Alois Herzig - Academia.edu (original) (raw)
Papers by Alois Herzig
Some information, based upon a ten years study, is given on the ecology of Rhinoglena fertiiensis... more Some information, based upon a ten years study, is given on the ecology of Rhinoglena fertiiensis, a cold stenothermic rotifer. The largest numbers were always found during winter months under ice. A remarkable increase in population density is recorded throughout the investigation and is explained by the good quality of the food supply and a parallel increase in its abundance. The dynamics of this species appear to be closely connected with water temperature gradients. The distribution of Rhinoglena fertiiensis is discussed in connection with water chemistry. Hydrobiologia 73, 161-167 (1980).
Rotifer Symposium IV : proceedings of the Fourth Rotifer Symposium, held in Edinburgh, Scotland, August 18-25, 1985
Bruno B?rzi?s, in memoriam, 1909-1985.- One: Taxonomy and Biogeography.- Keratella cochlearis (Go... more Bruno B?rzi?s, in memoriam, 1909-1985.- One: Taxonomy and Biogeography.- Keratella cochlearis (Gosse) in Africa.- Distribution of rotifers in African fresh and inland saline waters.- On species of the genus Lepadella (Eurotatoria: Monogononta: Colurellidae) from North-Eastern India, with remarks on Indian taxa.- The Rotifera of impoundments in Southeastern Australia.- Tasmanian Rotifera: Affinities with the Australian fauna.- Intraspecific variability of Brachionus plicatilis.- Rotifera from Northwestern Canada.- Coexistence of rotifer (Brachionus plicatilis) clones in Soda Lake, Nevada.- Rotifers from Turkey.- Distribution of Brachionus species in Spanish mediterranean wetlands.- Biometric variation in three strains of Brachionus plicatilis as a direct response to abiotic variables.- Taxonomical and ecological notes on Hexarthra bulgarica from high mountain lakes and ponds of Sierra Nevada, Spain.- Rotifer fauna of lakes and ponds over 2500 m above sea level in the Sierra Nevada, Spain, with description of a new subspecies.- Rotifer fauna in the periphyton of Karst rivers in Croatia, Yugoslavia.- Rotifer occurrence in relation to pH.- Two: Bdelloids.- Ecology of Bdelloids: How to be successful.- A bdelloid rotifer living as an inquiline in the leaves of the pitcher plant. Sarracenia purpurea.- Specificity of the alpha-tocopherol (vitamin E) effect on the lifespan and fecundity of Bdelloid rotifers.- Three: Colonial Rotifers.- Coloniality in the phylum Rotifera.- Conochilus in Lake Washington.- Four: Population Dynamics and Spatial Distribution.- The analysis of planktonic rotifer populations: a plea for long-term investigations.- The influence of sampling strategy on the apparent population dynamics of planktonic rotifers.- Abundance and distribution of pelagic rotifers in a cold, deep, oligotrophic alpine lake (Konigssee).- Population dynamics of hypolimnetic rotifers in the Pluss-see (north Germany).- Environmental factors influencing the vertical migration of planktonic rotifers in a hypereutrophic tarn.- Comparative population dynamics of the rotifers Brachionus angularis and Keratella cochlearis.- Changes in the population dynamics of Keratella cochlearis (Gosse), Kellicottia longispina (Gosse) and Polyarthra vulgaris (Carlin) in a fertilised enclosure.- The population dynamics of Keratella cochlearis in a hypereutrophic tarn and the possible impact of predation by young roach.- Post-encounter vulnerability of some rotifer prey types to predation by the copepod Acanthocyclops robustus.- The Polyarthra escape response: Defence against interference from Daphnia.- Rotifers, cladocerans and planktivorous fish: what are the major interactions?.- Five: Aquaculture, Feeding and Nutrition.- Raising rotifers for use in aquaculture.- Production and nutritional quality of the rotifer Brachionus plicatilis fed marine Chlorella sp. at different cell densities.- The use of marine yeast (Candida sp.) and bakers' yeast (Saccharomyces cerevisiae) in combination with Chlorella sp. for mass culture of the rotifer Brachionus plicatilis.- A consideration of why mass culture of the rotifer Brachionus plicatilis with bakers' yeast is unstable.- The components of feeding behavior in rotifers.- Effects of feeding on respiration of the rotifer Brachionus plicatilis.- A laboratory study of feeding and assimilation in Euchlanis dilatata lucksiana.- The potential for population growth of Ascomorpha ecaudis.- Further nutritional studies on the rotifer Encentrum linnhei.- Six: Reproduction.- Planktonic rotifers and temperature.- Effect of algal diet and temperature on the embryonic development time of the rotifer Brachionus plicatilis in culture.- Factors influencing the occurrence of males in natural populations of Synchaeta spp..- Fertilization and male fertility in the rotifer Brachionus plicatilis.- Effect of incubation temperature on the hatching of rotifer resting eggs collected from sediments.- Seven: Ultrastructure, Biochemistry and General Methodology.- Movement in rotifers: correlations of ultrastructure and behavior.- Ultrastructure and histochemistry of the stomach of Asplanchna sieboldi.- Neuropharmacology of rotifer feeding, oviposition and anesthesia.- Combined influences of particulate and dissolved factors in the toxicity of Microcystis aeruginosa (NRC-SS-17) to the rotifer Brachionus calyciflorus.- A centrifugation method for measuring the relative density (specific gravity) of planktonic rotifers (Rotifera), with values for the relative density of Polyarthra major (Burkhardt) and Keratella cochlearis (Gosse).
