Monitoring
In order to assess the progress towards the project´s ecological objectives a pre- and post-restoration monitoring program is carried out within which various limnological variables (functional describers) are to be observed.

Renaturation Wienfluss: Dynamics of nutrients, suspended solids and organic matter with regard to the flood prevention management of the Wienfluss reservoirs "Auhof-Retentionbecken"

Funded by MA 45 & BMLF
Duration: 1999-2005
Supervision: Prof. Dr. Fritz Schiemer
Coordination: Dr. Thomas Hein
Working-group: Dr. Tom J. Battin, Ingrid Kolar, Birgit Görnet

Summary
In the multidisciplinary project "Renaturation Wienfluss" the flood prevention reservoirs "Retentionsbecken Auhof" are re-integrated in the riverine network. The main aim of the hydrochemical investigations is the effect of the restoration on the nutrient and sediment dynamics as well as the selfpurification potential of the river. In the reservoirs the potential of matter processing is supposed to be significantly higher. In contrast, the over 100 years accumulated sediments can function as a nutrient trap increasing the nutrient load of the river. The filter efficiency of the reservoirs will be estimated by mass budget calculations. Bioreactors are used to evaluate the importance of heterotrophic biofilm.

The role of a re-connected side-arm for the biogeochemical cycling of the River Danube

Funded by: AC-IAD & NP Donau-Auen GmBH
Duration: 2003-2004
Supervision/Coordination:Dr. Thomas Hein
Working-group: Drozdowski Irene, Hein Thomas, Kraill Hubert, Preiner Stefan, Schagerl Michael & Schiemer Friedrich

Summary
Floodplains are important areas for the biogeochemical cycling in fluvial landscapes. Matter transport and transformation in lotic flow reduced areas are determined by the interaction of hydrology and physical, chemical and biological factors. The determination of the biological activity can be employed to estimate the importance of a specific subsystem for biogeochemical dynamics. Therefore, we investigated the rates of primary production and respiration in a re-connected side-arm from March to September 2003. The investigated side-arm system is part of the semi-natural Danube reach downstream of Vienna which represents the last remnant of alluvial landscape along the upper Danube.
The required hydrological conditions were derived by a hydrological model. Using the riverine water level and the morphology of the floodplain, the model calculates various hydrologic metrics like discharge, water level and water age. The parameter water age is an inverse measure of the hydrological connectivity to the river, with low age indicating high connectivity and a Danube-like character of the water, and vice-versa. To estimate the contribution of different compartments (pelagic, benthic), we used the light-dark bottle method (community respiration, 14C) and in-situ measurements and oxygen time curve analysis.

German report

Flood control on the Danube in Vienna

Funded by: MA 45
Duration: 1999-2005
Supervision: Prof. Dr. Fritz Schiemer
Coordination:Dr. Thomas Hein
Working-group: Dr. T. Hein, Dr. G. Weigelhofer, Mag. V. Kucera-Hirzinger, Mag. A. Funk,
S. Preiner, E. Bondar

