Nutrient addition hinders microarthropod-driven leaf litter decomposition in Patagonian woodlands

Aims Global change threatens ecosystem functions, including those driven by soil fauna. In temperate forests, soil nutrients, litter quality, and microarthropods are essential players during litter decomposition. However, the impact of nutrient enrichment on the functional role of soil fauna remains poorly understood. Methods We used a full factorial experiment to test the effects of nitrogen (N), phosphorus (P), and potassium (K) addition on litter decomposition through changes in soil conditions and litter quality. We incubated senesced leaves from fertilized and unfertilized control plots in litter bags with two different mesh sizes that included (2 mm) or excluded (45 µm) microarthropods. We assessed the interactive effects of nutrient addition and litter quality on microarthropod-driven decomposition using linear mixed-effects models. Results Nutrient addition was a stronger predictor than litter quality for organic matter remaining in litter bags over time. While N addition strongly influenced litter quality, it did not affect microarthropod activity in decomposition. P addition suppressed decomposition when microarthropods were present but enhanced it when microarthropods were absent. K strongly influenced litter quality and regulated the effects of phosphorus on decomposition. Conclusions Microarthropods may promote decomposition under conditions of limited nutrient availability in both litter and soil, potentially enhancing microbial activity. The responses of fungi and microbes to nutrient enrichment may explain the relatively modest effect of microarthropods on decomposition. Our study shows that nutrient enrichment in temperate forests may limit microarthropod participation in decomposition by possibly altering microsite conditions or affecting the availability of alternative food resources, thereby influencing carbon fluxes.info:eu-repo/semantics/acceptedVersio

Trophic role and predatory interactions between the blue crab, Callinectes sapidus, and native species in open waters of the Ebro Delta

The Ebro Delta has become a major blue crab (Callinectes sapidus) fishery area in the NW Mediterranean, but there is limited information on factors controlling the abundance of populations in open waters, a crucial habitat for ovigerous females. Here, we use a stable isotope approach (δ15N and δ13C), to assess blue crab trophic position, the potential consumption of food items using mixing models, and the isotopic niche overlap with local commercial species. For Octopus vulgaris, a potential blue crab key predator, a trophic enrichment experiment was also conducted to further assess predation control in wild populations. The blue crab showed 1.6 times higher trophic position than in other habitats of the Ebro Delta, and similar to that found in the harbor crab, Liocarcinus depurator, and several predatory fish. Additionally, the isotopic niche of blue crabs showed overlaps from 46.2 to 14.9% with native predators, and mixing models also suggest even dietary contributions throughout the food web. For O. vulgaris, field results showed a trophic position of 3.93, lower than that of blue crab, and lower δ15N signatures were also obtained in a captivity experiment drawing negative fractionation (−1.1‰). We conclude that high dietary contribution of animal prey might provide a high protein diet that could be crucial for allowing the maintenance of a large local population, but the overall functional trophic similarity could also disfavor local native species. The similarity between experimental fractionation and field differences between predator and prey (−1.6‰) suggests that predation of blue crab is possible, but further research is needed to clarify the metabolic routes involved in octopus δ15N fractionation.Financial support for fieldwork and SIA was provided by the Departament d’Agricultura, Ramaderia, Pesca i Alimentació through the BivalCat project (Ref. CAT 152CAT) to M. Ballesteros. P. Prado was contracted under the INIA-CCAA research program for postdoctoral incorporation from the Spanish National Institute for Agricultural and Food Research and Technology (INIA). Stabling of O. vulgaris was supported by the Spanish Government (Ministry of Science and Technology) under the ECESIS project (PID2020-118476RR-C21) to P. Prado and S. Falco. Authors are also grateful to C. Alcaraz for assessment with script preparation and interpretation of SIBER results, and to K.B. Andree, for a double comprehensive review and correction of English throughout the ms. We would also like to thank the detailed review conducted by two anonymous referees that has been of great help for improving the overall quality of the ms.info:eu-repo/semantics/acceptedVersio

