Orals: Tue, 29 Apr | Room 0.51
Agricultural soils in intensive farming sustain high crop production yields but endanger other regulating ecosystem services. Strengthening the simultaneous delivery of multiple soil functions is therefore essential to achieve high crop yields while lowering the environmental impact. We investigated how this so-called soil multifunctionality is related to management intensity in conventional and organic arable farming, and to specific practices regarding e.g. crop rotation, fertilization or tillage. We furthermore explored whether soil organic carbon and soil microbiotic parameters could explain relationships between agricultural management and soil functioning.
We collected 57 soil samples in Dutch arable fields and interviewed farmers about their farm management. Soil multifunctionality was measured by aggregating 9 indicators of different functions such as nutrient cycling, soil structure, and disease suppression. We characterized the species composition and abundance of the soil microbial community with 15 parameters, and soil carbon quantity and quality with 16 parameters.
We show that increasing management intensity is associated with declining soil multifunctionality across all fields, whereas multifunctionality was not related with organic vs. conventional farming. Greater soil multifunctionality was also associated with less frequent inversion tillage and higher frequency of grass-legume cover cropping. Bacterial biomass and total soil organic carbon content, respectively, were the strongest biotic and abiotic predictors of soil multifunctionality. No other biotic parameters were related to soil multifunctionality, whereas the majority of soil carbon parameters were significantly related. Our results suggest that reducing management intensity will enhance soil multifunctionality in both conventional and organic farming systems, so that in highly intensive and productive agricultural systems, the paradigm of sustainable intensification should be replaced by “productive de-intensification.”
How to cite: Koorneef, G., van Rijssel, S., Veen, C., Pulleman, M., de Goede, R., Comans, R., van der Putten, W., and Mason-Jones, K.: Exploring potential success factors for soil multifunctionality: effects of agricultural management, soil life and soil carbon, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-1059, https://doi.org/10.5194/egusphere-egu25-1059, 2025.
Bridging Morphological and Molecular Approaches in Soil Fauna Diversity Assessments at European level
Köninger, J., Potapov, A., Ross, G., Tsiafouli, M., Seeber, J., Beule, L., Hedlund, K., Frouz, J., Blasbichler, H., Orgiazzi, A., Briones, M.J. I.
Recent advances in molecular approaches to identify multiple species from a mixed sample, have expanded our availability to perform large-scale analyses of soil biodiversity. However, methodological challenges remain, particularly when trying to reconcile molecular results with those derived from traditional morphological-based identifications. For example, previous studies have recorded unexpected higher diversities in the more intensively managed agricultural lands compared to woodlands and grasslands, which contrasts with earlier morphological analyses and highlights the need for methodological cross-validation.
Here, we address these challenges by comparing soil fauna diversity data derived from several international large-scale surveys. For example, the SOB4ES EU-funded project encompassing diverse European land uses and the Biodiversa+ project (accronym) focussing on woodlands both collected morphological as well as molecular data. Additionally, we compared the DNA metabarcoding results from LUCAS (2018 survey) with morphological data derived from the EcoFINDERS and SOILSERVICE projects. Our analyses reveal the existence of a significant variability in diversity metrics between ecosystem types, emphasizing the importance of contextualizing molecular results through complementary morphological analyses. Furthermore, our results also highlight the need to refine molecular methods (e.g. primer choice and removal of relict DNA) to ensure the robustness of the data interpretations for their potential use in policy-making and biodiversity indicator development.
How to cite: Köninger, J.: Bridging Morphological and Molecular Approaches in Soil Fauna Diversity Assessments at European level, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4295, https://doi.org/10.5194/egusphere-egu25-4295, 2025.
Mycorrhizal symbiosis of plants is widely distributed worldwide, and most of the forests form either ectomycorrhizal (ECM) or arbuscular mycorrhizal (AM) fungal associations [1]. Therefore, mycelium of mycorrhizal fungi is being discussed as one of the important functional components of soil microbiome, and also as a feeding resource for soil biota. Nematodes are one of the key consumers of both roots and mycorrhizal fungi [2, 3]. In soil horizons deeper than 20-30 cm or subsoils [4], the mycelium of mycorrhizal fungi can be an even more important driver and source of nutrients compared to topsoil, due to the lack of plant-derived resources [5, 6]; but our knowledge on its functional role in subsoil is extremely scarce. Therefore, the high reliance of subsoil-living nematodes on the mycorrhizal fungi as a feeding substrate was hypothesized.
