Title of the Dissertation
Species composition and trophic ecology of beetle communities in disturbed landscapes (Working title)
The cluster elaborates characteristic signatures of disturbances in the Lower Lusatian post-mining landscapes based on community changes and carbon balances of terrestrial and aquatic landscape sub-systems compared with undisturbed reference systems. The “signature” of mining lakes is characterized by specific water qualities compared to adjacent landscapes which were not affected by mining activities. Acidic mining lakes are very young ecological systems with specific types of primary succession due to the acidification. This is particularly true with regard to limited food resources, limited structural diversity and the complexity of food webs. A serious problem is the dominance of mixotrophic species: the bacterial production exceeds the primary production and seems to be decoupled. Such ecologically relevant state transitions characterize matter fluxes from aquatic systems into food webs of the surrounding terrestrial habitats. In a terrestrial context, natural fires constitute another major disturbance that decouples consumers and resources in local food webs. The trajectory of recovery to pre-fire conditions in disturbed landscapes is a major component of the ecosystems resilience, which is addressed in a second subsystem focusing on terrestrial food webs. The interactions between organisms at a) the interface between disturbed and rather undisturbed post-mining lakes and adjacent terrestrial habitats and b) the impact of wildfires in disturbed landscapes will be investigated by means of community analyses and studies of naturally occurring carbon isotopes. These results will provide novel insights into effects of man-made and natural disturbances on food-webs and local communities in disturbed landscapes of Lower Lusatia.
Lanya Feng was born in Chongqing, China. In 2014, she finished her Bachelor degree in the faculty Resources Science and Technology in Beijing Normal University, with the thesis “Research of Spatio-temporal LUCC and Ecosystem Service in Dianchi Basin”. One year later, she came to BTU and continued Master study in ERM program and graduated in 2018 with the thesis “Diversity and Nutritional Condition of Emerging Carabidae (Coleoptera) in Cereal Fields and Fallows in Southern Sweden”. Since May 2018, Lanya Feng has started Doctoral study in the chair Ecology in the faculty of Environment and Natural Science in BTU.
Title of the dissertation
IRES sediment microbial structure and function signatures in severely disturbed landscapes and a changing climate
The research project aim is to understand the biochemical dynamics in land water interfaces with particular focus on intermittent rivers and ephemeral streams (IRES). More than half of the global inland fluvial network consists of IRES, and their numbers are increasing as a consequence of climate change and water withdrawn. The research focuses on carbon, nutrients, and microbial structure turnovers during submerge-dry-resubmerge transitions in temperate sediment and soil. In our first experiment, we conducted a spatiotemporal comparison of soil and sediment from small ephemeral corridors in a post-mining experimental watershed (Hühnerwasser), we analyzed the microbial community and the immediate metabolic response to flow resumption and compared it to existing data from 10 years before. The second experiment aims to comprehend the effects of various drying scenarios on sediment-associated microbial community and function in a temperate lowland river (Spree river). We believe results from this research will be useful for managing IRES under a changing climate and after post-mining disturbances.
Jose Schreckinger comes from Quito, Ecuador. Since January 2018, he started to perform his doctoral studies at the Brandenburg University of Technology (BTU) on the resilience of microbial functions in infrequently drying European lowland rivers. For several years he worked on the Aquatic Ecology Lab of the Universidad San Francisco de Quito, Ecuador, where he was involved in various studies related to tropical streams and rivers dynamics. He has a Master degree in Geographic Information Science and Systems from Salzburg University. He is also a passionate outdoors and wildlife photographer.
Title of the Dissertation
Transient water balance dynamics of highly disturbed landscapes
The water balance of transient landscapes such as post-mining areas are dynamical systems that are strongly affected by atmospheric drivers, mainly precipitation and evaporative demand. Aside from seasonal and diurnal fluctuations, soil water storage and groundwater levels change over periods of years and decades resulting in hydrological regime shifts. These regime shifts will then affect biogeochemical processes and drive to some extent the carbon cycle. In mature functional ecosystems, biogeochemical activities are often observed to occur in small areas so called hot spots and during intense short periods of time referred to as hot moments. This pattern can be viewed as a signature that will develop in transient landscapes in direct response to hydrological regime shifts.
This project will focus on developing a deeper understanding of how temporal variability of precipitation and evaporative demand affects the soil moisture dynamics and how this in turn affects the triggering of biogeochemical activity. To this end, the study will therefore involve statistical analysis of weather data and calibration of a rainfall generator. Based on field observations, soil moisture dynamics and statistical properties will then be modelled to obtain general patterns of soil moisture dynamics in highly disturbed transient landscapes.
I was born in Missoula, Montana (USA). In 2015 I completed my bachelor studies in Environmental and Resource Management (ERM) at the Brandenburg University of Technology Cottbus-Senftenberg (BTU) with the thesis “The Industrial Emissions Directive Baseline Report: Assessing Implementation and Practice with Focus on Germany”. After completing my B.Sc., I continued on to the master's program in ERM also at BTU, where I received my M.Sc. in 2018 with the thesis “Assessing Heavy Metal Mobility Induced by Salt Solutions and Chloride Complex Formation”.