PLOS ONE, Aug 16, 2012
Carotenoids are protective pigments present in many aquatic organisms that reduce the photooxidat... more Carotenoids are protective pigments present in many aquatic organisms that reduce the photooxidative stress induced by short-wavelenght solar radiation, yet increase their susceptibility to predators. Arctodiaptomus spinosus, a calanoid copepod typically found in many fishless shallow soda lakes, shows large between-lake differences in pigmentation. Here, we attribute these differences to the environmental state of these ecosystems, namely, 'dark water' lakes with submersed vegetation and turbid 'white' lakes lacking macrophytes. Copepod carotenoid concentration in the turbid 'white' lakes was significantly (about 20-fold) higher than in the 'dark water' ones, although the latter systems were characterized by higher transparency. In addition, males had on a dry weight basis around three times higher carotenoid concentrations than females. Mycosporine-like amino acids (direct UV screening substances) were found in all cases, but in low concentration. The environmental conditions in these ecosystems were largely shaped by the presence/absence of submersed macrophytes Thus, in the turbid lakes, the strong wind-driven mixis allows for copepods to be brought to the surface and being exposed to solar radiation, whereas in 'dark water' ones, macrophytes reduce water turbulence and additionally provide shelter. Our results explain the counter-intuitive notion of strong red pigmentation in copepods from a turbid ecosystem and suggest that factors other than high UV transparency favor carotenoid accumulation in zooplankton.
The EGU General Assembly, Apr 1, 2013
Trophic relationships in the pelagic zone of Mondsee, Austria
Springer eBooks, 1990
Data are presented on nutrient concentrations, phytoplankton biovolume development, zooplankton c... more Data are presented on nutrient concentrations, phytoplankton biovolume development, zooplankton composition and population dynamics, and fish from a deep, stratifying, alpine lake (Mondsee, Austria) during a three-year period between 1982 and 1984. Development of the phytoplankton is closely related to structuring events of the physico-chemical environment. Dissolved silicate and phosphorus concentrations are critical for the summer situation. During summer algal abundance is largely affected by grazing of zooplankton, but no clear-water phase was observed at the end of the spring peak of phytoplankton.
Verhandlungen, Sep 1, 2001
![Research paper thumbnail of The vertical distribution of zooplankton in the Goggausee (the influence of algae and Chaoborus flavicans) [Translation from: Carinthia II 166/186 373-385, 1976]](https://attachments.academia-assets.com/113717289/thumbnails/1.jpg)
](The Goggausee, a small, shallow, meromictic lake(700m long, 150m wide, max. depth=12m, mean depth... more The Goggausee, a small, shallow, meromictic lake(700m long, 150m wide, max. depth=12m, mean depth=6m), was the site of a week long study (19-26 May 1974) of the limnology department of the University of Vienna. The study comprised pollen analysis and palaeolimnological studies on the one hand, as well as a stock- taking of physiochemical factors, primary production, bacteria, zooplankton, zoo benthos and fish on the other. This paper studies the zooplankton of the lake. The Goggausee is a meromictic lake, with its anoxic deep water, that restricts the vertical distribution of most zooplankton. The aim of the study was to pursue the vertical distribution of the rotifers and Crustacea. Density of individuals, biomass, percentages of zooplankton together and crustaceans and rotifers as groups. Special consideration is given to the the Dipteran Chaoborus flavicans.
Verhandlungen, Jun 1, 1985
Microbial Ecology, Nov 4, 2010
Vibrio cholerae is a human pathogen and natural inhabitant of aquatic environments. Serogroups O1... more Vibrio cholerae is a human pathogen and natural inhabitant of aquatic environments. Serogroups O1/O139 have been associated with epidemic cholera, while non-O1/non-O139 serogroups usually cause human disease other than classical cholera. V. cholerae non-O1/non-O139 from the Neusiedler See, a large Central European lake, have caused ear and wound infections, including one case of fatal septicaemia. Recent investigations demonstrated rapid planktonic growth of V. cholerae non-O1/non-O139 and correlation with zooplankton biomass. The aim of this study was to elucidate the interaction of autochthonous V. cholerae with two dominant crustacean zooplankton species in the lake and investigate the influence of the natural bacterial community on this interaction. An existing data set was evaluated for statistical relationships between zooplankton species and V. cholerae and co-culture experiments were performed in the laboratory. A new fluorescence in situ hybridisation protocol was applied for quantification of V. cholerae non-O1/non-O139 cells, which significantly reduced analysis time. The experiments clearly demonstrated a significant relationship of autochthonous V. cholerae non-O1/non-O139 with cladocerans by promoting growth of V. cholerae non-O1/non-O139 in the water and on the surfaces of the cladocerans. In contrast, copepods had a negative effect on the growth of V. cholerae non-O1/ non-O139 via competing bacteria from their surfaces. Thus, beside other known factors, biofilm formation by V. cholerae on crustacean zooplankton appears to be zooplankton taxon specific and may be controlled by the natural bacterial community.
PCR und ELISA - Alternativen zum Maustest für die Analyse des Botulismus-Neurotoxin-C1 Giftbildungspotentiales in Umweltproben? [PCR and ELISA - in vitro alternatives to the mouse-bioassay for assessing the botulinum-neurotoxin-C1 production potential in environmental samples?]
