TY - JOUR A1 - Bjorneras, C. A1 - Weyhenmeyer, G. A. A1 - Evans, C. D. A1 - Gessner, M. O. A1 - Großart, Hans-Peter A1 - Kangur, K. A1 - Kokorite, I. A1 - Kortelainen, P. A1 - Laudon, H. A1 - Lehtoranta, J. A1 - Lottig, N. A1 - Monteith, D. T. A1 - Noges, P. A1 - Noges, T. A1 - Oulehle, F. A1 - Riise, G. A1 - Rusak, J. A. A1 - Raike, A. A1 - Sire, J. A1 - Sterling, S. A1 - Kritzberg, E. S. T1 - Widespread Increases in Iron Concentration in European and North American Freshwaters JF - Global biogeochemical cycles N2 - Recent reports of increasing iron (Fe) concentrations in freshwaters are of concern, given the fundamental role of Fe in biogeochemical processes. Still, little is known about the frequency and geographical distribution of Fe trends or about the underlying drivers. We analyzed temporal trends of Fe concentrations across 340 water bodies distributed over 10 countries in northern Europe and North America in order to gain a clearer understanding of where, to what extent, and why Fe concentrations are on the rise. We found that Fe concentrations have significantly increased in 28% of sites, and decreased in 4%, with most positive trends located in northern Europe. Regions with rising Fe concentrations tend to coincide with those with organic carbon (OC) increases. Fe and OC increases may not be directly mechanistically linked, but may nevertheless be responding to common regional-scale drivers such as declining sulfur deposition or hydrological changes. A role of hydrological factors was supported by covarying trends in Fe and dissolved silica, as these elements tend to stem from similar soil depths. A positive relationship between Fe increases and conifer cover suggests that changing land use and expanded forestry could have contributed to enhanced Fe export, although increases were also observed in nonforested areas. We conclude that the phenomenon of increasing Fe concentrations is widespread, especially in northern Europe, with potentially significant implications for wider ecosystem biogeochemistry, and for the current browning of freshwaters. Y1 - 2017 U6 - https://doi.org/10.1002/2017GB005749 SN - 0886-6236 SN - 1944-9224 VL - 31 SP - 1488 EP - 1500 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Plue, Jan A1 - De Frenne, Pieter A1 - Acharya, Kamal A1 - Brunet, Jörg 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 - Verheyen, Kris A1 - Wulf, Monika A1 - Cousins, Sara A. O. T1 - Where does the community start, and where does it end? BT - including the seed bank to reassess forest herb layer responses to the environment JF - Journal of vegetation science N2 - QuestionBelow-ground processes are key determinants of above-ground plant population and community dynamics. Still, our understanding of how environmental drivers shape plant communities is mostly based on above-ground diversity patterns, bypassing below-ground plant diversity stored in seed banks. As seed banks may shape above-ground plant communities, we question whether concurrently analysing the above- and below-ground species assemblages may potentially enhance our understanding of community responses to environmental variation. LocationTemperate deciduous forests along a 2000km latitudinal gradient in NW Europe. MethodsHerb layer, seed bank and local environmental data including soil pH, canopy cover, forest cover continuity and time since last canopy disturbance were collected in 129 temperate deciduous forest plots. We quantified herb layer and seed bank diversity per plot and evaluated how environmental variation structured community diversity in the herb layer, seed bank and the combined herb layer-seed bank community. ResultsSeed banks consistently held more plant species than the herb layer. How local plot diversity was partitioned across the herb layer and seed bank was mediated by environmental variation in drivers serving as proxies of light availability. The herb layer and seed bank contained an ever smaller and ever larger share of local diversity, respectively, as both canopy cover and time since last canopy disturbance decreased. Species richness and -diversity of the combined herb layer-seed bank community responded distinctly differently compared to the separate assemblages in response to environmental variation in, e.g. forest cover continuity and canopy cover. ConclusionsThe seed bank is a below-ground diversity reservoir of the herbaceous forest community, which interacts with the herb layer, although constrained by environmental variation in e.g. light availability. The herb layer and seed bank co-exist as a single community by means of the so-called storage effect, resulting in distinct responses to environmental variation not necessarily recorded in the individual herb layer or seed bank assemblages. Thus, concurrently analysing above- and below-ground diversity will improve our ecological understanding of how understorey plant communities respond to environmental variation. KW - Above-ground KW - Below-ground KW - Canopy KW - Disturbance KW - Diversity KW - Light availability KW - NWEurope KW - Plant community KW - Species co-existence KW - Storage effect Y1 - 2017 U6 - https://doi.org/10.1111/jvs.12493 SN - 1100-9233 SN - 1654-1103 VL - 28 IS - 2 SP - 424 EP - 435 PB - Wiley CY - Hoboken ER - TY - JOUR A1 - Koc-Januchta, Marta A1 - Höffler, Tim A1 - Thoma, Gun-Brit A1 - Prechtl, Helmut A1 - Leutner, Detlev T1 - Visualizers versus verbalizers BT - Effects of cognitive style on learning with texts and pictures - An eye-tracking study JF - Computers in human behavior N2 - This study was conducted in order to examine the differences between visualizers and verbalizers in the way they gaze at pictures and texts while learning. Using a collection of questionnaires, college