The aim of this project is to quantify the combined effect of redox regime and the concentration of inorganic electron acceptors on microbial carbon use efficiency of two soils with different inorganic electron acceptors content using integrated experimental and mathematical approach.
Project description:
Carbon Use Efficiency (CUE) of soil microbial communities is an emergent property, which determines the amount of carbon retained in soil or lost from soil to atmosphere or waters. As such, it is a central parameter of the state-of-the-art microbial-explicit soil biogeochemical models. However, CUE variability in respect to various soil conditions is not yet fully understood. Here we propose a long term incubation experiment coupled with fine temporal scale resolution chemical, isotope, genomic, microbial and biochemical analysis to understand the effect of redox potential and inorganic electron acceptors concentration on microbial community CUE. We intend to use two spruce forest soils with residual nitrate and sulfate loads and different iron content as the study subjects. To accurately quantify CUE and its variability across experimental treatments and time, we further propose to adopt a modelling approach that explicitly account for variable macromolecular composition of soil microbial biomass.
(Co)investigator from the Department: David Boukal
Funding provider: Czech Science Foundation
Duration: 2020 - 2022
Project goals:
We aim to unravel the combined impacts of anthropogenic chemical pollution and climate change on freshwater ecosystems, using a combination of laboratory and mesocosm experiments focusing on the biota of small standing waters dominated by freshwater invertebrates.
Project description:
Multiple human-induced environmental stressors pose a major threat to global biodiversity and ecosystem functioning. Climate change and chemical pollution are two widespread stressors whose impact on freshwaters is likely to increase. We currently lack data and unified framework to predict responses of freshwater ecosystems to these combined stressors. To fill this knowledge gap, we will use laboratory and mesocosm experiments to understand how commonly found pharmaceutically active compounds (PhACs) and pesticides affect whole ecosystems and energy flow in communities in small standing waters. Moreover, we will explore if expected climate warming alters the presumed negative effects of anthropogenic pollution. We will focus on three levels of organization that may affect ecosystems and the services they provide: (1) changes in community composition and ecosystem functioning that we will link to (2) changes in species interactions, and (3) alterations of individual physiology and behaviour.
(Co)investigator from the Department: Karolina Tahovská
Funding provider: The Czech Science Foundation
Duration: 2020 - 2022
Project goals:
To evaluate links among pools, fluxes and stoichiometry of carbon and nutrients in microbe-soil-water system on acidification and eutrophication gradients across forested catchments. To determine and quantify the role of microbes in nutrient retention and include microbes into modelling framework.
Project description:
The availability of nitrogen (N) and phosphorus (P) controls many aspects of ecosystem function including ecosystem productivity, organic matter decomposition and consequent ecosystem elements retention including carbon (C) storage. Since 1994 a network of forested catchments (GEOMON) has been used for biogeochemical assessment of nutrient fluxes of semi-natural forest ecosystems in the Czech Republic. We found stoichiometric imbalance of carbon and nutrients between stream and soil suggesting important role of soil microbial transformations in nutrient retention. We propose that by combining data on long-term catchment solute fluxes, with catchment soil chemistry, microbial activity and community characteristics along acidification and eutrophication gradient we will be able to elucidate and generalized (regional extent) the role of microbes in nutrient retention at the catchment scale. Furthermore, obtained data will be used to calibrate updated biogeochemical model MAGIC to correctly predict soil and stream chemistry under changing deposition loads of both acidity and nitrogen.
Funding provider: Grantová agentura České republiky
Duration:2020 - 2022
Project description: Permafrost thawing is likely the most important natural process that may translocate carbon (C) from terrestrial ecosystems to the atmosphere as response to global warming, thus initiating a positive feedback to climate change. While several estimates on C losses have been made for the next decades, major processes in soil development after permafrost thawing have not been accounted yet. Depending on ice richness and soil drainage, permafrost degradation can result in wetter or drier conditions.
Contrasting environmental conditions evolving under these scenarios will critically influence biotic-chemical processes shifting the microbial community composition, leading to different organic matter (OM) decomposition and potential OM stabilization processes. Based on a conceptual framework on permafrost thaw under dry and wet scenario, the main objective of CRYOVULCAN is to comparatively investigate OM decomposition and stabilization under these two scenarios. Our main hypothesis is that chemical and biological attenuation processes will partly compensate for the organic carbon (OC) losses caused by permafrost thaw. Under (1) a dry, oxic "rusty" scenario we hypothesize chemical and biological stabilization processes to be more pronounced, leading to aggregation and mineral-organic associations and partly compensate for the OC losses. Under (2) a wet, anoxic "pale" scenario low oxygen likely leads to a reduction of the microbial ability to decompose particularly lignin due to less efficient laccases and peroxidases of anaerobes. We have assembled a Czech-German interdisciplinary consortium with complementary expertise in soil science, soil microbiology and metagenomics, which will face the challenge by a unique combination of field and laboratory experiments. In the field, our studies are based on a comparison of intact permafrost soils with soils undergoing degradation under the two contrasting scenarios. Employing state-of-the art molecular, biomarker and spectroscopic techniques, the response of the microbial community composition, extracellular enzymes, metatranscriptomes on the different soil environmental conditions and the respective stabilization of OM species in the soils will be investigated. An in-situ 13C labeling experiment will further inform about the microbial utilization and fate of fresh substrate, depending on the environmental condition. Finally, specific incubation experiments will identify the impact of freeze-thaw cycles in OM processing, as well as the role of increasing root exudation in the formation of mineral-organic complexes in the dry scenario and the lignin decomposition potential in the wet scenario.
CRYOVULCAN will thus contribute to the urgently needed knowledge on the effect of the soil hydrological regime on OM stabilization in degraded permafrost soils, which will control the magnitude of greenhouse gases release to the atmosphere in a warmer world.
Branišovská 1645/31a, 370 05 České Budějovice Tel. 387 776 201 | This email address is being protected from spambots. You need JavaScript enabled to view it.
Branišovská 1645/31a, 370 05 České Budějovice Tel. 387 776 201 | This email address is being protected from spambots. You need JavaScript enabled to view it.