Summary
Riparian zones, floodplains and river-marginal wetlands are key landscape elements of strategic importance. They provide a wide range of ecological and socio-economic goods and services, including flood retention capacity, groundwater recharge, bioproduction, and aesthetic and recreational values.
The Lobau is a large floodplain area at the eastern border of the city of Vienna. During the regulation of the Danube in 1875, this former dynamic floodplain was disconnected from the main channel by the construction of a flood protection dam. Lateral embankments along the main river channel severely altered the geomorphic and hydrologic dynamics and impeded the natural sequence of erosion and sedimentation. Anthropogenic alterations were especially heavy in the upper part of the floodplain, the Obere Lobau. Thus, the Obere Lobau represents a groundwater-fed system, nowadays, in which sedimentation and terrestrification processes prevail. Due to diffuse lateral inputs of nutrients from the terrestrial surrounding most backwaters tend to be highly eutrophic. Without sustainable rehabilitation measures, the Obere Lobau will ultimately succeed to a primarily terrestrial ecosystem within the next decades, with major implications for its aquatic and amphibic biodiversity.
In 1986, the project “Dotation Obere Lobau” was initiated. This project proposed a hydrologically controlled water enhancement scheme via surface discharge of Danube water into the floodplain, in order to sustain the current ecological state of the Obere Lobau as well as to guarantee urgent socio-economic claims within this area (e.g. drinking water supply, recreation, flood protection). During 2001-2004, a large-scale field experiment, the so called “Wasserwirtschaftliche Versuch”, was accomplished. Between April and October, the Obere Lobau was connected to the main channel, receiving a mean of 180 to 250 ls-1 of Danube water (maximum granted discharge: 500 ls-1). In combination with the effects of the construction of a hydro power plant and a by-pass channel, these measurements led to an overall increase of surface and subsurface water levels within the nearby side-arms of the Danube. Furthermore, the input of water with lower nutrient loads yielded to a unification of the different water bodies within the main side-channel and a stabilisation of nutrient concentrations at moderate trophic levels. Because of the overall positive effects of the water enhancement scheme on the functioning and stability of the Obere Lobau, a proposal for the prolongation of this rehabilitation measure is currently in preparation.

Water Enhancement Scheme: Dotation Lobau

Funded by: MA 45
Duration: 1999-2005
Supervision: Prof. Dr. Fritz Schiemer
Coordination:Dr. Thomas Hein
Working-group: Dr. T. Hein, Dr. G. Weigelhofer, Mag. V. Kucera-Hirzinger, Mag. A. Funk,
S. Preiner, E. Bondar

Summary
The meadows of the Lobau, located East of the Danube, were integrated as a nature preserve in the Donau-Auen national park in 1996. The Marchfeld protective dike, constructed during 1870 and 1875, cut of the the Danube´s side arms; since then water exchange only takes place through the ground water body and backed-up flood water. Due the abscence of large scaled floods and the deepening of the Danube itself the groundwater level is decreasing continously. To improve this situation the activation of old side arms, an alteration of the existing flood protection system, to restore a dynamic wetland, and the widening of inflow areas are strived.
Flood plains always offer good opportunities to investigate the complex interactions between geomorphic, hydrologic and ecologic processes in highly dynamic landscape elements. The role of their complexity in maintaining the high diversity in terms of natural processes as well as socio-economic functions is understood to be the underlying principle. Recent concepts integrate all these subjects to quantify the role of geomorphic processes and hydrologic connectivity on ecosystem functions and services at different spatial and temporal scales. To take advantage of this complexity needs not only a sound scientific understanding of these functions, but also indicators, models and tools for assessing management options which harmonize different needs.
Thus, main question for the ecosystem management are:
1. What are the long term effects of the hydrogeomorphic alterations in this area and what future development can be predicted for different habitat types on the basis of the status-quo?
2. To what extent are these processes reversible by increased hydrologic connectivity, how can rehabilitation measures interact?
3. What strategies can be used to optimize the natural development with human needs – is there an option to combine ecosystem functions with socio-economic services for a sustainable integrated human and nature perspective in the Lobau?

