TY - JOUR A1 - Reusser, Dominik Edwin A1 - Zehe, Erwin T1 - Low-cost monitoring of snow height and thermal properties with inexpensive temperature sensors JF - Hydrological processes N2 - Small, self-recording temperature sensors were installed at several heights along a metal rod at five locations in a case study catchment. For each sensor, the presence or absence of snow cover was determined on the basis of its insulating effect and the resulting reduction of the diurnal temperature oscillations. Sensor coverage was then converted into a time series of snow height for each location. Additionally, cold content was calculated. Snow height and cold content provide valuable information for spring flood prediction. Good agreement of estimated snow heights with reference measurements was achieved and increased discharge in the study catchment coincided with low cold content of the snow cover. The results of the proposed distributed assessment of snow cover and snow state show great potential for (i) flood warning, (ii) assimilation of snow state data and (iii) modelling snowmelt process. KW - snow measurements KW - cold content KW - temperature index approach KW - heat diffusion KW - temperature Y1 - 2011 U6 - https://doi.org/10.1002/hyp.7937 SN - 0885-6087 SN - 1099-1085 VL - 25 IS - 12 SP - 1841 EP - 1852 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Hartwich, Melanie A1 - Straile, Dietmar A1 - Gaedke, Ursula A1 - Wacker, Alexander T1 - Use of ciliate and phytoplankton taxonomic composition for the estimation of eicosapentaenoic acid concentration in lakes JF - Freshwater biology N2 - 1. The polyunsaturated fatty acid eicosapentaenoic acid (EPA) plays an important role in aquatic food webs, in particular at the primary producerconsumer interface where keystone species such as daphnids may be constrained by its dietary availability. Such constraints and their seasonal and interannual changes may be detected by continuous measurements of EPA concentrations. However, such EPA measurements became common only during the last two decades, whereas long-term data sets on plankton biomass are available for many well-studied lakes. Here, we test whether it is possible to estimate EPA concentrations from abiotic variables (light and temperature) and the biomass of prey organisms (e.g. ciliates, diatoms and cryptophytes) that potentially provide EPA for consumers. 2. We used multiple linear regression to relate size- and taxonomically resolved plankton biomass data and measurements of temperature and light intensity to directly measured EPA concentrations in Lake Constance during a whole year. First, we tested the predictability of EPA concentrations from the biomass of EPA-rich organisms (diatoms, cryptophytes and ciliates). Secondly, we included the variables mean temperature and mean light intensity over the sampling depth (020 m) and depth (08 and 820 m) as factors in our model to check for large-scale seasonal- and depth-dependent effects on EPA concentrations. In a third step, we included the deviations of light and temperature from mean values in our model to allow for their potential influence on the biochemical composition of plankton organisms. We used the Akaike Information Criterion to determine the best models. 3. All approaches supported our proposition that the biomasses of specific plankton groups are variables from which seston EPA concentrations can be derived. The importance of ciliates as an EPA source in the seston was emphasised by their high weight in our models, although ciliates are neglected in most studies that link fatty acids to seston taxonomic composition. The large-scale seasonal variability of light intensity and its interaction with diatom biomass were significant predictors of EPA concentrations. The deviation of temperature from mean values, accounting for a depth-dependent effect on EPA concentrations, and its interaction with ciliate biomass were also variables with high predictive power. 4. The best models from the first and second approaches were validated with measurements of EPA concentrations from another year (1997). The estimation with the best model including only biomass explained 80%, and the best model from the second approach including mean temperature and depth explained 87% of the variability in EPA concentrations in 1997. 5. We show that it is possible to predict EPA concentrations reliably from plankton biomass, while the inclusion of abiotic factors led to results that were only partly consistent with expectations from laboratory studies. Our approach of including biotic predictors should be transferable to other systems and allow checking for biochemical constraints on primary consumers. KW - ciliates KW - diatoms KW - eicosapentaenoic acid KW - light KW - temperature Y1 - 2012 U6 - https://doi.org/10.1111/j.1365-2427.2012.02799.x SN - 0046-5070 VL - 57 IS - 7 SP - 1385 EP - 1398 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Piepho, Maike A1 - Arts, Michael T. A1 - Wacker, Alexander T1 - Species-specific variation in fatty acid concentrations of four phytoplankton species does phosphorus supply influence the effect of light intensity of temperature? JF - Journal of phycology N2 - We tested, in the laboratory, the influence of light intensity, temperature, and phosphorus (P) supply on fatty acid (FA) concentrations of four freshwater algae: the green algae Scenedesmus quadricauda (Turpin) Breb. and Chlamydomonas globosa J. Snow, the cryptophyte Cryptomonas ovata Ehrenb., and the diatom Cyclotella meneghiniana Kutz. We investigated the main and interactive effects of two variables on algal FA concentrations (i.e., light intensity and P supply or temperature and P supply). Interactive effects of light intensity and P supply were most pronounced in C. meneghiniana, but were also found in S. quadricauda and C. ovata. Changes in several saturated and unsaturated FA concentrations with light were more distinct in the low-P treatments than in the high-P treatments. Interactive effects of temperature and P supply on various FA concentrations were observed in all four species, but there was no consistent pattern. In lake ecosystems, P limitation often coincides with high light intensities and temperatures in summer. Therefore, it is important to examine how combinations of these environmental conditions affect FA concentrations of primary producers that are important sources of FAs for higher trophic levels. KW - Chlamydomonas KW - Cryptomonas KW - Cyclotella KW - fatty acids KW - light KW - lipids KW - phosphate KW - PUFA KW - Scenedesmus KW - temperature Y1 - 2012 U6 - https://doi.org/10.1111/j.1529-8817.2011.01103.x SN - 0022-3646 VL - 48 IS - 1 SP - 64 EP - 73 PB - Wiley-Blackwell CY - Malden ER - TY - JOUR A1 - Piepho, Maike A1 - Martin-Creuzburg, Dominik A1 - Wacker, Alexander T1 - Phytoplankton sterol contents vary with temperature, phosphorus and silicate supply a study on three freshwater species JF - European journal of phycology N2 - The understanding of environmentally induced changes in the biochemical