Biology subjects

Dacal, M.

Publications and source records attributed to Dacal, M..

3 recordsLinked to original sources

bioRxiv2026

Microplastics drive both linear and threshold-type shifts in soil multifunctionality along concentration gradients

Microplastics are increasingly recognized as emerging contaminants in terrestrial ecosystems, yet their mechanistic impacts on soil multifunctionality remain poorly understood. Here, we evaluated the influence of two microplastic polymers, polyethylene terephthalate and polypropylene, on soil functioning by subjecting soils to a gradient of concentrations of these microplastics, and measuring six variables representing soil physical, chemical, and biological functions. A statistical framework combining multi-model inference with threshold detection and machine learning was implemented in this study to identify the main pathways of soil multifunctional change. Most significant responses followed nonlinear trends and threshold shifts, primarily in physical properties, indicating that microplastic stress first impacts soil structure before cascading to chemical and biological processes. We identified two system-level thresholds at 0.3% PP and 0.55% PET w/w; while random forest highlighted water-stable aggregates as the dominant predictor of overall soil multifunctionality. Our findings provide new quantitative evidence of complex soil multifunctionality responses to microplastic pollution. Most importantly, physical deterioration emerged as an early-warning signal of microplastic disturbance, thereby advancing our understanding of microplastic pollution on soil systems.

ecology↗

bioRxiv2020

Temperature increases soil respiration across ecosystem types and soil development, but soil properties determine the magnitude of this effect

Soil carbon losses to the atmosphere, via soil heterotrophic respiration, are expected to increase in response to global warming, resulting in a positive carbon-climate feedback. Despite the well-known suite of abiotic and biotic factors controlling soil respiration, much less is known about how the magnitude of soil respiration responses to temperature changes over soil development and across contrasting soil properties. Here, we investigated the role of soil development stage and soil properties in driving the responses of soil heterotrophic respiration to increasing temperatures. We incubated soils from eight chronosequences ranging in soil age from hundreds to million years, and encompassing a wide range of vegetation types, climatic conditions, and chronosequences origins, at three assay temperatures (5, 15 and 25{degrees}C). We found a consistent positive effect of assay temperature on soil respiration rates across the eight chronosequences evaluated. However, soil properties such as organic carbon concentration, texture, pH, phosphorus content, and microbial biomass determined the magnitude of temperature effects on soil respiration. Finally, we observed a positive effect of soil development stage on soil respiration that did not alter the magnitude of assay temperature effects. Our work reveals that key soil properties alter the magnitude of the positive effect of temperature on soil respiration found across ecosystem types and soil development stages. This information is essential to better understand the magnitude of the carbon-climate feedback, and thus to establish accurate greenhouse gas emission targets.

ecology↗

bioRxiv2020

Abiotic and biotic drivers underly short- and long-term soil respiration responses to experimental warming in a dryland ecosystem

Soil carbon losses to the atmosphere through soil respiration are expected to rise with ongoing temperature increases, but available evidence from mesic biomes suggests that such response disappears after a few years of experimental warming. However, there is lack of empirical basis for these temporal dynamics in soil respiration responses, and of the mechanisms underlying them, in drylands, which collectively form the largest biome on Earth and store 32% of the global soil organic carbon pool. We coupled data from a ten-year warming experiment in a biocrust-dominated dryland ecosystem with laboratory incubations to confront 0-2 years (short-term hereafter) vs. 8-10 years (long-term hereafter) soil respiration responses to warming. Our results showed that increased soil respiration rates with short-term warming observed in areas with high biocrust cover returned to control levels in the long-term. Warming-induced increases in soil temperature were the main driver of the short-term soil respiration responses, whereas long-term soil respiration responses to warming were primarily driven by thermal acclimation and warming-induced reductions in biocrust cover. Our results highlight the importance of evaluating short and long-term soil respiration responses to warming as a mean to reduce the uncertainty in predicting the soil carbon - climate feedback in drylands.

ecology↗