20 documents found

Dissertation
All rights reserved
2021-05-20

Identification of ecosystem-specific markers in terrestrial dissolved organic...

The production and export of terrestrial DOM is intimately related to processes in soils and the critical zone, and society relies on the sustained functioning of these systems (Küsel et al., 2016). Understanding mechanisms of SOM turnover and DOM production are thus crucial for proper management of...
Dissertation
CC BY 4.0
2021

Towards a data-driven understanding of dissolved organic matter in the...

This dissertation presents modern approaches for the identification of molecular markers and marker patterns as indicators for natural processes that transform dissolved organic matter (DOM) in the Critical Zone. The attached manuscripts describe the transformation of plant-derived DOM in the litter...
Dissertation
CC BY-NC-ND 4.0
2019

Sources and environmental controls of microbial membrane lipids in soils...

Microorganisms have the ability to control the biophysical properties of their membrane lipids to thrive in natural environments. Different microbial species possess different membrane lipid compositions, even the composition of a single species is not always constant, but depends on the habitat conditions....
Dissertation
All rights reserved
2018

Mechanisms of resistance and resilience in the plant-soil system of Mountain...

Overall, the findings of this thesis highlight the importance of land use and plant-microbial interactions for the resilience of terrestrial ecosystems to extreme climatic events. The results from stable isotope (13C and 15N) labelling experiments on mountain grasslands extend the existing knowledge...
Dissertation
All rights reserved
2016

The effects of long-term drainage on processes governing CO2 und CH4 fluxes...

Arctic ecosystems have acted as a carbon sink, accumulating >1000 Pg of carbon in soils. However, increasing air temperatures and associated degradation of ice-rich permafrost in the Arctic hold the potential to modify soil topography and hydrology, with significant effects on carbon cycling. This study...
Dissertation
All rights reserved
2016

Ostracodes as indicators of Late Quaternary aquatic and monsoon system...

Knowledge on micro-crustaceans in high mountain-ecosystems and their potential in palaeoclimatic research is still limited. The study contributes to: 1) Ecology of Recent (living + dead) Ostracoda (‘Seed Shrimp’) from the southern Tibetan lakes (Tangqung Co, Tangra Yumco, Monco Bunnyi, and Xuru Co, ~...
Dissertation
All rights reserved
2016

Plant and soil related effects on the soil microbial community composition...

Soil microorganisms are key mediators of soil carbon (C) cycling; however several plant and soil related factors potentially influence the functions of soil microbial communities. In that sense, this thesis describes 3 studies which provide new knowledge of factors that influence processes mediated by...
Dissertation
2014-05-06

Reconstruction of Asian monsoon using compound-specific isotope signals...

The general aim of this thesis was the reconstruction of the Indian Ocean summer monsoon (IOSM) dynamics using compound-specific isotope signals of aquatic and terrestrial biomarkers in Tibetan lake systems. Monsoon winds and precipitation can be retraced using different proxies, indirect climate indicators,...
Dissertation
2014-01-21

Fagus sylvatica in temperate decidous forests differing in tree special...

The increasing loss of biodiversity prompts the need for a greater understanding of ecosystem functioning, particularly in forest ecosystems. The present work investigates if increased proportions of different deciduous tree species in beech forest ecosystems affect the microbial community due to an...
Dissertation
2013-04-10

Influence of the white-rot fungus Schizophyllum commune on organically...

Fungal alteration of organically coated sand particles, sampled in Eocene sediments in the open cast mining Profen, near Leipzig (Germany) was studied. The organic coatings formed non-continuous layers on quartz grains, measuring few micrometers up to 30 µm in thickness. Such sand particles efficiently...
Dissertation
2009-08-10

Influence of plant diversity on soil organic carbon storage and microbial...

Increasing plant diversity is known to be important for ecosystem functioning and an increase in soil organic carbon storage. The link between aboveground plant diversity and belowground diversity is currently under discussion. Furthermore, the mechanisms by which aboveground diversity impacts storage...
Dissertation
2009-06-19

Microbial mineralization processes influenced by water table changes and...

