ALBERT

Description: INHALT: Harth, W.: VLF-Atmospherics ‒ Ihre Messung und ihre Interpretation (S. 815); Kremser, G., A. Korth, K. H. Saeger, P. A. Jensen, V. N. Jensen, J. Taagholt: On the Longitudinal Extension of Electron Precipitation During Magnetospheric Substorms (S. 815); Stüdemann, W.: Untersuchung der Richtungsverteilung energiereicher Elektronen und Protonen im Morgensektor der Polarlichtzone während erhöhten Teilcheneinfalles (S. 863); Klostermeyer, J.: Influence of Viscosity, Thermal Conduction, and Ion Drag on the Propagation of Atmospheric Gravity Waves in the Thermosphere (S. 881); Schmidt, G.: Determination of the Height of Ionospheric Irregularities with the Holographic Method (S. 891); Eichmeier, J.: Vergleich der Beweglichkeitsspektren von „natürlichen“ Luftionen und der verwendeten Meßverfahren (S. 915); Kohnen, H.: Über die Beziehung zwischen seismischen Geschwindigkeiten und der Dichte in Firn und Eis (S. 925); D. Heye und H. Meyer: Ein Meßverfahren zur paläomagnetischen Messung an Tiefseesedimentkernen an Bord eines Schiffes (S. 937); Ernstson, K.: Geoelektrische Messungen im Nördlinger Ries ‒ Zum Verlauf des inneren Walls (S. 949); ‒ Brief an den Herausgeber ‒ R. Kramm, K. Schlegel and W. Weiss: Partial Reflection Measurements with FM-CW ‒ A Preliminary Investigation (S. 953); ‒ Brief an den Herausgeber ‒ Losecke, W.: Über die Bestimmung von Salzstockgrenzflächen mit Hilfe der Magnetotellurik (S. 959); Buchbesprechungen (S. 963).

Description: research

Description: DFG, SUB Göttingen

Description: Rock fractures play a major role in many geological processes, such as plate tectonics, earthquakes, volcanic eruptions and fluid transport in the earthś crust. The present volume contains the abstracts of all presentations of the symposium Rock Fractures in Geological Processes, held on 26-27 November 2013 in London honouring the 60th birthday of Ágúst Guðmundsson, chair in Structural Geology, Royal Holloway University of London, a leading expert in the field and author of a well known text book of the same title. The symposium covered all topics related to fractures in the earthś crust, e.g., crustal stresses, rock mechanical properties, field analysis of fractures - from joints and faults to mineral veins and dykes - , analytical, analogue and numerical models of fractures and related fluid transport, as well as the activity of faults and volcanoes including calderas, and economic aspects such as exploration and exploitation of hydrocarbons and geothermal energy.

Description: research

Description: conference

Description: Dieser Band enthält 26 Artikel zu Themengebieten der Geophysik, veröffentlicht durch die Deutsche Geophysikalische Gesellschaft in dem Jahr 1986.

Description: Inhaltsverzeichnis: Journal of Geophysics 60 〈html〉 〈body〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0011.pdf"〉Investigation of the velocity- and Q-structure of the lowermost mantle using 〈i〉PcP〈/i〉/〈i〉P〈/i〉 amplitude ratios from arrays at distances of 70°–84°〈/a〉〈br〉 (Schlittenhardt, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0014.pdf"〉Fast plane-wave and single-shot migration by Fourier transform〈/a〉〈br〉 (Temme, P., Müller, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0015.pdf"〉A method of calculating lithosphere thickness from observations of deglacial land uplift and tilt〈/a〉〈br〉 (Wolf, D.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0016.pdf"〉Volcanoes, fountains, earthquakes, and continental motion – What causes them? 〈/a〉〈br〉 (Kundt, W., Jessner, A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0017.pdf"〉Magnetic properties and oxidation experiments with synthetic olivines〈/a〉〈br〉 (Fe〈sub〉χ〈/sub〉Mg〈sub〉1–χ〈/sub〉)〈sub〉2〈/sub〉SiO〈sub〉4〈/sub〉, 0≦χ≦1 (Hoffmann, V., Soffel, H.C.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0018.pdf"〉Magnetic mineralogy of basalts from El-Bahnasa and Tahna, Egypt〈/a〉〈br〉 (Wassif, N.A.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0020.pdf"〉On the use of line current analogues in geomagnetic depth sounding〈/a〉〈br〉 (Jones, A.G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0021.pdf"〉Observations of the VLF quiet band phenomenon〈/a〉〈br〉 (Matthews, J.P.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0022.pdf"〉In memoriam Gustav Adolf Schulze (1911–1986)〈/a〉〈br〉 (Dürschner, H.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0023.pdf"〉Book reviews〈/a〉〈br〉 (Berckhemer, H., Dieminger, W., Engelhard, L.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0024.pdf"〉Hydromagnetic waves at low latitudes: a symposium review from the fifth IAGA assembly〈/a〉〈br〉 (Fraser, B.J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0025.pdf"〉Generation and propagation mechanisms of low-latitude magnetic pulsations – A review〈/a〉〈br〉 (Yumoto, K.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0026.pdf"〉Experimental aspects of low-latitude pulsations - A review〈/a〉〈br〉 (Verö, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0027.pdf"〉GRF broad-band array analysis of the 1982 Miramichi, New Brunswick earthquake sequence〈/a〉〈br〉 (Basham, P.W., Kind, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0028.pdf"〉Rockmagnetism and palaeomagnetism of an early Cretaceous/Late Jurassic dike swarm in Rio Grande do Norte, Brazil〈/a〉〈br〉 (Bücker, C., Schult, A., Bloch, W., Guerreiro, S.D.C.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0029.pdf"〉Second Conference on Scientific Ocean Drilling〈/a〉〈br〉 (COSOD II)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0030.pdf"〉Book reviews〈/a〉〈br〉 (Jentzsch, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0031.pdf"〉Deep-seated lateral velocity variations beneath the GRF array inferred from mislocation patterns and P residuals〈/a〉〈br〉 (Faber, S., Plomerová, J., Babuška, V.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0034.pdf"〉Lateral variations of the structure of the crust-mantle boundary from conversions of teleseismic 〈i〉P〈/i〉 waves〈/a〉〈br〉 (Qiyuan, L., Kind, R.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0035.pdf"〉Cross spectral analysis of Swabian Jura (SW Germany) three-component microearthquake recordings〈/a〉〈br〉 (Scherbaum, F., Wendler, J.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0036.pdf"〉The retrieval of the seismic moment tensor from first-order perturbation theory and generation of compatible models〈/a〉〈br〉 (Lana, X., Correig, A.M.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0037.pdf"〉Impulsive processes in the magnetotail during substorm expansion〈/a〉〈br〉 (Sergeev, V.A., Bösinger, T., Lui, A.T.Y)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0038.pdf"〉Spatial and temporal characteristics of impulsive structure of magnetospheric substorm〈/a〉〈br〉 (Sergeev, V.A., Pellinen, R.J., Bösinger, T., Baumjohann, W., Stauning, P., Lui, A.T.Y.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0039.pdf"〉Seismic signal velocity in absorbing media〈/a〉〈br〉 (Schmidt, T., Müller, G.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0040.pdf"〉In memoriam Nachruf Professor Ludwig Biermann〈/a〉〈br〉 (Treffitz, E.)〈/a〉〈/li〉 〈li〉〈a href="https://gdz.sub.uni-goettingen.de/download/pdf/PPN1015067948_0060/LOG_0041.pdf"〉Book Reviews〈/a〉〈br〉 (Korn, M.)〈/a〉〈/li〉 〈/body〉 〈/html〉

Description: research

Description: DFG, SUB Göttingen

Description: The results indicate that every bromeliad tank is a unique island with respect to its resident microbial community. The presence of methanogens and active methanotrophs in all tank slurries further indicates the potential for both methane formation and methane oxidation.

