Ulrike Obertegger

Ulrike Obertegger
Fondazione Edmund Mach - Istituto Agrario San Michele All'Adige | Fondazione Mach · Department of Sustainable Agro-Ecosystems and Bioresources (DASB)

PhD

About

75
Publications
22,117
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,631
Citations
Citations since 2017
36 Research Items
1212 Citations
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
2017201820192020202120222023050100150200
Additional affiliations
January 2007 - July 2010
Universität Innsbruck
Position
  • PhD Student
June 2002 - present
Fondazione Edmund Mach - Istituto Agrario San Michele All'Adige-CRI
Position
  • Researcher

Publications

Publications (75)
Poster
Full-text available
Body size is a key ecological trait that plays a significant role in determining the functioning of size-structured freshwater communities (e.g., predator-prey interactions, energy transfer). Furthermore, body size change has been posited as a universal response to global warming. Despite previous research efforts, most studies on zooplankton body...
Article
Little is known on the swimming activity and respiration rate of the cyclopoid copepod Cyclops vicinus. Here, the swimming speed and respiration rate of C. vicinus were measured at different temperatures using a high speed (up to 1200 frames per second) camera and a closed-system respirometry, respectively. For cruise and escape swimming, log-linea...
Article
Full-text available
The quality of lake ice is of uppermost importance for ice safety and under-ice ecology, but its temporal and spatial variability is largely unknown. Here we conducted a coordinated lake ice quality sampling campaign across the Northern Hemisphere during one of the warmest winters since 1880 and show that lake ice during 2020/2021 commonly consiste...
Article
Full-text available
Little is known on the dynamics of under-ice phytoplankton communities. We investigated phytoplankton communities in the upper (0–20 m) and lower (30–35 m) layer of oligotrophic Lake Tovel, Brenta Dolomites (Italy) over 6 years during summer and under ice. Winter conditions were different from one year to another with respect to ice thickness and s...
Article
Cyclopoid and calanoid copepods differ in how they move. Cyclopoid copepods use the thoracic legs for cruise and escape swimming while most calanoid copepods use the cephalic appendages for cruise swimming and the thoracic legs for escape reactions. Apart from this gross difference, little is known on the comparative aspects of the locomotor functi...
Article
Full-text available
Under-ice community dynamics are barely understood. Temporal and spatial studies are needed to fully understand the consequences of a declining ice cover on microbial biodiversity. Here, bacterial communities of different years (2015, 2017–2021) and layers (upper and lower euphotic layer, euphotic layer, hypolimnion) were assessed by Illumina seque...
Article
Full-text available
To determine the drivers of phytoplankton biomass, we collected standardized morphometric, physical, and biological data in 230 lakes across the Mediterranean, Continental, and Boreal climatic zones of the European continent. Multilinear regression models tested on this snapshot of mostly eutrophic lakes (median total phosphorus [TP] = 0.06 and tot...
Article
Mountain lakes are the most affected by climate change; however, few of these lakes are regularly sampled because of their remoteness. We discussed limnological data (e.g. water temperature, light transparency, and plankton diversity) of Lake Campo (1944 m above sea level, Adamello Mountains, Italy) scattered over almost forty years in the light of...
Article
• Microscopy and high‐throughput sequencing (HTS) detect and quantify algae differently. It is not known if microscopy‐based abundance or biomass better compare to HTS data or how methodological differences affect ecological inferences about the phytoplankton communities studied. • We investigated methodological (abundancemicroscopy vs. abundanceHT...
Article
Full-text available
A decrease in hypolimnetic dissolved oxygen (DO) is a commonly seen effect of climate change. However, in oligotrophic Lake Tovel (Italy), a deep mountain lake, annual mean DO (% saturation) has increased from near anoxia to >20% in the bottom layer (35–39 m). We analyzed long‐term patterns of DO (1937–2019) using different methods (correlation and...
Article
Full-text available