The research was carried out based on ten-years-old MyDiv tree diversity experiment, Bad Lauchstädt, Germany. The soil at the site is classified as Haplic Chernozem. The experiment manipulates tree species richness and mycorrhizal types; the detailed site description is given in Ferlian et al., 2018 [7]. We exclusively focused on plots exclusively represented by either ectomycorrhizal (ECM, four plots) or arbuscular mycorrhizal (AM, four plots) tree stands. Soil cores, 5 cm in diameter were sampled up to the depth of 1 meter using motorized soil auger. Soil profile was studied divided by genetic horizons: Ap1 (~0-10 cm), Ap2 (~10-35 cm), Ah (~40-60 cm) and C (~60-100 cm). Nematodes were extracted within a week of sampling using a modified Baermann method. Soil parameters (water content, % and bulk density, g*cm-3) were estimated in parallel. Nematodes were counted and biomass estimated using an inverse microscope (Leica DM) under ×400 magnification, and then 100 specimens per sample were identified to genus level. Feeding types of nematodes were assigned to genera following Yeates et al. (1993) [8].
Our data show that the nematode community of only top soil horizon Ap1 (~0-10 cm) differ (MANOVA, F = 2.525; p = 0.0332) between ECM and AM dominated ecosystems. Both biomass and density of nematodes significantly decreased with depth, being the most pronounced for bacterivores in ECM systems (Least-squared Means test, t-ratio ≤ -5.293; p < 0.0001). The shown effects are likely related to the legacy of post-agricultural soil and high buffer capacity of Chernozem soils. The importance of further subsoil studies in mature forest stands, as well as the research on the nematode communities of post-agricultural reforestation successions is proposed.
References:
-
Soudzilovskaia NA, et al. (2019). Nat Commun 10:5077. https://doi.org/10.1038/s41467-019-13019-2
-
Kudrin AA, et al. (2021). Soil Biol Biochem 155:108184. https://doi.org/10.1016/j.soilbio.2021.108184
-
Li Y, et al. (2009). Soil Biol Biochem 41:877–882. https://doi.org/10.1016/j.soilbio.2008.07.031
-
Frelih-Larsen A, et al. (2018). Sustainability 10:3006. https://doi.org/10.3390/su10093006
-
Callesen I, et al. (2016). For Ecol Manag 359. https://doi.org/10.1016/j.foreco.2015.08.019
-
Dietzel R, et al. (2017). Soil 3:139–152. https://doi.org/10.5194/soil-3-139-2017
-
Ferlian O, et al. (2018). Ecosphere 9:e02226. https://doi.org/10.1002/ecs2.2226
-
Yeates GW, et al. (1993). J Nematol 25(3):315-331.
How to cite: Zuev, A., Peter, S., Eisenhauer, N., Ferlian, O., Hohberg, K., and Potapov, A.: Nematodes in deep soil profiles under young mycorrhizal forest stands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8542, https://doi.org/10.5194/egusphere-egu25-8542, 2025.
Soil microbial biodiversity studies commonly rely on molecular datasets from microbial communities extracted from their natural contexts. While immensely important for many research questions, this can lead to artefacts such as falsely interpreting interactions where organisms were strongly spatially separated in the soil habitat, and difficulties in differentiating active from passive or dormant organisms.
We developed a way to overcome some of the problems of the extraction steps: Microfluidic soil chips, transparent micromodels of the soil pore space, can be incubated in, or inoculated with, soil, from which the microorganisms move into, grow into, or are transported into it by water streaming. This allows for direct microscopic examination of bacteria, fungi, and protist communities under closer-to natural conditions. AI-aided image analysis helps to quantify population sizes and gives information on the community’s morphodiversity: Changes in cellular size and shapes, and the spatial distribution of the cells including group formation up to simple biofilms. Direct observations can be made on the growth and interactions of the organisms, with each other and with their immediate environment.
We found differences in microbial communities over large geographical patterns (Arctic via temperate to tropical soil bacteria) in bacterial cell sizes and their microspatial distribution. Morphodiversity of the bacterial community were also found to change across microscale soil pore space characteristics, where cells were larger in more connected microhabitats compared to less connected and more tortuous ones. Comparing the molecular microbial biodiversity in chips to the microbial biodiversity of the adjacent soil via metabarcoding, we found in chips an amplicon sequence variant richness of around 30% of the adjacent soil, indicating a reduced but still relevantly diverse microbial community. Also, fungal and protist communities can be studied in soil chips, especially valuable for research questions of interactions such as interactions with the pore space, predation, behavior, and direct reactions to experimental factors such as a pollutant.
We argue that soil chips are an intriguing complement to molecular techniques to study soil microbial diversity, and will help us to better understand soil microbial activity and interactions with each other and their environment.
How to cite: Hammer, E., Pinholt, F., Klinghammer, F., Karlsson, E., Sopasakis, A., Ohlsson, P., Lake, F., Maillard, F., and Zou, H.: Studying soil microbial diversity and their ecological interactions via Soil Chips, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9034, https://doi.org/10.5194/egusphere-egu25-9034, 2025.