Description: Max Planck Gesellschaft; LOEWE (Synmicro) Programm der hessischen Landesregierung zur Entwicklung wissenschaftlicher-ökonomischer Exzellenz

Description: research

Description: Institut für Geographische Wissenschaften, Freie Universität Berlin

Description: research

Description: We focus on new gravity and gravity gradient data sets from modern satellite missions GOCE, GRACE and CHAMP, and their geophysical interpretation at passive continental margins of the South Atlantic. Both sides, South Africa and South America, have been targets of hydrocarbon exploration and academic research of the German Priority Program SAMPLE (South Atlantic Margin Processes and Links with onshore Evolution). The achievable spatial resolution, driven by GOCE, is 70–80 km. Therefore, most of the geological structures, which cause a significant gravity effect (by both size and density contrast), can be resolved. However, one of the most important aspects is the evaluation of the omission error, which is not always in the focus of interpreters. It results from high-frequency signals of very rough topographic and bathymetric structures, which cannot be resolved by satellite gravimetry due to the exponential signal attenuation with altitude. The omission error is estimated from the difference of the combined gravity model EIGEN-6C4 and the satellite-only model GOCO05S. It can be significantly reduced by topographic reductions. Simple 2D density models and their related mathematical formulas provide insights in the magnitude of the gravity effect of masses that form a passive continental margin. They are contrasted with results from satellite-only and combined gravity models. Example geophysical interpretations are given for the western and eastern margin of the South Atlantic Ocean, where standard deviations vary from 25 to 16 mGal and 21–11 mGal, respectively. It could be demonstrated, that modern satellite gravity data provide significant added value in the geophysical gravity data processing domain and in the validation of heterogeneous terrestrial data bases. Combined models derived from high-resolution terrestrial gravity and homogeneous satellite data will lead to more detailed and better constrained lithospheric density models, and hence will improve our knowledge about structure, evolution and state of stress in the lithosphere.

Description: DFG

Description: research

Description: The mechanism of granting Economic Land Concessions (ELCs) to (inter-)national investors for agro-industrial exploitation was the starting point of a wave of large-scale land acquisitions in Cambodia since the Royal Government of Cambodia (RGC) issued a respective directive in 2005. While ELCs are supposed to combine overall economic benefits on the one hand with poverty reduction and the compliance with environmental standards on the other hand, it turned out that there is a wide gap between the legal framework, which is supposed to govern the granting of ELCs, and its actual implementation on the ground. Eventually, the granting of ELCs led to severe human rights violations and several land conflicts, involving the local population, investor companies, political and economic elites as well as authorities. This situation is especially difficult for the Indigenous Peoples of Cambodia, who not just struggle to claim rights to their lands, but for whom land is also an essential component of livelihood. Drawing on a literature review and the results of a two-month field study, this thesis aims at shedding light at the relationship between different actors of society and land as a resource in the context of asymmetrical power constellations within the land conflict of Samot Leu Village in Seda Commune, Lumphat District, Ratanakiri Province.

Description: Stiftung der Deutschen Wirtschaft (sdw)

Description: research

Description: The temperate Eurasian steppe (TES) is a region where various environmental, social, and economic stresses converge. Multiple types of disturbance exist widely across the landscape, and heavily influence carbon cycling in this region. However, a current quantitative assessment of the impact of disturbances on carbon sequestration is largely lacking. In this study, we combined the boreal ecosystem productivity simulator (BEPS), the Shiyomi grazing model, and the global fire model (Glob-FIRM) to investigate the impact of the two major types of disturbance in the TES (i.e. domestic grazing and fire) on regional carbon sequestration. Model performance was validated using satellite data and field observations. Model outputs indicate that disturbance has a significant impact on carbon sequestration at a regional scale. The annual total carbon lost due to disturbances was 7.8 TgCyr−1, accounting for 14.2% of the total net ecosystem productivity (NEP). Domestic grazing plays the dominant role in terrestrial carbon consumption, accounting for 95% of the total carbon lost from the two disturbances. Carbon losses from both disturbances significantly increased from 1999 to 2008 (R2=0.82, P 〈 0.001 for grazing, R2=0.51, P〈0.05 for fire). Heavy domestic grazing in relatively barren grasslands substantially reduced carbon sequestration, particularly in the grasslands of Turkmenistan, Uzbekistan, and the far southwest of Inner Mongolia. This spatially-explicit information has potential implications for sustainable management of carbon sequestration in the vast grassland ecosystems.

Description: The Sierras Pampeanas in central and north-western Argentina constitute a distinct morphotectonic feature between 27°S and 33°S. The last stage of uplift and deformation in this area are interpreted to be closely related to the Andean flat-slab subduction of the Nazca plate beneath the South American plate. K–Ar fault gouge dating and low-temperature thermochronology along two transects within the Sierra de Comechingones reveal a minimum age for the onset of brittle deformation about 340 Ma, very low exhumation rates since Late Paleozoic time, as well as a total exhumation of about 2.3 km since the Late Cretaceous. New Ar–Ar ages (7.54–1.91 Ma) of volcanic rocks from the San Luis volcanic belt support the eastward propagation of the flat-slab magmatic front, confirming the onset of flat-slab related deformation in this region at 11.2 Ma. Although low-temperature thermochronology does not clearly constrain the signal of the Andean uplift, it is understood that the current structural relief related to the Comechingones range has been achieved after the exhumation of both fault walls (circa 80–70 Ma).

Description: Open-Access Publikationsfonds 2015

Description: THESIS ABSTRACT

Description: research

Description: Microbial iron oxyhydroxides are common deposits in natural waters, recent sediments, and mine drainage systems. Along with these minerals, trace and rare earth elements (TREE) are being accumulated within the mineralizing microbial mats. TREE patterns are widely used to characterize minerals and rocks, and to elucidate their evolution and origin. However, whether and which characteristic TREE signatures distinguish between a biological and an abiological origin of iron minerals is still not well-understood. Here we report on long-term flow reactor studies performed in the Tunnel of Äspö (Äspö Hard Rock Laboratory, Sweden). The development of microbial mats dominated by iron-oxidizing bacteria (FeOB), namely Mariprofundus sp. and Gallionella sp were investigated. The feeder fluids of the flow reactors were tapped at 183 and 290 m below sea-level from two brackish, but chemically different aquifers within the surrounding, ~1.8 Ga old, granodioritic rocks. The experiments investigated the accumulation and fractionation of TREE under controlled conditions of the subsurface continental biosphere, and enabled us to assess potential biosignatures evolving within the microbial iron oxyhydroxides. After 2 and 9 months, concentrations of Be, Y, Zn, Zr, Hf, W, Th, Pb, and U in the microbial mats were 103- to 105-fold higher than in the feeder fluids whereas the rare earth elements and Y (REE+Y) contents were 104- and 106-fold enriched. Except for a hydrothermally induced Eu anomaly, the normalized REE+Y patterns of the microbial iron oxyhydroxides were very similar to published REE+Y distributions of Archaean Banded Iron Formations (BIFs). The microbial iron oxyhydroxides from the flow reactors were compared to iron oxyhydroxides that were artificially precipitated from the same feeder fluid. Remarkably, these abiotic and inorganic iron oxyhydroxides show the same REE+Y distribution patterns. Our results indicate that the REE+Y mirror closely the water chemistry, but they do not allow to distinguish microbially mediated from inorganic iron precipitates. Likewise, all TREE studied showed an overall similar fractionation behavior in biogenic, abiotic, and inorganic iron oxyhydroxides. Exceptions are Ni and Tl, which were only accumulated in the microbial iron oxyhydroxides and may point to a potential utility of these elements as microbial biosignatures.

Description: Preservation of liverworts in amber, a fossilized tree resin, is often exquisite. Twenty-three fossil species of liverworts have been described to date from Eocene (35-50 Ma) Baltic amber. In addition, two inclusions have been assigned to the extant species Ptilidium pulcherrimum (Ptilidiales or Porellales). However, the presence of the boreal P. pulcherrimum in the subtropical or warm-temperate Baltic amber forest challenges the phytogeographical interpretation of the Eocene flora. A re-investigation of one of the fossils believed to be P. pulcherrimum reveals that this specimen in fact represents the first fossil evidence of the genus Tetralophozia, and thus is re-described here as Tetralophozia groehnii sp. nov. A second fossil initially assigned to P. pulcherrimum is apparently lost, and can be reassessed only based on the original description and illustrations. This fossil is morphologically similar to the extant North Pacific endemic Ptilidium californicum, rather than P. pulcherrimum. Divergence time estimates based on chloroplast DNA sequences provide evidence of a Miocene origin of P. pulcherrimum, and thus also argue against the presence of this taxon in the Eocene. Ptilidium californicum originated 25-43 Ma ago. As a result, we cannot rule out that the Eocene fossil belongs to P. californicum. Alternatively, the fossil might represent a stem lineage element of Ptilidium or an early crown group species with morphological similarities to P. californicum.

