@phdthesis{Bajerski2013, author = {Bajerski, Felizitas}, title = {Bacterial communities in glacier forefields of the Larsemann Hills, East Antarctica : structure, development \& adaptation}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-67424}, school = {Universit{\"a}t Potsdam}, year = {2013}, abstract = {Antarctic glacier forfields are extreme environments and pioneer sites for ecological succession. The Antarctic continent shows microbial community development as a natural laboratory because of its special environment, geographic isolation and little anthropogenic influence. Increasing temperatures due to global warming lead to enhanced deglaciation processes in cold-affected habitats and new terrain is becoming exposed to soil formation and accessible for microbial colonisation. This study aims to understand the structure and development of glacier forefield bacterial communities, especially how soil parameters impact the microorganisms and how those are adapted to the extreme conditions of the habitat. To this effect, a combination of cultivation experiments, molecular, geophysical and geochemical analysis was applied to examine two glacier forfields of the Larsemann Hills, East Antarctica. Culture-independent molecular tools such as terminal restriction length polymorphism (T-RFLP), clone libraries and quantitative real-time PCR (qPCR) were used to determine bacterial diversity and distribution. Cultivation of yet unknown species was carried out to get insights in the physiology and adaptation of the microorganisms. Adaptation strategies of the microorganisms were studied by determining changes of the cell membrane phospholipid fatty acid (PLFA) inventory of an isolated bacterium in response to temperature and pH fluctuations and by measuring enzyme activity at low temperature in environmental soil samples. The two studied glacier forefields are extreme habitats characterised by low temperatures, low water availability and small oligotrophic nutrient pools and represent sites of different bacterial succession in relation to soil parameters. The investigated sites showed microbial succession at an early step of soil formation near the ice tongue in comparison to closely located but rather older and more developed soil from the forefield. At the early step the succession is influenced by a deglaciation-dependent areal shift of soil parameters followed by a variable and prevalently depth-related distribution of the soil parameters that is driven by the extreme Antarctic conditions. The dominant taxa in the glacier forefields are Actinobacteria, Acidobacteria, Proteobacteria, Bacteroidetes, Cyanobacteria and Chloroflexi. The connection of soil characteristics with bacterial community structure showed that soil parameter and soil formation along the glacier forefield influence the distribution of certain phyla. In the early step of succession the relative undifferentiated bacterial diversity reflects the undifferentiated soil development and has a high potential to shift according to past and present environmental conditions. With progressing development environmental constraints such as water or carbon limitation have a greater influence. Adapting the culturing conditions to the cold and oligotrophic environment, the number of culturable heterotrophic bacteria reached up to 108 colony forming units per gram soil and 148 isolates were obtained. Two new psychrotolerant bacteria, Herbaspirillum psychrotolerans PB1T and Chryseobacterium frigidisoli PB4T, were characterised in detail and described as novel species in the family of Oxalobacteraceae and Flavobacteriaceae, respectively. The isolates are able to grow at low temperatures tolerating temperature fluctuations and they are not specialised to a certain substrate, therefore they are well-adapted to the cold and oligotrophic environment. The adaptation strategies of the microorganisms were analysed in environmental samples and cultures focussing on extracellular enzyme activity at low temperature and PLFA analyses. Extracellular phosphatases (pH 11 and pH 6.5), β-glucosidase, invertase and urease activity were detected in the glacier forefield soils at low temperature (14°C) catalysing the conversion of various compounds providing necessary substrates and may further play a role in