Microorganisms in agricultural soils play a key role in nutrient recycling and nutrient availability for plants. The diversity and abundance of these microorganisms and the subsequent microbiological processes can however be influenced by different factors. This includes among others the crop type grown on the field, the farmers’ agricultural field management and various soil parameters as these farming processes may highly affect the soil microbiological diversity and abundance. Some farming practices aiming at increasing crop yield such as ploughing or nitrogen fertilization might actually endanger soil processes provided by microorganisms supporting crop yield. It is therefore important to better understand the complexity of soil microbial abundance and diversity – including bacterial, fungal and protist – in relation to agricultural soil management.
The objective of this study is to determine the structure of the microbiota (including bacteria, fungi and protists) in agricultural soils in Skåne, Sweden, across different farming conditions and soil characteristics.
To achieve this, soil samples were collected from agricultural fields with the primary focus on two crops: small grain cereals (annual) and ley (perennial). Samples were collected from a total of 25 farms including conventional farms and organic farms, varying in time since transition, to account for potential differences in farming practices. The soil samples were incubated using soil chips to observe the abundance of the various types of microorganisms. We also compared microbial morphodiversity with molecular biodiversity measurements. In addition, the soil characteristics such as pH, organic matter and electrical conductivity were determined for correlation analysis with microbiological presence/abundance.
The abundance of microbiological groups examined via microscopic analysis in soil chips proved to be highly variable within crop types and agricultural field management (conventional/organic). However, time since transition to organic farming practices might influence the abundance for the microbiological groups with an increase in abundance for older organic farms. In addition, the analysis of soil parameters such as pH, soil organic matter and electrical conductivity also showed to be highly variable within crop types and agricultural field management.
This study shows that abundances of microbiological groups in various types of agricultural soils might be highly variable, in which the years of organic farming, but not the categorical farming practices tend to affect microbiological group abundance.
How to cite: Lake, F. B., Carrié, R., Bacon, C. D., Ekroos, J., and Hammer, E. C.: Soil microbiome diversity under annual and perennial crops in conventional and organic agriculture. , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11990, https://doi.org/10.5194/egusphere-egu25-11990, 2025.
Soil biota can sustain a wide range of functions and as such are intrinsically connected to soil health, which is defined as the capacity of a soil to function within ecosystem and land-use boundaries. Land use, soil management and land degradation can affect soil biodiversity and ultimately soil health. Soil fauna is an integral part of soil biodiversity connected at various levels of the food web with other important soil organisms such as bacteria and fungi. Nematodes are ubiquitous organisms sensitive to disturbances, and can be divided into functional groups based on feeding preferences and life-history strategies. Mites and collembola are two groups of microarthropods that are sensitive to land use change and soil management. These different groups of organisms can be used as indicators of soil biodiversity and health and can be measured with both morphological and molecular methods. Molecular methods offer great advantages compared to morphological methods, such as increase throughput and decrease costs and expertise needed for analysis, however only few studies have compared the information coming from both analyses. The objective of this study is to compare results of nematodes and microarthopods characterization obtained from morphological and eDNA methods in the framework of the European project SOILGUARD. To achieve this, nematodes, acari and collembola community characteristics have been assessed in seven European NUTS regions with different land use (forest, grassland and arable land), management (clearcutting vs continuous cover, grass monoculture vs grass-clover mix, organic vs conventional agriculture), pedo-climatic (texture, climate) characteristics, and land degradation gradient (organic matter levels). Soi fauna communities have been analysed with traditional morphological characterisation after extraction from soil and molecular methods with direct eDNA extraction from soil. Fauna-based soil health indices based on their abundance were calculated with information coming from both assessment methods. Results show disagreement between the two methods. More details about the outcome of this comparison will be presented and discussed during the conference.
How to cite: Bongiorno, G., Sanchez-Cuetos, P., Llado’, S., Soliveres, S., and De Goede, R. G. M.: Effects of land use and agricultural management along soil degradation gradients on soil fauna in European sites (SOILGUARD) – a comparison between morphological and molecular data, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15401, https://doi.org/10.5194/egusphere-egu25-15401, 2025.
Soil ecosystems harbor a vast diversity of organisms—ranging from microbes (bacteria, fungi, archaea) to meso- and macrofauna (e.g., protists, nematodes, mites, insects)—that collectively drive soil functions such as nutrient cycling, organic matter decomposition, and plant productivity. These processes depend on intricate interactions within the soil food web. Despite the acknowledged importance of meso- and macrofauna in maintaining soil health and mediating biogeochemical cycles, effective chemical proxies for these organisms remain constrained to specific groups, limiting their use in comprehensive soil biodiversity assessments.
To address this gap, we applied a lipidomic approach to more than 80 single species spanning 26 phyla of soil biota, including Euryarchaeota (archaea), Proteobacteria and Actinobacteriota (bacteria), Ascomycota and Mucoromycota (fungi), Chlorophyta (algae), Arthropoda, Nematoda and Mollusca (meso- and macrofauna), and Tracheophyta (higher plants). Through high-resolution mass spectrometry and molecular networking, we identified more than 700 novel molecular lipid families within 12,000 lipid compounds, many lipid families being unique to specific phyla. These findings establish a robust framework for developing phylum-specific biomarkers and deepen our understanding of the soil food web. By focusing the current study on pure species, and by quantifying their content in the specific organisms, we enable biomass quantification across the whole soil food web and improve taxonomic resolution with phylum-specific chemical proxies, revealing distinct lipid signatures—such as ceramides in arthropods and cardiolipins in bacteria—that illustrate the metabolic specializations and ecological adaptations of these organisms.