ALTEX-Alternatives to Animal Experimentation, 2002
Microbial Ecology, Jul 6, 2007
Moderately saline soda lakes harbor extremely abundant and fast growing bacterial communities. An... more Moderately saline soda lakes harbor extremely abundant and fast growing bacterial communities. An interesting phenomenon of an explosive bacterial growth in shallow soda lakes in Eastern Austria after dilution with rainwater, concomitantly with a significant decrease in temperature was observed in a former study. In the present study, we tried to identify the factors being responsible for this enhanced bacterial growth in laboratory batch cultures. Three experiments were performed with water taken from two different lakes at different seasons. Natural soda lake water was diluted with distilled water, artificial lake water, sterile filtered soda lake water, and grazer-free water to test (1) for the influence of compatible solutes released to the environment and reduced salt stress after osmotic downshock, (2) for the influence of nutrients, which may be washed in from the dry areas of the lake bottom after rainfall and (3) for the decrease of grazing pressure due to dilution. The potential influence of (4) viruses was indirectly deduced. The response of the bacterial community to the manipulations was measured by changes in bacterial numbers, the incorporation of 3 H-leucine and the concomitant determination of the amount of 3 H-leucine uptaking bacteria by microautoradiography. The influence of the environmental factors enhancing bacterial growth after a simulated rainfall event showed variations between the lakes and over the seasons. The addition of nutrients was, in all experiments, the main factor triggering bacterial growth. The decrease in grazing pressure and viral lysis after dilution was of significant importance in two of three experiments. In the experiment with the highest salinity, we could show that either compatible solutes released after osmotic down-shock and used as a source of nutrients for the soda lake bacterial populations or reduced salt stress were most probably responsible for the observed marked enhancement of bacterial growth.
Cowx/Interactions, 2007
Data from two projects carried out within the extensive (180 km 2) reed belt of Lake Neusiedl, Au... more Data from two projects carried out within the extensive (180 km 2) reed belt of Lake Neusiedl, Austria-one about the fish community and the other about the colonial breeding piscivorous birds, great white egret, Casmerodius albus L., purple heron, Ardea purpurea L., grey heron, Ardea cinerea L., and spoonbill, Platalea leucorodia L.-were used to assess the impact of fish-eating birds on the fish population. Piscivorous birds ate about 12% of total fish standing stock within the reed belt. Their food intake was estimated to account for 21% of fish production within a size range of 3-25 cm total length (potential prey size). Competition between fish-eating birds and commercial fisheries was considered to be negligible.
Surveillance of microbial water quality in Neusiedler See—from single annual observations to a problem orientated adaptive management
This study gives an overview on the surveillance of microbial water quality in Neusiedler See. Fi... more This study gives an overview on the surveillance of microbial water quality in Neusiedler See. First, the historical aspect of the development of a monitoring programme is presented. Then a stochastic and geostatistical analysis of a large data set of water quality data (1992 bis 2013) of standard fecal indicator bacteria (SFIB), water quality and meteorological variables sampled at 26 sampling sites is given. For the whole investigation period open water and the EU-bathing sites met the bacteriological requirements. It also revealed hotspots of fecal pollution and these are exclusively related to sites with elevated anthropogenic activity. Background pollution from wildlife or diffuse agricultural run-off at more remote sites was comparatively low. The analysis also showed that variability in the incidence of SFIB was driven mainly by meteorological phenomena. Geostatistical analysis revealed that the current spatial sampling density was insufficient to cover SFIB variance over the...
To be able to protect the water quality of any water system from the negative effects of urbaniza... more To be able to protect the water quality of any water system from the negative effects of urbanization and industrialization its main influencing processes should be understood. Principal component analysis was conducted on mainly chemical and biological parameters of the River Tisza (HU), Kis-Balaton Water Protection System (HU) and Lake Neusiedl (AU). Because of their different spatial structures the need to show spatial changes in the background processes and their factor scores, called for different interpretation methods. In each case PCA indicated a presumed anthropogenic influence and its exact location.
Pathways, chemical processes and long-term changes of nutrients in Lake Neusiedl
This paper deals with nutrient dynamics at Lake Neusiedl, an issue that is inseparable from the i... more This paper deals with nutrient dynamics at Lake Neusiedl, an issue that is inseparable from the inputs and exchange processes of suspended matter. Older studies from the early 1980s are summarised, discussed and compared with new findings from an ongoing EU INTERREG project (REBEN). The article first deals with the suspended matter and nutrient loads in Lake Neusiedl via the largest tributary of the lake, the river Wulka. In a second section changes due to chemical processes during the passage of the river Wulka through the reed belt at Donnerskirchen are described. The long-term development of nutrients in the open lake are discussed in the third part of the paper, which closes with the description of the horizontal distribution of suspended matter and nutrients in the reed belt and conclusions about horizontal currents and exchange processes. The most important finding of the data analysis is the decline of the phosphorus load of the river Wulka in recent decades, a corresponding ...
