Connecting calorimetry with microbial traits and activity
The SPP SoilSystems aims to better understand complex soil systems, their biodiversity, metabolic performance and ecosystem services by incorporating the laws, methods and models of thermodynamics. To accomplish this, calorimetry and thermal analysis needs to be optimized and linked to microbial activities, microbial functions and nutrient fluxes via thermokinetic models. The working group (WG) “Connecting Calorimetry with microbial traits and activity in soil ecosystems” was established to implement this approach by:
- further developing the theory underlying calorimetric analyses in soils and the relation between microbial activities and matter/energy flows,
- unifying and improving experimental approaches in calorimetry and calorespirometry,
- combining analyses of mass flows and microbial activities with calorimetric measurements,
- deriving approaches to estimate mass and energy balances that consider complex substrates, necromass formation and their interactions with different soil components,
- providing the basis for data interpretation and modeling of soil processes.
Data integration and modelling (WG DIM)
In order to understand the roles of soil physico-chemical and biological factors in energy and matter turnover, the SoilSystems projects will generate a wide range of data. Joint use and exchange of measurements and data across these projects will support linking complementary experimental evidence and thus maximize the use of information within the SoilSystems data space. The joint data set will support process-based modeling, which allows for the testing of hypotheses related to energy dissipation and matter turnover on quantitative grounds. WG DIM coordinates the data-model nexus in SoilSystems by addressing the following aims:
- Identify and leverage synergies within SoilSystems projects to better integrate experiments and modeling
- Coordinate the exchange and interpretation of data between experimental approaches and modeling
- Harmonize the processing of energetic, mass balance, and taxon abundance data between experimental projects and the data used for models (in collaboration with the other SoilSystems working groups)
- Support the implementation of the data management center in developing metadata templates for central data storage
Micro food web
The exploitation of resources by microorganism can only be understood as part of the soil food web. This is addressed by the working group “Micro-Food Web”, which is a forum for projects linking energy and/or heat fluxes to microbial activity, functional traits and trophic interactions within the soil microbiome. The top-down and bottom-up forces in the soil micro-food web directly affect microbial activity, and thus C and energy flow in decomposition pathways. Additionally, interspecific interactions such as predation, can determine the degree to which microorganisms regulate turnover processes. However, the transfer of energy and C from microorganisms to higher trophic levels is only marginally understood. Within the SPP, the key-biota investigated in the micro-food web are bacteria and fungi as base, myxobacteria as bacterial predators and nematodes with functional groups at each trophic level. Our working group is an opportunity to collaboratively extend the work of individual projects into a broader framework. We further aim to improve experimental approaches and methods, and develop tool-kits for efficient flux/energy measurements. Overall, we want to share diverse perspectives, pool expert knowledge and skills to bridge trophic levels.
Organo-mineral interactions & C stabilization
The working group “Organo-Mineral Interactions & Carbon Stabilization” bundles all SPP projects or members that deal with (or are interested in) learning about the effects of minerals or their experimental equivalents (glass beads, milled quartz sand, etc.) on mass and energy balances of soil systems. Minerals and mineral surfaces are integral components of soil systems and play a prominent role in organic matter stabilization against mineralization: The largest part of soil organic matter is associated with minerals and represents a fraction of soil C that is turned over comparably slow, which makes it not only a climatically relevant carbon sink, but also an energy sink. We aim to understand the processes and thermodynamics of the association of organic matter with minerals and their effects on the stabilization of organic matter in soils. Combined, we aim to contribute to a better understanding of energetic controls on SOM stabilization. We meet regularly (at least twice a year) to exchange data and knowledge, discuss recent findings and commonalities, identify open questions and discuss how to tackle them with novel experiments.
Soil Functional Complexity in Space and Time
The SPP explores soil as a system of energy and matter exchanges between organisms and their surroundings from a thermodynamic perspective. This WG investigates more closely the role of complexity and heterogeneity in soil systems and their functions. For instance, various soil functions are emergent properties of diverse soil communities and their interactions with and within a spatially heterogeneous and temporally variable environment of soil minerals, organic matter, pore space, and aggregates. We welcome all who are interested to regular meetings and seminars to exchange results of different approaches, collaborate on new analytical methods of heterogeneity and complexity, and synthesize new understanding on the functioning of complex adaptive soil systems.