Description: Open-Access Publikationsfonds 2015

Description: Water treatment with metallic iron (Fe0) is still based on the premise that Fe0 is a reducing agent. An alternative concept stipulates that contaminants are removed by adsorption, co-precipitation and size-exclusion in a reactive filtration process. This article underlines the universal validity of the alternative concept. It is shown that admixing non-expansive material to Fe0 as a pre-requisite for sustainable Fe0-based filtration systems. Fe0-based filters are demonstrated an affordable, appropriate and efficient decentralized water treatment technology.

Description: One of the most important issues in molecular dating studies concerns the incorporation of reliable fossil taxa into the phylogenies reconstructed from DNA sequence variation in extant taxa. Lichens are symbiotic associations between fungi and algae and/or cyanobacteria. Several lichen fossils have been used as minimum age constraints in recent studies concerning the diversification of the Ascomycota. Recent evolutionary studies of Lecanoromycetes, an almost exclusively lichen-forming class in the Ascomycota, have utilized the Eocene amber inclusion Alectoria succinic as a minimum age constraint. However, a re-investigation of the type material revealed that this inclusion in fact represents poorly preserved plant remains, most probably of a root. Consequently, this fossil cannot be used as evidence of the presence of the genus Alectoria (Parmeliaceae, Lecanorales) or any other lichens in the Paleogene. However, newly discovered inclusions from Paleogene Baltic and Bitterfeld amber verify that alectorioid morphologies in lichens were in existence by the Paleogene. The new fossils represent either a lineage within the alectorioid group or belong to the genus Oropogon.

Description: Open-Access-Publikationsfonds 2015

Description: Since its introduction about 25 years ago, metallic iron (Fe0) has shown its potential as the key component of reactive filtration systems for contaminant removal in polluted waters. Technical applications of such systems can be enhanced by numerical simulation of a filter design to improve, e.g., the service time or the minimum permeability of a prospected system to warrant the required output water quality. This communication discusses the relevant input quantities into such a simulation model, illustrates the possible simplifications and identifies the lack of relevant thermodynamic and kinetic data. As a result, necessary steps are outlined that may improve the numerical simulation and, consequently, the technical design of Fe0 filters. Following a general overview on the key reactions in a Fe0 system, the importance of iron corrosion kinetics is illustrated. Iron corrosion kinetics, expressed as a rate constant kiron, determines both the removal rate of contaminants and the average permeability loss of the filter system. While the relevance of a reasonable estimate of kiron is thus obvious, information is scarce. As a conclusion, systematic experiments for the determination of kiron values are suggested to improve the database of this key input parameter to Fe0 filters.

Description: Open-Access Publikationsfonds 2016

Description: Conversion of tropical forests into intensely managed plantations is a threat to ecosystem functions. On Sumatra, Indonesia, oil palm (Elaeis guineensis) plantations are rapidly expanding, displacing rain forests and extensively used rubber (Hevea brasiliensis) agro-forests. Here, we tested the influence of land use systems on root traits including chemical traits (carbon, nitrogen, mineral nutrients, potentially toxic elements [aluminium, iron] and performance traits (root mass, vitality, mycorrhizal colonization). Traits were measured as root community-weighed traits (RCWTs) in lowland rain forests, in rubber agro-forests mixed with rain forest trees, in rubber and oil palm plantations in two landscapes (Bukit Duabelas and Harapan, Sumatra). We hypothesized that RCWTs vary with land use system indicating increasing transformation intensity and loss of ecosystem functions. The main factors found to be related to increasing transformation intensity were declining root vitality and root sulfur, nitrogen, carbon, manganese concentrations and increasing root aluminium and iron concentrations as well as increasing spore densities of arbuscular mycorrhizas. Mycorrhizal abundance was high for arbuscular and low for ectomycorrhizas and unrelated to changes in RCWTs. The decline in RCWTs showed significant correlations with soil nitrogen, soil pH and litter carbon. Thus, our study uncovered a relationship between deteriorating root community traits and loss of ecosystem functionality and showed that increasing transformation intensity resulted in decreasing root nutrition and health. Based on these results we suggest that land management that improves root vitality may enhance the ecological functions of intense tropical production systems.

Description: Oüpen-Access Publikationsfonds 2015

Description: We sketch the eventful life of Willy Stoffregen and summarise his engineering and scientific achievements.

Description: Niphargus is a speciose amphipod genus found in groundwater habitats across Europe. Three Niphargus species living in the sulphidic Frasassi caves in Italy harbour sulphur-oxidizing Thiothrix bacterial ectosymbionts. These three species are distantly related, implying that the ability to form ectosymbioses with Thiothrix may be common among Niphargus. Therefore, Niphargus-Thiothrix associations may also be found in sulphidic aquifers other than Frasassi. In this study, we examined this possibility by analysing niphargids of the genera Niphargus and Pontoniphargus collected from the partly sulphidic aquifers of the Southern Dobrogea region of Romania, which are accessible through springs, wells and Movile Cave. Molecular and morphological analyses revealed seven niphargid species in this region. Five of these species occurred occasionally or exclusively in sulphidic locations, whereas the remaining two were restricted to nonsulphidic areas. Thiothrix were detected by PCR on all seven Dobrogean niphargid species and observed using microscopy to be predominantly attached to their hosts' appendages. 16S rRNA gene sequences of the Thiothrix epibionts fell into two main clades, one of which (herein named T4) occurred solely on niphargids collected in sulphidic locations. The other Thiothrix clade was present on niphargids from both sulphidic and nonsulphidic areas and indistinguishable from the T3 ectosymbiont clade previously identified on Frasassi-dwelling Niphargus. Although niphargids from Frasassi and Southern Dobrogea are not closely related, the patterns of their association with Thiothrix are remarkably alike. The finding of similar Niphargus-Thiothrix associations in aquifers located 1200 km apart suggests that they may be widespread in European groundwater ecosystems.

Description: In the light of global change, the necessity to monitor atmospheric depositions that have relevant effects on ecosystems is ever increasing particularly for tropical sites. For this study, atmospheric ionic depositions were measured on tropical Central Sulawesi at remote sites with both a conventional bulk water collector system (BWS collector) and with a passive ion exchange resin collector system (IER collector). The principle of IER collector to fix all ionic depositions, i.e. anions and cations, has certain advantages referring to (1) post-deposition transformation processes, (2) low ionic concentrations and (3) low rainfall and associated particulate inputs, e.g. dust or sand. The ionic concentrations to be measured for BWS collectors may easily fall below detection limits under low deposition conditions which are common for tropical sites of low land use intensity. Additionally, BWS collections are not as independent from the amount of rain fallen as are IER collections. For this study, the significant differences between both collectors found for nearly all measured elements were partly correlated to the rainfall pattern, i.e. for calcium, magnesium, potassium and sodium. However, the significant differences were, in most cases, not highly relevant. More relevant differences between the systems were found for aluminium and nitrate (434–484 %). Almost five times higher values for nitrate clarified the advantage of the IER system particularly for low deposition rate which is one particularity of atmospheric ionic deposition in tropical sites of extensive land use. The monthly resolution of the IER data offers new insights into the temporal distribution of annual ionic depositions. Here, it did not follow the tropical rain pattern of a drier season within generally wet conditions.

Description: The enormous leaps of growth and development experienced by Eastern and Southeast Asian states since the 1960s on account of their astonishing industrial development have led to concerns that a resulting global economic and political shift might favour the Pacific region at the expense of the "Atlantic region". A "Pacific century" was proclaimed, in which it was predicted that Asian-Pacific countries would outpace the traditional leading powers of the West. A more careful look quickly reveals that this view is too simplistic. From the point of view of various disciplines and covering different nations like China, Vietnam, Indonesia, Singapore, the Philippines and Papua New Guinea the authors of this publication pursue the question whether the 21st century can already be labelled the "Pacific Century". This was also the title of the interdisciplinary series of lectures held at the University of Göttingen/Germany in the winter semester 2003/2004. This series of lectures was jointly organized by the Department of Geography, the University of Göttingen and the Association of Pacific Studies e.V. (APSA). This 10th volume of the publication series "Pazifik Forum" contains contributions by W. Kreisel, M. Taube & Ka-Wai Yiu, M. Waibel, A. Croissant, B. Dahm, H. Schneider, R. Seib and R. Jordan.

