@article{TittelBorkRoepkeetal.2000, author = {Tittel, J{\"o}rg and Bork, Rudolf and R{\"o}pke, Bj{\"o}rn and Geldmacher, Karl and Schnur, Tilo and Faust, Berno and Schaphoff, Sibyll and Dalchow, Claus and Woithe, Franka and Bronstert, Axel and Jeltsch, Florian and Jessel, Beate and Zschalich, Andrea and R{\"o}ßling, Holger and Spindler, Joris and Gaedke, Ursula and Tielb{\"o}rger, Katja and Kadmon, R. and M{\"u}ller, J. and Bissinger, Vera and Weithoff, Guntram and Wallschl{\"a}ger, Hans-Dieter and Wiegleb, Gerhard}, title = {Umweltforschung f{\"u}r das Land Brandenburg}, series = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, volume = {8}, journal = {Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakult{\"a}t der Universit{\"a}t Potsdam}, issn = {1434-2375}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-3828}, pages = {80 -- 134}, year = {2000}, abstract = {BISSINGER, V.; TITTEL, J.: Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 - 3) mining lakes in Germany ; BORK, H.-R. et al.: Erodierte Autos und Brunnen in Oregon, USA ; BRONSTERT, A. et al.: Bewirtschaftunsm{\"o}glichkeiten im Einzugsgebiet der Havel ; JELTSCH, F. et al.: Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen ; JELTSCH, F. et al.: Entstehung und Bedeutung r{\"a}umlicher Vegetationsstrukturen in Trockensavannen: Baum-Graskoexistenz und Artenvielfalt ; JESSEL, B. et al.: Bodenbewertung f{\"u}r Planungs- und Zulassungsverfahren in Brandenburg ; JESSEL, B.; ZSCHALICH, A.: Erarbeitung von Ausgleichs- und Ersatzmaßnahmen f{\"u}r die Wert- und Funktionselemente des Landschaftsbildes ; R{\"O}ßLING, H. et al.: Umsetzung von Ausgleichs- und Ersatzmaßnahmen beim Ausbau der Bundesautobahn A 9 ; SPINDLER, J.; GAEDKE, U.: Estimating production in plankton food webs from biomass size spectra and allometric relationships ; TIELB{\"O}RGER, K. et al.: Sukzessionsprozesse in einem Sandd{\"u}nengebiet nach Ausschluß von Beweidung ; TIELB{\"O}RGER, K. et al.: Populationsdynamische Funktionen von Ausbreitung und Dormanz ; TIELB{\"O}RGER, K. et al.: Raum-zeitliche Populationsdynamik von einj{\"a}hrigen W{\"u}stenpflanzen ; TITTEL, J. et al.: Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees ; WALLSCHL{\"A}GER, D.; WIEGLEB, G.: Offenland-Management auf ehemaligen und in Nutzung befindlichen Truppen{\"u}bungspl{\"a}tzen im pleistoz{\"a}nen Flachland Nordostdeutschlands: Naturschutzfachliche Grundlagen und praktische Anwendungen ; WEITHOFF, G.; GAEDKE, U.: Planktische R{\"a}uber-Beute-Systeme: Experimentelle Untersuchung von {\"o}kologischen Synchronisationen}, language = {de} } @article{WeithoffBell2022, author = {Weithoff, Guntram and Bell, Elanor Margaret}, title = {Complex Trophic Interactions in an Acidophilic Microbial Community}, series = {Microorganisms}, volume = {10}, journal = {Microorganisms}, edition = {7}, publisher = {MDPI}, address = {Basel, Schweiz}, issn = {2076-2607}, doi = {10.3390/microorganisms10071340}, pages = {1 -- 10}, year = {2022}, abstract = {Extreme habitats often harbor specific communities that differ substantially from non-extreme habitats. In many cases, these communities are characterized by archaea, bacteria and protists, whereas the number of species of metazoa and higher plants is relatively low. In extremely acidic habitats, mostly prokaryotes and protists thrive, and only very few metazoa thrive, for example, rotifers. Since many studies have investigated the physiology and ecology of individual species, there is still a gap in research on direct, trophic interactions among extremophiles. To fill this gap, we experimentally studied the trophic interactions between a predatory protist (Actinophrys sol, Heliozoa) and its prey, the rotifers Elosa woralli and Cephalodella sp., the ciliate Urosomoida sp. and the mixotrophic protist Chlamydomonas acidophila (a green phytoflagellate, Chlorophyta). We found substantial predation pressure on all animal prey. High densities of Chlamydomonas acidophila reduced the predation impact on the rotifers by interfering with the feeding behaviour of A. sol. These trophic relations represent a natural case of intraguild predation, with Chlamydomonas acidophila being the common prey and the rotifers/ciliate and A. sol being the intraguild prey and predator, respectively. We further studied this intraguild predation along a resource gradient using Cephalodella sp. as the intraguild prey. The interactions among the three species led to an increase in relative rotifer abundance with increasing resource (Chlamydomonas) densities. By applying a series of laboratory experiments, we revealed the complexity of trophic interactions within a natural extremophilic community.