This integrative approach underscores lipidomics as a powerful tool for linking molecular-level data with taxonomy and allowing biomass quantitation across complete food webs. As global environmental pressures intensify, our findings pave the way for biomarker-driven strategies to monitor, conserve, and elucidate soil biodiversity, ultimately supporting the essential services that soil ecosystems provide.
How to cite: Samrat, R. and Wanek, W.: Revealing Phylum-Specific Signatures in Intact Lipids: A Novel Biomarker Approach in Soil Biodiversity Research, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17948, https://doi.org/10.5194/egusphere-egu25-17948, 2025.
Environmental DNA (eDNA) analysis can facilitate biodiversity monitoring within a bulk sample, especially valuable to evaluate soil ecosystems. eDNA can persist in soil as living cells, dead cells, and extracellular DNA either as free or adsorbed to particles in the soil. Each of these ‘states’ of eDNA can have differing persistence times from a few days to hundreds of years. Better understanding to target and isolate particular states of eDNA is imperative to derive valuable information, for instance, recent occupancy indicated by freshly released eDNA or eDNA within living cells.
This presentation will present cases showing the variability of eDNA persistence in different states with a focus on the adsorbed state. I will then discuss the adsorption mechanism of eDNA and introduce novel methods of isolating the states of eDNA from a single sample for independent analysis. Lastly, I will show data from a landscape level study with water samples collected from 221 sites from 58 streams in eight Swiss watersheds. All the samples were state sorted and analyzed with board range metabarcoding assays for identifying metazoan diversity. The results show that each state consists of unique diversity information and state sorting methodologies should be considered when processing bulk soil samples for eDNA analysis. While this presentation will have some studies using water samples, they elucidate the behavior of eDNA bound to soil and sediment particles as well.
How to cite: Kirtane, A.: Consideration of eDNA states to analyze bulk soil samples via metabarcoding, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-18094, https://doi.org/10.5194/egusphere-egu25-18094, 2025.
Soil health is defined as the capacity of soil to function as a vital living system within ecosystem and land-use boundaries to sustain biological productivity, maintain environmental quality, and promote plant, animal, and human health. The decline of soil health due to human impacts is an urgent ecological issue.
This study explores the diversity patterns and within-field variability of soil macrofauna communities across different land management systems in Portugal, employing a robust, multi-faceted approach. Two case studies were conducted to evaluate diversity patterns in forests (oak- and pine-dominated) and olive groves (intensive and extensive systems). Sampling was carried out in April and May 2024, utilizing a systematic grid design that incorporated two spatial methodologies: a k-means-based grid and random point allocation, resulting in 36–39 sampling points per system. To enhance comparability, an additional sampling point was included following the LUCAS methodology.
Macrofauna were identified morphologically at the order level, and abundance data were systematically recorded. For each land-use type, a subset of samples was analysed to quantify the biomass of individual taxonomic orders, providing deeper insights into the relevance of biomass as an ecological parameter. Species richness was assessed using incidence frequency data and compared across the various management systems, with a focus on Hill numbers.
Diversity estimates for the agricultural sites indicate that extensive agricultural systems support higher potential species diversity as sampling efforts increase, while intensive agricultural systems generally sustain a lower and less diverse macrofauna community. Similarly, forested site estimates reveal that oak-dominated habitats harbour significantly greater species diversity compared to pine-dominated habitats. The metabarcoding approach corroborated these patterns, providing complementary insights, and the correlation between high-throughput sequencing (HTS) reads and biomass is critically analysed.
This methodological framework underscores the profound impact of land-use practices on soil macrofauna diversity, highlighting their essential role in sustaining soil health and broader ecosystem functionality. By integrating soil macrofauna diversity into soil health assessments, this study addresses a significant knowledge gap and offers practical guidance for developing improved soil management strategies that support sustainable land-use practices.
How to cite: Steiner, E., Campello, C., Reis, F., Fraga Dornellas, L., Leitão, R., Simões, S., Sousa, J. P., and Cunha, L.: Soil Health Through the Lens of Macrofauna Diversity: Insights from Forests and Olive Groves, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-19428, https://doi.org/10.5194/egusphere-egu25-19428, 2025.