Description: The incorporation of hydrogen in enstatite in a hydrous system containing various amounts of NaCl was investigated at 25 kbar. The hydrogen content in enstatite shows a clear negative correlation to the NaCl-concentration in the system. The most favourable explanation is the reduction of water fugacity due to dilution. Other reasons for the limited hydrogen incorporation at high NaCl levels, such as a significant influence of Na+ on the defect chemistry or an exchange between OH- and Cl-in enstatite, appear much less important. A partition coefficient D Na En/Fluid = 0.0013 could be determined, demonstrating that Na is less incompatible in enstatite than H. The new results support the idea that dissolved components have to be considered when the total hydrogen storage capacity in nominally anhydrous minerals is estimated, especially in geological settings with high levels of halogens, such as subduction zones.

Description: The mechanism of aqueous contaminant removal by elemental iron (Fe0) materials (e.g., in Fe0-H2O systems) has been largely discussed in the iron technology literature. Two major removal mechanisms are usually discussed: (i) contaminant adsorption onto Fe0 oxidation products, and (ii) contaminant reduction by Fe0, FeII or H/H2. However, a closer inspection of the chemistry of the Fe0-H2O system reveals that co-precipitation could be the primary removal mechanism. The plausibility of contaminant co-precipitation with iron corrosion products as independent contaminant removal mechanism is discussed here. It shows that the current concept does not take into account that the corrosion product generation is a dynamic process in the course of which contaminants are entrapped in the matrix of iron hydroxides. It is recalled that contaminant co-precipitation with iron hydroxides/oxides is an unspecific removal mechanism. Contaminant co-precipitation as primary removal mechanism is compatible with subsequent reduction and explains why redoxinsensitive species are quantitatively removed. Adsorption and co-precipitation precede reduction and abiotic reduction, when it takes place, occurs independently by a direct (electrons from Fe0) or an indirect (electrons from FeII/H2) mechanism.

Description: The deconvolution of the deformation history of rocks is one of the main goals of texture analysis in geology. The frequent observation that the macroscopic structures are obliquely oriented with respect to the margins of the deformation zone gave rise to the hypotheses that the deformation path might be complex, and that the lattice preferred orientation of the rock-forming minerals should reflect such complicated deformation conditions as well. Hence, texture determinations of polyphase rock samples were carried out and the relationship of the mineral textures to the commonly used sample reference frame foliationlineation, which is assumed to represent the principal axes of the bulk finite strain tensor, was investigated. It was confirmed that particular mineral textures are typical for different stages of the deformation path. Especially the quartz textures exhibit an uncommon but consistent deviation from the sample reference frame, which is consistent with respect to the geographical coordinates, too. Such a characteristic may be used to evaluate the direction of a large-scale horizontal shear component, which is known as the transpressive shear vector in the geological literature.

Description: Texture formation in pure shear deformed rock salt has been studied by neutron diffraction. The textures developed are comparable to those of rolled face-centered cubic metals with high stacking fault energy. At room temperature the texture consists of a strong S and copper and a weaker brass component. It is replaced by static and/or dynamic recrystallization by a strong cube and a subordinate Goss component. Comparison of the experimental textures with simulations based on different models shows that the low temperature high strain deformation texture can be qualitatively well explained by the Taylor model using slip on {110}?110?, {100}?110? and {111}?110? systems with equal critical resolved shear stresses. Relaxation with increasing temperature introduces the cube and Goss component, which may represent the nuclei for recrystallization. The study shows that texturesimulations on salt without considering recrystallization lead to misleading conclusions.

Description: Open-Access-Publikationsfonds 2011

Description: The coprecipitation of U (VI) with iron corrosion products from aqueous solutions by zero valent iron was investigated. The evidence of coprecipitation was demonstrated by conducting experiments with well characterized scrap iron,pyrite and a mixture of both materials with experimental durations of up to four months. Results indicate that under anoxic conditions only less than one tenth of the immobilized U(VI) was associated with the surface of scrap iron, whereas theremaining amount is entrapped in aging corrosion products.

Description: One of the most unexpected insights that followed from the completion of the human genome a decade ago was that more than half of our DNA is derived from transposable elements (TEs). Due to advances in high throughput sequencing technologies it is now clear that TEs comprise the largest molecular class within most metazoan genomes. TEs, once categorised as "junk DNA", are now known to influence genomic structure and function by increasing the coding and non-coding genetic repertoire of the host. In this way TEs are key elements that stimulate the evolution of metazoan genomes. This review highlights several lines of TE research including the horizontal transfer of TEs through host-parasite interactions, the vertical maintenance of TEs over long periods of evolutionary time, and the direct role that TEs have played in generating morphological novelty.

Description: Fossil catshark egg capsules, Scyliorhinotheca goederti gen. et sp. nov., are reported from a Late Eocene deep−water methane−seep calcareous deposit in western Washington State, USA. The capsules are preserved three−dimensionally and some show mineralized remnants of the ribbed capsule wall consisting of small globular crystals that are embedded in a microsparitic matrix. The globules are calcitic, but a strontium content of 2400–3000 ppm suggests that they were origi− nally aragonitic. The carbonate enclosing the egg capsules, and the capsule wall itself, show 13C values as low as −36.5‰, suggesting that formation was induced by the anaerobic oxidation of methane and hence in an anoxic environ− ment. We put forward the following scenario for the mineralization of the capsule wall: (i) the collagenous capsules expe− rienced a sudden change from oxic to anoxic conditions favouring an increase of alkalinity; (ii) this led to the precipitation of aragonitic globules within the collagenous capsule wall; (iii) subsequently the remaining capsule wall was mineralized by calcite or aragonite; (iv) finally the aragonitic parts of the wall recrystallized to calcite. The unusual globular habit of the early carbonate precipitates apparently represents a taphonomic feature, resulting from mineralization mediated by an organic matrix. Taphonomic processes, however, are at best contributed to an increase of alkalinity, which was mostly driven by methane oxidation at the ancient seep site

Description: THESIS ABSTRACT

Description: research

Description: We propose that organic compounds found in a Miocene limestone from Marmorito (Northem Italy) are source markers for organic matter present in aneient methane vent systems (cold seeps). The limestone contains high concentrations of the tail-to-taillinked, acyclic C20 isoprenoid 2,6,11,15-tetramethylhexadecane (crocetane), a C25 homolog 2,6,10,15,19-pentamethylicosane (PME), and a distinctive glycerol ether lipid containing 3,7,1l,15-tetramethylhexadecyl (phytanyl-) moieties. The chemical structures of these biomarkers indicate a common origin from archaea. Their extreme1y l3C-depleted isotope compositions (813C "'" -108 to -115.6%0 PDB) suggest that the respective archaea have directly or indirectly introduced isotopically depleted, methane-derived carbon into their biomass. We postulate that a second major cluster of biomarkers showing heavier isotope values (8l3C "'" -88%0) is derived from sulfate-redueing bacteria (SRB). The observed biomarkers sustain the idea that methanogenic bacteria, in a syntrophic community with SRB, are responsible for the anaerobic oxidation of methane in marine sediments. Marmorito may thus represent a conceivable aneient scenario for methane consumption performed by a defined, two-membered bacterial consortium: (1) archaea that perform reversed methanogenesis by oxidizing methane and produeing CO2 and H2; and (2) SRB that consume the resulting H2. Furthermore, the respective organic molecules are, unlike other compounds, tightly bound to the crystalline carbonate phase. The Marmorito carbonates can thus be regarded as "cold seep microbialites" rather than mere "authigenic" carbonates.