the soil formation and total carbon turnover of the habitat. The PLFA analysis of the newly isolated species C. frigidisoli showed that the cold-adapted strain develops different strategies to maintain the cell membrane function under changing environmental conditions by altering the PLFA inventory at different temperatures and pH values. A newly discovered fatty acid, which was not found in any other microorganism so far, significantly increased at decreasing temperature and low pH and thus plays an important role in the adaption of C. frigidisoli. This work gives insights into the diversity, distribution and adaptation mechanisms of microbial communities in oligotrophic cold-affected soils and shows that Antarctic glacier forefields are suitable model systems to study bacterial colonisation in connection to soil formation.}, language = {en} } @misc{BoettleRybskiKropp2016, author = {Boettle, Markus and Rybski, Diego and Kropp, J{\"u}rgen}, title = {Quantifying the effect of sea level rise and flood defence}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {559}, issn = {1866-8372}, doi = {10.25932/publishup-41240}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-412405}, pages = {18}, year = {2016}, abstract = {In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage typically increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage.}, language = {en} } @article{BreitkopfSchlueterXuetal.2013, author = {Breitkopf, Hendrik and Schl{\"u}ter, P. M. and Xu, S. and Schiestl, Florian P. and Cozzolino, S. and Scopece, G.}, title = {Pollinator shifts between Ophrys sphegodes populations: might adaptation to different pollinators drive population divergence?}, series = {Journal of evolutionary biology}, volume = {26}, journal = {Journal of evolutionary biology}, number = {10}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {1010-061X}, doi = {10.1111/jeb.12216}, pages = {2197 -- 2208}, year = {2013}, abstract = {Local adaptation to different pollinators is considered one of the possible initial stages of ecological speciation as reproductive isolation is a by-product of the divergence in pollination systems. However, pollinator-mediated divergent selection will not necessarily result in complete reproductive isolation, because incipient speciation is often overcome by gene flow. We investigated the potential of pollinator shift in the sexually deceptive orchids Ophrys sphegodes and Ophrys exaltata and compared the levels of floral isolation vs. genetic distance among populations with contrasting predominant pollinators. We analysed floral hydrocarbons as a proxy for floral divergence between populations. Floral adoption of pollinators and their fidelity was tested using pollinator choice experiments. Interpopulation gene flow and population differentiation levels were estimated using AFLP markers. The Tyrrhenian O.sphegodes population preferentially attracted the pollinator bee Andrena bimaculata, whereas the Adriatic O.sphegodes population exclusively attracted A.nigroaenea. Significant differences in scent component proportions were identified in O.sphegodes populations that attracted different preferred pollinators. High interpopulation gene flow was detected, but populations were genetically structured at species level. The high interpopulation gene flow levels independent of preferred pollinators suggest that local adaptation to different pollinators has not (yet) generated detectable genome-wide separation. Alternatively, despite extensive gene flow, few genes underlying floral isolation remain differentiated as a consequence of divergent selection. Different pollination ecotypes in O.sphegodes might represent a local selective response imposed by temporal variation in a geographical mosaic of pollinators as a consequence of the frequent disturbance regimes typical of Ophrys habitats.