composition of phytoplankton species is of great importance in both physiological studies and ecological food web research. In extensive laboratory experiments we tested the influence of two different temperatures (10 degrees C and 25 degrees C) and a phosphorus supply gradient on the sterol concentrations of the three freshwater phytoplankton species Scenedesmus quadricauda, Cryptomonas ovata and Cyclotella meneghiniana. The diatom C. meneghiniana was additionally exposed to a silicate gradient. In two separate experiments we analysed (1) possible interactive effects of temperature and phosphorus supply and (2) the effect of four phosphorus levels and three silicate levels on algal sterol concentrations. We observed that sterol concentrations were higher at 25 degrees C than at 10 degrees C in S. quadricauda and C. meneghiniana, but were not affected by temperature in C. ovata. Interactive effects of temperature and phosphorus supply on sterol concentrations were found in C. meneghiniana. This presumably was due to the bioconversion of one sterol (24-methylenecholesterol) into another (22-dihydrobrassicasterol). Increasing phosphorus supply resulted in species-specific effects on sterol concentrations, viz. an optimum curve response in S. quadricauda, a saturation curve response in C. meneghiniana and no change in sterol concentration in C. ovata. Effects of silicate supply on the sterols of C. meneghiniana equalled the effects of phosphorus supply. Albeit we did not observe a general trend in the three phytoplankton species tested, we conclude that sterol concentrations of phytoplankton are strongly affected by temperature and nutrient supply. Interactive effects point out the importance of taking into account more than just one environmental factor when assessing the effects of environmentally induced changes on phytoplankton sterol concentrations. KW - algae KW - Chlorophyta KW - Cryptomonas KW - Cryptophyta KW - Cyclotella KW - diatoms KW - phosphorus KW - Scenedesmus KW - silicate KW - sterols KW - temperature Y1 - 2012 U6 - https://doi.org/10.1080/09670262.2012.665484 SN - 0967-0262 VL - 47 IS - 2 SP - 138 EP - 145 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - De Frenne, Pieter A1 - Graae, Bente J. A1 - Brunet, Jörg A1 - Shevtsova, Anna A1 - De Schrijver, An A1 - Chabrerie, Olivier A1 - Cousins, Sara A. O. A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Hermy, Martin A1 - Heinken, Thilo A1 - Kolb, Annette A1 - Nilsson, Christer A1 - Stanton, Sharon A1 - Verheyen, Kris T1 - The response of forest plant regeneration to temperature variation along a latitudinal gradient JF - Annals of botany N2 - The response of forest herb regeneration from seed to temperature variations across latitudes was experimentally assessed in order to forecast the likely response of understorey community dynamics to climate warming. Seeds of two characteristic forest plants (Anemone nemorosa and Milium effusum) were collected in natural populations along a latitudinal gradient from northern France to northern Sweden and exposed to three temperature regimes in growth chambers (first experiment). To test the importance of local adaptation, reciprocal transplants were also made of adult individuals that originated from the same populations in three common gardens located in southern, central and northern sites along the same gradient, and the resulting seeds were germinated (second experiment). Seedling establishment was quantified by measuring the timing and percentage of seedling emergence, and seedling biomass in both experiments. Spring warming increased emergence rates and seedling growth in the early-flowering forb A. nemorosa. Seedlings of the summer-flowering grass M. effusum originating from northern populations responded more strongly in terms of biomass growth to temperature than southern populations. The above-ground biomass of the seedlings of both species decreased with increasing latitude of origin, irrespective of whether seeds were collected from natural populations or from the common gardens. The emergence percentage decreased with increasing home-away distance in seeds from the transplant experiment, suggesting that the maternal plants were locally adapted. Decreasing seedling emergence and growth were found from the centre to the northern edge of the distribution range for both species. Stronger responses to temperature variation in seedling growth of the grass M. effusum in the north may offer a way to cope with environmental change. The results further suggest that climate warming might differentially affect seedling establishment of understorey plants across their distribution range and thus alter future understorey plant dynamics. KW - Anemone nemorosa KW - climate change KW - common garden KW - growth chambers KW - latitudinal gradient KW - local adaptation KW - Milium effusum KW - plant regeneration KW - range edges KW - recruitment KW - seedling establishment KW - temperature Y1 - 2012 U6 - https://doi.org/10.1093/aob/mcs015 SN - 0305-7364 VL - 109 IS - 5 SP - 1037 EP - 1046 PB - Oxford Univ. Press CY - Oxford ER - TY - JOUR A1 - Plue, Jan A1 - De Frenne, Pieter A1 - Acharya, Kamal P. A1 - Brunet, Jorg A1 - Chabrerie, Olivier A1 - Decocq, Guillaume A1 - Diekmann, Martin A1 - Graae, Bente J. A1 - Heinken, Thilo A1 - Hermy, Martin A1 - Kolb, Annette A1 - Lemke, Isgard A1 - Liira, Jaan A1 - Naaf, Tobias A1 - Shevtsova, Anna A1 - Verheyen, Kris A1 - Wulf, Monika A1 - Cousins, Sara A. O. T1 - Climatic control of forest herb seed banks along a latitudinal gradient JF - Global ecology and biogeography : a journal of macroecology N2 - Aim Seed banks are central to the regeneration strategy of many plant species. Any factor altering seed bank density thus affects plant regeneration and population dynamics. Although seed banks are dynamic entities controlled by multiple environmental drivers, climatic factors are the most comprehensive, but still poorly understood. This study investigates how climatic variation structures seed production and resulting seed bank patterns. Location Temperate forests along a 1900km latitudinal gradient in north-western (NW) Europe. Methods Seed production and seed bank density were quantified in 153 plots along the gradient for four forest herbs with different seed longevity: Geum urbanum, Milium effusum, Poa nemoralis and Stachys sylvatica. We tested the importance of climatic and local environmental factors in shaping seed production and seed bank density. Results Seed production was determined by population size, and not by climatic factors. G.urbanum and M.effusum seed bank density declined with decreasing temperature (growing degree days) and/or increasing temperature range (maximum-minimum temperature). P.nemoralis and S.sylvatica seed bank density were limited by population size and not by climatic variables. Seed bank density was also influenced by other, local environmental factors such as soil pH or light availability. Different seed bank patterns emerged due to differential seed longevities. Species