Description: The study investigates the overall vulnerability of vegetation in the River Ili delta (Lake Balkhash, Southern Kazakhstan) to locust hazards using correlation between the normalized difference vegetation index data from advanced very high resolution radiometer and the TOPEX/POSEIDON/JASON-1 satellite altimetry derived water level of Lake Balkhash. The study develops a new monitoring and evaluation system to detect the annual vegetated areas infested by locusts and to quantify the overall recurrence of locust damage in these areas throughout the period 1992 to 2006. The monitoring system-based annual estimations of locust-affected areas were validated against ground survey data. The validation reveals a good correspondence of the estimations with the information from ground truth. The results of the overall vulnerability assessment showed that, for the River Ili delta vegetative land, ∼17% of the total area was characterized by moderate and high vulnerability of vegetation to locust hazards, whereas ∼3% showed low vulnerability. Most parts of the Ili delta area are not sensitive to locust hazard.

Description: The Palaeogene was the most recent greenhouse period on Earth. Especially for the Late Palaeocene and Early Eocene, several superimposed short-term hyperthermal events have been described, including extremes such as the Palaeocene–Eocene Thermal Maximum. Major faunal and floral turnovers in the marine and terrestrial realms were recorded in association with these events. High-resolution palynological analysis of the early Middle Eocene maar lake sediments at Messel, near Darmstadt, Germany, provides an insight into the dynamics of a climax vegetation during the Middle Eocene greenhouse climate in a time span without significant climatic excursions. Numerical techniques like detrended correspondence analysis and wavelet analysis have been applied to recognize cyclic fluctuations and long-term trends in the vegetation through a time interval of approximately 640 kyr. Based on the numerical zoning of the pollen diagram, three phases in the development of the vegetation may be distinguished. Throughout these phases, the climax vegetation did not change substantially in qualitative composition, but a trend towards noticeably less humid conditions probably in combination with a drop of the water level in the lake may be recognized. A shift in algal population from the freshwater dinoflagellate cyst Messelodinium thielepfeifferae to a dominance of Botryococcus in the uppermost part of the core is interpreted as a response to changes in acidity and nutrient availability within the lake. Time series analyses of pollen assemblages show that variations in the Milankovitch range of eccentricity, obliquity and precession can be distinguished. In addition, fluctuations in the sub-Milankovitch range are indicated. This demonstrates that floral changes during steady depositional conditions in the Middle Eocene of Messel were controlled by orbital forcing.

Description: In this paper we report on the herbivore-affected C and N concentrations in the throughfall and altered canopy to soil transfer during a Pine Lappet (Dendrolimus pini L) mass infestation in 60-year-old Scots Pine (Pinus sylvestris L) forests. Our investigations covered a period of 7 months and could show, that herbivore defoliation significantly altered C and N concentrations in the throughfall solution and enhanced organic matter input situation to the forest floor. Compared to the uninfested site mean concentrations of the throughfall solution at the infested site under strong frass activity contained 80% more C and 61% more N. Additionally, C and N inputs were with 131 kg C ha-1 time-1 and 9.6 kg N ha-1 time-1 higher under strong frass activity during 3 months compared to the input at the uninfested site. We assume that outbreaks of phytophagous insects play an important key role in monoculture forest by influencing the nutrient turnover.

Description: In the presented case study, ascomycete fungi and green algae on a marble monument were identified by comparisons of the 18S rRNA gene sequences, which were obtained from DNA either from environmental samples or from enrichment cultures. The organisms were found to be responsible for either black or green surface coverings on different areas of the monument surface. Most fungi were related to plant-inhabiting genera, corresponding to a heavy soiling of the marble surface with honeydew. Whereas green algae of the genera Stichococcus, Chloroidium and Apatococcus were found to be dominant in all samples, isolates of two additional genera were recovered only from enrichment cultures. A reference strain of Apatococcus lobatus and an isolate of Prasiolopsis sp. were investigated with respect to putative surface adhesive structures of the cell envelope. The Prasiolopsis cell walls were covered with a thin adhesive exopolysaccharide layer involved in biofilm formation.

Description: Due to its extreme salinity and high Mg concentration the Dead Sea is characterized by a very low density of cells most of which are Archaea. We discovered several underwater fresh to brackish water springs in the Dead Sea harboring dense microbial communities. We provide the first characterization of these communities, discuss their possible origin, hydrochemical environment, energetic resources and the putative biogeochemical pathways they are mediating. Pyrosequencing of the 16S rRNA gene and community fingerprinting methods showed that the spring community originates from the Dead Sea sediments and not from the aquifer. Furthermore, it suggested that there is a dense Archaeal community in the shoreline pore water of the lake. Sequences of bacterial sulfate reducers, nitrifiers iron oxidizers and iron reducers were identified as well. Analysis of white and green biofilms suggested that sulfide oxidation through chemolitotrophy and phototrophy is highly significant. Hyperspectral analysis showed a tight association between abundant green sulfur bacteria and cyanobacteria in the green biofilms. Together, our findings show that the Dead Sea floor harbors diverse microbial communities, part of which is not known from other hypersaline environments. Analysis of the water’s chemistry shows evidence of microbial activity along the path and suggests that the springs supply nitrogen, phosphorus and organic matter to the microbial communities in the Dead Sea. The underwater springs are a newly recognized water source for the Dead Sea. Their input of microorganisms and nutrients needs to be considered in the assessment of possible impact of dilution events of the lake surface waters, such as those that will occur in the future due to the intended establishment of the Red Sea - Dead Sea water conduit.

Description: Bowing is a well-known phenomenon seen in marbles used as building veneers. This form of rock weathering occurs as a result of external factors such as temperature, humidity, the system for anchoring the marble slabs or the panel dimensions. Under the same external conditions, many factors will determine the degree of deformation including petrography, thermal properties and residual locked stresses. The usual way to solve the problem of bowed marble slabs is to replace them with other materials, such as granites, in which the deformation still exists but is less common. In this study, eight ornamental granites with different mineralogy, grain size, grain shape, porosity and fabric were tested in a laboratory to assess their susceptibility to bowing. Three slabs of granite, each cut with a different orientation, were studied under different conditions of temperature (90 and 120°C) and water saturation (dry and wet) to investigate the influence of these factors together with that of anisotropy. At 90°C, only the granite with the coarsest grain size and low porosity exhibited deformation under wet conditions. At 120°C and wet conditions, three of the granites showed evident signs of bowing. Again, the granite with the coarsest grain size was the most deformed. It was concluded that the wide grain size distribution influences microcracking more than other expected factors, such as the quartz content of the rock. Also, mineral shape-preferred orientation and porosity play an important role in the bowing of the studied granites.

Description: : From the Early Aptian ("Töck") of Heligoland (North Germany) three new species, one new genus and one new family of Teuthids are described: M astigophora stuehmeri n. sp., Boreopeltis helgolandiae n. gen. n. sp. and Maioteuthis damesi n. sp. The new genus Boreopeltis n. gen. ist placed in the family Plesioteuthididae NAEF 1921. The genus Mastigophora OWEN 1856 previously attributed to the family Loligosepiidae VAN REGTEREN ALTENA 1949 is proposed as type genus of the new family Mastigophoridae. Two poorly preserved specimens cannot"be identified specifically (?Trachyteuthis sp. and Plesioteuthis sp.). Kurz fas sung: Aus dem Unterapt (»Töck«) von Helgoland werden drei neue Arten, eine neue Gattung und eine neue Familie von Teuthiden beschrieben: M astigophora stuehmeri n. sp., Boreopeltis helsolandiae n. gen. n. sp. und Maioteuthis damesi n. sp. Die Gattung Boreopeltis n. gen. wird zur Familie PleslOteuthididae NAEF 1921 gestellt. Die Gattung Mastigophora OWEN 1856, bisher zur Familie Loligosepiidae VAN REGTEREN ALTENA 1949 gestellt, wird zur Typusgattung der neuen Familie Mastigophoridae vorgeschlagen. Zwei weitere Exemplare können nicht näher bestimmt werden (?Trachyteuthis sp. und Plesioteuthis sp.).