Swimming is a fundamental trait of many protists and optimizes growth and survival. We present an easy to use set-up for filming algal cells using Apocalathium aciculiferum and Borghiella dodgei as case studies; both dinoflagellates are model organisms of psychrophilic dinoflagellates. We filmed at low temperature (4.5°C) using a digital camera dir...
Article
Full-text available
Many inland waters exhibit complete or partial desiccation, or have vanished due to global change, exposing sediments to the atmosphere. Yet, data on carbon dioxide (CO 2) emissions from these sediments are too scarce to upscale emissions for global estimates or to understand their fundamental drivers. Here, we present the results of a global surve...
Article
Full-text available
Ultra-violet radiation (UVR) is an environmental stressor in several ecosystems and can affect organisms’ survival and reproduction, and community structure. Rotifers cope with UVR stress adopting preventive behavioral and metabolic mechanisms. However, the demonstration of an immediate behavioral response in rotifers is missing. We investigated th...
Article
Community composition of freshwater prokaryotes and protists varies through time. Few studies contemporarily investigate temporal variation of these freshwater communities for more than one year. We compared the temporal patterns of prokaryotes and protists in three distinct habitats for four years (2014‐2017) in Lake Tovel, a cold‐water lake. This...
Article
Most monogonont rotifers usually reproduce by cyclical parthenogenesis. For many rotifer species the factor inducing sexual reproduction is high population density (crowding). While Keratella cochlearis is one of the most ubiquitous monogonont freshwater rotifers, little is known about its reproduction. We provide experimental evidence that the swi...
Article
Global warming is affecting ecosystems worldwide, with mountainous regions particularly vulnerable. At mid-altitudes, changes in winter precipitation will have immediate effects on lake functioning. Lake Tovel (1178 m a.s.l.), a deep (39 m) aquifer-fed lake in the Brenta Dolomites (Italy), showed unusually high water temperatures in 2017. As eviden...
Article
Full-text available
Mougeotia (Zygnematales, Charophyta) first appeared in the plankton of Lake Kinneret in 1998. While initially rare, from 2004 onwards it was present in the plankton continuously, forming massive blooms in spring (2005, 2006, 2012) or in winter (2010), occasionally appearing in different morphological and life cycle forms. Mougeotia maintained its p...
Data
Trajectories of monogonont rotifers (Brachionus calyciflorus, Keratella cochlearis and Keratella quadrata) tested under 3 cycles (30:30 sec) of visible and UVA (380nm) radiation. More information available at the publication https://doi.org/10.1007/s10750-018-3801-y
Article
Full-text available
Community assembly depends on dispersal, environmental parameters and species interactions. Here, we compared rotifer communities from two environmentally distinct, but connected basins of Lake Tovel for 5 years, with biweekly (2002) and monthly (2003–2006) sampling. We applied taxonomic and functional diversity-based multivariate analyses (princip...
Article
Full-text available
Under ongoing climate change and increasing anthropogenic activity, which continuously challenge ecosystem resilience, an in-depth understanding of ecological processes is urgently needed. Lakes, as providers of numerous ecosystem services, face multiple stressors that threaten their functioning. Harmful cyanobacterial blooms are a persistent probl...
Article
Temporal dynamics of bacterioplankton are rarely investigated for multiple habitats and years within individual lakes, limiting our understanding of the variability of bacterioplankton community (BC) composition with respect to environmental factors. We assessed the BC composition of a littoral and two pelagic habitats (euphotic zone and hypolimnio...
Article
Swimming is of vital importance for aquatic organisms because it determines several aspects of fitness, such as encounter rates with food, predators, and mates. Generally, rotifer swimming speed is measured by manual tracking of the swimming paths filmed in videos. Recently, an open-source package has been developed that integrates different open-s...
Article
Full-text available
Insight into how environmental change determines the production and distribution of cyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus on hepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g., anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to thei...
Article
Full-text available