with long-lived seeds maintained constant seed bank densities by counteracting the reduced chance of regular years with high seed production at colder northern latitudes. Main conclusions Seed bank patterns show clear interspecific variation in response to climate across the distribution range. Not all seed banking species may be as well equipped to buffer climate change via their seed bank, notably in short-term persistent species. Since the buffering capacity of seed banks is key to species persistence, these results provide crucial information to advance climatic change predictions on range shifts, community and biodiversity responses. KW - Climate change KW - interspecific variation KW - plant-climate interaction KW - seed longevity KW - seed production KW - temperate deciduous forest KW - temperature Y1 - 2013 U6 - https://doi.org/10.1111/geb.12068 SN - 1466-822X SN - 1466-8238 VL - 22 IS - 10 SP - 1106 EP - 1117 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Liu, Xingqi A1 - Herzschuh, Ulrike A1 - Wang, Yongbo A1 - Kuhn, Gerhard A1 - Yu, Zhitong T1 - Glacier fluctuations of Muztagh Ata and temperature changes during the late Holocene in westernmost Tibetan Plateau, based on glaciolacustrine sediment records JF - Geophysical research letters N2 - Late Holocene glacier variations in westernmost Tibetan Plateau were studied based on the analysis of grain size, magnetic susceptibility, and elements from an 8.3m long distal glaciolacustrine sediment core of Kalakuli Lake. Our results show that there are four glacier expansion episodes occurring in 4200-3700calibrated years (cal years) B.P., 2950-2300cal years B.P., 1700-1070cal years B.P., and 570-100cal years B.P. and four glacier retreat periods of 3700-2950cal years B.P., 2300-1700cal years B.P., 1070-570cal years B.P., and 50cal years B.P.-present. The four glacier expansion episodes are generally in agreement with the glacier activities indicted by the moraines at Muztagh Ata and Kongur Shan, as well as with the late Holocene ice-rafting events in the North Atlantic. Over the last 2000years, our reconstructed glacier variations are in temporal agreement with reconstructed temperature from China and the Northern Hemisphere, indicating that glacier variations at centennial time scales are very sensitive to temperature in western Tibetan Plateau. KW - glaciolacustrine sediment KW - westernmost Tibetan Plateau KW - glacier variation KW - Kalakuli Lake KW - late Holocene KW - temperature Y1 - 2014 U6 - https://doi.org/10.1002/2014GL060444 SN - 0094-8276 SN - 1944-8007 VL - 41 IS - 17 SP - 6265 EP - 6273 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Caron, Maria Mercedes A1 - De Frenne, Pieter A1 - Brunet, J. A1 - Chabrerie, Olivier A1 - Cousins, S. A. O. A1 - De Backer, L. A1 - Decocq, G. A1 - Diekmann, M. A1 - Heinken, Thilo A1 - Kolb, A. A1 - Naaf, T. A1 - Plue, J. A1 - Selvi, Federico A1 - Strimbeck, G. R. A1 - Wulf, Monika A1 - Verheyen, Kris T1 - Interacting effects of warming and drought on regeneration and early growth of Acer pseudoplatanus and A. platanoides JF - Plant biology N2 - Climate change is acting on several aspects of plant life cycles, including the sexual reproductive stage, which is considered amongst the most sensitive life-cycle phases. In temperate forests, it is expected that climate change will lead to a compositional change in community structure due to changes in the dominance of currently more abundant forest tree species. Increasing our understanding of the effects of climate change on currently secondary tree species recruitment is therefore important to better understand and forecast population and community dynamics in forests. Here, we analyse the interactive effects of rising temperatures and soil moisture reduction on germination, seedling survival and early growth of two important secondary European tree species, Acer pseudoplatanus and A.platanoides. Additionally, we analyse the effect of the temperature experienced by the mother tree during seed production by collecting seeds of both species along a 2200-km long latitudinal gradient. For most of the responses, A.platanoides showed higher sensitivity to the treatments applied, and especially to its joint manipulation, which for some variables resulted in additive effects while for others only partial compensation. In both species, germination and survival decreased with rising temperatures and/or soil moisture reduction while early growth decreased with declining soil moisture content. We conclude that although A.platanoides germination and survival were more affected after the applied treatments, its initial higher germination and larger seedlings might allow this species to be relatively more successful than A.pseudoplatanus in the face of climate change. KW - Acer platanoides KW - Acer pseudoplatanus KW - climate change KW - drought KW - reproduction KW - seed KW - temperature Y1 - 2015 U6 - https://doi.org/10.1111/plb.12177 SN - 1435-8603 SN - 1438-8677 VL - 17 IS - 1 SP - 52 EP - 62 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Kormann, C. A1 - Francke, Till A1 - Renner, M. A1 - Bronstert, Axel T1 - Attribution of high resolution streamflow trends in Western Austria BT - an approach based on climate and discharge station data JF - Hydrology and earth system sciences N2 - The results of streamflow trend studies are often characterized by mostly insignificant trends and inexplicable spatial patterns. In our study region, Western Austria, this applies especially for trends of annually averaged runoff. However, analysing the altitudinal aspect, we found that there is a trend gradient from higher-altitude to lower-altitude stations, i.e. a pattern of mostly positive annual trends at higher stations and negative ones at lower stations. At midaltitudes, the trends are mostly insignificant. Here we hypothesize that the streamflow trends are caused by the following two main processes: on the one hand, melting glaciers produce excess runoff at higher-altitude watersheds. On the other hand, rising temperatures potentially alter hydrological conditions in terms of less snowfall, higher infiltration, enhanced evapotranspiration, etc., which in turn results in decreasing streamflow trends at lower-altitude watersheds. However, these patterns are masked at mid-altitudes because the resulting positive and negative trends balance each other. To support these hypotheses, we attempted to attribute the detected trends to specific causes. For this purpose, we analysed trends of filtered daily streamflow data, as the causes for these changes might be restricted to a smaller temporal scale than the annual one. This allowed for the explicit determination of the exact days of year (DOYs) when certain streamflow trends emerge, which were then linked with the corresponding DOYs of the trends and characteristic dates of other observed variables, e.g. the average DOY when temperature crosses the freezing point in spring. Based on these analyses, an empirical statistical model was derived that was able to simulate daily