Subprojects
Hochwasserschutz Wien – Abschnitt Untere Lobau, Erstellung des UVE-Konzeptes, Abstimmung des vorläufigen Untersuchungsumfanges, Untersuchungsprogramm für weiter notwendige Bearbeitungen: Fachbereich – Ökologie
„Erweiterungsprojekt Dotation Lobau: Istzustandserhebung der unteren Lobau“, Projektteam Ökologie Lobau im Auftrag der MA45
Dauer : 1996 – 2000
„Hochwasser bedingter Sedimenteintrag aus der Donau in das Schönauer Wasser, Untere Lobau“, Inst. für Ökologie und Naturschutz im Auftrag der MA 45
Dauer : 2001 – 2003
„Dotation Lobau - Obere Lobau, Wasserwirtschaftlicher Versuch, ökologische Beweissicherung“
Inst. für Ökologie und Naturschutz im Auftrag der Gemeinde Wien
Dotationsbegleitende ökologische Untersuchungen 2001 (MA 45–HY–105/2001)
Dotationsbegleitende ökologische Untersuchungen 2002 (MA 45–HY–46/2002)
Dotationsbegleitende ökologische Untersuchungen 2003 (MA 45–WH– 67/2003)
Dotationsbegleitende ökologische Untersuchungen 2004 (MA 45–WH/WW–14/2004)
„Dotation Lobau – Obere Lobau, Faunistische Untersuchungen 2004“
Inst. für Ökologie und Naturschutz im Auftrag der MA 45 (MA 45–WH/lob–69/2004)
„Monitoring Untere Lobau“
Inst. für Ökologie und Naturschutz im Auftrag der Gemeinde Wien (MA 45)
Limnologische Untersuchungen 2003
Limnologische Untersuchungen 2004
„Ökologische Untersuchungen Hochwasser Lobau August 2002“
Inst. f. Ökologie und Naturschutz im Auftrag der Gemeinde Wien (MA45 –SB/lob–243/02)
„Sanierung Tanklager Lobau, Hydrochemische Untersuchungen“
Inst. f. Ökologie und Naturschutz im Auftrag der Gemeinde Wien
Hydrochemische Untersuchungen 2003 (MA 45 – Al 22.58 – 7/03)
Hydrochemische Untersuchungen 2004 (MA 45 – Al 22.58/ - 4/04)
„Wasserwirtschaftliches Projekt Dotation Panozzalacke und Weiterer Dotationsweg Fasangartenarm/Tischwasser Variante 3a“
Inst. f. Ökologie und Naturschutz im Auftrag der Gemeinde Wien
Wasserqualitätsentwicklung 2003 (MA 45 – SB 22 – 84/2002)
Wasserqualitätsentwicklung 2004 (MA 45 – PN22 – 51/2004)
„Ökologischen Begleituntersuchung zur Einreichung des Wasserwirtschaftlichen Projektes - Absenkung des Hochpunktes beim Uferhaus 2003“
Inst. für Ökologie und Naturschutz im Auftrag der Gemeinde Wien (MA 45 –SB22–84/2002)
„Einreichprojekt Dotation Obere Lobau 2004“
Inst. für Ökologie und Naturschutz im Auftrag der Gemeinde Wien (MA 45–WH/WW–23/2004)
„Hochwasserschutz Wien, Untere Lobau, kurzfristige Untersuchungen Ökologie, Grundwasserqualität, Sedimente, Hydrologie und Grundwasserdynamik“
Inst. für Ökologie und Naturschutz im Auftrag der Gemeinde Wien (MA 45)
Hochwasserschutz Wien – Abschnitt Untere Lobau 2003. Ausarbeitung eines Untersuchungsprogramms entsprechend der Stellungnahme der obersten Wasserrechtsbehörde, Inst. f. Ökologie und Naturschutz im Auftrag der Gemeinde Wien

Impact of suspended matter on the ecology of Viruses in a river floodplain system of the Danube (Austria)

Funded by: FWF
Duration: 2001 - 2004
Principal Investigator/Coordination: a.o.Prof. Peter Peduzzi
Cooperations: Netherlands Institute of Sea Research (NIOZ); Centre for Environmental Research (UFZ), Leipzig/Magdeburg; National Water Research Institute, Canada Centre for Inland Waters,
Burlington, Ontario (Canada)
Working group: Dr. Martin Agis, Mag. Birgit Hussarek, Mag. Birgit Luef

Summary
Due to their high abundance, viruses in aquatic systems are considered as significant biological agents in microbial processes. They are thought to impact the activity, life strategy and diversity of their hosts and apparently influence organic matter fluxes. Suspended particulate material plays a significant role in biogeochemical cycles and for biological processes in natural aquatic environments. Riverine systems sometimes carry high loads of this material, thus underlining the particular relevance. Particle-bound microbial abundance and activity can contribute significantly to overall microbial processes depending on the quality of particles and the type of organisms involved. Research on the interaction between suspended matter and the natural assemblage of viruses infecting microplankton organisms is surprisingly scarce.