Wassersättigung und anoxische Bedingungen verringern die Mineralisation der organischen Substanzen in Mooren und dennoch sind sie als Quellen der klimarelevanten Gase CH4 und CO2 bekannt. Das Ziel dieser Arbeit bestand darin, den Einfluss von wechselnden Wasserständen und unterschiedlichen Torfqualitäten...
Dissertation
2008-10-01

Paleoclimate reconstruction using compound - specific hydrogen isotope...

This dissertation would not have been written without the encouragement and a tremendous amount of support of a large number of people. First of all, I would like to thank my supervisors PD. Dr. Gerd Gleixner at Max-Planck Institute for Biogeochemistry and Prof. Dr. Roland Mäusbacher at the Friedrich-Schiller...
Dissertation
2006-07-05

Einfluss der Biodiversität von Pflanzen auf die Speicherung von Kohlenstoff...

Die langfristige Speicherung von Kohlenstoff in terrestrischen Ökosystemen stellt eine Möglichkeit dar, dem anthropogen verursachten Anstieg der CO2 – Konzentration in der Atmosphäre und der damit verbundenen Klimaveränderung entgegenzuwirken. Die direkte Aufnahme von CO2 in die Pflanzen stellt lediglich...
Dissertation
2006-01-18

Development of compound-specific hydrogen isotope ratio analysis of biomarkers...

Das Wasserstoffisotopenverhältnis (deltaD) von kontinentalem Wasser wird durch die Abreicherung von Deuterium im Niederschlag während der Kondensation von Wasser und beim Durchzug über kontinentale Gebiete bestimmt. Die Primär-produzenten in aquatischen Systemen sowie Landpflanzen produzieren ein deltaD...
Dissertation
2005-11-09

Characterization of coexisting dissolved organic carbon and haevy metals...

In this thesis attempts were made to investigate dissolved organic carbon (DOC) and coexisting heavy metals in an area highly polluted with organic waste from municipal sewage and heavy metals from acid mine drainage. DOC was sampled and prefiltrated to < 0.45 µm. Prefiltrated samples were enriched by...
Dissertation
2005-06-29

Compound-specific hydrogen isotope ratios of sedimentary n-alkanes : a new pal ...

In der vorliegenden Arbeit wurde untersucht, ob sich die Wasserstoffisotopenverhältnisse von organischen Sustanzen, die in Seesedimenten erhalten bleiben, sogenannte Biomarker, eigen, um Veränderungen des Klimas zur Zeit der Ablagerung der Substanzen zu rekonstruieren. Es konnte gezeigt werden, dass...
Dissertation
All rights reserved
2004-11-17

Umsatz und Stabilisierung von organischem Kohlenstoff in Böden

Im Rahmen der vorliegenden Arbeit sollte die Dynamik des Kohlenstoffumsatzes im Boden im Hinblick einer möglichen Stabilisierung von organischem Kohlenstoff untersucht werden. Besonderes Interesse galt dabei dem Umsatz molekularer Bestandteile der organischen Bodensubstanz sowie der...
Dissertation
2004-02-02

Trophic interactions as indicators of ecosystem regeneration in disturbed...

Stable isotope techniques were used to identify regeneration patterns in the trophic structure of the reassembling communities in order to describe the development of a disturbed grassland ecosystem (Steudnitz) that had been subjected to anthropogenic pollution for more than 30 years. Mean values of...
Dissertation
All rights reserved
2001-07-11

Origin and genesis of dissolved organic matter : a study by Py-GC/MS-IRMS

Dissolved organic matter (DOM) is influenced by the diversity of potential sources and processes which results in a heterogeneous mixture with a characteristic organic chemical signature for individual aquatic ecosystems. Reference samples (DFG-Special Research Program ROSIG) from natural systems such...