PLANT UNCOUPLING MITOCHONDRIAL PROTEIN 2 localizes to the Golgi

Mitochondria act as cellular hubs of energy transformation and metabolite conversion in most ukaryotes. Plant mitochondrial electron transport chains are particularly flexible, featuring components that can bypass proton translocation steps, such as ALTERNATIVE NAD(P)H DEHYDROGENASES and ALTERNATIVE OXIDASES (AOXs). PLANT UNCOUPLING MITOCHONDRIAL PROTEINS (PUMPs or plant UNCOUPLING PROTEINS [UCPs]) have been identified in plants as homologs of mammalian UCPs, and their physiological roles have been investigated in the context of mitochondrial energy metabolism. To dissect UCP function in Arabidopsis (Arabidopsis thaliana), the 2 most conserved family members, UCP1 and UCP2, have been genetically ablated assuming that they both reside in the inner mitochondrial membrane. Yet, contradicting results have been reported on plant UCP2 localization.This work was supported by the Deutsche Forschungsge meinschaft (DFG, German Research Foundation) through the Research Training Group GRK 2064 “Water use efficiency and drought stress responses: From Arabidopsis to Barley” to A.J.M. and M.S., a joint project grant to A.R.F. and M.S. (FE 552/44-1; SCHW 1719/9-1), the infrastructure grant INST 211/903-1 FUGG for a confocal microscope as operated by the Imaging Network of the University of Münster (RI_00497), and the Spanish Ministry for Science and Innovation (MCIN)/Agencia Estatal de Investigación (AEI)/ 10.13039/501100011033 project PID2020-120229RA-I00. E.F.-P. was supported by a predoctoral fellowship PRE2021-097120 and I.F.S. by the “Ramón y Cajal” contract RYC2019-028030-I, both funded by MCIN/AEI/10.13039/ 501100011033 and by “ESF Investing in your future.” P.B. was supported by a postdoctoral fellowship 200385/2022-4 funded by the Brazilian National Council for Scientific and Technological Development (CNPq).info:eu-repo/semantics/publishedVersio

Developing robust food composition models: Strategies for handling temperature and packaging variations in dry-cured ham using near infrared spectrometry

Low-cost near infrared devices intended for consumers able to easily determine composition and quality of food products may boost adoption of sustainable healthy diets. However, predictive algorithms robust to external variations are needed. The aim of this work was to evaluate different data analysis strategies to develop robust predictive models for food composition when using spectrometric data subjected to external variations, specifically temperature and packaging material, acquired using low-cost sensors. Usefulness of global modelling (GM), Generalised least squares weighting (GLSW), Loading space standardisation (LSS), Multiplicative Effects Model (MEM) were explored, and the effect of samples heterogeneity evaluated. To do so, two low-cost handheld NIR-based devices with different spectral ranges and resolutions were used. The food matrix samples were obtained from different anatomical muscles of commercial dry-cured ham. Spectra were acquired on two types of packaging films at different temperatures to further explore the usefulness of global modelling (GM), generalised least squares weighting (GLSW), loading space standardisation (LSS), and multiplicative effects model (MEM) to retrieve these effects. Results show that the inherent food sample heterogeneity produces as much spectral variability as temperature and packaging materials. For temperature compensation, LSS did not decrease the predictive error caused by this factor probably due to the heterogeneity of the samples used. In contrast, the GLSW method decreased the predictive errors from 0.52% to 0.46% for salt and from 2.10% to 1.40% for water.. Only a slight effect of packaging was observed, and GM models were found to be the best strategy to compensate it, showing a decrease of bias from −1.35 to 0.012. The examined compensation strategies could facilitate the deployment of low-cost spectrometers for consumer use, as they offer an effective means to mitigate or eliminate variations from any source in the data that are unrelated to the properties of interest.This work was supported by CCLabel project (RTI-2018–096883-R-C41) funded by the Spanish Ministry of Science and Innovation of the Spanish Government (MCIN/AEI/ 10.13039/501100011033). Ricardo dos Santos received a grant [PRE2022-103798] funded by MICIU/AEI/10.13039/501100011033 and ESF + . Acknowledgements are extended to the consolidated Research Group (2021 SGR 00461), CERCA programme from Generalitat de Catalunya, Centre for Process Analytics and Control Technology (CPACT) and Engineering and Physical Sciences research Council (EPSRC; EP/P006965/1). Elena Fulladosa acknowledges the receipt of a fellowship from the OECD Co-operative Research Programme: Sustainable Agricultural and Food Systems in 2022 and a mobility grant from the Institute of Agrifood Research and Technology (IRTA) within the Incentives For Research Program 2023.info:eu-repo/semantics/acceptedVersio