}, language = {en} } @misc{BubeckAertsdeMoeletal.2016, author = {Bubeck, Philip and Aerts, Jeroen C. J. H. and de Moel, Hans and Kreibich, Heidi}, title = {Preface}, series = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, journal = {Postprints der Universit{\"a}t Potsdam : Mathematisch-Naturwissenschaftliche Reihe}, number = {609}, issn = {1866-8372}, doi = {10.25932/publishup-41238}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-412387}, pages = {6}, year = {2016}, abstract = {kein abstract}, language = {en} } @misc{CampbellHofreiter2015, author = {Campbell, Kevin L. and Hofreiter, Michael}, title = {Resurrecting phenotypes from ancient DNA sequences: promises and perspectives}, series = {Canadian journal of zoology = Revue canadienne de zoologie}, volume = {93}, journal = {Canadian journal of zoology = Revue canadienne de zoologie}, number = {9}, publisher = {NRC Research Press}, address = {Ottawa}, issn = {0008-4301}, doi = {10.1139/cjz-2014-0337}, pages = {701 -- 710}, year = {2015}, abstract = {Anatomical changes in extinct mammalian lineages over evolutionary time, such as the loss of fingers and teeth and the rapid increase in body size that accompanied the late Miocene dispersal of the progenitors of Steller's sea cows (Hydrodamalis gigas (Zimmermann, 1780)) into North Pacific waters and the convergent development of a thick pelage and accompanying reductions in ear and tail surface area of woolly mammoths (Mammuthus primigenius (Blumenbach, 1799)) and woolly rhinoceros (Coelodonta antiquitatis (Blumenbach, 1799)), are prime examples of adaptive evolution underlying the exploitation of new habitats. It is likely, however, that biochemical specializations adopted during these evolutionary transitions were of similar or even greater biological importance. As these "living" processes do not fossilize, direct information regarding the physiological attributes of extinct species has largely remained beyond the range of scientific inquiry. However, the ability to retrieve genomic sequences from ancient DNA samples, combined with ectopic expression systems, now permit the evolutionary origins and structural and functional properties of authentic prehistoric proteins to be examined in great detail. Exponential technical advances in ancient DNA retrieval, enrichment, and sequencing will soon permit targeted generation of complete genomes from hundreds of extinct species across the last one million years that, in combination with emerging in vitro expression, genome engineering, and cell differentiation techniques, promises to herald an exciting new trajectory of evolutionary research at the interface of biochemistry, genomics, palaeontology, and cell biology.}, language = {en} } @article{DellingerEsslHojsgaardetal.2016, author = {Dellinger, Agnes S. and Essl, Franz and Hojsgaard, Diego and Kirchheimer, Bernhard and Klatt, Simone and Dawson, Wayne and Pergl, Jan and Pysek, Petr and van Kleunen, Mark and Weber, Ewald and Winter, Marten and Hoerandl, Elvira and Dullinger, Stefan}, title = {Niche dynamics of alien species do not differ among sexual and apomictic flowering plants}, series = {New phytologist : international journal of plant science}, volume = {209}, journal = {New phytologist : international journal of plant science}, publisher = {Wiley-Blackwell}, address = {Hoboken}, issn = {0028-646X}, doi = {10.1111/nph.13694}, pages = {1313 -- 1323}, year = {2016}, abstract = {We compiled global occurrence data sets of 13 congeneric sexual and apomictic species pairs, and used principal components analysis (PCA) and kernel smoothers to compare changes in climatic niche optima, breadths and unfilling/expansion between native and alien ranges. Niche change metrics were compared between sexual and apomictic species. All 26 species showed changes in niche optima and/or breadth and 14 species significantly expanded their climatic niches. However, we found no effect of the reproductive system on niche dynamics. Instead, species with narrower native niches showed higher rates of niche expansion in the alien ranges. Our results suggest that niche shifts are frequent in plant invasions but evolutionary potential may not be of major importance for such shifts. Niche dynamics rather appear to be driven by changes of the realized niche without adaptive change of the fundamental climatic niche.