streamflow trends sufficiently well. Analyses of subdaily streamflow changes provided additional insights. Finally, the present study supports many modelling approaches in the literature which found out that the main drivers of alpine streamflow changes are increased glacial melt, earlier snowmelt and lower snow accumulation in wintertime. KW - alpine KW - catchments KW - impacts KW - regimes KW - seasonality KW - snow KW - switzerland KW - temperature KW - time-series KW - variability Y1 - 2015 U6 - https://doi.org/10.5194/hess-19-1225-2015 SN - 1607-7938 SN - 1027-5606 VL - 19 SP - 1225 EP - 1245 PB - EGU CY - Katlenburg-Lindau ER - TY - JOUR A1 - Braune, Steffen A1 - Froehlich, G. M. A1 - Lendlein, Andreas A1 - Jung, Friedrich T1 - Effect of temperature on platelet adherence JF - Clinical hemorheology and microcirculation : blood flow and vessels N2 - BACKGROUND: Thrombogenicity is one of the main parameters tested in vitro to evaluate the hemocompatibility of artificial surfaces. While the influence of the temperature on platelet aggregation has been addressed by several studies, the temperature influence on the adherence of platelets to body foreign surfaces as an important aspect of biomedical device handling has not yet been explored. Therefore, we analyzed the influence of two typically applied incubation-temperatures (22 degrees C and 37 degrees C) on the adhesion of platelets to biomaterials. MATERIAL AND METHODS: Thrombogenicity of three different polymers - medical grade poly(dimethyl siloxane) (PDMS), polytetrafluoroethylene (PTFE) and polyethylene terephthalate (PET) - were studied in an in vitro static test. Platelet adhesion was studied with stringently characterized blood from apparently healthy subjects. Collection of whole blood and preparation of platelet rich plasma (PRP) was carried out at room temperature (22 degrees C). PRP was incubated with the polymers either at 22 degrees C or 37 degrees C. Surface adherent platelets were fixed, fluorescently labelled and assessed by an image-based approach. RESULTS AND DISCUSSION: Differences in the density of adherent platelets after incubation at 22 degrees C and 37 degrees C occurred on PDMS and PET. Similar levels of adherent platelets were observed on the very thrombogenic PTFE. The covered surface areas per single platelet were analyzed to measure the state of platelet activation and revealed no differences between the two incubation temperatures for any of the analyzed polymers. Irrespective of the observed differences between the low and medium thrombogenic PDMS and PET and the higher variability at 22 degrees C, the thrombogenicity of the three investigated polymers was evaluated being comparable at both incubation temperatures. KW - Biomaterial KW - thrombogenicity KW - platelet adhesion KW - platelet activation KW - temperature Y1 - 2016 U6 - https://doi.org/10.3233/CH-152028 SN - 1386-0291 SN - 1875-8622 VL - 61 SP - 681 EP - 688 PB - IOS Press CY - Amsterdam ER - TY - JOUR A1 - Koussoroplis, Apostolos-Manuel A1 - Pincebourde, Sylvain A1 - Wacker, Alexander T1 - Understanding and predicting physiological performance of organisms in fluctuating and multifactorial environments JF - Ecological monographs : a publication of the Ecological Society of America. N2 - Understanding how variance in environmental factors affects physiological performance, population growth, and persistence is central in ecology. Despite recent interest in the effects of variance in single biological drivers, such as temperature, we have lacked a comprehensive framework for predicting how the variances and covariances between multiple environmental factors will affect physiological rates. Here, we integrate current theory on variance effects with co-limitation theory into a single unified conceptual framework that has general applicability. We show how the framework can be applied (1) to generate mathematically tractable predictions of the physiological effects of multiple fluctuating co-limiting factors, (2) to understand how each co-limiting factor contributes to these effects, and (3) to detect mechanisms such as acclimation or physiological stress when they are at play. We show that the statistical covariance of co-limiting factors, which has not been considered before, can be a strong driver of physiological performance in various ecological contexts. Our framework can provide powerful insights on how the global change-induced shifts in multiple environmental factors affect the physiological performance of organisms. KW - co-limitation KW - covariance KW - eco-physiology KW - feeding rate KW - global change KW - multiple stressors KW - nonlinear averaging KW - nutrients KW - scale transition KW - temperature KW - temporal ecology KW - variance Y1 - 2017 U6 - https://doi.org/10.1002/ecm.1247 SN - 0012-9615 SN - 1557-7015 VL - 87 SP - 178 EP - 197 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Bachmann, Jennifer A1 - Heimbach, Tabea A1 - Hassenrück, Christiane A1 - Kopprio, German A. A1 - Iversen, Morten Hvitfeldt A1 - Grossart, Hans-Peter A1 - Gärdes, Astrid T1 - Environmental Drivers of Free-Living vs. Particle-Attached Bacterial Community Composition in the Mauritania Upwelling System JF - Frontiers in microbiology N2 - Saharan dust input and seasonal upwelling along North-West Africa provide a model system for studying microbial processes related to the export and recycling of nutrients. This study offers the first molecular characterization of prokaryotic particle-attached (PA; > 3.0 mu m) and free-living (FL; 0.2-3.0 mu m) players in this important ecosystem during August 2016. Environmental drivers for alpha-diversity, bacterial community composition, and differences between FL and PA fractions were identified. The ultra-oligotrophic waters off Senegal were dominated by Cyanobacteria while higher relative abundances of Alphaproteobacteria, Bacteroidetes, Verrucomicrobia, and Planctomycetes (known particle-degraders) occurred in the upwelling area. Temperature, proxy for different water masses, was the best predictor for changes in FL communities. PA community variation was best explained by temperature and ammonium. Bray Curtis dissimilarities between FL and PA were generally very high and correlated with temperature and salinity in surface waters. Greatest similarities between FL and PA occurred at the deep chlorophyll maximum, where bacterial substrate availability was likely highest. This indicates that environmental drivers do not only influence changes among FL and PA communities but also differences between them. This could provide an explanation for contradicting results obtained by different studies regarding the dissimilarity/similarity between FL and PA communities and their biogeochemical functions. KW - prokaryotes KW - biodiversity KW - microbial ecology KW - alpha diversity KW - Bray Curtis dissimilarity KW - temperature KW - salinity KW - 16S rRNA Illumina amplicon sequencing Y1 - 2018 U6 - https://doi.org/10.3389/fmicb.2018.02836 SN - 1664-302X VL - 9 PB - Frontiers Research