Particularly in freshwater systems, where suspended matter is often a prominent factor determining a variety of processes, there is an intolerable lack of information. The proposed project will add substantial information to our current knowledge. We will attempt to answer several scientific key questions:
- Does particle quality and quantity determine virus abundance and virus - bacteria interactions?
- Is particulate material a means of removal versus survival and production of viruses?
- Does the viral community structure differ between particle and ambient water environments?
- Does viral activity influence the community structure of free-living and attached bacteria?
- What is the potential role of viruses in particle formation/dissolution?

The Danube river-floodplain system provides a broad spectrum of almost every type of particles (from mineral particulates to lake and river snow) and is an ideal study site for this type of investigation. Three subsystems with different hydrological characteristics and particle regimes have been selected as study locations. Our approach is expected to provide further insights into the structure and function of aquatic microbial food webs and carbon cycling in a sequence of systems with varying particle loads.

Impact of public recreational activity on the bacterial community structure in an urban river system

Funded by: Hochschuljubiläumsstiftung, Gemeinde Wien
Duration: 2002-2004
Principal Investigator/Coordination: a.o.Prof. Peter Peduzzi
Working group: Kathi Besemer

Summary
Global freshwater resources are under severe human impact and are fairly vulnerable. Naturally occurring bacteria of the waterbody and sediment substantially contribute to the processing of natural or anthropogenically introduced organic material; this is also important e.g. in urban-influenced waters. Therefore, both the stability and activity of bacterial communities of the water column and the sediment strongly determine the speed and efficiency of microbial degradation processes. There is a considerable lack of information on the taxonomic structure of the bacterial communities mediating the bulk of energy and material fluxes in natural waters. The Danube-river system in the city area of Vienna is largely modified and influenced by human activity. Since there is a considerable public interest in the stability and maintenance of these urban water bodies, it is worthwhile and important to know more about bacterial responses to anthropogenic influences. Stability of an ecosystem is also a function of taxonomic diversity (species richness, species evenness) and vice versa, therefore, bacterial community structure can be a valuable indicator for allochthonous disturbance. The proposed research aims to investigate the impact of recreational activity in an urban river system on the biodiversity and stability of the aquatic bacterial community applying recently developed techniques. This should provide additional new information on the capacity of this system (and its respective subsystems) in compensating anthropogenic influences and maintaining stability.

Linking diagenetic state and nicrobial reactivity of organic matter in waters of a river floodplain system

Funded by: University of Vienna, Faculty Fund & Facultas AG
Duration: 2002-2005
Principal Investigator/Coordination: Prof.Dr. Peter Peduzzi
Working group: Mag. Kathi Besemer, Mag. Birgit Hussarek, Mag. Birgit Luef

Summary
The aim of the study is to demonstrate that the diagenetic state and bioreactivity of organic matter is distinct in different river-floodplain subsystems and under different hydrological regimes. Allochthonous (riverine) organic matter should mirror biochemical characteristics of strong degradation whereas autochthonous material resembles a more recent origin. Abrupt changes in DOM quality in river-floodplain systems are thought to influence bacterial growth strongly. Chemical characteristics of organic material will be related to its ability to support microbial growth. We attempt to develop a predictive understanding of the utilization of organic matter in distinct river-floodplain subsystems that are important contributors to downstream organic chemistry. This should improve our knowledge of factors influencing the pathways and processing of organic material and lead to a better understanding of the ecological significance of restoration measures.