Description: Carbon sequestration was estimated in a semi-arid grassland region in Central Kazakhstan using an approach that integrates remote sensing, field measurements and meteorological data. Carbon fluxes for each pixel of 1 × 1 km were calculated as a product of photosynthetically active radiation (PAR) and its fraction absorbed by vegetation (fPAR), the light use efficiency (LUE) and ecosystem respiration (Re). The PAR is obtained from a mathematical model incorporating Earth-Sun distance, solar inclination, solar elevation angle, geographical position and cloudiness information of localities. The fPAR was measured in field using hemispherical photography and was extrapolated to each pixel by combination with the Normalized Difference Vegetation Index (NDVI) obtained by the Vegetation instrument on board the Satellite Pour l’Observation de la Terra (SPOT) satellite. Gross Primary Production (GPP) of the aboveground and belowground vegetation of 14 sites along a 230 km west-east transect within the study region were determined at the peak of growing season in different land cover types and linearly related to the amount of PAR absorbed by vegetation (APAR). The product of this relationship is LUE = 0.61 and 0.97 g C/MJ APAR for short grassland and steppe, respectively. The Re is estimated using complex models driven by climatic data. Growing season carbon sequestration was calculated for the modelling year of 2004. Overall, the short grassland was a net carbon sink, whereas the steppe was carbon neutral. The evaluation of the modelled carbon sequestration against independent reference data sets proved high accuracy of the estimations.

Description: The objective of this work is the simulation of saturated and unsaturated flow in a karstified aquifer using a double continuum approach. The HydroGeoSphere code ( Therrien et al. , 2006 ) is employed to simulate spring dis- charge with the Richards equations and van Genuchten pa- rameters to represent flow in the (1) fractured matrix and (2) conduit continuum coupled by a linear exchange term. Rapid vertical small-scale flow processes in the unsaturated conduit continuum are accounted for by applying recharge boundary conditions at the bottom of the saturated model do- main. An extensive sensitivity analysis is performed on sin- gle parameters as well as parameter combinations. The tran- sient hydraulic response of the karst spring is strongly con- trolled by the matrix porosity as well as the van Genuchten parameters of the unsaturated matrix, which determine the head dependent inter-continuum water transfer when the con- duits are draining the matrix. Sensitivities of parameter com- binations partially reveal a non-linear dependence over the parameter space. This can be observed for parameters not belonging to the same continuum as well as combinations, which involve the exchange parameter, showing that results of the double continuum model may depict a certain de- gree of ambiguity. The application of van Genuchten pa- rameters for simulation of unsaturated flow in karst systems is critically discussed.

Description: Due to their heterogeneous nature, karst aquifers pose a major challenge for hydrogeological investigations. Important procedures like the delineation of catchment areas for springs are hindered by the unknown locations and hy- draulic properties of highly conductive karstic zones. In this work numerical modeling was employed as a tool in delineating catchment areas of several springs within a karst area in southwestern Germany. For this purpose, different distributive modeling approaches were implemented in the finite element simulation software Comsol Multiphysics ® . The investigation focuses on the question to which degree the effect of karstification has to be taken into account for accurately simulating the hydraulic head distribution and the observed spring discharges. The results reveal that the representation of heterogeneities has a large influence on the delineation of the catchment areas. Not only the location of highly conductive elements but also their geometries play a major role for the resulting hydraulic head distribution and thus for catchment area de- lineation. The size distribution of the karst conduits derived from the numerical models agrees with knowledge from karst genesis. It was thus shown that numerical modeling is a use- ful tool for catchment delineation in karst aquifers based on results from different field observations.

Description: Open-Access-Publikationsfonds 2013

Description: Neutron texture measurements on YBCO bulk samples show a very sharp texture of the superconducting phase YBa2Cu3O7-x with half-widths of less than 5°. Even with a rather coarse measurement grid of only 722 points per complete pole figure, satisfactory results for the recalculated (002) pole figures could be obtained. However, for a reliable calculation of a complete ODF, finer grids will have to be used. Due to the importance of a good alignment of the c-axes in the material, a quantitative analysis of the (002) pole figures, including an error estimation due to measurement grid and counting statistics, was made. An outline for the determination of a reliable background estimate is given.

Description: Geochemical markers are being increasingly applied to fundamental questions in population and community ecology in marine habitats because they allow inferences on individuals dispersal, but vital effects, small sample size and instrumental limitation are still challenging particularly in deep-sea studies. Here we use shells of the deep-sea bivalve Idas modiolaeformis to assess potential effects of sample storage, mineralogy, and valve orientation on LA-ICPMS measurements. Trace element concentrations of (24)Mg, (43)Ca, (88)Sr, (137)Ba, (208)Pb, and (238)U are not affected by the two most commonly used storage methods of biologic deep-sea samples (frozen at -20°C and fixed in 95% ethanol); thus combined analysis of differently preserved specimens is possible when the number of individuals is insufficient and distinct sample fixation is needed for multiple purposes. Valve orientation had a strong impact on quantification of trace elements in the calcitic but not in the aragonitic layer of adult shells. Hence, to enable comparisons between adult shells and entirely aragonitic embryonic shells, a reference map of site-specific signatures can potentially be generated using the aragonitic layer of the adult shells. Understanding ontogenetic changes and environmental effects in trace element incorporation is critical before geochemical fingerprinting can be used as a tool for larval dispersal studies in the deep-sea.

Description: The author used a recent article on lindane reductive dechlorination by Fe/Pd bimetallics to complain that dozen of published works in several journals are not conform to the state-of-the-art knowledge on the mechanism of aqueous contaminant removal by metallic iron (e.g. in Fe(0)/H(2)O systems). It is shown that the contribution of adsorbed Fe(II) to the process of contaminant reduction has been neglected while discussing the whole process of contaminant reduction in the presence of bimetallics.

Description: Ditopic N-donor ligands with terminal 4-pyridyl groups are omnipresent in coordination-based selfassembly. The utilization of ligands with 3-pyridyl donor groups is significantly less common, because the intrinsic conformational flexibility of these ligands tends to favor the formation of small aggregates. Here, we show that large Pd6L12 12+ cages can be obtained by reaction of Pd(II) salts with metallo-ligands L bearing terminal 3-pyridyl groups. The easy-to-access metallo-ligands contain an Fe(II) clathrochelate core. These sterically demanding clathrochelate complexes prevent the formation of smaller aggregates, which is observed for less bulky analogous building blocks. The cages were shown to bind BF4 and BPh4 anions in aqueous solvent mixtures, whilst the lateral size of the clathrochelate significantly affects their guest encapsulation behavior.

Description: Microstructures from deep ice cores reflect the dynamic conditions of the drill location as well as the thermodynamic history of the drill site and catchment area in great detail. Ice core parameters (crystal lattice-preferred orientation (LPO), grain size, grain shape), mesostructures (visual stratigraphy) as well as borehole deformation were measured in a deep ice core drilled at Kohnen Station, Dronning Maud Land (DML), Antarctica. These observations are used to characterize the local dynamic setting and its rheological as well as microstructural effects at the EDML ice core drilling site (European Project for Ice Coring in Antarctica in DML). The results suggest a division of the core into five distinct sections, interpreted as the effects of changing deformation boundary conditions from triaxial deformation with horizontal extension to bedrock-parallel shear. Region 1 (uppermost approx. 450 m depth) with still small macroscopic strain is dominated by compression of bubbles and strong strain and recrystallization localization. Region 2 (approx. 450–1700 m depth) shows a girdle-type LPO with the girdle plane being perpendicular to grain elongations, which indicates triaxial deformation with dominating horizontal extension. In this region (approx. 1000 m depth), the first subtle traces of shear deformation are observed in the shape-preferred orientation (SPO) by inclination of the grain elongation. Region 3 (approx. 1700–2030 m depth) represents a transitional regime between triaxial deformation and dominance of shear, which becomes apparent in the progression of the girdle to a single maximum LPO and increasing obliqueness of grain elongations. The fully developed single maximum LPO in region 4 (approx. 2030–2385 m depth) is an indicator of shear dominance. Region 5 (below approx. 2385 m depth) is marked by signs of strong shear, such as strong SPO values of grain elongation and strong kink folding of visual layers. The details of structural observations are compared with results from a numerical ice sheet model (PISM, isotropic) for comparison of strain rate trends predicted from the large-scale geometry of the ice sheet and borehole logging data. This comparison confirms the segmentation into these depth regions and in turn provides a wider view of the ice sheet.

Description: Three new genera of endocochleate cephalopods from the Lower Devonian cast new light on the evolution of modern and fos sil coleoids. Protoaulacoceras n. g. represents the r03trum-bearing line of aulacocerid-belemnitid type, while the ontogeny shows still features of the michelinoceratid ancestors. In contrast, Boletzkya n. g. and Naefiteuthis n. g., in which the chambered part of the shell looses its function during ontogeny, show a trend towards Mesozoic Loligosepiidae and recent teuthids.