}, language = {en} } @phdthesis{Derežanin2023, author = {Derežanin, Lorena}, title = {Contribution of structural variation to adaptive evolution of mammalian genomes}, doi = {10.25932/publishup-59144}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus4-591443}, school = {Universit{\"a}t Potsdam}, pages = {188}, year = {2023}, abstract = {Following the extinction of dinosaurs, the great adaptive radiation of mammals occurred, giving rise to an astonishing ecological and phenotypic diversity of mammalian species. Even closely related species often inhabit vastly different habitats, where they encounter diverse environmental challenges and are exposed to different evolutionary pressures. As a response, mammals evolved various adaptive phenotypes over time, such as morphological, physiological and behavioural ones. Mammalian genomes vary in their content and structure and this variation represents the molecular mechanism for the long-term evolution of phenotypic variation. However, understanding this molecular basis of adaptive phenotypic variation is usually not straightforward. The recent development of sequencing technologies and bioinformatics tools has enabled a better insight into mammalian genomes. Through these advances, it was acknowledged that mammalian genomes differ more, both within and between species, as a consequence of structural variation compared to single-nucleotide differences. Structural variant types investigated in this thesis - such as deletion, duplication, inversion and insertion, represent a change in the structure of the genome, impacting the size, copy number, orientation and content of DNA sequences. Unlike short variants, structural variants can span multiple genes. They can alter gene dosage, and cause notable gene expression differences and subsequently phenotypic differences. Thus, they can lead to a more dramatic effect on the fitness (reproductive success) of individuals, local adaptation of populations and speciation. In this thesis, I investigated and evaluated the potential functional effect of structural variations on the genomes of mustelid species. To detect the genomic regions associated with phenotypic variation I assembled the first reference genome of the tayra (Eira barbara) relying on linked-read sequencing technology to achieve a high level of genome completeness important for reliable structural variant discovery. I then set up a bioinformatics pipeline to conduct a comparative genomic analysis and explore variation between mustelid species living in different environments. I found numerous genes associated with species-specific phenotypes related to diet, body condition and reproduction among others, to be impacted by structural variants. Furthermore, I investigated the effects of artificial selection on structural variants in mice selected for high fertility, increased body mass and high endurance. Through selective breeding of each mouse line, the desired phenotypes have spread within these populations, while maintaining structural variants specific to each line. In comparison to the control line, the litter size has doubled in the fertility lines, individuals in the high body mass lines have become considerably larger, and mice selected for treadmill performance covered substantially more distance. Structural variants were found in higher numbers in these trait-selected lines than in the control line when compared to the mouse reference genome. Moreover, we have found twice as many structural variants spanning protein-coding genes (specific to each line) in trait-selected lines. Several of these variants affect genes associated with selected phenotypic traits. These results imply that structural variation does indeed contribute to the evolution of the selected phenotypes and is heritable. Finally, I suggest a set of critical metrics of genomic data that should be considered for a stringent structural variation analysis as comparative genomic studies strongly rely on the contiguity and completeness of genome assemblies. Because most of the available data used to represent reference genomes of mammalian species is generated using short-read sequencing technologies, we may have incomplete knowledge of genomic features. Therefore, a cautious structural variation analysis is required to minimize the effect of technical constraints. The impact of structural variants on the adaptive evolution of mammalian genomes is slowly gaining more focus but it is still incorporated in only a small number of population studies. In my thesis, I advocate the inclusion of structural variants in studies of genomic diversity for a more comprehensive insight into genomic variation within and between species, and its effect on adaptive evolution.