Substrate-quality as triggering factor for bacterial diversity in waters of a river floodplain system

Funded by: ÖAW (KIÖS)
Duration: 2003-2004
Principal Investigator/Coordination: Prof.Dr. Peter Peduzzi
Working group: Mag. Katharina Besemer

Summary
The aim of the study is to demonstrate that the diagenetic state and bioreactivity of organic matter is distinct in different river-floodplain subsystems and under different hydrological regimes. This implies that the quality of the organic material is variable. Since the occurrence of various bacterial “types” is at least in part linked to the available substrate, bacterial diversity should be influenced. Abrupt changes in DOM quality in river-floodplain systems are a common phenomenon. Chemical characteristics of organic material will be related to the structure of the bacterial community using “fingerprinting” techniques. This should improve our knowledge of factors influencing microbial diversity and lead to a better understanding of the ecological significance of restoration measures.

Assessment of the ecological status of river/floodplain systems according to the EU-Water Framework Directive, based on bioindicators (part II)

Funded by: Austrian Environmental Agency
Duration: 2004-2006
Principal Investigator/Coordination: Prof. Dr. Johann Waringer
Working group: Prof. Dr. Johann Waringer, Dr. Andreas Chovanec, DI Michael Straif, Dr. Wolfram Graf, Dr. Walter Reckendorfer, Dr. Andrea Waringer-Löschenkohl, Prof, Dr. Herwig Waidbacher, Heike Schultz

Summary
According to the Water Framework Directive of the European Union (WFD), habitat connectivity on a macroscale is of major importance for migrating organisms. Therefore practical bioindication procedures should be developed, which can be applied both on a local level for classifying individual sites or short stretches as well as on a landscape level for assessing e. g. river reaches including parts of a catchment area. As far as the assessment of river/floodplain-systems is concerned, Molluscs, Odonata, Trichoptera, Amphibians and Fish are valuable indicators of the structural and hydrological properties of a water body, of the ecological integrity of the land/water-interface and of habitat heterogeneity and microhabitat patchiness of a given area. In the line with the WFD, a scheme for assessing the ecological status of floodplain areas will be developed, using the bioindicator groups addressed above, and tested on a local level (Altenwörth) in Austria.

Light-trapping of Trichoptera at the March River (Lower Austria)

Funded by: ÖN-IAD
Duration: 2003-2005
Principal Investigator/Coordination: Prof. Dr. Johann Waringer

Summary
Adult Trichoptera were caught from September 2001 to September 2002 at the March River at Angern, Lower Austria, using a Jermy-type light trap. The analysis is still in progress and will reveal important information on phenology, sex ratios, meteorological effects on catching success and bioindication parameters for the March river.

Criteria for the nomination of Natura 2000 areas and water-dependent land ecosystems pertinent to the Water Framework Directive of the European Union

Funded by: Austrian Environmental Agency
Duration: 2003-2005
Principal Investigator/Coordination: Prof. Dr. Johann Waringer


Summary
Two important questions associated with the implementation of the Water Framework Directive of the European Union are addressed in this project:
(i) which areas should be nominated as Natura 2000 areas, based on habitat inventories and biological quality criteria and
(ii) creating a criteria catalogue for the definition and delimitation of water-dependent land ecosystems.

Nutrient retention within the hyporheic zone of Flysch and calcareous Wienerwald streams

Funded by: University Foundation of the City of Vienna
Duration: 2004-2005
Principal Investigator/Coordination: Prof. Dr. Johann Waringer
Working group: Dr. Gabriele Weigelhofer, Stefanie Wallner, Gerhard Schretter

Summary
This project investigates the hyporheic zone of the Weidlingbach, a stream situated in the Flysch area of the Wienerwald, and its impact for hydrological retention of solutes and the uptake of nutrients. By adding conservative tracers and nutrients, take-up parameters based on the nutrient spiralling concept and the transient storage model will be calculated. Furthermore, we study the vertical transport processes of solutes deep in the sediments of the hyporheic zone.