Foundation CY - Lausanne ER - TY - JOUR A1 - Mantzouki, Evanthia A1 - Lurling, Miquel A1 - Fastner, Jutta A1 - Domis, Lisette Nicole de Senerpont A1 - Wilk-Wozniak, Elzbieta A1 - Koreiviene, Judita A1 - Seelen, Laura A1 - Teurlincx, Sven A1 - Verstijnen, Yvon A1 - Krzton, Wojciech A1 - Walusiak, Edward A1 - Karosiene, Jurate A1 - Kasperoviciene, Jurate A1 - Savadova, Ksenija A1 - Vitonyte, Irma A1 - Cillero-Castro, Carmen A1 - Budzynska, Agnieszka A1 - Goldyn, Ryszard A1 - Kozak, Anna A1 - Rosinska, Joanna A1 - Szelag-Wasielewska, Elzbieta A1 - Domek, Piotr A1 - Jakubowska-Krepska, Natalia A1 - Kwasizur, Kinga A1 - Messyasz, Beata A1 - Pelechata, Aleksandra A1 - Pelechaty, Mariusz A1 - Kokocinski, Mikolaj A1 - Garcia-Murcia, Ana A1 - Real, Monserrat A1 - Romans, Elvira A1 - Noguero-Ribes, Jordi A1 - Parreno Duque, David A1 - Fernandez-Moran, Elisabeth A1 - Karakaya, Nusret A1 - Haggqvist, Kerstin A1 - Demir, Nilsun A1 - Beklioglu, Meryem A1 - Filiz, Nur A1 - Levi, Eti E. A1 - Iskin, Ugur A1 - Bezirci, Gizem A1 - Tavsanoglu, Ulku Nihan A1 - Ozhan, Koray A1 - Gkelis, Spyros A1 - Panou, Manthos A1 - Fakioglu, Ozden A1 - Avagianos, Christos A1 - Kaloudis, Triantafyllos A1 - Celik, Kemal A1 - Yilmaz, Mete A1 - Marce, Rafael A1 - Catalan, Nuria A1 - Bravo, Andrea G. A1 - Buck, Moritz A1 - Colom-Montero, William A1 - Mustonen, Kristiina A1 - Pierson, Don A1 - Yang, Yang A1 - Raposeiro, Pedro M. A1 - Goncalves, Vitor A1 - Antoniou, Maria G. A1 - Tsiarta, Nikoletta A1 - McCarthy, Valerie A1 - Perello, Victor C. A1 - Feldmann, Tonu A1 - Laas, Alo A1 - Panksep, Kristel A1 - Tuvikene, Lea A1 - Gagala, Ilona A1 - Mankiewicz-Boczek, Joana A1 - Yagci, Meral Apaydin A1 - Cinar, Sakir A1 - Capkin, Kadir A1 - Yagci, Abdulkadir A1 - Cesur, Mehmet A1 - Bilgin, Fuat A1 - Bulut, Cafer A1 - Uysal, Rahmi A1 - Obertegger, Ulrike A1 - Boscaini, Adriano A1 - Flaim, Giovanna A1 - Salmaso, Nico A1 - Cerasino, Leonardo A1 - Richardson, Jessica A1 - Visser, Petra M. A1 - Verspagen, Jolanda M. H. A1 - Karan, Tunay A1 - Soylu, Elif Neyran A1 - Maraslioglu, Faruk A1 - Napiorkowska-Krzebietke, Agnieszka A1 - Ochocka, Agnieszka A1 - Pasztaleniec, Agnieszka A1 - Antao-Geraldes, Ana M. A1 - Vasconcelos, Vitor A1 - Morais, Joao A1 - Vale, Micaela A1 - Koker, Latife A1 - Akcaalan, Reyhan A1 - Albay, Meric A1 - Maronic, Dubravka Spoljaric A1 - Stevic, Filip A1 - Pfeiffer, Tanja Zuna A1 - Fonvielle, Jeremy Andre A1 - Straile, Dietmar A1 - Rothhaupt, Karl-Otto A1 - Hansson, Lars-Anders A1 - Urrutia-Cordero, Pablo A1 - Blaha, Ludek A1 - Geris, Rodan A1 - Frankova, Marketa A1 - Kocer, Mehmet Ali Turan A1 - Alp, Mehmet Tahir A1 - Remec-Rekar, Spela A1 - Elersek, Tina A1 - Triantis, Theodoros A1 - Zervou, Sevasti-Kiriaki A1 - Hiskia, Anastasia A1 - Haande, Sigrid A1 - Skjelbred, Birger A1 - Madrecka, Beata A1 - Nemova, Hana A1 - Drastichova, Iveta A1 - Chomova, Lucia A1 - Edwards, Christine A1 - Sevindik, Tugba Ongun A1 - Tunca, Hatice A1 - OEnem, Burcin A1 - Aleksovski, Boris A1 - Krstic, Svetislav A1 - Vucelic, Itana Bokan A1 - Nawrocka, Lidia A1 - Salmi, Pauliina A1 - Machado-Vieira, Danielle A1 - de Oliveira, Alinne Gurjao A1 - Delgado-Martin, Jordi A1 - Garcia, David A1 - Cereijo, Jose Luis A1 - Goma, Joan A1 - Trapote, Mari Carmen A1 - Vegas-Vilarrubia, Teresa A1 - Obrador, Biel A1 - Grabowska, Magdalena A1 - Karpowicz, Maciej A1 - Chmura, Damian A1 - Ubeda, Barbara A1 - Angel Galvez, Jose A1 - Ozen, Arda A1 - Christoffersen, Kirsten Seestern A1 - Warming, Trine Perlt A1 - Kobos, Justyna A1 - Mazur-Marzec, Hanna A1 - Perez-Martinez, Carmen A1 - Ramos-Rodriguez, Eloisa A1 - Arvola, Lauri A1 - Alcaraz-Parraga, Pablo A1 - Toporowska, Magdalena A1 - Pawlik-Skowronska, Barbara A1 - Niedzwiecki, Michal A1 - Peczula, Wojciech A1 - Leira, Manel A1 - Hernandez, Armand A1 - Moreno-Ostos, Enrique A1 - Maria Blanco, Jose A1 - Rodriguez, Valeriano A1 - Juan Montes-Perez, Jorge A1 - Palomino, Roberto L. A1 - Rodriguez-Perez, Estela A1 - Carballeira, Rafael A1 - Camacho, Antonio A1 - Picazo, Antonio A1 - Rochera, Carlos A1 - Santamans, Anna C. A1 - Ferriol, Carmen A1 - Romo, Susana A1 - Miguel Soria, Juan A1 - Dunalska, Julita A1 - Sienska, Justyna A1 - Szymanski, Daniel A1 - Kruk, Marek A1 - Kostrzewska-Szlakowska, Iwona A1 - Jasser, Iwona A1 - Zutinic, Petar A1 - Udovic, Marija Gligora A1 - Plenkovic-Moraj, Andelka A1 - Frak, Magdalena A1 - Bankowska-Sobczak, Agnieszka A1 - Wasilewicz, Michal A1 - Ozkan, Korhan A1 - Maliaka, Valentini A1 - Kangro, Kersti A1 - Grossart, Hans-Peter A1 - Paerl, Hans W. A1 - Carey, Cayelan C. A1 - Ibelings, Bas W. T1 - Temperature effects explain continental scale distribution of cyanobacterial toxins JF - Toxins N2 - 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 their potency. Most studies examine the relationship between individual toxin variants and environmental factors, such as nutrients, temperature and light. In summer 2015, we collected samples across Europe to investigate the effect of nutrient and temperature gradients on the variability of toxin production at a continental scale. Direct and indirect effects of temperature were the main drivers of the spatial distribution in the toxins produced by the cyanobacterial community, the toxin concentrations and toxin quota. Generalized linear models showed that a Toxin Diversity Index (TDI) increased with latitude, while it decreased with water stability. Increases in TDI were explained through a significant increase in toxin variants such as MC-YR, anatoxin and cylindrospermopsin, accompanied by a decreasing presence of MC-LR. While global warming continues, the direct and indirect effects of increased lake temperatures will drive changes in the distribution of cyanobacterial toxins in Europe, potentially promoting selection of a few highly toxic species or strains. KW - microcystin KW - anatoxin KW - cylindrospermopsin KW - temperature KW - direct effects KW - indirect effects KW - spatial distribution KW - European Multi Lake Survey Y1 - 2018 U6 - https://doi.org/10.3390/toxins10040156 SN - 2072-6651 VL - 10 IS - 4 PB - MDPI CY - Basel ER - TY - JOUR A1 - Eugenia Tietze, Hedwig Selma A1 - Joshi, Jasmin Radha A1 - Pugnaire, Francisco Ignacio A1 - Dechoum, Michele de Sa T1 - Seed germination and seedling establishment of an invasive tropical tree species under different climate change scenarios JF - Austral ecology N2 - Increasing air temperature and atmospheric CO2 levels may affect the distribution of invasive species. Whereas there is wide knowledge on the effect of global change on temperate species, responses of tropical invasive species to these two global change drivers are largely unknown. We conducted a greenhouse experiment on Terminalia catappa L. (Combretaceae), an invasive tree species on Brazilian coastal areas, to evaluate the effects of increased air temperature and CO2 concentration on seed germination and seedling growth on the island of Santa Catarina (Florianopolis, Brazil). Seeds of the invasive tree were subjected to two temperature levels (ambient and +1.6 degrees C) and two CO2 levels (ambient and 