A recent study based on DNA taxonomy indicated that the widespread rotifer Keratella cochlearis comprises several evolutionarily significant units (ESUs). Identification of ESUs based on DNA taxonomy alone is problematic and usually requires morphological, demographic, and/or ecological evidence. We isolated three haplotypes belonging to two ESUs o...
Article
Full-text available
Insight into how environmental change determines the production and distribution ofcyanobacterial toxins is necessary for risk assessment. Management guidelines currently focus onhepatotoxins (microcystins). Increasing attention is given to other classes, such as neurotoxins (e.g.,anatoxin-a) and cytotoxins (e.g., cylindrospermopsin) due to their p...
Article
A first synoptic and trans-domain overviewof plankton dynamics was conducted across the aquatic sites belonging to the Italian Long-Term Ecological Research Network (LTER-Italy). Based on published studies, checked and complemented with unpublished information, we investigated phytoplankton and zooplankton annual dynamics and long-term changes acro...
Article
Discordance between mitochondrial and nuclear phylogenies is being increasingly recognized in animals and may confound DNA-based taxonomy. This is especially relevant for taxa whose microscopic size often challenges any effort to distinguish between cryptic species without the assistance of molecular data. Regarding mitonuclear discordance, two str...
Article
We describe Stammericaris destillans sp. nov., and re-describe Stammericaris trinacriae (Pesce, Galassi and Cottarelli 1988) based on new material. The two species were collected from epikarstic drips and pools on the floor of two different caves: a karstic (Molara Cave) and a gypsum (Entella Cave) cave, respectively, both located in Sicily, Italy....
Article
Under-ice dissolved oxygen (DO) metabolism and DO depletion are poorly understood, limiting our ability to predict how changing winter conditions will affect lake ecosystems. We analyzed under-ice DO dynamics based on high frequency (HF) data at two depths (5 and 25 m) for three winters (January to March 2014, 2015, and 2016) in oligotrophic Lake T...
Article
Full-text available
Rotifers are ubiquitous freshwater animals for which many complexes of cryptic species (i.e. distinct species that are morphologically difficult to distinguish) are described. Keratella cochlearis occurs globally and shows a wide phenotypic diversity indicating the potential presence of a species complex. We sampled lakes of the Trentino-South Tyro...
Article
During recent decades, climate change and re-oligotrophication have been affecting many lakes. Most long-term research focuses on large North American and northern European lakes, but climate forcing south of the Alps seems to be different. Furthermore, lake restoration frequently involves smaller lakes (<10 km²) that are often overlooked in long-t...
Article
Full-text available
Here we report the lipid profiles of ten dinoflagellate species originating from different freshwater habitats and grown at 4, 13, or 20°C akin to their natural occurrence. Lipids were determined by High Performance Liquid Chromatography-ElectroSpray Ionization-Mass Spectrometry in positive and negative ion modes. Besides the well-studied monogalac...
Article
Full-text available
Filming live organisms can give new insights into the hidden life of plankton. Accessibly priced digital cameras are now available for a large range of users. Here, we demonstrate the technical setup and workflow of using a single-lens reflex (DSLR) camera to film the behaviour of males of two rotifer species, Brachionus angularis Gosse (1851) and...
Article
Trait patterns can give insights into how communities assemble under a functional perspective. We constructed a rotifer trait matrix related to food acquisition and predator defence and calculated Rao’s quadratic entropy (Q) as an index of functional diversity to investigate trait patterns in different layers (0–2, 5–35, 0–35 m) for a 5-year datase...
Article
Full-text available
We explored phytoplankton communities from a functional perspective in two connected but hydro-morphologically distinct basins during the ice-free period in the cold and oligotrophic Lake Tovel, Italy. Despite the absence of dispersal barriers, we expected a clear separation of the phytoplankton communities between basins based on their physical di...
Article
Full-text available