Limnology and Oceanography, 1997
In a humic-rich, Shallow lake (Lake Neusicdl), the seasonal dynamics of the humic and the nonhumi... more In a humic-rich, Shallow lake (Lake Neusicdl), the seasonal dynamics of the humic and the nonhumic dissolved organic carbon (DOC) were investigated and the photochemical oxygen consumption rates of these DOC fractions exposed to surface solar radiation levels were compared with that of the bulk DOC and bacterial respiration. Furthermore, bacterial utilization of the humic, nonhumic, and bulk DOC pm-exposed to solar radiation was compared with utilization of the different fractions of DOC held in the dark prior to inoculating natural bacterial assemblages. The concentration of the unfractionated DOC pool ranged from-3 mmol C liter-' during summer to 1.3 mmol C liter-' in late spring. The mean contribution of humic DOC was 35.2% of bulk DOC. Under the full spectrum of solar radiation, photochemical oxygen consumption of the unfractionated DOC was 3.3 pmol O2 liter I h-l, 1.8 pmol 0, liter-' h I of the humic DOC, and 1.7 pmol 0, liter I h-l of the nonhumic DOC. In the absence of UVB, photochemical oxygen consumption was reduced by 35% in the unfractionated DOC, 38% in the humic, and 27.5% in the nonhumic DOC. Under the full spectrum of solar radiation, the photochemical oxygen consumption normalized to DOC was more than twice as high (2.83 pmol 0, mmol-I C h I) for humic than for nonhumic DOC. The bacterial oxygen consumption rate was-30% of the photochcmical oxygen consumption of the unfractionated DOC. In batch culture experiments with natural bacterial assemblages as inocula, the bacterial yield was generally higher with substrate exposed to the full spectrum of solar radiation than with substrate held in the dark prior to inoculation. Exposure of O.&pm filtered water to the full spectrum of surface solar radiation for 2-3 h resulted in a decline in activity (measured by thymidine incorporation) to 47% of the activity measured in the dark. If UVB was excluded, bacterial activity was 62% of that in the dark. Subsequent incubation at 5-20-cm depth under in situ radiation for another 2-3 h resulted in bacterial activity similar to that detected in the dark incubations at the surface. Bacteria exposed to the full range of solar radiation at the surface and incubated subsequently in the dark exhibited significantly lower activity than bacteria exposed to in situ solar radiation in distinct depth layers. This result indicates that bacteria rapidly recover from previous UV stress in the absence of UVB. Based on our results, we estimate that the photooxidation-mediated residence times in the top 5-cm layer of the water column are 90 and 45.5 d for the nonhumic and humic fractions and 75 d for unfractionated DOC. For the entire water column,-10% of the remineralization activity (bacterial respiration + photochcmical oxygen consumption) is due to photooxidation of the DOC, and the mean residence time of DOC is-80 d.
Österreichische Wasser- und Abfallwirtschaft, 2019
Zusammenfassung Die vorliegende Arbeit behandelt die Nährstoffdynamik am Neusiedler See, ein Them... more Zusammenfassung Die vorliegende Arbeit behandelt die Nährstoffdynamik am Neusiedler See, ein Thema, das untrennbar mit den Einträgen und Austauschprozessen der Fest-oder Schwebstoffe verbunden ist. Es werden zusammenfassend ältere Untersuchungen von Anfang der 1980er-Jahre diskutiert und neueren Erkenntnissen aus einem laufenden EU-INTERREG-Projekt (REBEN) gegenübergestellt. Der Beitrag behandelt zunächst die Schwebstoffund Nährstofffrachten in den Neusiedler See über den größten Zubringer des Sees, die Wulka. In einem zweiten Abschnitt werden Veränderungen durch Umsetzungsprozesse beim Durchtritt der Wulka durch den Schilfgürtel-Mündungsbereich Höhe Donnerskirchen beschrieben. Die Langzeitentwicklung der Nährstoffe im offenen See bildet den dritten Abschnitt, während abschließend die horizontale Verteilung von Schweb-und Nährstoffen im Schilfgürtel und Rückschlüsse auf horizontale Strömungen und Austauschprozesse behandelt werden. Der wichtigste Befund der Datenanalysen ist der Rückgang der Phosphorfrachten der Wulka in den letzten Jahrzehnten, eine ent
Assessing the ecological vulnerability of the shallow steppe Lake Neusiedl (Austria-Hungary) to climate-driven hydrological changes using a palaeolimnological approach
Journal of Great Lakes Research, 2021
Abstract Lake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate v... more Abstract Lake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate variations due to its extreme shallowness (zmax = 1.8 m) and low ratio of catchment to lake area (3.5 : 1). Changes in water budget, salinity and turbidity have key implications for the lake’s ecology and management. Here, we present a multi-proxy palaeolimnological reconstruction of the evolution of Lake Neusiedl since the end of its last complete desiccation (1865–1868), based on an undisturbed radiometrically dated core taken from the open water portion of the lake. Geochemical and biological (algal) proxies outline the succession of three major ecological stages since 1873 ± 16 yrs, with the first major changes appearing already in the 1930s as driven by climate related hydrological variability. Subfossil diatoms proved to be reliable for tracking long-term changes in the trophic conditions of Lake Neusiedl while diatom-inferred lake conductivity revealed to be unreliable due to a combination of lake environmental settings and the absence of a site-specific training set. Nonetheless, multivariate statistical analyses and comparisons with limnological data confirm a great potential of subfossil diatoms for revealing past ecological changes and tipping points of shallow lakes, as long as studies rely on a multi-proxy approach. In agreement with limnological surveys, the sediment record corroborates the high vulnerability of Lake Neusiedl, both in present and past times, towards climate-driven changes in water level and salinity, and allows the prediction, by analogy with the past, of future ecological changes in a context of global warming and increasing nutrient inputs from non-point sources.
Artenzusammensetzeung und saisonale Dynamik der Cladocera- und Copepoda-Fauna in künstlichen Natrongewässern
Ciliates and flagellates in shallow saline pans within the area of the Nationalpark Neusiedler See/Seewinkel, Austria
The role of planktonie protozoa as major links in rnatter and energy fluxes within freshwater sys... more The role of planktonie protozoa as major links in rnatter and energy fluxes within freshwater systems has been deseribed by various studies in reeent years. Protozoa are known to be an important food souree for metazoa (WEISSE 1991, SANDERS & WICKHAM 1993) and effeetively transfer pieoplanktonie produetion to higher trophie 1eve1s (FENCHEL 1987, SHERR & SHERR 1987). They ean feed on autotrophie and heterotrophie pieoand nanoplankton (PORTER et al. 1985, SIMEK et al. 1995) and provide dissolved organie material as nutrients to baeteria. Different trophie levels ean even be influeneed simultaneous1y by ornnivorous feeding aetivities in eertain protozoan groups (PFISTER & ARNDT 1998). Some studies have addressed the influenee of different habitats on the pe1agie protozoan eommunities (BEAVER & CRISMAN 1989, PFISTER et al. 2002), but extreme inland waters, sueh as fluetuating saline environments (RUINEN 1938a, 1938b, RUINEN & BAASBECKING 1938, PFISTER et al. 2002) have so far been modes...