Description: Die neuen Formen endocochleater Cephalopoden aus dem Unterdevon werden die Vorstellungen über die Evolution der fossilen wie auch der modernen Cephalopoden verändern. Im Falle von Protoaulacoceras n. g. handelt es sich um eine r03trumtragende Form, wie die späteren Aulacocerida und Belemnitida, deren Gehäusejugendstadien noch den michelinoceratiden Vorfahren gleicht. Die Gattungen Boletzkya n. g. und Naefiteuthis n. g. zeigen dagegen eine Entwicklung in Richtung auf die mesozoischen Loligosepiidae und Verwandte und die rezenten Teuthiden, indem der gekammerte Teil der Schale während der OntOgenese immer stärker reduziert wird.

Description: Rapid eclogitisation of the Dabie–Sulu UHP terrane: Constraints from Lu–Hfgarnet geochronologyAlexander Schmidta,⁎, Stefan Weyera, Klaus Mezgerb, Erik E. Schererb, Yilin Xiaoc,d,Jochen Hoefsd, Gerhard P. BreyaaInstitut für Geowissenschaften, Facheinheit Mineralogie, JWG-Universität, Frankfurt, Altenhöferallee 1, 60438 Frankfurt, GermanybZentrallabor für Geochronologie, Institut für Mineralogie, Universität Münster, Corrensstr. 24, 48149 Münster, GermanycCAS Key Laboratory of Crust–Mantle Materials and Environments, School of Earth, and Space Sciences, University of Science and Technology of China, Hefei, 230026 ChinadGeowissenschaftliches Zentrum Göttingen, Universität Göttingen, Goldschmidtstr. 26 1-3, 37077 Göttingen, GermanyABSTRACTARTICLE INFOArticle history:Received 8 February 2008Received in revised form 18 June 2008Accepted 20 June 2008Available online 4 July 2008Editor: R.W. CarlsonKeywords:Lu–Hf geochronologySm–Nd geochronologyeclogiteultrahigh-pressureeclogitisationThe Qinling–Dabie–Sulu orogenic belt in eastern China is one of the largest ultrahigh-pressure (UHP)terranes worldwide. Mineral Sm–Nd- and zircon U–Pb dating has been widely used to reveal themetamorphic history of this collisional orogen. However, the exact timing of the UHP metamorphic event(s)remains controversial and ages ranging from 245 Ma to 220 Ma have been suggested. We present highprecision garnet–cpx Lu–Hf ages for six eclogites from the Dabie and Sulu areas. All ages fall in a narrowrange between 219.6 and 224.4 Ma. Five samples define a mean age of 223.0±0.9 Ma and one sample yields aslightly younger age of 219.6±1.4 Ma. This very tight age range is particularly remarkable considering thelarge regional distribution of sample localities (on the order of 100 km at the time of UHP metamorphism)and the wide variety of garnet and eclogite chemical compositions represented. Two samples yield Sm–Ndages that are indistinguishable from their Lu–Hf ages, albeit with larger uncertainties.The identical ages of eclogites from both the Dabie and the Sulu region emphasize their close geneticrelationship and similar metamorphic histories. The Lu–Hf results appear to date a punctuated event ofgarnet growth. Alternatively, the Lu–Hf garnet ages may represent the onset of rapid, contemporaneousuplift and subsequent cooling. However, trace element zoning of Lu and Hf is still preserved in garnetporphyroblasts, even in those with a homogeneous major element distribution. Thus, complete re-equilibration of the Lu–Hf system during peak-temperature conditions probably did not occur. The garnetforming event can be placed toward thefinal stage of the UHP metamorphism, in agreement with somepublished U–Pb zircon ages. A possible trigger for this short-lived and widespread mineral growth episodemay have been afluid that became available at that stage of the metamorphic history. Although HREE-depleted patterns of older zircon grains may indicate the presence of an older generation of garnet, completeeclogitisation may have been inhibited during the major part of the prograde P–T path due to dry conditionsduring most of the UHP metamorphism. The uniform Lu–Hf (and Sm–Nd) ages of all investigated Dabie andSulu eclogites suggest that garnet growth and thus possiblyfluid availability were limited to a short timeinterval over a remarkably large regional scale.

Description: The lipid assemblages of the "living fossil" stromatoporoid Astrosclera willeyana (Great Barrier Reet) and the demosponge Agelas aroides (Mediterranean Sea) were investigated. Large amounts of branched carboxylic acids are present in the sponges studied. These compounds include terminally branched carboxylic acids (isa -/anteisa-) and abundant mid-chain branched carboxylic acids (MBCA) wh ich are characterized by an intriguing variety of structural isomers present in the C 15- C25 range. The most prominent MBCA are comprised of isomeric methylhexadecanoic acids and methyloctadecanoic acids. A second cluster of MBCA includes methyldocosanoic acids and methyltetracosanoic acids, but other homologues are also present. Methyl branching points were generally observed between the w5- and w9-positions. These complex isomeric mixtures apparently derive from symbiotic bacteria living exclusively in demosponges. Comparison with hydrocarbon compositions of ancient carbonates reveals evidence that the MBCA found are potential lipid precursors of mid-chain branched monomethylalkanes often observed in fossil sediments and oils. As a working hypo thesis, we suggest that their bacterial source organisms have been widespread in the geological past, and are found " inherited" in the protective environment of distinctive sponge hosts in recent marine ecosystems. Furthermore, both sponges contain abundant linear, longchain C24- C26 dienoic "demospongic" acids. The demospongic acid distribution and the presence of phytanic acid in A. willeyana match the patterns found in A. aroides and other members of the Agelasida. These findings confirm the systematic position of A. willeyana within this demosponge taxon.

Description: A new multi-decade national-wide coarse-resolution data set of leaf area index (LAI) over the Republic of Kazakhstan has been developed based on data from the Advanced Very High Resolution Radiometer (AVHRR) and in situ measurements of vegetation structure. The Kazakhstan-wide LAI product has been retrieved using an algorithm based on a physical radiative transfer model establishing a relationship between LAI and given patterns of surface reflectance, view-illumination conditions and optical properties of vegetation at the per-pixel scale. The results revealed high consistencies between the produced AVHRR LAI data set and ground truth information and the 30-m resolution Landsat ETM+ LAI estimated using the similar algorithm. Differences in LAI between the AVHRR-based product and the Landsat ETM+-based product are lower than 0.4 LAI units in terms of RMSE. The produced Kazakhstan-wide LAI was also compared with the global 8-km AVHRR LAI (LAI_PAL_BU_V3) and 1-km MODIS LAI (MOD15A2 LAI) products. Results show remarkable consistency of the spatial distribution and temporal dynamics between the new LAI product and both examined global LAI products. However, the results also revealed several discrepancies in LAI estimates when comparing the global and the Kazakhstan-wide products. The discrepancies in LAI estimates were outlined and discussed.

Description: The structure of the title compound, C17H18FN3O3 6H2O, has been redetermined at 120 K. An invariom refinement, a structural refinement using aspherical scattering factors from theoretically predicted multipole population parameters, yields accurate geometry and anisotropic displacement parameters, including hydrogen-bonding parameters. All potential hydrogen-bond donors and acceptors are involved in hydrogen bonding, forming an intricate three-dimensional network of N—H O and O—H O bonds

Description: The objective of this study is to evaluate a representative elementary volume (REV) in a fractured geothermal sandstone reservoir in Germany using the discrete fracture network (DFN) model approach. Due to the lack of in situ data from the deep geothermal reservoir, field measurements of outcrop reservoir analogues were conducted to get a quantitative description of the DFN. Field measurements reveal that the geometry of the DFN is largely influenced by the lithological layering (e.g. relationship between joint spacing and bed thickness). Thus, DFN models have to be completed individually for each layer since each bed is distinct compared to its neighbouring beds. Various DFNs were generated using statistical-derived fracture input data. The two-dimensional universal distinct element code UDEC was used for fracture flow simulations. In order to determine the minimum REV, the equivalent average conductivity tensors were obtained with increasing block size. Plots of conductivity tensor coefficients versus block size exhibit only minor variation of the hydraulic properties with increasing block size. Hence, an REV size of 10 m × 10 m could be determined for all studied stochastically derived discrete fracture networks.