We explored phytoplankton communities from a functional perspective in two connected but hydro-morphologically distinct basins during the ice-free period in the cold and oligotrophic Lake Tovel, Italy. Despite the absence of dispersal barriers, we expected a clear separation of the phytoplankton communities between basins based on their physical di...
Article
Cryptic species (species that are difficult or impossible to distinguish morphologically) are found worldwide and neglecting them may hamper our understanding of species-environment relationships. The rotifer Polyarthra dolichoptera occurs across wide environmental gradients, indicating the potential for a cryptic species complex. We used P. dolich...
Data
. Specimen collection information and accessions numbers for the sequences generated for this study. Table S2. Summary information for each of the 13 datasets, including number of sequences, number of unique haplotypes, estimated diversity, constancy of diversification statistics, estimated ages, and accessions. Table S3. Intra- and interspecific d...
Article
Full-text available
Why organisms diversify into discrete species instead of showing a continuum of genotypic and phenotypic forms is an important yet rarely studied question in speciation biology. Does species discreteness come from adaptation to fill discrete niches or from interspecific gaps generated by reproductive isolation? We investigate the importance of repr...
Article
Life at low temperature imposes many constraints linked to sustaining cellular functions. The cold-adapted freshwater dinoflagellate Peridinium aciculiferum has overcome these barriers, often causing blooms in winter but forming resting cysts in spring. Little is known of the biochemical changes that accompany this temperature-induced transformatio...
Article
Altitude encompasses broad environmental gradients that influence the isotopic composition of lake water. We selected 55 lakes in the Eastern Alps along an altitudinal gradient [214–2,532 m above sea level (a.s.l.)] to model the isotopic signal of surface water dependent on intrinsic (lake geomorphometry) and extrinsic (air temperature, precipitati...
Article
The freshwater dinoflagellate Borghiella dodgei is adapted to cold temperatures. We investigated the effects of small temperature changes on its galactolipid composition, choosing 3 and 7°C as deviations from its optimal growth temperature (5°C). The galactolipid profile, important for maintenance of membrane fluidity, was determined by liquid chro...
Article
Full-text available
Molecular tools have revolutionized the exploration of biodiversity, especially in organisms for which traditional taxonomy is difficult, such as for microscopic animals (meiofauna). Environmental (eDNA) metabarcode surveys of DNA extracted from sediment samples are increasingly popular for surveying biodiversity. Most eDNA surveys use the nuclear...
Article
Summary1. The occurrence of unresolved complexes of cryptic species may hinder the identification of the main ecological drivers of biodiversity when different cryptic taxa have different ecological requirements.2. We assessed factors influencing the occurrence of Synchaeta species (monogonont rotifers) in 17 waterbodies of the Trentino‐South Tyrol...
Article
Full-text available
Identification of Ameles species is a difficult task requiring much experience because of ambiguous descriptions with few drawings and great intraspecific morphological variability. Our objective was to find characteristics that could be reliably used for species identification and would be independent of experience. We identified 12 to 60 specimen...
Article
Full-text available
Patterns of diversity reflect the balance between speciation and extinction over time. Here we estimate net diversification rates for samples of sexual and asexual rotifers using phylogenetic reconstructions from sequence data of one mtDNA locus, cytochrome oxidase c subunit I. All four clades of bdelloid rotifers, obligate asexuals, had higher num...
Article
Full-text available
Information based on taxon-based indices is species-specific while information gained from function-based research can give a comprehensive view of ecosystem processes. We applied the guild-ratio, an index based on the proportion of functional groups of rotifers (i.e. microphagous and raptorial species), on a long-term data set of Lago Maggiore. By...
Article
Little is known about the UV photobiology of psychrophilic dinoflagellates, particularly in freshwater systems. We addressed the life strategies of Borghiella dodgei Moestrup, Gert. Hansen et Daugbjerg to cope with ambient levels of ultraviolet radiation (UVR) under cold conditions. Several physiological parameters related to growth, metabolism, an...