}, language = {en} } @article{DerežaninBlažytėDobryninetal.2022, author = {Derežanin, Lorena and Blažytė, Asta and Dobrynin, Pavel and Duch{\^e}ne, David A. and Grau, Jos{\´e} Horacio and Jeon, Sungwon and Kliver, Sergei and Koepfli, Klaus-Peter and Meneghini, Dorina and Preick, Michaela and Tomarovsky, Andrey and Totikov, Azamat and Fickel, J{\"o}rns and F{\"o}rster, Daniel W.}, title = {Multiple types of genomic variation contribute to adaptive traits in the mustelid subfamily Guloninae}, series = {Molecular ecology}, volume = {31}, journal = {Molecular ecology}, number = {10}, publisher = {Wiley}, address = {Hoboken}, issn = {0962-1083}, doi = {10.1111/mec.16443}, pages = {2898 -- 2919}, year = {2022}, abstract = {Species of the mustelid subfamily Guloninae inhabit diverse habitats on multiple continents, and occupy a variety of ecological niches. They differ in feeding ecologies, reproductive strategies and morphological adaptations. To identify candidate loci associated with adaptations to their respective environments, we generated a de novo assembly of the tayra (Eira barbara), the earliest diverging species in the subfamily, and compared this with the genomes available for the wolverine (Gulo gulo) and the sable (Martes zibellina). Our comparative genomic analyses included searching for signs of positive selection, examining changes in gene family sizes and searching for species-specific structural variants. Among candidate loci associated with phenotypic traits, we observed many related to diet, body condition and reproduction. For example, for the tayra, which has an atypical gulonine reproductive strategy of aseasonal breeding, we observed species-specific changes in many pregnancy-related genes. For the wolverine, a circumpolar hypercarnivore that must cope with seasonal food scarcity, we observed many changes in genes associated with diet and body condition. All types of genomic variation examined (single nucleotide polymorphisms, gene family expansions, structural variants) contributed substantially to the identification of candidate loci. This argues strongly for consideration of variation other than single nucleotide polymorphisms in comparative genomics studies aiming to identify loci of adaptive significance.}, language = {en} } @misc{Hallermeier2011, type = {Master Thesis}, author = {Hallermeier, Larissa Diane}, title = {K{\"u}sten und Klimawandel in den Augen von Touristen : eine Wahrnehmungsanalyse an der deutschen Ostsee}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:517-opus-53855}, school = {Universit{\"a}t Potsdam}, year = {2011}, abstract = {Aufgrund seiner wirtschaftlichen Bedeutung spielt der Tourismus in Mecklenburg-Vorpommern eine große Rolle. Insbesondere die K{\"u}stengebiete sind beliebte Reiseziele. In den letzten Jahren konnte ein kontinuierlicher Anstieg der Ank{\"u}nfte und {\"U}bernachtungen verzeichnet werden. Neben anderen Faktoren werden die regionalen Auswirkungen des Klimawandels jedoch in Zukunft eine Herausforderung f{\"u}r den Tourismussektor darstellen. Die globale Erw{\"a}rmung wird f{\"u}r den Strand- und Badetourismus sowohl negative, als auch positive Folgen haben, auf die reagiert werden muss. Neben vorbeugenden Klimaschutzmaßnahmen werden k{\"u}nftig auch Anpassungsstrategien entwickelt werden m{\"u}ssen, die den zu erwartenden Ver{\"a}nderungen Rechnung tragen. Doch zu welchen tourismusrelevanten Ver{\"a}nderungen wird es {\"u}berhaupt kommen und was geschieht bereits aktuell? Sind die Folgen des Klimawandels durch Touristen schon jetzt wahrnehmbar? Wie reagieren die Urlauber auf eventuelle Ver{\"a}nderungen? Diese und andere Fragen soll die vorliegende Arbeit, die innerhalb des RAdOST-Vorhabens (Regionale Anpassungsstrategien f{\"u}r die deutsche Ostseek{\"u}ste) angesiedelt ist, beantworten. Dazu wurde zum einen eine Literaturrecherche zu tourismusrelevanten Klimawandelfolgen an der deutschen Ostseek{\"u}ste durchgef{\"u}hrt. Zum anderen erfolgte in den Sommermonaten 2010 eine Befragung der Strandg{\"a}ste in Markgrafenheide, Warnem{\"u}nde und Nienhagen an der mecklenburgischen Ostseek{\"u}ste. Im Mittelpunkt der Umfrage stand die Wahrnehmung von Erscheinungen (z.B. viele Quallen oder warmes Ostseewasser) sowie kurz- oder langfristigen