Freshwater biota in the Wienerwald: Conservation and management of woodland streams and standing waterbodies

Funded by: Austrian Naturschutzbund, Austrian Federal Forest Agency
Duration: 2003-2005
Principal Investigator/Coordination Amphibs: Dr. Andrea Waringer-Löschenkohl
Working group: Dr. Hans Martin Berg, Dr. Erich Eder, G. Pfundner, Norbert Sauberer, Mag.Gabriel Singer, W. Willner

Summary
The study focuses on the assessment of the status quo of woodland streams and standing water bodies using morphological descriptors, structural diversity and bioindicators (vegetation, decapods, odonates and amphibians). The aim is a catalogue of conservation and management strategies for forestry to protect and improve the situation of freshwater biota in the Wienerwald, paying special attention on umbrella species, such as firesalamanders.

Riverbank and riverbed management and meander reconnection measures at the Morava river near Marchegg (km 15-25) – ecological survey (Austrian Federal Environment Agency

Funded by: Austrian Environmental Agency in cooperation with Slovak project participants
Duration: 2004-2005
Principal Investigator/Coordination Amphibs: Dr. Andrea Waringer-Löschenkohl
Working group: Dr. Wolfram Graf, Prof. Dr. Otto Moog, Mag. Karin Pall, Mag. Dr. Peter Pfister, Mag. Heike Schultz, Dr. Thomas Spindler, Reinhard Wimmer

Summary
In cooperation with Slovakia restoration measures on the Morava river were conducted in the winter of 2002/03 in order to improve riverbank and riverbed structure, river-floodplain connectivity and to prepare the reconnection of some meanders. In 2004/05 the effectiveness of these measures on structure heterogenity, connectivity, saprobity and trophy will be evaluated by bioindicator groups (phytoplankton, macrophytes, macrozoobenthos, odonates, fish and amphibians).
The results obtained at the Morava river will be the basis of other pilot-projects for the restoration of lowland river- floodsplain systems.

STREAMES: Human effects on nutrient cycling in fluvial ecosystems: The development of an expert system to assess stream water quality management at reach scale

Funded by: European Union (EVK1-CT-2000-00081)
Duration: 2001-2004
Principal Investigator and coordination: Dr. Tom J. Battin
Working group: Mag. Michaela Panzenböck, Dr. Gabriele Weigelhofer, Mag. Gabriel Singer, Christina Marchesani, Andrea Rauter, Pia Huber

Summary
Streams in developed regions are under significant stress due to nutrient enrichment. Humans affect streams by:
(1) Changing land uses in the catchment or modifying the landscape in ways that increase the transport of nutrients to surface waters.
(2) Directly dumping urban or industrial sewage (point sources) into the stream.
(3) Modifying the streams themselves in ways that reduce their ability torespond to increased nutrient loads.
Whereas these processes operate at diverse scales -from within-stream processes to watershed processes-, stream managers are often constrained to act at the reach scale. The goal of STREAMES is to develop a tool to help streams managers in two ways:
(1) It will help them to evaluate the sources and magnitudes of nutrient (nitrogen and phosphorus) loads affecting the stream reach of interest.
(2) it will help them decide on the best strategy for stream amelioration at that particular reach, with special emphasis on actions directed towards increasing nutrient retention within the stream (i.e., enhancing the stream self-purifying capacity).
The tool is an Expert System, a computer application that aids in the process of decision making by encompassing heuristic (expert) and empirical information. To build this Expert System, it is necessary to create a knowledge base and a set of rules for interpreting that knowledge. These will be derived from expert knowledge from participating water management agencies, from the existing scientific literature, and from original research on a set of streams selected to encompass the diversity of stream management situations encountered in the Mediterranean region, from Portugal to Israel, plus some central European sites that serve as contrast.
link: www.streames.org

Implications of sludge particles on microbial biofilms and the functionality of human altered streams : Pressure and Impact

Marie Curie FP6-2002-Mobility-5 (Structuring the European Research Area)
SLUDPRESS (Proposal N° 514949) (2005 –2007)
Host: Dr. Tom J. Battin
Post-doctoral fellow: Roura Carol Montserrat (University of Barcelona)

