|Ecosystem Matter Fluxes||Biological Processes||Stable Isotope Analysis||Regionalization|
WE DON'T NEED THIS SECTION ANYMORE Biosphere: Research Foci
Ecosystem Matter Fluxes
The aims of this Research Focus are the detailed analysis and quantification of C and N matter fluxes within climate- and/or use sensitive semi-natural ecosystems and with the adjacent compartments atmosphere/pedosphere and hydrosphere. Thereby an important contribution is made to an improved understanding of the system, which is a basic prerequisite for the evaluation of the impact of Global Change on the biosphere.
This task comprises
- the establishment, upgrading and operation of long term measuring stations and satellite sites for the determination of the exchange of environmentally important trace substances (CO2, CH4, VOC, N2O, N2, NO, NO2) between pedosphere, phyllosphere and atmosphere in high spatial and temporal resolution using modern chamber and micrometeorological techniques and
- the development/improvement of modern measuring techniques for the quantification of ecosystem C- and N-transformations and/or -fluxes.
- Improving system understanding by matter fluxes analysis.
- Impacts of land use/land management changes on C and N matter fluxes and pools in savanna and grassland ecosystems.
- Mid- and long-term effects of different forest conversion strategies on the magnitude of trace gas exchange at the pedosphere/atmosphere interface and on net ecosystem exchange.
- Impact of climate change on ecosystem matter fluxes and identification of feedback mechanisms.
Biological Processes of C- and N-Trace Gas Formation
This Research Focus aims to elucidate the biosynthesis of volatile organic compounds (BVOC) in plants, their regulation by environmental factors, and their role in the interaction between phyllosphere and atmosphere. The work comprises the molecular and biochemical characterization of pathways, the quantification of C-fluxes with respect to BVOC emission, and the functional analysis and importance of BVOC for plants themselves and the ecosystem.
Merging together all the information on biological pathways and their regulation, process-based emission models are developed, which are able to predict BVOC emissions under recent and future conditions.
As another main task in this Resarch Focus we analyse complex organismic interactions between microorganisms and plants related to C- and N-cycling within ecosystems and the atmosphere to understand ecosystem functioning and acclimation/adaptation to future climate.
Stable Isotope Analysis
The Biosphere Research Area at IMK-IFU performs stable isotope research in the Center of Stable Isotopes (CSI). The main objective of this Research Focus is to characterize and to quantify the biotic and abiotic processes underlying the function and the stability of natural and anthropogenically influenced ecosystems with the aid of stable isotope analysis. The aim is to make contributions of understanding ecosystem matter fluxes as well as the impact of Global Change on ecosystems.
The specific objectives are:
to study the complex microbial, physico-chemical, plant physiological and atmospheric processes contributing to C, N and water cycling in ecosystems and their interactions.
to quantify matter fluxes within ecosystems and surrounding compartments (atmosphere, soil, groundwater) and their spatial and temporal variability.
to study the impact of Global Change (climate, land use, atmospheric deposition) on ecosystems processes and related matter fluxes.
The research tools used in field and laboratory experiments are
- analysis of the natural abundance of the stable isotopes of C, N, O, and H in key compounds of ecosystem fluxes.
- tracer experiments using compounds enriched in the rare stable isotopes as markers for process studies.
Regionalization of Trace Gas Fluxes
Environmental conditions such as soil and vegetation properties or soil moisture and temperature affect in various ways biogenic processes involved in the production, consumption and emission of environmentally important trace gases (N2O, CH4, CO2, NOx). In consequence, the biosphere-atmosphere exchange of trace gases is highly variable on temporal and spatial scales. This also limits the reliability of simplified approaches in estimating the importance of terrestrial ecosystems for the mentioned gases (sink or source strength).
In order to provide information on the exchange of trace substances between the biosphere, the atmosphere and the hydrosphere, and to improve existing estimates on regional and global scales for past, present and future environmental conditions – as needed e.g. for UNFCCC reporting – within this Research Focus biogeochemical models, capable of simulating the complex interactions of the involved biogenic and physico-chemical processes, are further developed. The model development is based on detailed field and laboratory measurements in various ecosystems, and regionalization is obtained by linking these models to detailed GIS databases. Typical outputs are emission inventories or scenarios on site and regional scales, allowing e.g. the evaluation of effects of land use and/or climate changes on regional trace gas exchange.
Linking methods, bridging scales