Some information, based upon a ten years study, is given on the ecology of Rhinoglena fertiiensis... more Some information, based upon a ten years study, is given on the ecology of Rhinoglena fertiiensis, a cold stenothermic rotifer. The largest numbers were always found during winter months under ice. A remarkable increase in population density is recorded throughout the investigation and is explained by the good quality of the food supply and a parallel increase in its abundance. The dynamics of this species appear to be closely connected with water temperature gradients. The distribution of Rhinoglena fertiiensis is discussed in connection with water chemistry. Hydrobiologia 73, 161-167 (1980).
Rotifer Symposium IV : proceedings of the Fourth Rotifer Symposium, held in Edinburgh, Scotland, August 18-25, 1985
Bruno B?rzi?s, in memoriam, 1909-1985.- One: Taxonomy and Biogeography.- Keratella cochlearis (Go... more Bruno B?rzi?s, in memoriam, 1909-1985.- One: Taxonomy and Biogeography.- Keratella cochlearis (Gosse) in Africa.- Distribution of rotifers in African fresh and inland saline waters.- On species of the genus Lepadella (Eurotatoria: Monogononta: Colurellidae) from North-Eastern India, with remarks on Indian taxa.- The Rotifera of impoundments in Southeastern Australia.- Tasmanian Rotifera: Affinities with the Australian fauna.- Intraspecific variability of Brachionus plicatilis.- Rotifera from Northwestern Canada.- Coexistence of rotifer (Brachionus plicatilis) clones in Soda Lake, Nevada.- Rotifers from Turkey.- Distribution of Brachionus species in Spanish mediterranean wetlands.- Biometric variation in three strains of Brachionus plicatilis as a direct response to abiotic variables.- Taxonomical and ecological notes on Hexarthra bulgarica from high mountain lakes and ponds of Sierra Nevada, Spain.- Rotifer fauna of lakes and ponds over 2500 m above sea level in the Sierra Nevada, Spain, with description of a new subspecies.- Rotifer fauna in the periphyton of Karst rivers in Croatia, Yugoslavia.- Rotifer occurrence in relation to pH.- Two: Bdelloids.- Ecology of Bdelloids: How to be successful.- A bdelloid rotifer living as an inquiline in the leaves of the pitcher plant. Sarracenia purpurea.- Specificity of the alpha-tocopherol (vitamin E) effect on the lifespan and fecundity of Bdelloid rotifers.- Three: Colonial Rotifers.- Coloniality in the phylum Rotifera.- Conochilus in Lake Washington.- Four: Population Dynamics and Spatial Distribution.- The analysis of planktonic rotifer populations: a plea for long-term investigations.- The influence of sampling strategy on the apparent population dynamics of planktonic rotifers.- Abundance and distribution of pelagic rotifers in a cold, deep, oligotrophic alpine lake (Konigssee).- Population dynamics of hypolimnetic rotifers in the Pluss-see (north Germany).- Environmental factors influencing the vertical migration of planktonic rotifers in a hypereutrophic tarn.- Comparative population dynamics of the rotifers Brachionus angularis and Keratella cochlearis.- Changes in the population dynamics of Keratella cochlearis (Gosse), Kellicottia longispina (Gosse) and Polyarthra vulgaris (Carlin) in a fertilised enclosure.- The population dynamics of Keratella cochlearis in a hypereutrophic tarn and the possible impact of predation by young roach.- Post-encounter vulnerability of some rotifer prey types to predation by the copepod Acanthocyclops robustus.- The Polyarthra escape response: Defence against interference from Daphnia.- Rotifers, cladocerans and planktivorous fish: what are the major interactions?.- Five: Aquaculture, Feeding and Nutrition.- Raising rotifers for use in aquaculture.- Production and nutritional quality of the rotifer Brachionus plicatilis fed marine Chlorella sp. at different cell densities.- The use of marine yeast (Candida sp.) and bakers' yeast (Saccharomyces cerevisiae) in combination with Chlorella sp. for mass culture of the rotifer Brachionus plicatilis.- A consideration of why mass culture of the rotifer Brachionus plicatilis with bakers' yeast is unstable.- The components of feeding behavior in rotifers.- Effects of feeding on respiration of the rotifer Brachionus plicatilis.- A laboratory study of feeding and assimilation in Euchlanis dilatata lucksiana.- The potential for population growth of Ascomorpha ecaudis.- Further nutritional studies on the rotifer Encentrum linnhei.- Six: Reproduction.- Planktonic rotifers and temperature.- Effect of algal diet and temperature on the embryonic development time of the rotifer Brachionus plicatilis in culture.- Factors influencing the occurrence of males in natural populations of Synchaeta spp..- Fertilization and male fertility in the rotifer Brachionus plicatilis.- Effect of incubation temperature on the hatching of rotifer resting eggs collected from sediments.- Seven: Ultrastructure, Biochemistry and General Methodology.- Movement in rotifers: correlations of ultrastructure and behavior.- Ultrastructure and histochemistry of the stomach of Asplanchna sieboldi.- Neuropharmacology of rotifer feeding, oviposition and anesthesia.- Combined influences of particulate and dissolved factors in the toxicity of Microcystis aeruginosa (NRC-SS-17) to the rotifer Brachionus calyciflorus.- A centrifugation method for measuring the relative density (specific gravity) of planktonic rotifers (Rotifera), with values for the relative density of Polyarthra major (Burkhardt) and Keratella cochlearis (Gosse).
