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Institute
Can old organic carbon drive microbial activity in surface waters of a newly created landscape?
(2010)
Ecosystems are characterized as complex systems with abiotic and biotic processes interacting between the various components that have evolved over long-term periods. Most ecosystem studies so far have been carried out in mature systems. Only limited knowledge exists on the very initial phase of ecosystem development. Concepts on the development of ecosystems are often based on assumptions and extrapolations with respect to structure–process interactions in the initial stage. To characterize the effect of this initial phase on structure and functioning of ecosystems in later stages, it is necessary to disentangle the close interaction of spatial and temporal patterns of ecosystem structural assemblages with processes of ecosystem development. The study of initial, less complex systems could help to better identify and characterize coupled patterns and processes. This paper gives an overview of concepts for the initial development of different ecosystem compartments and identifies open questions and research gaps. The artificial catchment site “Chicken Creek” is introduced as a new research approach to investigate these patterns and processes of initial ecosystem development under defined boundary conditions. This approach allows to integrate the relevant processes with related pattern and structure development over temporal and spatial scales and to derive thresholds and stages in state and functioning of ecosystems at the catchment level.
Aquatic protists accelerate microbial activity associated with mineral surfaces and leaf litter
(2012)
Microbial activity and sediment disturbance modulate the vertical water flux in sandy sediments
(2013)
Fungal importance extends beyond litter decomposition in experimental early-successional streams
(2012)
Variability of heterotrophic metabolism in small stream corridors of an early successional watershed
(2011)
Effect of acid mine drainage on the chemical composition and fall velocity of fine organic particles
(2005)
Eigenentwicklung von Fließgewässern in den ehemaligen Braunkohletagebaugebieten der Niederlausitz
(2002)
Ausgewählte Aspekte der Morphologie und Ökologie von Fließgewässern der Bergbaufolgelandschaft
(2000)
Is the epipsammic community modulated by trajectory of historic or current sediment shifting?
(2019)
When temperate streams fall dry: Humidity and trophic interactions control biofilm resilience
(2020)
Is the epipsammic community modulated by trajectory of historic or current sediment shifting?
(2020)
Importance of advective mass transfer and sediment surface area for streambed microbial communities
(2017)
The interaction of the water residence time in hyporheic sediments with the sediment metabolic rates is believed
to be a key factor controlling whole stream metabolism. However, due to the methodological difficulties, there
is little data that investigates this fundamental theory of aquatic ecology. Here, we report on progress made to
combine numerical modeling with a series of manipulation to laboratory flumes overcoming methodological difficulties. In these flumes, hydraulic conditions were assessed using non-reactive tracer and heat pulse sensor.
Metabolic activity was measured as the consumption and production of oxygen and the turnover of reactive tracers. Residence time and metabolic processes were modeled using a multicomponent reactive transport code called Min3P and calibrated with regard to the hydraulic conditions using the results obtained from the flume experiments. The metabolic activity was implemented in the model via Monod type expressions e.g. for aerobic respiration rates. A number of sediment structures differing in residence time distributions were introduced in both, the model and the flumes, specifically to model the biogeochemical performance and to validate the model results. furthermore, the DOC supply and surface water flow velocity were altered to test the whole stream metabolic response. Using the results of the hydrological process model, a sensitivity analysis of the impact of residence time distributions on the metabolic activity could yield supporting proof of an existing link between the two.
Naturgemäßer Totholzeintrag als kostengünstige Methode zur Renaturierung sandgeprägter Tieflandbäche
(2000)
The interaction of the water residence time (RT) in hyporheic sediments with the sediment metabolic rates is believed to be a key factor controlling whole stream metabolism. However, due to the methodological difficulties, there is little data that investigates this fundamental theory of aquatic ecology. Here, we report on progress made to combine numerical modelling with a series of modification to laboratory flumes overcoming methodological difficulties e.g. by creating steady flow paths for assessment of metabolic rates. To model the biogeochemical performance and to validate the model results, sediment structures were introduced in both, the model and the flumes, leading to differing RT distributions. Furthermore, the DOC supply in the flumes was manipulated to test the whole stream metabolic
response with regard to RT distributions. In the flumes, hydraulic conditions were assessed using conservative tracer and heat as tracer. Metabolic activity was assessed using oxygen dynamics as a proxy of community respiration (CR). Residence time and metabolic processes were modelled using a multicomponent reactive transport code called MIN3P
and calibrated with regard to the hydraulic conditions using the results obtained from the flume experiments. Monod type expressions were used to implement metabolic activity terms in the model. Using the results of the hydrological process model, a sensitivity analysis of the impact of RT distributions on the metabolic activity could yield supporting proof of an existing link between the two.