Posters on site: Tue, 29 Apr, 16:15–18:00 | Hall X4
Most soils in the Amazon rainforest are highly weathered, acidic, and nutrient-poor. Under those conditions, most soil phosphorus (P) is bound to minerals, making it unavailable to plants and turning P into a limiting factor for plant growth. To adapt, plants in the Amazon have developed complex interactions with soil microorganisms to facilitate nutrient cycling, depending heavily on the soil organic P pool for nutrient uptake. However, converting forests into agriculture poses significant threats by disrupting the intricate interactions that maintain soil nutrient cycles and plant productivity, ultimately impacting the region's long-term stability. Our study investigated the long-term (30-year) effects of converting Primary Forest into two distinct agricultural systems: Agroforestry and Citrus monoculture. We assessed how bacterial and fungal communities interacted with soil physicochemical attributes and different P pools, such as labile, moderately labile, and non-labile P. Our preliminary results indicated that Agroforestry soils retained properties similar to those of Forest soils. In contrast, Citrus soils exhibited higher pH and micronutrient levels and reduced organic matter and dissolved organic carbon content. Total soil P was higher in Citrus soils due to fertilization, while Forest and Agroforestry had larger organic P pools, considering both soil and litter layer. Additionally, phosphatase activity and the abundance of P-cycling genes were higher in Forest and Agroforestry, suggesting greater organic P cycling and stronger reliance on microbial processes for nutrient acquisition. Bacterial and fungal composition were strongly influenced by soil micronutrient levels and the moderately labile P pool. These findings indicate that microbial processes are crucial to maintaining P cycling in Forest and Agroforestry, whereas monocultures primarily depend on synthetic fertilizers to support plant productivity. Further, our ongoing metagenomics and metabolomics analyses will provide deeper insights into functional and metabolic pathways through which organic P is cycled by soil microbiota in the Amazon region.
Keywords: Metagenomics; Metabolomics; Microbial Ecology; Conservative agriculture; Tropical Forest; Soil restoration.
How to cite: Martins, G., Monteiro, G., Pellegrinetti, T., de Freitas, A., Barbosa, L., Mendes, L., Gleixner, G., and Tsai, S. M.: Organic phosphorus cycling by soil microbiota is crucial to maintaining sustainable agricultural systems in the Amazon, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-232, https://doi.org/10.5194/egusphere-egu25-232, 2025.
Microbially mediated N fixation is widespread in rice paddy ecosystems and crucial in maintaining soil fertility. However, our understanding of the factors determining the distribution of free-living diazotrophic microorganisms that perform this process in paddy fields is limited. This study investigated the spatial distribution and factors influencing presence and potential activity of free-living microorganisms capable of N2 fixation in addition to dissimilatory nitrate reduction to ammonium (DNRA), anaerobic ammonium oxidation (anammox), and denitrification in 50 paddy soils across China. Using 15N isotope tracing in laboratory incubations and microbial community analysis via metagenomics, we demonstratethat paddy soils may represent a previously underappreciated hotspot for N2 fixation with mean potential rates of 24.4±17.8 nmol N g-1 h-1, 10-fold higher than DNRA (2.55±0.4 nmol N g-1 h-1), and could counterbalance a portion of N2 losses through anammox and denitrification (9.24±1.1 nmol N g-1 h-1). Site longitude and organic carbon (C) concentrations, as well as the diazotrophic community composition, were the dominant abiotic and biotic factors accounting for regional variations in potential N2 fixation rates. The N2 metabolic pathways predicted from the metagenome-assembled genomes (MAGs) revealed significant co-occurrence of the diazotroph marker gene nifH withdenitrification-associated genes (nirS/K and nosZ) and organic C oxidation-related genes (yiaY and galM). Furthermore, enzymes involved in organic C oxidation, particularly glycoside hydrolases and glycosyltransferases, were not only phenotypically correlated with free-living N2 fixation rates but were also identified in nifH-containing MAGs, indicating the heterotrophic capabilities of diazotrophs in paddy soils. Collectively, our results underscore the substantial contribution of free-living N2 fixation to soil N fertility in paddy fields, and highlight the importance of coupling organic C oxidation with nitrate reduction to enhance N2 fixation.
How to cite: Wang, X., Shan, J., and Yan, X.: Investigating drivers of free-living diazotroph activity in paddy soils across China, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-7848, https://doi.org/10.5194/egusphere-egu25-7848, 2025.
Viruses are present in any cellular organism and are numerous in the environment. Though they influence nutrient cycles, interactions and energy flows in food webs, viral diversity distribution and assembly in ecosystems are still understudied [1].
In our project “Viral hotspots and fluxes across above- and belowground food webs (ViralWeb)” we aim to clarify mechanisms of distribution of viruses and their diversity forming across above- and belowground ecosystem compartments and food webs. We focus on plants, fungi, and invertebrate animals as model potential hosts. We also concentrate on RNA viruses, as they dominate eukaryotic viromes [2].