PLOS ONE, Aug 16, 2012
Carotenoids are protective pigments present in many aquatic organisms that reduce the photooxidat... more Carotenoids are protective pigments present in many aquatic organisms that reduce the photooxidative stress induced by short-wavelenght solar radiation, yet increase their susceptibility to predators. Arctodiaptomus spinosus, a calanoid copepod typically found in many fishless shallow soda lakes, shows large between-lake differences in pigmentation. Here, we attribute these differences to the environmental state of these ecosystems, namely, 'dark water' lakes with submersed vegetation and turbid 'white' lakes lacking macrophytes. Copepod carotenoid concentration in the turbid 'white' lakes was significantly (about 20-fold) higher than in the 'dark water' ones, although the latter systems were characterized by higher transparency. In addition, males had on a dry weight basis around three times higher carotenoid concentrations than females. Mycosporine-like amino acids (direct UV screening substances) were found in all cases, but in low concentration. The environmental conditions in these ecosystems were largely shaped by the presence/absence of submersed macrophytes Thus, in the turbid lakes, the strong wind-driven mixis allows for copepods to be brought to the surface and being exposed to solar radiation, whereas in 'dark water' ones, macrophytes reduce water turbulence and additionally provide shelter. Our results explain the counter-intuitive notion of strong red pigmentation in copepods from a turbid ecosystem and suggest that factors other than high UV transparency favor carotenoid accumulation in zooplankton.
The EGU General Assembly, Apr 1, 2013
Trophic relationships in the pelagic zone of Mondsee, Austria
Springer eBooks, 1990
Data are presented on nutrient concentrations, phytoplankton biovolume development, zooplankton c... more Data are presented on nutrient concentrations, phytoplankton biovolume development, zooplankton composition and population dynamics, and fish from a deep, stratifying, alpine lake (Mondsee, Austria) during a three-year period between 1982 and 1984. Development of the phytoplankton is closely related to structuring events of the physico-chemical environment. Dissolved silicate and phosphorus concentrations are critical for the summer situation. During summer algal abundance is largely affected by grazing of zooplankton, but no clear-water phase was observed at the end of the spring peak of phytoplankton.
Verhandlungen, Sep 1, 2001
The Goggausee, a small, shallow, meromictic lake(700m long, 150m wide, max. depth=12m, mean depth... more The Goggausee, a small, shallow, meromictic lake(700m long, 150m wide, max. depth=12m, mean depth=6m), was the site of a week long study (19-26 May 1974) of the limnology department of the University of Vienna. The study comprised pollen analysis and palaeolimnological studies on the one hand, as well as a stock- taking of physiochemical factors, primary production, bacteria, zooplankton, zoo benthos and fish on the other. This paper studies the zooplankton of the lake. The Goggausee is a meromictic lake, with its anoxic deep water, that restricts the vertical distribution of most zooplankton. The aim of the study was to pursue the vertical distribution of the rotifers and Crustacea. Density of individuals, biomass, percentages of zooplankton together and crustaceans and rotifers as groups. Special consideration is given to the the Dipteran Chaoborus flavicans.
Verhandlungen, Jun 1, 1985
Microbial Ecology, Nov 4, 2010
Vibrio cholerae is a human pathogen and natural inhabitant of aquatic environments. Serogroups O1... more Vibrio cholerae is a human pathogen and natural inhabitant of aquatic environments. Serogroups O1/O139 have been associated with epidemic cholera, while non-O1/non-O139 serogroups usually cause human disease other than classical cholera. V. cholerae non-O1/non-O139 from the Neusiedler See, a large Central European lake, have caused ear and wound infections, including one case of fatal septicaemia. Recent investigations demonstrated rapid planktonic growth of V. cholerae non-O1/non-O139 and correlation with zooplankton biomass. The aim of this study was to elucidate the interaction of autochthonous V. cholerae with two dominant crustacean zooplankton species in the lake and investigate the influence of the natural bacterial community on this interaction. An existing data set was evaluated for statistical relationships between zooplankton species and V. cholerae and co-culture experiments were performed in the laboratory. A new fluorescence in situ hybridisation protocol was applied for quantification of V. cholerae non-O1/non-O139 cells, which significantly reduced analysis time. The experiments clearly demonstrated a significant relationship of autochthonous V. cholerae non-O1/non-O139 with cladocerans by promoting growth of V. cholerae non-O1/non-O139 in the water and on the surfaces of the cladocerans. In contrast, copepods had a negative effect on the growth of V. cholerae non-O1/ non-O139 via competing bacteria from their surfaces. Thus, beside other known factors, biofilm formation by V. cholerae on crustacean zooplankton appears to be zooplankton taxon specific and may be controlled by the natural bacterial community.
PCR und ELISA - Alternativen zum Maustest für die Analyse des Botulismus-Neurotoxin-C1 Giftbildungspotentiales in Umweltproben? [PCR and ELISA - in vitro alternatives to the mouse-bioassay for assessing the botulinum-neurotoxin-C1 production potential in environmental samples?]