650 ppmv) with a factorial design. Increased temperature enhanced germination rate and shortened germination time of T. catappa seeds. It also increased plant height, number of leaves and above-ground biomass. By contrast, increased atmospheric CO2 concentration had no significant effects, and the interaction between temperature and CO2 concentration did not affect any of the measured traits. Terminalia catappa adapts to a relatively broad range of environmental conditions, being able to tolerate cooler temperatures in its invasive range. As T. catappa is native to tropical areas, global warming might favour its establishment along the coast of subtropical South America, while increased CO2 levels seem not to have significant effects on seed germination or seedling growth. KW - CO2 concentration KW - coastal dunes KW - establishment KW - invasive plant KW - plant invasion KW - temperature KW - Terminalia catappa Y1 - 2019 U6 - https://doi.org/10.1111/aec.12809 SN - 1442-9985 SN - 1442-9993 VL - 44 IS - 8 SP - 1351 EP - 1358 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Lemaire, Olivier N. A1 - Honore, Flora A. A1 - Tempel, Sebastien A1 - Fortier, Emma M. A1 - Leimkühler, Silke A1 - Mejean, Vincent A1 - Iobbi-Nivol, Chantal T1 - Shewanella decolorationis LDS1 Chromate Resistance JF - Applied and environmental microbiology N2 - The genus Shewanella is well known for its genetic diversity, its outstanding respiratory capacity, and its high potential for bioremediation. Here, a novel strain isolated from sediments of the Indian Ocean was characterized. A 16S rRNA analysis indicated that it belongs to the species Shewanella decolorationis. It was named Shewanella decolorationis LDS1. This strain presented an unusual ability to grow efficiently at temperatures from 24 degrees C to 40 degrees C without apparent modifications of its metabolism, as shown by testing respiratory activities or carbon assimilation, and in a wide range of salt concentrations. Moreover, S. decolorationis LDS1 tolerates high chromate concentrations. Indeed, it was able to grow in the presence of 4 mM chromate at 28 degrees C and 3 mM chromate at 40 degrees C. Interestingly, whatever the temperature, when the culture reached the stationary phase, the strain reduced the chromate present in the growth medium. In addition, S. decolorationis LDS1 degrades different toxic dyes, including anthraquinone, triarylmethane, and azo dyes. Thus, compared to Shewanella oneidensis, this strain presented better capacity to cope with various abiotic stresses, particularly at high temperatures. The analysis of genome sequence preliminary data indicated that, in contrast to S. oneidensis and S. decolorationis S12, S. decolorationis LDS1 possesses the phosphorothioate modification machinery that has been described as participating in survival against various abiotic stresses by protecting DNA. We demonstrate that its heterologous production in S. oneidensis allows it to resist higher concentrations of chromate. IMPORTANCE Shewanella species have long been described as interesting microorganisms in regard to their ability to reduce many organic and inorganic compounds, including metals. However, members of the Shewanella genus are often depicted as cold-water microorganisms, although their optimal growth temperature usually ranges from 25 to 28 degrees C under laboratory growth conditions. Shewanella decolorationis LDS1 is highly attractive, since its metabolism allows it to develop efficiently at temperatures from 24 to 40 degrees C, conserving its ability to respire alternative substrates and to reduce toxic compounds such as chromate or toxic dyes. Our results clearly indicate that this novel strain has the potential to be a powerful tool for bioremediation and unveil one of the mechanisms involved in its chromate resistance. KW - Shewanella KW - bioremediation KW - chromium KW - decolorization KW - dndBCDE KW - dyes KW - temperature Y1 - 2019 U6 - https://doi.org/10.1128/AEM.00777-19 SN - 0099-2240 SN - 1098-5336 VL - 85 IS - 18 PB - American Society for Microbiology CY - Washington ER - TY - THES A1 - Paraskevopoulou, Sofia T1 - Adaptive genetic variation and responses to thermal stress in brachionid rotifers N2 - The importance of cryptic diversity in rotifers is well understood regarding its ecological consequences, but there remains an in depth comprehension of the underlying molecular mechanisms and forces driving speciation. Temperature has been found several times to affect species spatio-temporal distribution and organisms’ performance, but we lack information on the mechanisms that provide thermal tolerance to rotifers. High cryptic diversity was found recently in the freshwater rotifer “Brachionus calyciflorus”, showing that the complex comprises at least four species: B. calyciflorus sensu stricto (s.s.), B. fernandoi, B. dorcas, and B. elevatus. The temporal succession among species which have been observed in sympatry led to the idea that temperature might play a crucial role in species differentiation. The central aim of this study was to unravel differences in thermal tolerance between species of the former B. calyciflorus species complex by comparing phenotypic and gene expression responses. More specifically, I used the critical maximum temperature as a proxy for inter-species differences in heat-tolerance; this was modeled as a bi-dimensional phenotypic trait taking into consideration the intention and the duration of heat stress. Significant differences on heat-tolerance between species were detected, with B. calyciflorus s.s. being able to tolerate higher temperatures than B. fernandoi. Based on evidence of within species neutral genetic variation, I further examined adaptive genetic variability within two different mtDNA lineages of the heat tolerant B. calyciflorus s.s. to identify SNPs and genes under selection that might reflect their adaptive history. These analyses did not reveal adaptive genetic variation related to heat, however, they show putatively adaptive genetic variation which may reflect local adaptation. Functional enrichment of putatively positively selected genes revealed signals of adaptation in genes related to “lipid metabolism”, “xenobiotics biodegradation and metabolism” and “sensory system”, comprising candidate genes which can be utilized in studies on local adaptation. An absence of genetically-based differences in thermal adaptation between the two mtDNA lineages, together with our knowledge that B. calyciflorus s.s. can withstand a broad range of temperatures, led to the idea to further investigate shared transcriptomic responses to long-term exposure to high and low temperatures regimes. With this, I identified candidate genes that are involved in the response to temperature imposed stress. Lastly, I used comparative transcriptomics to examine responses to imposed heat-stress in heat-tolerant and heat-sensitive Brachionus species. I found considerably different patterns of gene expression in the two species. Most striking are patterns of expression