students were classified according to their visual or verbal cognitive style and were asked to learn about two different, in terms of subject and type of knowledge, topics by means of text-picture combinations. Eye-tracking was used to investigate their gaze behavior. The results show that visualizers spent significantly more time inspecting pictures than verbalizers, while verbalizers spent more time inspecting texts. Results also suggest that both visualizers' and verbalizers' way of learning is active but mostly within areas providing the source of information in line with their cognitive style (pictures or text). Verbalizers tended to enter non-informative, irrelevant areas of pictures sooner than visualizers. The comparison of learning outcomes showed that the group of visualizers achieved better results than the group of verbalizers on a comprehension test. KW - Cognitive style KW - Verbalizer KW - Visualizer KW - Eye-tracking KW - Multimedia learning Y1 - 2016 U6 - https://doi.org/10.1016/j.chb.2016.11.028 SN - 0747-5632 SN - 1873-7692 VL - 68 SP - 170 EP - 179 PB - Elsevier CY - Oxford ER - TY - JOUR A1 - Dong, Chao A1 - Yang, Jing A1 - Reschke, Stefan A1 - Leimkühler, Silke A1 - Kirk, Martin L. T1 - Vibrational Probes of Molybdenum Cofactor-Protein Interactions in Xanthine Dehydrogenase JF - Inorganic chemistry N2 - The pyranopterin dithiolene (PDT) ligand is an integral component of the molybdenum cofactor (Moco) found in all molybdoenzymes with the sole exception of nitrogenase. However, the roles of the PDT in catalysis are still unknown. The PDT is believed to be bound to the proteins by an extensive hydrogen bonding network, and it has been suggested that these interactions may function to fine-tune Moco for electron- and atom-transfer reactivity in catalysis. Here, we use resonance Raman (rR) spectroscopy to probe Moco-protein interactions using heavy-atom congeners of lumazine, molecules that bind tightly to both wild-type xanthine dehydrogenase (wt-XDH) and its Q102G and Q197A variants following enzymatic hydroxylation to the corresponding violapterin product molecules. The resulting enzyme-product complexes possess intense near-IR absorption, allowing high-quality rR spectra to be collected on wt-XDH and the Q102G and Q197A variants. Small negative frequency shifts relative to wt-XDH are observed for the low-frequency Moco vibrations. These results are interpreted in the context of weak hydrogen-bonding and/or electrostatic interactions between Q102 and the -NH2 terminus of the PDT, and between Q197 and the terminal oxo of the Mo equivalent to O group. The Q102A, Q102G, Q197A, and Q197E variants do not appreciably affect the kinetic parameters k(red) and k(red)/K-D, indicating that a primary role for these glutamine residues is to stabilize and coordinate Moco in the active site of XO family enzymes but to not directly affect the catalytic throughput. Raman frequency shifts between wt-XDH and its Q102G variant suggest that the changes in the electron density at the Mo ion that accompany Mo oxidation during electron-transfer regeneration of the catalytically competent active site are manifest in distortions at the distant PDT amino terminus. This implies a primary role for the PDT as a conduit for facilitating enzymatic electron-transfer reactivity in xanthine oxidase family enzymes. Y1 - 2017 U6 - https://doi.org/10.1021/acs.inorgchem.7b00028 SN - 0020-1669 SN - 1520-510X VL - 56 SP - 6830 EP - 6837 PB - American Chemical Society CY - Washington ER - TY - THES A1 - Yang, Lei T1 - Verification of systemic mRNAs mobility and mobile functions Y1 - 2017 ER - TY - THES A1 - Zimmermann, Heike Hildegard T1 - Vegetation changes and treeline dynamics in northern Siberia since the last interglacial revealed by sedimentary ancient DNA metabarcoding and organelle genome assembly of modern larches Y1 - 2017 ER - TY - JOUR A1 - Reil, Daniela A1 - Imholt, Christian A1 - Rosenfeld, Ulrike M. A1 - Drewes, Stephan A1 - Fischer, S. A1 - Heuser, Emil A1 - Petraityte-Burneikiene, Rasa A1 - Ulrich, R. G. A1 - Jacob, J. T1 - Validation of the Puumala virus rapid field test for bank voles in Germany JF - Epidemiology and infection N2 - Puumala virus (PUUV) causes many human infections in large parts of Europe and can lead to mild to moderate disease. The bank vole (Myodes glareolus) is the only reservoir of PUUV in Central Europe. A commercial PUUV rapid field test for rodents was validated for bank-vole blood samples collected in two PUUV-endemic regions in Germany (North Rhine-Westphalia and Baden-Wurttemberg). A comparison of the results of the rapid field test and standard ELISAs indicated a test efficacy of 93-95%, largely independent of the origin of the antigens used in the ELISA. In ELISAs, reactivity for the German PUUV strain was higher compared to the Swedish strain but not compared to the Finnish strain, which was used for the rapid field test. In conclusion, the use of the rapid field test can facilitate short-term estimation of PUUV seroprevalence in bank-vole populations in Germany and can aid in assessing human PUUV infection risk. KW - Antibody detection KW - early warning KW - Europe KW - hantavirus KW - Myodes glareolus Y1 - 2017 U6 - https://doi.org/10.1017/S0950268816002557 SN - 0950-2688 SN - 1469-4409 VL - 145 IS - 3 SP - 434 EP - 439 PB - Cambridge Univ. Press CY - New York ER - TY - THES A1 - Sedaghatmehr, Mastoureh T1 - Unraveling the regulatory mechanisms of heat stress memory in Arabidopsis thaliana Y1 - 2017 ER - TY - THES A1 - Weiß, Lina T1 - Understanding the emergence and maintenance of biodiversity in grasslands BT - linking individual plant responses to community patterns Y1 - 2017 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 -