ALTEX-Alternatives to Animal Experimentation, 2002
Microbial Ecology, Jul 6, 2007
Moderately saline soda lakes harbor extremely abundant and fast growing bacterial communities. An... more Moderately saline soda lakes harbor extremely abundant and fast growing bacterial communities. An interesting phenomenon of an explosive bacterial growth in shallow soda lakes in Eastern Austria after dilution with rainwater, concomitantly with a significant decrease in temperature was observed in a former study. In the present study, we tried to identify the factors being responsible for this enhanced bacterial growth in laboratory batch cultures. Three experiments were performed with water taken from two different lakes at different seasons. Natural soda lake water was diluted with distilled water, artificial lake water, sterile filtered soda lake water, and grazer-free water to test (1) for the influence of compatible solutes released to the environment and reduced salt stress after osmotic downshock, (2) for the influence of nutrients, which may be washed in from the dry areas of the lake bottom after rainfall and (3) for the decrease of grazing pressure due to dilution. The potential influence of (4) viruses was indirectly deduced. The response of the bacterial community to the manipulations was measured by changes in bacterial numbers, the incorporation of 3 H-leucine and the concomitant determination of the amount of 3 H-leucine uptaking bacteria by microautoradiography. The influence of the environmental factors enhancing bacterial growth after a simulated rainfall event showed variations between the lakes and over the seasons. The addition of nutrients was, in all experiments, the main factor triggering bacterial growth. The decrease in grazing pressure and viral lysis after dilution was of significant importance in two of three experiments. In the experiment with the highest salinity, we could show that either compatible solutes released after osmotic down-shock and used as a source of nutrients for the soda lake bacterial populations or reduced salt stress were most probably responsible for the observed marked enhancement of bacterial growth.
Cowx/Interactions, 2007
Data from two projects carried out within the extensive (180 km 2) reed belt of Lake Neusiedl, Au... more Data from two projects carried out within the extensive (180 km 2) reed belt of Lake Neusiedl, Austria-one about the fish community and the other about the colonial breeding piscivorous birds, great white egret, Casmerodius albus L., purple heron, Ardea purpurea L., grey heron, Ardea cinerea L., and spoonbill, Platalea leucorodia L.-were used to assess the impact of fish-eating birds on the fish population. Piscivorous birds ate about 12% of total fish standing stock within the reed belt. Their food intake was estimated to account for 21% of fish production within a size range of 3-25 cm total length (potential prey size). Competition between fish-eating birds and commercial fisheries was considered to be negligible.
Surveillance of microbial water quality in Neusiedler See—from single annual observations to a problem orientated adaptive management
This study gives an overview on the surveillance of microbial water quality in Neusiedler See. Fi... more This study gives an overview on the surveillance of microbial water quality in Neusiedler See. First, the historical aspect of the development of a monitoring programme is presented. Then a stochastic and geostatistical analysis of a large data set of water quality data (1992 bis 2013) of standard fecal indicator bacteria (SFIB), water quality and meteorological variables sampled at 26 sampling sites is given. For the whole investigation period open water and the EU-bathing sites met the bacteriological requirements. It also revealed hotspots of fecal pollution and these are exclusively related to sites with elevated anthropogenic activity. Background pollution from wildlife or diffuse agricultural run-off at more remote sites was comparatively low. The analysis also showed that variability in the incidence of SFIB was driven mainly by meteorological phenomena. Geostatistical analysis revealed that the current spatial sampling density was insufficient to cover SFIB variance over the...
To be able to protect the water quality of any water system from the negative effects of urbaniza... more To be able to protect the water quality of any water system from the negative effects of urbanization and industrialization its main influencing processes should be understood. Principal component analysis was conducted on mainly chemical and biological parameters of the River Tisza (HU), Kis-Balaton Water Protection System (HU) and Lake Neusiedl (AU). Because of their different spatial structures the need to show spatial changes in the background processes and their factor scores, called for different interpretation methods. In each case PCA indicated a presumed anthropogenic influence and its exact location.
Pathways, chemical processes and long-term changes of nutrients in Lake Neusiedl
This paper deals with nutrient dynamics at Lake Neusiedl, an issue that is inseparable from the i... more This paper deals with nutrient dynamics at Lake Neusiedl, an issue that is inseparable from the inputs and exchange processes of suspended matter. Older studies from the early 1980s are summarised, discussed and compared with new findings from an ongoing EU INTERREG project (REBEN). The article first deals with the suspended matter and nutrient loads in Lake Neusiedl via the largest tributary of the lake, the river Wulka. In a second section changes due to chemical processes during the passage of the river Wulka through the reed belt at Donnerskirchen are described. The long-term development of nutrients in the open lake are discussed in the third part of the paper, which closes with the description of the horizontal distribution of suspended matter and nutrients in the reed belt and conclusions about horizontal currents and exchange processes. The most important finding of the data analysis is the decline of the phosphorus load of the river Wulka in recent decades, a corresponding ...
Limnology and Oceanography, 1997
In a humic-rich, Shallow lake (Lake Neusicdl), the seasonal dynamics of the humic and the nonhumi... more In a humic-rich, Shallow lake (Lake Neusicdl), the seasonal dynamics of the humic and the nonhumic dissolved organic carbon (DOC) were investigated and the photochemical oxygen consumption rates of these DOC fractions exposed to surface solar radiation levels were compared with that of the bulk DOC and bacterial respiration. Furthermore, bacterial utilization of the humic, nonhumic, and bulk DOC pm-exposed to solar radiation was compared with utilization of the different fractions of DOC held in the dark prior to inoculating natural bacterial assemblages. The concentration of the unfractionated DOC pool ranged from-3 mmol C liter-' during summer to 1.3 mmol C liter-' in late spring. The mean contribution of humic DOC was 35.2% of bulk DOC. Under the full spectrum of solar radiation, photochemical oxygen consumption of the unfractionated DOC was 3.3 pmol O2 liter I h-l, 1.8 pmol 0, liter-' h I of the humic DOC, and 1.7 pmol 0, liter I h-l of the nonhumic DOC. In the absence of UVB, photochemical oxygen consumption was reduced by 35% in the unfractionated DOC, 38% in the humic, and 27.5% in the nonhumic DOC. Under the full spectrum of solar radiation, the photochemical oxygen consumption normalized to DOC was more than twice as high (2.83 pmol 0, mmol-I C h I) for humic than for nonhumic DOC. The bacterial oxygen consumption rate was-30% of the photochcmical oxygen consumption of the unfractionated DOC. In batch culture experiments with natural bacterial assemblages as inocula, the bacterial yield was generally higher with substrate exposed to the full spectrum of solar radiation than with substrate held in the dark prior to inoculation. Exposure of O.&pm filtered water to the full spectrum of surface solar radiation for 2-3 h resulted in a decline in activity (measured by thymidine incorporation) to 47% of the activity measured in the dark. If UVB was excluded, bacterial activity was 62% of that in the dark. Subsequent incubation at 5-20-cm depth under in situ radiation for another 2-3 h resulted in bacterial activity similar to that detected in the dark incubations at the surface. Bacteria exposed to the full range of solar radiation at the surface and incubated subsequently in the dark exhibited significantly lower activity than bacteria exposed to in situ solar radiation in distinct depth layers. This result indicates that bacteria rapidly recover from previous UV stress in the absence of UVB. Based on our results, we estimate that the photooxidation-mediated residence times in the top 5-cm layer of the water column are 90 and 45.5 d for the nonhumic and humic fractions and 75 d for unfractionated DOC. For the entire water column,-10% of the remineralization activity (bacterial respiration + photochcmical oxygen consumption) is due to photooxidation of the DOC, and the mean residence time of DOC is-80 d.
