13C on mangroves are particularly rare although they have a key role in coastal carbon (C) cycling. In this study, we investigated the 13C exchanges between leaves and the atmosphere and between the main plant’s organs in two common mangrov...

Peatlands are a highly effective natural carbon sink. However, the future of the carbon stored in these ecosystems is still uncertain because of the pressure they undergo. An estimation of the peatland carbon balance shows whether the system functions as a carbon sink or a carbon source. La Guette peatland is a temperate Sphagnum-dominated peatland...

Methane (CH4) emissions from natural landscapes constitute roughly half of global CH4 contributions to the atmosphere, yet large uncertainties remain in the absolute magnitude and the seasonality of emission quantities and drivers. Eddy covariance (EC) measurements of CH4 flux are ideal for constraining ecosystem-scale CH4 emissions, including thei...

Can Gio mangrove is the largest mangrove forest in Vietnam, covering approximately 35,000 hectares. This forest was partially destroyed during the war, and restored between the late 1970s and the early 1990s. Currently, the Can Gio mangrove forest regenerates naturally, and presents a specific species zonation along the intertidal elevation gradien...

The effect of climate change on peatlands is of great importance due to their large carbon stocks. In this study, we examined microbial biomass and effect of temperature and O2 availability on soil respiration of surface and subsurface Sphagnum peat. The interactive effect of biotic and abiotic factors significantly affects soil respiration. Increa...

Can Gio mangrove is the largest mangrove forest in Vietnam, covering approximately 35,000 hectares. This forest was partially destroyed during the war, and restored between the late 70s and the early 90s. Currently, the Can Gio mangrove forest regenerates naturally, and presents a specific species zonation along the intertidal elevation gradient wi...

Data of meteorological and soil physics measured on La Guette peatland in two stations (lgt/bm1 and lgt/bm2). Measurements start on 12-10-2010 and are regularly updated with new data. The measured parameters are: Air temperature (°C), Air pressure (mbar), Precipitation (mm), Relative humidity (%), ShortWave/LongWave outgoing/incoming radiation (W/m...

In the framework of climate changes, peatland ecosystems are compartments of the Critical Zone of growing importance for greenhouse gas (GHG) exchanges with the atmosphere. Peatlands contain about 30 % of the total organic soil carbon worldwide (IPCC, 2019). Interactions of GHG between atmosphere and peatland are potentially controlled by organic m...

Peatlands act as a powerful carbon (C) sink. This specificity results from their particular environment, composed of Shagnum mosses, and the acidic state of the soil combined with a high water saturation that strongly limit organic matter decomposition. Future natural and anthropogenic global changes are expected to modify peatlands functioning and...

We investigated the effects of elevated CO2 concentrations and longer tidal flooding duration on two-year-old Avicennia marina and Rhizophora stylosa seedlings for a full year. The seedlings were grown in greenhouses for ambient CO2 (400 ppm) and in enclosed CO2-controlled chambers, which were installed inside the greenhouses for elevated CO2 (800...

Peatlands act as a powerful carbon (C) sink. This specificity notably results from their particular environment, composed of Shagnum mosses, and the acidic state of the soil combined with a high water saturation that strongly limit organic matter decomposition. Future natural and anthropogenic global changes are expected to modify peat-lands functi...

Many Sphagnum peatlands are experiencing vegetation change caused mainly by hydrological disturbances. In this, greenhouse gases (GHG) fluxes are affected by peat oxygenation, changes in litter composition (and thus decomposition) and rhizospheric processes. This could lead a C sink system to switch to a source. To restore peatland functioning, eco...

Peatlands are sensitive ecosystems that act as a powerful carbon (C) sink, and are possibly impacted by future natural and anthropogenic global changes. We can anticipate a direct effect of these changes, which can modify the functioning and the species distributions of peatlands, and therefore can alter their valuable role in C sequestration and t...

In this study, we examined interactive effects of elevated atmospheric CO2, concentrations, and increased tidal flooding on two mangroves species, Avicennia marina and Rhizophora stylosa. Leaf gas-exchange parameters (photosynthesis, transpiration rates, water-use efficiency, stomatal conductance, and dark respiration rates) were measured monthly o...

Seasonal variations of CO2 and CH4 fluxes were investigated in a Rhizophora mangrove forest that develops under a semi-arid climate, in New Caledonia. Fluxes were measured using closed incubation chambers connected to a CRDS analyzer. They were performed during low tide at light, in the dark, and in the dark after having removed the top 1–2 mm of s...

Due to their richness in soil organic matter, mangroves have been shown to be a net source of greenhouse gases to the atmosphere, however, the variability of these emissions remains poorly characterized and understood. We, thus, investigated these emissions in a Rhizophora mangrove forest in New Caledonia. Fluxes were measured using closed incubati...

In New Caledonia, shrimp ponds are built not on cleared mangroves but on salt flats behind the mangroves. The objectives of this study were to determine the variability of CO 2 fluxes from a semi-intensive shrimp pond during active and non-active periods of the farm and to determine the carbon dynamics from the upstream tidal creek to the downstrea...

La mangrove est un écosystème complexe qui se développe sur les zones intertidales, le long des littoraux (sub)tropicaux. Dû à sa production primaire élevée, couplée à une grande capacité de séquestration du carbone organique, la mangrove a été nommée écosystème à « Carbone Bleu ». Toutefois, le changement climatique à venir, et particulièrement le...

Mangroves are hyper productive habitats located on intertidal areas and therefore may be impacted by future climate change. Among the different scenarii, the more likely is that we can expect an atmospheric CO2 concentration of more than 500 ppm in 2050, and over 800 at the end of the century. We can anticipate a direct positive effect of increased...

In this article, a new and original approach to characterize tephra layers based on high resolution magnetic susceptibility (MS) mapping is applied to the tephra deposits of Rocourt (Belgium). A series of MS maps of selected sections show the 3D morphology of tephra horizons, including local dip and reworked structures of the Rocourt and Eltville t...