Ver{\"a}nderungen an der K{\"u}ste (z.B. schmalere Str{\"a}nde, vermehrter Strandanwurf) durch die Urlauber. Außerdem wurden die Einstellung und der Informationsgrad der G{\"a}ste zum Thema Klimawandel an der Ostseek{\"u}ste analysiert. Ziel war es, aus den Umfrageergebnissen Handlungsempfehlungen f{\"u}r das lokale Strandmanagement hinsichtlich k{\"u}nftiger Anpassungsstrategien abzuleiten. Die Literaturrecherche zeigte, dass in einigen Bereichen schon jetzt Ver{\"a}nderungen (z.B. der Luft- und Wassertemperatur oder des Meeresspiegels) nachweisbar sind und laut verschiedener Modellprojektionen von weiteren Ver{\"a}nderungen ausgegangen werden kann. Wie die Umfrage deutlich machte, sind die Ver{\"a}nderungen momentan durch Touristen jedoch kaum oder gar nicht wahrnehmbar. Dementsprechend gering ist auch ihre Reaktion auf die einzelnen Ph{\"a}nomene. Generell ist die Wahrnehmung der Urlauber sehr subjektiv und selektiv. Manche Gegebenheiten wie beispielsweise existierende K{\"u}stenschutzmaßnahmen werden von einem großen Teil der Touristen gar nicht wahrgenommen. Hinsichtlich anderer Erscheinungen wie Strandanwurf und Quallen sind viele Besucher wiederum sehr sensibel. Es zeigte sich außerdem, dass es f{\"u}r die meisten Urlauber schwierig ist, zu beurteilen, ob bestimmte Gegebenheiten am Strand und an der K{\"u}ste mit der globalen Erw{\"a}rmung in Verbindung stehen oder nicht. Es besteht eine große Unsicherheit zu diesem Thema und oft wird der Klimawandel als Ursache f{\"u}r Erscheinungen genannt, auch wenn der kausale Zusammenhang wissenschaftlich nicht nachzuweisen ist. Es zeigte sich, dass die Urlauber sehr wenig {\"u}ber die regionalen Auswirkungen des Klimawandels informiert sind, sich aber Informationen w{\"u}nschen. Folglich sollte zun{\"a}chst die Aufkl{\"a}rung und Information der Urlauber {\"u}ber die Folgen der Ver{\"a}nderung des Klimas im Vordergrund stehen. Denn manche Aspekte, wie der Verlust von Strandabschnitten durch Erosion oder eine eventuelle Zunahme von Blaualgen in der Sommersaison, k{\"o}nnen nicht g{\"a}nzlich vermieden werden. Durch gezielte Aufkl{\"a}rung k{\"o}nnte jedoch beispielsweise eine Akzeptanz f{\"u}r naturnahe Str{\"a}nde oder f{\"u}r den R{\"u}ckzug aus einzelnen Gebieten geschaffen werden. Dar{\"u}ber hinaus sollte die zu erwartende Saisonverl{\"a}ngerung systematisch genutzt werden, um sowohl die K{\"u}ste, als auch das Hinterland durch gezielte Angebote f{\"u}r Touristen attraktiv zu machen. Auf diese Weise k{\"o}nnte eine Entzerrung der Hauptsaison und eine bessere Auslastung der Beherbergungsbetriebe sowie der touristischen Infrastruktur erreicht werden.}, language = {de} } @article{HeffnerFuhrmeisterLuthraetal.2022, author = {Heffner, Christopher C. and Fuhrmeister, Pamela and Luthra, Sahil and Mechtenberg, Hannah and Saltzman, David and Myers, Emily B.}, title = {Reliability and validity for perceptual flexibility in speech}, series = {Brain and language : a journal of clinical, experimental and theoretical research}, volume = {226}, journal = {Brain and language : a journal of clinical, experimental and theoretical research}, publisher = {Elsevier}, address = {Amsterdam [u.a.]}, issn = {0093-934X}, doi = {10.1016/j.bandl.2021.105070}, pages = {11}, year = {2022}, abstract = {The study of perceptual flexibility in speech depends on a variety of tasks that feature a large degree of variability between participants. Of critical interest is whether measures are consistent within an individual or across stimulus contexts. This is particularly key for individual difference designs that are deployed to examine the neural basis or clinical consequences of perceptual flexibility. In the present set of experiments, we assess the split-half reliability and construct validity of five measures of perceptual flexibility: three of learning in a native language context (e.g., understanding someone with a foreign accent) and two of learning in a non-native context (e.g., learning to categorize non-native speech sounds). We find that most of these tasks show an appreciable level of split-half reliability, although construct validity was sometimes weak. This provides good evidence for reliability for these tasks, while highlighting possible upper limits on expected effect sizes involving each measure.}, language = {en} }