We hypothesize that the diversity and distribution of viruses in ecosystems depend on the diversity of hosts and flows of matter and biomass among ecosystem compartments and food-web nodes. We have three specific hypotheses:
1) the RNA viral diversity of the ecosystem is positively correlated with the diversity of potential viral hosts in this ecosystem;
2) there are local hotspots of viral diversity in systems, such as “cumulative” substrates (e.g., leaf litter) and hosts (top predators);
3) patterns of viral distribution in food webs are correlated with flows of matter and energy among food-web nodes and ecosystem compartments. We expect to detect a positive correlation between the similarity of viral community and connectedness of two nodes in a food web.
We plan to conduct our investigation based on biodiversity manipulation experiments in central Germany (the Jena Experiment and MyDiv). Our sampling design is based on plots with different diversity levels of hosts (plants, fungi, and invertebrates).
Green parts of plants, fungi, litter, soil, and invertebrate consumers by ecological groups [3] will be sampled. The diversity of hosts will be accessed using DNA analysis and morphological identification. The presence of viruses and replication evidences will be detected via high-throughput sequencing and strand-specific RT-PCR [4].
For both study sites food webs will be reconstructed and energy fluxes across above- and belowground compartments will be calculated [5]. Invertebrate hosts’ classification and body size measurement will be facilitated using image analysis approach [6]. Based on obtained average consumer sizes the biomass of food web nodes will be calculated [7]. Energy fluxes will be estimated from metabolic rates of invertebrates accounting for temperature and assimilation efficiency [8].
We expect the results of ViralWeb project to help us better understand the mechanisms of spread of viruses and clarify and predict the roles of viruses in ecosystems.
The project was supported by the Flexpool funding mechanism of the German Centre for Integrative Biodiversity Research (iDiv).
Refernces
[1] Williamson KE et al. (2017). Annual review of virology, 4:201-219. https://doi.org/10.1146/annurev-virology-101416-041639
[2] Wolf YI et al. (2018). MBio, 9(6):10-1128. https://doi.org/10.1128/mbio.02329-18
[3] Potapov AM et al. (2022). Biological Reviews 97:1057–1117. doi:https://doi.org/10.1111/brv.12832
[4] Baty JW et al. (2020). Myrmecol. News 30:213-228. https://doi.org/10.25849/myrmecol.news_030:213
[5] Potapov AM et al. (2024). Nature, 1-7. https://doi.org/10.1038/s41586-024-07083-y
[6] Sys S et al. (2022). Methods in Ecology and Evolution 2041–210X.14001. doi:10.1111/2041-210X.14001
[7] Sohlström EH et al. (2018). Ecology and Evolution 8:12737–12749. doi:10.1002/ece3.4702
[8] Potapov AM (2022). Biological Reviews, 97(4):1691-1711. https://doi.org/10.1111/brv.12857
How to cite: Zueva, A., Eisenhauer, N., Chatzinotas, A., and Potapov, A.: Viral diversity and distribution across above- and belowground food webs: the project concept, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8782, https://doi.org/10.5194/egusphere-egu25-8782, 2025.
Biodiversity monitoring programs often focus on aboveground organisms but ignore soil organisms. Among soil organisms, earthworms (Lumbricidae) are vital macrofaunal components of soil ecosystems and serve as bioindicators of soil health due to their significant ecological functions and interactions with above – and below-ground organisms. Moreover, earthworm species richness is crucial for biodiversity monitoring because of its manageable diversity and ease of sampling. This study aims to investigate the distribution of earthworms in the open landscape and potential site- and landscape-level factors influencing their distribution.
The study was conducted in the Waldviertel region of Austria, bordering to Czech Republic and Slovakia. The region is characterized by a dense network of Natura 2000 nature conservation areas and is known for its high biodiversity and fragmented landscape with many semi-natural structures. Additionally, the identified threats and pressures to Natura 2000 sites in the region, such as eutrophication, intensive grassland management, and landscape simplification are considered in terms of their impact on earthworms. In particular, we focused on the effects of semi-natural landscape elements, such as hedgerows or grass strips, on earthworm abundance and diversity. Hedgerow soils, characterized by high organic matter content, litter cover, and structural complexity, provide ideal habitats for earthworms.
The objectives of this study were to (1) assess earthworm communities (biomass, abundance and species richness) in grasslands and arable land, (2) investigate the influence of soil chemical and physical parameters, and intensity of agricultural management, and (3) examine the extent to which landscape structures at different scales influence earthworm communities. Preliminary analyses suggest that earthworms are influenced by both site-level and landscape-level. By linking earthworm communities to landscape features, this study aims to contribute to a better understanding of soil life and its role in sustainable land management. Additionally, promoting earthworm populations may have benefits for other soil organisms, soil health and overall biodiversity.
The study was conducted as part of the Austrian soil biodiversity monitoring project “BodenBiodiv” funded by the Austrian Biodiversity Fund and the Next Generation EU.
How to cite: Zottl, M., Mittmannsgruber, M., Gruber, E., Wiedenegger, E., Monoshyn, D., and Zaller, J. G.: Earthworm communities in the Austrian biodiversity hotspot region Waldviertel: Effects of site vs landscape factors, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-15726, https://doi.org/10.5194/egusphere-egu25-15726, 2025.