Summary
In the last decades, wastewater treatment plants (WWTP) have substantially diminished sewage emissions on receiving streams and rivers throughout Europe. Society has recognized this as a major step towards the implementation of the Water Framework Directive 2000/60/EC. However, a largely unresolved question remains whether WWTP represent an impact or pressure on the receiving streams and rivers. In fact, among their ecosystem services figure the performance to process and attenuate WWTP emissions through selfpurification. Understanding these relationships is part of STREAMES (EVK1-CT-2000-00081), which, however, focuses only on the solute emissions from WWTPs. Strikingly, virtually nothing is known on the implications of WWTP solid emissions. In fact, WWTP malfunctioning inducing sludge rising, pin floc formation or slime bulking can cause dramatic solid losses into the receiving streams. Sewage particles are highly active that beside their high carbon (e. g. microbial exopolymer substances) load can serve as vehicles for allochthonous bacteria (e. g. nitrifiers), pathogens (e. g. Cryptosporidium), contaminants (e. g. heavy metals), antibiotics and various pharmaceutical substances. Solid emissions are more frequent as usually admitted — a fact that is particularly true for low-capacity WWTPs discharging into small streams. These headwater streams, however, are particularly numerous in drainage networks and the malfunctioning of WWTP has thus the potential to affect downstream ecosystems.
This proposal aims at studying the transportation fate of sewage particles and their implications (impact or pressure) on stream microbial biofilms and functions. In a first step, transportation behaviour will be studied on experimentally injected, labelled particles in large-scale streamside flumes. This mesocosm experiment will address the questions of how far sewage particles travel in function of hydrology and environmental heterogeneity and how they affect system metabolism. Next, in laboratory experiments, the influence of sewage particles will be studied on the structure-function-coupling of model stream microbial biofilms. This microcosm approach will elucidate some of the patterns emerging from the mesocosm experiment and addresses the question whether sewage particles inhibit or support the metabolic performance (i. e., selfpurification) of microbial biofilms.

Microbial biofilms, flow heterogeneity and organic carbon cycling: bridging basic and applied research in streams

Funded by: FWF P16935-B03
Duration: 2004-2007
Principal Invastigator and coordination: Dr. Tom J. Battin
Team: Mag. Kathi Besemer, Mag. Gabriel Singer, Pia Huber, Gerald Hochedliner

Summary
Stream ecosystems have arguably experienced the most dramatic habitat loss during the last decades and a new era of restoration ecology is now emanating. Understanding the relationships between habitat heterogeneity, biodiversity and ecosystem functioniong across scales is imperative for successful restoration practices. Biofilms, which are now recognized as the dominant form of microbial life in many aquatic ecosystems, are particularly important in streambeds where they govern major ecosystems processes and ecosystem health. However, in contrast to detrimental biofilms from medical and industrial systems, the structure and function of environmental biofilms and their ecosystem implications remain obsure. Here, I propose a first comprehensive study that relates flow as the major physical determinant in streams to biofilm structure and function at both the cellular and community level. I consider microbial biofilms as ecologically functional communities and postulate the interplay of their architecture, community composition and function as a response to an oligotrophic flow environment. Next, these microscale relationships will be upscaled to streams as inherently heterogeneous flow landscapes to explain more global processes such as carbon cycling and selfpurification. I postulate niche differentiation and complementarity as the mechanisms underlying these large-scale biogeochemical processes. In fact, spatial flow heterogeneity creates biofilm structural and functional differentiation which results in the complementary use of resources. The empirical knowledge of this proposal will be then used to test current engineering approaches relevant to selfpurification. This proposal thus integrates timely concepts in stream and microbial ecology with cutting-edge techniques, and bridges basic and applied research.

Wie beeinflussen Schwebstoffe aus den Abwässern von Kläranlagen die Selbstreinigungsprozesse in Fließgewässern?

Funded by: Hochschuljubiläumsstiftung der Stadt Wien
Duration: 2003-2004
Principal Investigator and coordination: Dr. Tom J. Battin
Team: Mag. Gabriele Weigelhofer, Mag. Andrea Rauter