Article
Ecological research is moving from a species-based to a functional-based approach to better understand the underlying principles that govern community dynamics. Studies of functional-based ecology, however, have been limited for zooplankton and particularly for rotifers. While rotifers show a variety of trophi types and coronal shapes, suggesting t...
Article
Aim Biodiversity patterns along altitudinal gradients are less studied in aquatic than terrestrial systems, even though aquatic sites provide a more homogeneous environment independent of moisture constraints. We studied the altitudinal species richness pattern for planktonic rotifers in freshwater lakes and identified the environmental predictors...
Article
Full-text available
Zooplankton abundance was related to hydrological and environmental variables in a hydrologically dynamic lake fed by a pseudokarstic aquifer. The study period (2002–2006) in Lake Tovel covered different hydrological situations with water residence time (WRT) having the lowest values in 2002 and the highest values in 2003. WRT was negatively correl...
Article
Full-text available
Stable isotopes offer an opportunity to investigate lake dynamics in the absence of whole catchment studies. This study considered multi-year δ18O values for six different lakes located in the Italian Alps. We studied δ18O values of two large (L. Caldonazzo and L. Levico) and four small lakes (L. Lavarone, L. Santo di Cembra, L. Serraia, and L. Tov...
Article
In Lake Tovel, an oligotrophic and weakly stratified lake, the dinoflagellate Borghiella dodgei Moestrup, Hansen et Daugbjerg, showed a peculiar spatial–temporal pattern with highest abundances in the bottom of the shallow side bay (4m) along with remarkable abundance variations from year to year. We investigated B. dodgei’s growth in laboratory cu...
Article
Rotifer preference for the upper (0–2 m) or deeper layer (5–35 m) of the water column was assessed at midday and midnight in an oligotrophic mountain lake during summer, and related to temperature, food availability, presence of predators and exposure to solar ultraviolet radiation (UVR). Whereas Keratella cochlearis and Synchaeta pectinata showed...
Article
Full-text available
We studied zooplankton dynamics in a groundwater-fed, montane lake during four consec-utive years and assessed the importance of water residence time for zooplankton dynamics. Crustacean abundance and biomass were significantly correlated with water residence time and temperature, but showed no significant correlation with phytoplankton biovolume....
Article
A study of temporal and spatial distribution of zooplankton frequently requires identification to species level. In such studies, samples are usually fixed, but according to different authors rotifer genera such as Synchaeta (Ehrenberg, 1832) can only be identified in live samples. A procedure for the identification of preserved specimens of Syncha...
Article
To determine the importance of Al-availability for soil micro-organisms 95 forest soils from Tyrol/Austria with comparable topography, vegetation, climatic conditions, soil type and with low soil pH (median = 3.9) were investigated for their physical (percentage of stable aggregates, water holding capacity), chemical (pH, electrical conductivity, c...
Article
To determine the importance of Al-availability for soil micro-organisms 95 forest soils from Tyrol/Austria with comparable topography, vegetation, climatic conditions, soil type and with low soil pH (median = 3.9) were investigated for their physical (percentage of stable aggregates, water holding capacity), chemical (pH, electrical conductivity, c...
Article
Full-text available
Presence of the genus Synchaeta EhrEnbErg, 1832 (Rotifera: Monogononta: Synchaetidae) in lakes of South-Tyrol The rotifer genus Synchaeta is widespread in temperate lakes, but is seldom identified to species level because of identification difficulties. In summer 2006, zooplankton samples from 82 montane as well as alpine lakes of South-Tyrol were...

Questions

Question (1)
Question
Hi Veronika, do you also plan to do some genetic research on rotifer egg bank? e.g. to see if the haplotypes of rotifers did change or not?  all the best from Italy, Ulrike

Network

Cited By

Projects

Project (1)
Project
My PhD project is about high genetic and morphological diversity of the rotifer Keratella cochlearis in Alpine lakes. I also study reproduction patterns and male induction in various cryptic species of K. cochlearis.