Tree associated microbes are an important component of forest biodiversity and they are essential for forest ecosystem functioning. Most plant–microbe research has focused on the rhizosphere, while composition of microbial communities in the phyllosphere remains underexplored. By using 16S rRNA gene sequencing analyses, we investigated differences between beech and Scots pine phyllospheric microbiomes across an environmental gradient from Fennoscandia to the Mediterranean area, map their functional profiles, and elucidate drivers of phyllosphere microbiota assembly. We identified tree species and the associated foliar trait (specifically carbon:nitrogen ratio) as primary drivers of the bacterial communities. Moreover, we also found that temperature and nitrogen deposition played a crucial role in affecting microbial assembly for both tree species. Functions related to ureolysis and methanol oxidation were more represented in beech than Scots pine, whereas Scots pine phyllosphere were richer in microbes able to perform methanotrophy, nitrogen-fixation, nitrate reduction, and hydro-carbon degradation. This study contributes to advancing our understanding on the vast diversity of microbial communities hidden in tree canopies of two of the most common tree species in European forests, and on factors shaping it. Moreover, it highlights the need of broad-scale comparative studies (covering a wide range of foliar traits and environmental conditions) to elucidate how phyllosphere microbiota mediates forest ecosystem responses to global change.
How to cite: Guerrieri, R., Sangiorgio, D., Cáliz, J., Mattana, S., Casamayor, E., Peñuelas, J., and Mencuccini, M. and the Collaborators at the ICP Forests sites: Assessing composition and drivers of phyllosphere microbiota of beech and Scots pine across European forests, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-12525, https://doi.org/10.5194/egusphere-egu25-12525, 2025.
Grasslands and arable lands differ in their use – grasslands are primarily used as grazing areas or sources of forage while arable lands are designated for intensive crop production, often requiring cultivation practices and fertilization. Earthworms have a crucial role in both ecosystems by influencing soil structure, enhancing aeration processes, and contributing to the decomposition of organic matter.
This study aims to compare the density and species diversity of earthworms in arable soils and grasslands and evaluate the stability of soil aggregates in these environments. It also seeks to explore the relationship between land use, soil structure, and earthworms, emphasizing their influence on soil quality.
The research was carried out in eight areas, comprising four grasslands and four arable lands, situated in the Wieliczka Foothills, Nowy Wiśnicz Foothills, Rożnów Foothills, Ciężkowice Foothills, and the Low Beskids in southern Poland. Five soil blocks measuring 20 × 20 cm and 25 cm deep in each study area were collected, and earthworms from these samples were extracted using the hand-sorting method. The collected earthworms were washed and classified using an identification key according to their maturity stage, ecological categories, and species. Soil samples (100 g from each block) were combined, mixed, dried, and analyzed for properties such as pH, carbon and nitrogen content, texture, and aggregate stability.
The lowest earthworm density was recorded on arable land, at 10 individuals per square meter (ind. m-2). The tillage treatment that was carried out on the arable land 18 days before the study included soil loosening methods (ploughing, tillage, ridge-making or deep ploughing). The tillage treatment carried out on the arable land 18 days before the study involved soil loosening methods such as ploughing, tillage, ridge-making, or deep ploughing. These processes, including soil inversion by ploughing, can disturb the natural habitat of earthworms, leading to their migration to other areas or a reduction in their numbers within the field. In contrast, the highest density was observed in grasslands (480 ind.m-2), which were characterized by rare trampling or its absence and no use of fertilizers. The earthworm density in grasslands (349 ind. m-2) was more than twice that of arable lands (133 ind. m-2), highlighting the more favourable environmental conditions in grassland ecosystems.
This research was funded through the 2022-2023 Biodiversa+ COFUND call, under the European Biodiversity Partnership programme, and with the funding organisations: National Science Centre 2023/05/Y/ST10/00098.
How to cite: Szlachta, N., Pacanowski, P., and Józefowska, A.: A Comparative Study of Earthworm Density and Diversity in Grasslands and Arable Lands, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17527, https://doi.org/10.5194/egusphere-egu25-17527, 2025.
The mobility of soil bacteria plays a crucial role in rhizosphere colonisation, as exemplified by the complex chemotactic machinery required for effective biofilm formation on growing roots [1]. However, the nature of soil bacterial movements in the soil pore space is poorly characterised. It is difficult to observe the trajectories of individual cells, and the complexity of soil structure makes any observation difficult to replicate. To overcome these difficulties, we have developed a range of microcosm systems that allow live observation of bacterial movement in porous media with precisely controlled physical or chemical properties. Paper-based microfluidic systems have been developed for the in situ extraction of root exudates, which act as a potent chemoattractant for bacteria [2]. Microfluidic devices made of semi-permeable materials allowed the construction of pores through which nutrient release can be controlled, and transparent soil and custom-made microscopes were used to observe bacterial movements when co-cultured with plants [3]. Using Bacillus subtilis as a model organism, we observed that the bacterium occupies very specific regions of pore space in relation to distance from the root [4] or the presence of nutrients, and that movements can be coordinated at a population level [3]. Future work will focus on understanding the conditions under which collective movements of bacteria occur in soil.