regarding the heat shock proteins (hsps) between the two species. In the heat-tolerant, B. calyciflorus s.s., significant up-regulation of hsps at low temperatures was indicative of a stress response at the cooler end of the temperature regimes tested here. In contrast, in the heat-sensitive B. fernandoi, hsps generally exhibited up-regulation of these genes along with rising temperatures. Overall, identification of differences in expression of genes suggests suppression of protein biosynthesis to be a mechanism to increase thermal tolerance. Observed patterns in population growth are correlated with the hsp gene expression differences, indicating that this physiological stress response is indeed related to phenotypic life history performance. N2 - Obwohl die kryptische Diversität von Rotatorien (Rädertierchen) und die daraus resultierenden ökologischen Konsequenzen inzwischen sehr gut verstanden sind, sind die zugrunde liegenden molekularen Mechanismen und die Artbildungsprozesse bisher weitgehend unbekannt. Bekannt ist, dass die Temperatur eine bedeutende Rolle in den raum-zeitlichen Verbreitungsmustern der Arten sowie der Leistungsfähigkeit der Organismen, spielt. Es fehlen jedoch konkrete Informationen über die der Thermotoleranz zugrundeliegenden Mechanismen bei Rotatorien. Vor kurzem wurde hohe kryptische Diversität in der unter anderem in Süßwasser vorkommenden Art „Brachionus calyciflorus“ gefunden, so dass diese nun in mindestens vier Arten (B. calyciflorus sensu stricto (s.s.), B. fernandoi, B. dorcas und B. elevatus) unterteilt wurde. Beobachtungen von in Sympatrie vorkommenden Arten haben gezeigt, dass eine zeitliche Suksession innerhalb dieser Arten existiert, was vermuten lässt, dass Temperatur eine entscheidende Rolle bei der Artbildung gespielt haben könnte. Ziel dieser Arbeit ist es, Thermotoleranzunterschiede zwischen Arten des früheren B. calyciflorus-Artenkomplexes durch den Vergleich von phänotypischen und molekularen (Genexpression) Reaktionen auf Temperatur festzustellen. Die in dieser Untersuchung ermittelte kritische Maximaltemperatur wurde als Schätzer für zwischenartliche Hitzetoleranz verwendet. Mit Hilfe eines zweidimensionalen Verfahrens, welches sowohl die Dauer als auch die Stärke des Hitzestresses detektiert, konnte festgestellt werden, dass B. calyciflorus s.s. im Vergleich zu B. fernandoi hitzetoleranter ist. Auf Basis der innerartlichen genetischen Variation erfolgte eine tiefergehende Untersuchung zweier unterschiedlicher maternaler (mtDNA) Evolutionslinien der hitzetoleranteren Art B. calyciflorus s.s mit dem Ziel, unter divergenter Selektion stehende SNPs und Gene zu identifizieren, welche die Anpassung an verschiedene Temperaturen widerspiegeln könnten. Mit Hilfe dieses Experimentes war es möglich, potentiell positiv selektiere Kandidatengene zu identifizieren, welche im Zusammenhang mit dem „Lipidmetabolismus“, dem „Metabolismus und Abbau von Xenobiotika“ sowie dem „Sensorischen System“ stehen. Diese Kandidatengene lassen Rückschlüsse auf lokale Anpassungen zu. Es konnten keine genetischen Unterschiede gefunden werden, die im Zusammenhang mit der Temperaturanpassung der beiden untersuchten Evolutionslinien stehen. Um molekulare Grundlagen für die Toleranz von B. calyciflorus s.s für einen großen Temperaturbereich zu identifizieren, wurde das Transkriptom untersucht. Mit Hilfe der erhobenen Daten konnten Kandidatengene identifiziert werden, die für die Temperaturtoleranz von Bedeutung sind. Der letzte Teil dieser Arbeit konzentrierte sich auf die Untersuchung der Hitzestressantwort in einer hitzetoleranten und einer hitzesensitiven Brachionus Art. Diese Untersuchung konnte erhebliche Unterschiede in den Genexpre-ssionsmustern der beiden Arten aufzeigen. Die deutlichsten Unterschiede der Genexpression wurden hierbei in der Expression von Genen detektiert, die für die sogenannten Hitze-Schock-Proteinen (Heat-shock-proteins: hsp) codieren. In der hitzetoleranten Art B. calyciflorus s.s wurde ein signifikanter Anstieg der hsp-Genexpression bei geringen Temperaturen festgestellt, während bei der hitzesensitiven Art B. fernandoi ein signifikanter Anstieg bei hohen Temperaturen detektiert wurde. Die in dieser Arbeit gefundenen Unterschiede in der Genexpression zeigen, dass Temperaturstress eine Hemmung der Proteinbiosynthese bewirken kann, was zu einer erhöhten Thermotoleranz führt. Darüber hinaus ist Populationswachstum mit der Expression von Hitze-Schock-Proteingenen korreliert. Dies deutet darauf hin, dass die hier beschriebene physiologische Temperaturstressantwort tatsächlich mit den beobachteten phänotypischen Fitnessparametern im Zusammenhang steht. KW - Brachionus KW - zooplankton KW - temperature KW - RNA-seq KW - transcriptome KW - adaptation Y1 - 2019 ER - TY - JOUR A1 - Mardoukhi, Ahmad A1 - Mardoukhi, Yousof A1 - Hokka, Mikko A1 - Kuokkala, Veli-Tapani T1 - Effects of test temperature and low temperature thermal cycling on the dynamic tensile strength of granitic rocks JF - Rock mechanics and rock engineering N2 - This paper presents an experimental procedure for the characterization of the granitic rocks on a Mars-like environment. To gain a better understanding of the drilling conditions on Mars, the dynamic tensile behavior of the two granitic rocks was studied using the Brazilian disc test and a Split Hopkinson Pressure Bar. The room temperature tests were performed on the specimens, which had gone through thermal cycling between room temperature and - 70 degrees C for 0, 10, 15, and 20 cycles. In addition, the high strain rate Brazilian disc tests were carried out on the samples without the thermal cyclic loading at test temperatures of - 30 degrees C, - 50 degrees C, and - 70 degrees C. Microscopy results show that the rocks with different microstructures respond differently to cyclic thermal loading. However, decreasing the test temperature leads to an increasing in the tensile strength of both studied rocks, and the softening of the rocks is observed for both rocks as the temperature reaches - 70 degrees C. This paper presents a quantitative assessment of the effects of the thermal cyclic loading and temperature on the mechanical behavior of studied rocks in the Mars-like environment. The results of this work will bring new insight into the mechanical response of rock material in extreme environments. KW - granite KW - dynamic loading KW - high strain rate KW - fractal dimension KW - low KW - temperature KW - split Hopkinson pressure bar Y1 - 2020 U6 - https://doi.org/10.1007/s00603-020-02253-6 SN - 0723-2632 SN - 1434-453X VL - 54 IS - 1 SP - 443 EP - 454 PB - Springer CY - Wien ER - TY - JOUR A1 - Reschke, Maria A1 - Kröner, Igor A1 - Laepple, Thomas T1 - Testing the consistency of Holocene and Last Glacial Maximum spatial correlations in temperature proxy records JF - Journal of quaternary science : JQS N2 - Holocene temperature proxy records are commonly used in quantitative synthesis and model-data comparisons. However, comparing correlations between time series from records collected in proximity