}, language = {en} } @article{PawlakNoetzelDragoetal.2022, author = {Pawlak, Julia and Noetzel, Dominique Christian and Drago, Claudia and Weithoff, Guntram}, title = {Assessing the toxicity of polystyrene beads and silica particles on the microconsumer Brachionus calyciflorus at different timescales}, series = {Frontiers in Environmental Science}, journal = {Frontiers in Environmental Science}, publisher = {Frontiers}, address = {Lausanne, Schweiz}, issn = {2296-665X}, doi = {10.3389/fenvs.2022.955425}, pages = {1 -- 11}, year = {2022}, abstract = {Environmental pollution by microplastics has become a severe problem in terrestrial and aquatic ecosystems and, according to actual prognoses, problems will further increase in the future. Therefore, assessing and quantifying the risk for the biota is crucial. Standardized short-term toxicological procedures as well as methods quantifying potential toxic effects over the whole life span of an animal are required. We studied the effect of the microplastic polystyrene on the survival and reproduction of a common freshwater invertebrate, the rotifer Brachionus calyciflorus, at different timescales. We used pristine polystyrene spheres of 1, 3, and 6 µm diameter and fed them to the animals together with food algae in different ratios ranging from 0 to 50\% nonfood particles. As a particle control, we used silica to distinguish between a pure particle effect and a plastic effect. After 24 h, no toxic effect was found, neither with polystyrene nor with silica. After 96 h, a toxic effect was detectable for both particle types. The size of the particles played a negligible role. Studying the long-term effect by using life table experiments, we found a reduced reproduction when the animals were fed with 3 µm spheres together with similar-sized food algae. We conclude that the fitness reduction is mainly driven by the dilution of food by the nonfood particles rather than by a direct toxic effect.}, language = {en} } @article{KiemelGurkeParaskevopoulouetal.2022, author = {Kiemel, Katrin and Gurke, Marie and Paraskevopoulou, Sofia and Havenstein, Katja and Weithoff, Guntram and Tiedemann, Ralph}, title = {Variation in heat shock protein 40 kDa relates to divergence in thermotolerance among cryptic rotifer species}, series = {Scientific Reports}, volume = {12}, journal = {Scientific Reports}, publisher = {Springer Nature}, address = {London}, issn = {2045-2322}, doi = {10.1038/s41598-022-27137-3}, pages = {14}, year = {2022}, abstract = {Genetic divergence and the frequency of hybridization are central for defining species delimitations, especially among cryptic species where morphological differences are merely absent. Rotifers are known for their high cryptic diversity and therefore are ideal model organisms to investigate such patterns. Here, we used the recently resolved Brachionus calyciflorus species complex to investigate whether previously observed between species differences in thermotolerance and gene expression are also reflected in their genomic footprint. We identified a Heat Shock Protein gene (HSP 40 kDa) which exhibits cross species pronounced sequence variation. This gene exhibits species-specific fixed sites, alleles, and sites putatively under positive selection. These sites are located in protein binding regions involved in chaperoning and may therefore reflect adaptive diversification. By comparing three genetic markers (ITS, COI, HSP 40 kDa), we revealed hybridization events between the cryptic species. The low frequency of introgressive haplotypes/alleles suggest a tight, but not fully impermeable boundary between the cryptic species.}, language = {en} }