Österreichische Wasser- und Abfallwirtschaft, 2019
Zusammenfassung Die vorliegende Arbeit behandelt die Nährstoffdynamik am Neusiedler See, ein Them... more Zusammenfassung Die vorliegende Arbeit behandelt die Nährstoffdynamik am Neusiedler See, ein Thema, das untrennbar mit den Einträgen und Austauschprozessen der Fest-oder Schwebstoffe verbunden ist. Es werden zusammenfassend ältere Untersuchungen von Anfang der 1980er-Jahre diskutiert und neueren Erkenntnissen aus einem laufenden EU-INTERREG-Projekt (REBEN) gegenübergestellt. Der Beitrag behandelt zunächst die Schwebstoffund Nährstofffrachten in den Neusiedler See über den größten Zubringer des Sees, die Wulka. In einem zweiten Abschnitt werden Veränderungen durch Umsetzungsprozesse beim Durchtritt der Wulka durch den Schilfgürtel-Mündungsbereich Höhe Donnerskirchen beschrieben. Die Langzeitentwicklung der Nährstoffe im offenen See bildet den dritten Abschnitt, während abschließend die horizontale Verteilung von Schweb-und Nährstoffen im Schilfgürtel und Rückschlüsse auf horizontale Strömungen und Austauschprozesse behandelt werden. Der wichtigste Befund der Datenanalysen ist der Rückgang der Phosphorfrachten der Wulka in den letzten Jahrzehnten, eine ent
Assessing the ecological vulnerability of the shallow steppe Lake Neusiedl (Austria-Hungary) to climate-driven hydrological changes using a palaeolimnological approach
Journal of Great Lakes Research, 2021
Abstract Lake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate v... more Abstract Lake Neusiedl, the largest steppe lake in Europe, is particularly sensitive to climate variations due to its extreme shallowness (zmax = 1.8 m) and low ratio of catchment to lake area (3.5 : 1). Changes in water budget, salinity and turbidity have key implications for the lake’s ecology and management. Here, we present a multi-proxy palaeolimnological reconstruction of the evolution of Lake Neusiedl since the end of its last complete desiccation (1865–1868), based on an undisturbed radiometrically dated core taken from the open water portion of the lake. Geochemical and biological (algal) proxies outline the succession of three major ecological stages since 1873 ± 16 yrs, with the first major changes appearing already in the 1930s as driven by climate related hydrological variability. Subfossil diatoms proved to be reliable for tracking long-term changes in the trophic conditions of Lake Neusiedl while diatom-inferred lake conductivity revealed to be unreliable due to a combination of lake environmental settings and the absence of a site-specific training set. Nonetheless, multivariate statistical analyses and comparisons with limnological data confirm a great potential of subfossil diatoms for revealing past ecological changes and tipping points of shallow lakes, as long as studies rely on a multi-proxy approach. In agreement with limnological surveys, the sediment record corroborates the high vulnerability of Lake Neusiedl, both in present and past times, towards climate-driven changes in water level and salinity, and allows the prediction, by analogy with the past, of future ecological changes in a context of global warming and increasing nutrient inputs from non-point sources.
Artenzusammensetzeung und saisonale Dynamik der Cladocera- und Copepoda-Fauna in künstlichen Natrongewässern
Ciliates and flagellates in shallow saline pans within the area of the Nationalpark Neusiedler See/Seewinkel, Austria
The role of planktonie protozoa as major links in rnatter and energy fluxes within freshwater sys... more The role of planktonie protozoa as major links in rnatter and energy fluxes within freshwater systems has been deseribed by various studies in reeent years. Protozoa are known to be an important food souree for metazoa (WEISSE 1991, SANDERS & WICKHAM 1993) and effeetively transfer pieoplanktonie produetion to higher trophie 1eve1s (FENCHEL 1987, SHERR & SHERR 1987). They ean feed on autotrophie and heterotrophie pieoand nanoplankton (PORTER et al. 1985, SIMEK et al. 1995) and provide dissolved organie material as nutrients to baeteria. Different trophie levels ean even be influeneed simultaneous1y by ornnivorous feeding aetivities in eertain protozoan groups (PFISTER & ARNDT 1998). Some studies have addressed the influenee of different habitats on the pe1agie protozoan eommunities (BEAVER & CRISMAN 1989, PFISTER et al. 2002), but extreme inland waters, sueh as fluetuating saline environments (RUINEN 1938a, 1938b, RUINEN & BAASBECKING 1938, PFISTER et al. 2002) have so far been modes...