to one another with the expected correlations based on climate model simulations indicates either regional or noisy climate signals in Holocene temperature proxy records. In this study, we evaluate the consistency of spatial correlations present in Holocene proxy records with those found in data from the Last Glacial Maximum (LGM). Specifically, we predict correlations expected in LGM proxy records if the only difference to Holocene correlations would be due to more time uncertainty and more climate variability in the LGM. We compare this simple prediction to the actual correlation structure in the LGM proxy records. We found that time series data of ice-core stable isotope records and planktonic foraminifera Mg/Ca ratios were consistent between the Holocene and LGM periods, while time series of Uk'37 proxy records were not as we found no correlation between nearby LGM records. Our results support the finding of highly regional or noisy marine proxy records in the compilation analysed here and suggest the need for further studies on the role of climate proxies and the processes of climate signal recording and preservation. KW - Holocene KW - LGM KW - spatial correlation KW - temperature KW - Uk'37 Y1 - 2020 U6 - https://doi.org/10.1002/jqs.3245 SN - 0267-8179 SN - 1099-1417 VL - 36 IS - 1 SP - 20 EP - 28 PB - Wiley CY - New York ER - TY - JOUR A1 - Aldiyarov, Abdurakhman A1 - Sokolov, Dmitriy A1 - Akylbayeva, Aigerim A1 - Nurmukan, Assel A1 - Tokmoldin, Nurlan T1 - On thermal stability of cryovacuum deposited CH4+H2O films JF - Low temperature physics N2 - Whereas stable homogenous states of aqueous hydrocarbon solutions are typically observed at high temperatures and pressures far beyond the critical values corresponding to individual components, the stability of such system may be preserved upon transition into the region of metastable states at low temperatures and low pressures. This work is dedicated to the study of the thermal stability of a water-methane mixture formed by cryogenic vapor phase deposition. The obtained thin films were studied using vibrational spectroscopy in the temperature range of 16-180 K. During thermal annealing of the samples, characteristic vibrational C-H modes of methane were monitored alongside the chamber pressure to register both structural changes and desorption of the film material. The obtained results reveal that upon the co-deposition of methane and water, methane molecules appear both in non-bound and trapped states. The observed broadening of the characteristic C-H stretching mode at 3010 cm(-1) upon an increase in temperature of the sample from 16 to 90 K, followed by narrowing of the peak as the temperature is reduced back to 16 K, indicates localization of methane molecules within the water matrix at lower temperatures. KW - molecular crystals KW - water-methane films KW - vibrational spectroscopy KW - low KW - temperature KW - methane localization Y1 - 2020 U6 - https://doi.org/10.1063/10.0002156 SN - 1063-777X SN - 1090-6517 VL - 46 IS - 11 SP - 1121 EP - 1124 PB - American Institute of Physics CY - Melville ER - TY - JOUR A1 - Rainer, Edda M. A1 - Seppey, Christophe Victor William A1 - Hammer, Caroline A1 - Svenning, Mette M. A1 - Tveit, Alexander Tosdal T1 - The influence of above-ground herbivory on the response of Arctic soil methanotrophs to increasing CH4 concentrations and temperatures JF - Microorganisms : open access journal N2 - Rising temperatures in the Arctic affect soil microorganisms, herbivores, and peatland vegetation, thus directly and indirectly influencing microbial CH4 production. It is not currently known how methanotrophs in Arctic peat respond to combined changes in temperature, CH4 concentration, and vegetation. We studied methanotroph responses to temperature and CH4 concentration in peat exposed to herbivory and protected by exclosures. The methanotroph activity was assessed by CH4 oxidation rate measurements using peat soil microcosms and a pure culture of Methylobacter tundripaludum SV96, qPCR, and sequencing of pmoA transcripts. Elevated CH4 concentrations led to higher CH4 oxidation rates both in grazed and exclosed peat soils, but the strongest response was observed in grazed peat soils. Furthermore, the relative transcriptional activities of different methanotroph community members were affected by the CH4 concentrations. While transcriptional responses to low CH4 concentrations were more prevalent in grazed peat soils, responses to high CH4 concentrations were more prevalent in exclosed peat soils. We observed no significant methanotroph responses to increasing temperatures. We conclude that methanotroph communities in these peat soils respond to changes in the CH4 concentration depending on their previous exposure to grazing. This "conditioning " influences which strains will thrive and, therefore, determines the function of the methanotroph community. KW - methanotroph KW - methane oxidation KW - pmoA amplicon sequencing KW - Methylobacter KW - grazing pressure KW - peat soil microcosms KW - temperature KW - Arctic Y1 - 2021 U6 - https://doi.org/10.3390/microorganisms9102080 SN - 2076-2607 VL - 9 IS - 10 PB - MDPI CY - Basel ER - TY - JOUR A1 - López de Guereñu Kurganova, Anna A1 - Klier, Dennis Tobias A1 - Haubitz, Toni A1 - Kumke, Michael Uwe T1 - Influence of Gd3+ doping concentration on the properties of Na(Y,Gd)F-4 BT - Yb3+, Tm3+ upconverting nanoparticles and their long-term aging behavior JF - Photochemical & photobiological sciences / European Society for Photobiology N2 - We present a systematic study on the properties of Na(Y,Gd)F-4-based upconverting nanoparticles (UCNP) doped with 18% Yb3+, 2% Tm3+, and the influence of Gd3+ (10-50 mol% Gd3+). UCNP were synthesized via the solvothermal method and had a range of diameters within 13 and 50 nm. Structural and photophysical changes were monitored for the UCNP samples after a 24-month incubation period in dry phase and further redispersion. Structural characterization was performed by means of X-ray diffraction (XRD), transmission electron microscopy (TEM) as well as dynamic light scattering (DLS), and the upconversion luminescence (UCL) studies were executed at various temperatures (from 4 to 295 K) using time-resolved and steady-state spectroscopy. An increase in the hexagonal lattice phase with the increase of Gd3+ content was found, although the cubic phase was prevalent in most samples. The Tm3+-luminescence intensity as well as the Tm3+-luminescence decay times peaked at the Gd3+ concentration of 30 mol%. Although the general upconverting luminescence properties of the nanoparticles were preserved, the 24-month incubation period lead to irreversible agglomeration of the UCNP and changes in luminescence band ratios and lifetimes. KW - Upconversion luminescence KW - Lanthanides KW - Near infra-red KW - Ultra-low KW - temperature KW - Time-resolved spectroscopy Y1 - 2022 U6 - https://doi.org/10.1007/s43630-021-00161-4 SN - 1474-905X SN - 1474-9092 VL - 21 IS - 2 SP - 235 EP - 245 PB - Springer CY - Heidelberg ER -