Biology subjects

Revaillot, S.

Publications and source records attributed to Revaillot, S..

3 recordsLinked to original sources

bioRxiv2025

Non-living respiration: another breath in the soil?

The present study challenges the traditional view that respiration of organic carbon to CO2 is exclusively an intracellular process, revealing that organic compound respiration can occur spontaneously in an extracellular context in soils. Using 1H nuclear magnetic resonance spectroscopy to analyse the dynamics of the sterile soil exometabolomes alongside C-CO2 flux analyses and sterile soil fuel cells, we show that soil catalysts facilitate a diverse array of substrate-driven reactions, leading to the complete oxidation of organic compounds to CO2 with O2 consumption. Our results indicate that soil particles are capable of transferring electrons from substrates to the final acceptor, sustaining metabolic processes independently of living cells. Notably, some soil catalysts and induced respiration remain stable for over six years. Our results support the coexistence of cellular and non-cellular metabolic pathways in soil respiration.

ecology↗

bioRxiv2025

Use of massive DNA barcoding to monitor biodiversity: a test on forest soil fauna

Biodiversity monitoring primarily focuses on particular taxonomic groups for which identification expertise is widely available, such as vascular plants or birds. As a result, the response of many taxonomic groups to forest management is much less documented. With the advent of low-cost next generation barcoding approaches, it is now possible to envisage monitoring strategies based on molecular approaches, beyond metabarcoding/eDNA strategies that do not give access to species abundances and integrate species presence over largely unknown spatio-temporal scales. In this contribution, we demonstrate the use of massive DNA barcoding - also referred as megabarcoding - as a promising solution to overcome identification difficulties in demanding taxonomic groups. We performed a proof of concept study in a mountainous beech forest in the Massif Central, France. We sampled soil macrofauna at 25 sampling sites and managed to visually identify at the species level 130 out of the 1413 sampled individuals. Using megabarcoding on the 1283 remaining non-identified individuals, we managed to assign 1124 additional individuals to an operational taxonomic species at a competitive cost. We present the summary statistics of barcoding success in the different taxonomic groups encountered and in larvae versus adult individuals. We demonstrate that larvae individuals, which can hardly be visually identified at the species level, make a substantial contribution to overall macrofauna diversity. We finally showcase how this megabarcoding approach provides a concrete avenue for forest biodiversity monitoring, by assessing the cost and labour intensity of this approach.

ecology↗

bioRxiv2024

Vegetative stage and soil horizon respectively determine direction and magnitude of rhizosphere priming effects in contrasting treeline soils

O_LITreelines in high latitudes and high altitudes are considered sentinels of global change. This manifests in accelerated encroachment of trees and shrubs and enhanced plant productivity, with currently unknown implications for the carbon balance of these biomes. Given the large soil organic carbon stocks in many treeline soils, we here wondered whether introducing highly productive plants would accelerate carbon cycling through rhizosphere priming effects and if certain soils would be more vulnerable to carbon loss from positive priming than others. C_LIO_LITo test this, organic and mineral soils were sampled above and below treelines in the Swedish sub-arctic and the Peruvian Andes. A greenhouse experiment was then performed to quantify plant-induced changes in soil mineralisation rates (rhizosphere priming effect) and new C formation using natural abundance labelling and the C4-species Cynodon dactylon. Several environmental, plant, soil and microbial parameter were monitored during the experiment to complement the observations on soil C cycling. C_LIO_LIPriming was predominantly positive at the beginning of the experiment, then systematically decreased in all soils during the plant growth season to be mostly negative at the end of the experiment at plant senescence. Independent of direction of priming, the magnitude of priming was always greater in organic than in corresponding mineral soils, which was best explained by the higher C contents of these soils. Integrated over the entire study period, the overall impact of priming (positive and negative) on the soil C balance was mostly negligible. Though, net soil C loss was observed in organic soils from the sub-arctic tundra in Sweden. C_LIO_LIMost notably, positive and negative priming effects were not mutually exclusive, rather omnipresent across ecosystems, depending on sampling time. The direction of priming seems to be fluctuating with plant productivity, rhizosphere carbon inputs and nutrient uptake. This highlights the need for integrative long-term studies if we aim to understand priming effects at ecosystem scale and greenhouse and laboratory studies must be validated in situ to enable reliable ecological upscaling. C_LI

ecology↗