Are Argentinians ready for plant-based meat alternatives? A case study on awareness and willingness for consumption

Meat alternatives’ popularity is increasing worldwide. Nevertheless, the attitudes and motivations underpinning their adoption still evolve and may differ by region. In Argentina, where meat consumption per capita is among the highest globally, the market for plant-based meat alternatives (PBMAs) is just beginning to develop. Few reports attempt to explain the behavior of the Argentinian population regarding these products. This study explored the knowledge, attitudes, and perceptions of meat analogues and hybrid products through a national online survey (N = 2339). Also, barriers and drivers to their consumption as well as the target segments were identified. Participants were classified as omnivores 73.8%, flexitarians 19.5%, vegetarians 6%, and vegans 0.7%. Despite the significant lack of awareness about PBMAs, there is a strong willingness to adopt them, with females, younger respondents, and those with lower incomes more open to these options. The main drivers for consumption were health concerns, animal welfare, and environmental awareness. Familiarity was a key factor influencing the adoption, as evidenced by the openness of well-informed omnivores. Lack of available options represented the main limitation for consumption and distrust regarding their origin and sensory appeal were the primary reasons for rejection. This study reveals a potential market for PBMAs in Argentina, highlighting that guaranteeing nutritional and sensory quality is crucial. Educating consumers is also essential for their widespread acceptance.This work was supported by Instituto Nacional de Tecnología Agropecuaria, INTA (INTA PD-E7-I153).info:eu-repo/semantics/acceptedVersio

Assessing Nature Based Solutions for Managing Coastal Bays

Aquest recurs no està disponible en accés obert per política de l’editorial. This item isn't open access because of publisher's policyThis work investigates the hydrodynamic response of two small and shallow bays located in the Ebro Delta, in order to solve the problems affecting mussel farms, such as the high temperatures reached in the summer period (>28 °C), causing the death of these bivalves, and the limited water renewal that causes anoxia within the bay. Nature Based Solutions are described focusing on two aspects: one, modifying the flow of these drainage channels, increasing the arrival of freshwater to the bays; and two, opening a gap in the sand bars so that there is a flow of sea water in and out through the innermost zone, which is where both bays have greater problems of water renewal. The impact of those solutions simulated with the Regional Oceans Modeling System (ROMS), consist of a set of nested domains that use CMEMS-IBI data for the initial and open boundary conditions (coarser domain). To validate the numerical model, data from in situ campaigns have been used for one full year (2014) for Alfacs Bay, and for the summer period (July-August 2017) for Fangar Bay. In addition, the Sea Surface Temperature (SST) is also studied as an indicator to reduce the mortality problems of mussels, but the results obtained do not reduce this variable. What the results do show is a decrease in residence time in both bays for both experiments, with the increase in flow being more viable than the increase in sand bar breakage.info:eu-repo/semantics/publishedVersio

Sellaphora mayrii (Bacillariophyceae), a new diatom from the Argentinean Patagonia

Aquest recurs no està disponible en accés obert per política de l’editorial. This item isn't open access because of publisher's policyA new species of Sellaphora was found in modern and fossil sediments from shallow-lake Laguna Gemelas Este, Santa Cruz, Argentina. The new taxon was studied with light microscopy and scanning electron microscopy. We present a detailed analysis of its morphology, supporting its placement in the genus Sellaphora Mereschkowsky, and report the physico-chemical characteristics of the lake where it was found. Sellaphora mayrii sp. nov. is most similar to S. smirnovii Chudaev & Gololobova, a small-celled species first reported from Russia. Both species have in common the valve outline, but the new species from Argentina has a wider size range and, when observed with electron microscopy, is visibly different regarding stria pattern, central area, and shape of the areolae.info:eu-repo/semantics/publishedVersio