References
[1] Allard-Massicotte, R, et al (2016) “Bacillus subtilis early colonization of Arabidopsis thaliana roots involves multiple chemotaxis receptors” MBio, 7(6), 10-1128. [2] Patko, D, et al (2024) "Spatial and temporal detection of root exudates with a paper-based microfluidic device" Soil Biology and Biochemistry 195 (2024): 109456. [3] Liu, Y, et al (2021) "Plant–environment microscopy tracks interactions of Bacillus subtilis with plant roots across the entire rhizosphere" Proceedings of the National Academy of Sciences 118.48: e2109176118. [3] Engelhardt, I C, et al (2022) "Novel form of collective movement by soil bacteria" The ISME Journal 16.10: 2337-2347. [4] Engelhardt, I C, et al (2024) “Mobility and growth in confined spaces are important mechanisms for the establishment of Bacillus subtilis in the rhizosphere” Microbiology, 170(8), 001477.
How to cite: Patko, D., Meza, B., Engelhardt, I., de las Heras, G., Liu, Y., Basabe-Desmonts, L., Benito-Lopez, F., and Dupuy, L.: Studying the mechanisms of bacterial mobility in the rhizosphere using soil model systems, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-9736, https://doi.org/10.5194/egusphere-egu25-9736, 2025.
Fungi are key agents in decomposing high-lignin, low-nutrient content deadwood, yet how variations in carbon quality and nutrient availability shape fungal communities and their decay activities remains poorly understood. Here, we investigated how carbon quality (lignin vs. cellulose) and nutrient inputs (nitrogen and phosphorus) interact to influence fungal community composition and decomposition of angiosperm versus gymnosperm deadwood in a subtropical forest. Our results reveal contrasting fungal responses to nutrient additions in angiosperm and gymnosperm deadwood, leading to distinct impacts on decomposition rates. In nutrient-rich, low-lignin angiosperm wood, nitrogen and phosphorus additions shifted the community from Basidiomycota dominance toward Ascomycota and markedly increased fungal diversity. Fungal community shifts enhanced hydrolytic enzyme activity targeting decomposition of cellulose, accelerating overall carbon mineralization rates. Conversely, in nutrient-poor, high-lignin gymnosperm wood, nutrient additions strengthened the dominance of Basidiomycota, reduced fungal diversity, and disproportionately enhanced lignin decomposition. These findings emphasize that wood carbon quality mediates how nutrient inputs accelerate deadwood decomposition through the reassembly of fungal taxa with specific metabolic traits. The nutrient–carbon trade-off in fungal communities highlights a previously underappreciated mechanism controlling wood decay and carbon cycling in tropical forest ecosystems. Understanding these processes is pivotal for improving predictions of carbon storage and turnover under changing nutrient regimes.
How to cite: Xu, Z., Hu, Z., Qiu, T., and Anthony, M.: Carbon quality mediates the nutrient accelerating effects of fungi on wood decomposition, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-5770, https://doi.org/10.5194/egusphere-egu25-5770, 2025.
Reducing the frequency of lawn mowing can be a nature-based solution for adapting to climate change in urban areas. Reducing mowing has many ecological benefits, but it is not clear how it affects soil mesofauna, an extremely important element of terrestrial ecosystems. This study is based on a field experiment conducted on the public grounds of a university campus in Poland. In the experiment, 64 experimental plots were established and paired into 32 adjacent plots, where one plot was mowed once a year and the other plot in the pair was mowed in a different regime, including one mowing every 2 years and mowing 4, 6 and 8 times a year (n=8). The effect of mowing on the feeding activity (FA) of the soil mesofauna was assessed during the 2-year experiment using the bait lamina test. The mean FA on individual plots was 2.95% (± 1.24%) per day and was not affected by mowing frequency, soil temperature, or soil moisture. However, more frequent mowing (4, 6, and 8 times per year) resulted in a steeper decline in FA with soil depth, and the effect was most significant for mowing 8 times per year, amounting to an additional 15% decline in FA along the vertical soil gradient sampled. Therefore, in temperate climates, the recommended frequency of mowing is the same as for other groups of organisms, including plants, i.e. once or twice a year. Reduced mowing frequency allows better functioning of the anthroposols for their naturalisation by activating the deeper soil horizons.
How to cite: Klimek, B. and Kajzer-Bonk, J.: To mow or not to mow? Effect of mowing frequency of urban lawns on soil mesofauna feeding activity, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6040, https://doi.org/10.5194/egusphere-egu25-6040, 2025.
