Dual-labelled (13C/15N) green manure to differentiate between plant uptake of organic and inorganic N

Experimental data is still lacking for determining whether plant uptake of organic nitrogen in agricultural soils contributes substantially to the total N uptake. Pulseinjection studies with dual-labelled amino acids have confirmed that non-mycorrhizal crops possess the capacity to take up organic N but failed to quantify the uptake relative to total N uptake

Collembola’s role in regulating mass fluxes in soil and the effects of contrasting life histories

The study determined metabolic rates and elemental pools for two Collembola species with contrasting life histories. The fittest of the two species, P. minuta, excreted the equivalent of 10–12% of the elemental body content per day, and P. armata 7–10%. Most elements are lost to excretion (CO2 and N-waste). These figures in combination with stoichiometry and life histories indicate that the cost of P. minuta’s better fitness is a requirement for a higher quality diet than P. armata. The data produced in this study can be used to estimate the collembolan contribution to C and N fluxes in the soil

Nutrient allocations and metabolism in two collembolans with contrasting reproduction and growth strategies

Physiological mechanisms such as allocation and release of nutrients are keys to understanding an animal\u27s adaptation to a particular habitat. This study investigated how two detrivores with contrasting life‐history traits allocated carbon (C) and nitrogen (N) to growth, reproduction and metabolism. As model organisms we used the collembolans, Proisotoma minuta (Tullberg 1871) and Protaphorura fimata (Gisin 1952). To estimate allocations of C and N in tissue, we changed the isotopic composition of the animal\u27s yeast diets when they became sexually mature and followed isotope turnover in tissue, growth and reproduction for 28 days. In addition, we measured the composition of C, N and phosphorus (P) to gain complementary information on the stoichiometry underlying life‐history traits and nutrient allocation. For P. minuta, the smallest and most fecund of the two species, the tissue turnover of C and N were 13% and 11% day−1, respectively. For P. fimata, the equivalent rates were 5% and 4% d−1, respectively. Protaphorura fimata had the lowest metabolic rate relative to total body mass but the highest metabolic rates relative to reproductive investment. Adult P. fimata retained approximately 17% of the nutrient reserves acquired while a juvenile and adult P. minuta about 11%. N and P contents of total tissue were significantly higher in P. minuta than in P. fimata, suggesting that tissue turnover was correlated with high protein‐N and RNA‐P. Our results suggest that the lower metabolism and nutritional requirements by P. fimata than P. minuta is an adaptation to the generally low availability and quality of food in its natural habitat. The methodological approach we implemented tracking mass balance, isotope turnover and elemental composition is promising for linking nutrient budgets and life‐history traits in small invertebrates such as Collembola

Deliverable D2.4. Modelling module for biological diversity and functions in land surface water balance

The WP2 "Soil Functioning and Ecosystem Services", of the EcoFINDERS project, has produced a modelling module linking soil biodiversity and its functioning to hydrological properties of agricultural soil. The scope is of a proof-of-concept, including only earthworm burrows as a proxy for cropping systems. The biodiversity focus is on anecic earthworm burrows, which traverse vertically into the deep soil. At the LTO Lusignan this group of earthworms dominates the cropping systems of permanent grass (T5) and of three years of grass in a sequence with three years of annual crops (T2). In contrast, a cropping system without grass and with frequent tillage (T1) is dominated by the soil dwelling endogeic earthworms. The hydrological modelling starting point was the Joint UK Land Environment Simulator (JULES), but the soil hydrology module in JULES only considers water-flow through the soil matrix. Hence, we incorporated a representation of the water flow through macropores made by earthworms by adopting representation of macropore soil water flow in the open source soil-plant-atmosphere model, DAISY. The macropore parameters used for this module are: density, diameter, depth, conductivity of the macropore wall and soil water pressure. The approach has enabled the assessment of events of waterlogging and water deficiency in agricultural soils in real case scenarios, identifying the periods of risk in relation to earthworm burrowing. Two metrics were calculated from the simulated soil water contents: trafficability and vegetation soil water stress, corresponding to detrimental effects of water logging and insufficient plant accessible water. The presence of burrows could somewhat mitigate the risks for soil water logging and hence increase trafficability of the land. However, a trade-off was observed in a corresponding increase of the risk for water deficiency, although this may be a model artefact as water uptake related to crop type was not included in the model. A sensitive aspect in our data is the number of hydrologically active earthworm burrows which vary by season. The results of this study should not be extrapolated to other soil types or land uses and management. For extrapolation purposes, further research would be required. The output of the modelling is input to an economic assessment, e.g. by quantitatively assessing the occurrences of soil water deficiency and water logging as risk to farmers’ income stability as a result of reduced yields or loss of entire crops

NORMA-Gene: A simple and robust method for qPCR normalization based on target gene data

<p>Abstract</p> <p>Background</p> <p>Normalization of target gene expression, measured by real-time quantitative PCR (qPCR), is a requirement for reducing experimental bias and thereby improving data quality. The currently used normalization approach is based on using one or more reference genes. Yet, this approach extends the experimental work load and suffers from assumptions that may be difficult to meet and to validate.</p> <p>Results</p> <p>We developed a data driven normalization algorithm (NORMA-Gene). An analysis of the performance of NORMA-Gene compared to reference gene normalization on artificially generated data-sets showed that the NORMA-Gene normalization yielded more precise results under a large range of parameters tested. Furthermore, when tested on three very different real qPCR data-sets NORMA-Gene was shown to be best at reducing variance due to experimental bias in all three data-sets compared to normalization based on the use of reference gene(s).</p> <p>Conclusions</p> <p>Here we present the NORMA-Gene algorithm that is applicable to all biological and biomedical qPCR studies, especially those that are based on a limited number of assayed genes. The method is based on a data-driven normalization and is useful for as little as five target genes comprising the data-set. NORMA-Gene does not require the identification and validation of reference genes allowing researchers to focus their efforts on studying target genes of biological relevance.</p

Interaction webs in arctic ecosystem : Determinants of arctic change?

Peer reviewe

EUdaphobase - building bridges between cohabiting soil communities, environments, and methodologies

Aim: Edaphobase is a database previously constructed by the Senckenberg Natural Museum in Görlitz in Germany for the purpose of connecting soil invertebrate taxa to their environment. To extend Edaphobase into a warehouse for data on soil biodiversity at the European level and improve its usefulness, COST Action “EUdaphobase” was launched. Action gathers a network of European specialists working on enlarging existing capacities, and improving the technical capabilities, to provide a unique database that would be used by the different levels of stakeholders (from farmers, research and education institutions to decision makers). Taxonomists, ecologists, modelers of soil ecosystem processes, financial and IT specialists joined to form a holistic picture of soil biodiversity and introduce it into the decision-making process in Europe. Method: WG 7 of EUdaphobase is focused on two goals - to enable a framework for integrating the data on fungi, bacteria and microeukaryotes, and collating the data derived by molecular methods (metabarcoding, NGS-based, environmental DNA/RNA), on all soil organism groups. Results: The highly demanding technical problems of incorporating fungal and molecular data into the already existing framework of Edaphobase were resolved. The joint work of researchers working on different soil organisms and techniques resulted in the unique possibility for a variety of users to provide/analyze/use data that include cohabiting taxa, their environments, and mutual relationships. Conclusions: The outcome will enable the usage of the upgraded Edaphobase for holistic soil state evaluation and monitoring, as well as monitoring of the dynamics of soil communities/environments involved in different ecosystem services on the European level.Abstract book was not published in hard copy and can be viewed on the congress site only https://gsb2023.org