Description: In this case study, we present the implementation of a finite element method (FEM)-based numerical pore-scale model that is able to track and quantify the propagating fluid–fluid interfacial area on highly complex micro-computed tomography (μ-CT)-obtained geometries. Special focus is drawn to the relationship between reservoir-specific capillary pressure (pc), wetting phase saturation (Sw) and interfacial area (awn). The basis of this approach is high-resolution μ-CT images representing the geometrical characteristics of a georeservoir sample. The successfully validated 2-phase flow model is based on the Navier–Stokes equations, including the surface tension force, in order to consider capillary effects for the computation of flow and the phase-field method for the emulation of a sharp fluid–fluid interface. In combination with specialized software packages, a complex high-resolution modelling domain can be obtained. A numerical workflow based on representative elementary volume (REV)-scale pore-size distributions is introduced. This workflow aims at the successive modification of model and model set-up for simulating, such as a type of 2-phase problem on asymmetric μ-CT-based model domains. The geometrical complexity is gradually increased, starting from idealized pore geometries until complex μ-CT-based pore network domains, whereas all domains represent geostatistics of the REV-scale core sample pore-size distribution. Finally, the model can be applied to a complex μ-CT-based model domain and the pc–Sw–awn relationship can be computed.

Description: The validity of the specific reaction rate constants (k(SA)) in modelling contaminant removal in Fe-0/H2O systems is questioned. It is shown that the current k(SA)-model does not consider the large reactive surface area provided by the in-situ formed oxide film, and thus the adsorptive interactions between contaminants and film materials. Furthermore, neither the dynamic nature of film formation nor the fact that the Fe-0 surface is shielded by the film is considered. Suggestions are made how the k(SA)-model could be further developed to meet its original goal.

Description: Gas seeps in the euxinic northwestern Black Sea provide an excellent opportunity to study anaerobic, methane-based ecosystems with minimum interference from oxygen-dependent processes. An integrated approach using fluorescence- and electron microscopy, fluorescence in situ hybridization, lipid biomarkers, stable isotopes (δ13C), and petrography revealed insight into the anatomy of concretionary methane-derived carbonates currently forming within the sediment around seeps. Some of the carbonate concretions have been found to be surrounded by microbial mats. The mats harbour colonies of sulphate-reducing bacteria (DSS-group), and archaea (ANME-1), putative players in the anaerobic oxidation of methane. Isotopically-depleted lipid biomarkers indicate an uptake of methane carbon into the biomass of the mat biota. Microbial metabolism sustains the precipitation of concretionary carbonates, significantly depleted in 13C. The concretions consist of rectangularly orientated, rod- to dumbbell-shaped crystal aggregates made of fibrous high Mg-calcite. The sulphate-reducing bacteria exhibit intracellular storage inclusions, and magnetosomes with greigite (Fe3S4), indicating that iron cycling is involved in the metabolism of the microbial population. Transfer of Fe3+ into the cells is apparently mediated by abundant extracellular vesicles resembling known bacterial siderophore vesicles (marinobactine) in size (20 to 100 nm) and structure.

Description: Two new reflection seismic profiles over the Paleozoic successions of the western part of the Siljan Ring impact structure show a contrasting seismic signature. The more southerly c. 10 km long Mora profile reveals a highly disturbed structure, with only a few kilometers of relatively horizontally layered structures observed. However, interpretations of refracted arrivals in the data, that can be correlated to reflections, indicate the Silurian clastic rocks to be about 200 m thick in the central part of the profile. Weak reflections from about 600 m depth suggest a 400 m thick Ordovician limestone sequence to be present. Cores from the area show a mainly shale lithology for the Silurian and only a thin sequence of Ordovician strata, suggesting a rapid thickening of the Ordovician towards the north. On the more northern c. 12 km Orsa profile clear reflections from the Paleozoic successions are seen along the entire profile, except on the southernmost few kilometers. Based on interpretations of refracted arrivals, the Silurian succession appears to be considerably thinner here, and possibly absent at some locations. The Ordovician is also interpreted to be thinner in this area, with a maximum thickness of about 200–300 m along most of the profile. A deeper reflection from about 2 km within the crystalline basement may represent a dolerite sill. The lack of clear basement reflections on the Mora profile can be attributed to near-surface conditions and the acquisition geometry. The seismic data and recent coring in the area suggest the presence of a deeper paleo-basin towards the southwest with significantly more shales being deposited and the Paleozoic successions being severely disturbed. The shallow coring and seismic data will help form the basis for locating future boreholes for deeper drilling to study impact processes and the Paleozoic evolution of central Sweden.

Description: Background Archosaurs (birds, crocodilians and their extinct relatives including dinosaurs) dominated Mesozoic continental ecosystems from the Late Triassic onwards, and still form a major component of modern ecosystems (〉10,000 species). The earliest diverse archosaur faunal assemblages are known from the Middle Triassic (c. 244 Ma), implying that the archosaur radiation began in the Early Triassic (252.3–247.2 Ma). Understanding of this radiation is currently limited by the poor early fossil record of the group in terms of skeletal remains. Methodology/Principal Findings We redescribe the anatomy and stratigraphic position of the type specimen of Ctenosauriscus koeneni (Huene), a sail-backed reptile from the Early Triassic (late Olenekian) Solling Formation of northern Germany that potentially represents the oldest known archosaur. We critically discuss previous biomechanical work on the ‘sail’ of Ctenosauriscus, which is formed by a series of elongated neural spines. In addition, we describe Ctenosauriscus-like postcranial material from the earliest Middle Triassic (early Anisian) Röt Formation of Waldhaus, southwestern Germany. Finally, we review the spatial and temporal distribution of the earliest archosaur fossils and their implications for understanding the dynamics of the archosaur radiation. Conclusions/Significance Comprehensive numerical phylogenetic analyses demonstrate that both Ctenosauriscus and the Waldhaus taxon are members of a monophyletic grouping of poposauroid archosaurs, Ctenosauriscidae, characterised by greatly elongated neural spines in the posterior cervical to anterior caudal vertebrae. The earliest archosaurs, including Ctenosauriscus, appear in the body fossil record just prior to the Olenekian/Anisian boundary (c. 248 Ma), less than 5 million years after the Permian–Triassic mass extinction. These earliest archosaur assemblages are dominated by ctenosauriscids, which were broadly distributed across northern Pangea and which appear to have been the first global radiation of archosaurs.

Description: Paleoarchean rocks from the Pilbara Craton of Western Australia provide a variety of clues to the existence of early life on Earth, such as stromatolites, putative microfossils and geochemical signatures of microbial activity. However, some of these features have also been explained by non-biological processes. Further lines of evidence are therefore required to convincingly argue for the presence of microbial life. Here we describe a new type of microbial mat facies from the 3.4 Ga Strelley Pool Formation, which directly overlies well known stromatolitic carbonates from the same formation. This microbial mat facies consists of laminated, very fine-grained black cherts with discontinuous white quartz layers and lenses, and contains small domical stromatolites and wind-blown crescentic ripples. Light- and cathodoluminescence microscopy, Raman spectroscopy, and time of flight-secondary ion mass spectrometry (ToF-SIMS) reveal a spatial association of carbonates, organic material, and highly abundant framboidal pyrite within the black cherts. Nano secondary ion mass spectrometry (NanoSIMS) confirmed the presence of distinct spheroidal carbonate bodies up to several tens of μm that are surrounded by organic material and pyrite. These aggregates are interpreted as biogenic. Comparison with Phanerozoic analogues indicates that the facies represents microbial mats formed in a shallow marine environment. Carbonate precipitation and silicification by hydrothermal fluids occurred during sedimentation and earliest diagenesis. The deciphered environment, as well as the δ13C signature of bulk organic matter (-35.3‰), are in accord with the presence of photoautotrophs. At the same time, highly abundant framboidal pyrite exhibits a sulfur isotopic signature (δ34S = +3.05‰; Δ33S = 0.268‰; and Δ36S = -0.282‰) that is consistent with microbial sulfate reduction. Taken together, our results strongly support a microbial mat origin of the black chert facies, thus providing another line of evidence for life in the 3.4 Ga Strelley Pool Formation.

Description: Open-Access Publikationsfonds 2016

Description: Open-Access-Publikationsfonds 2014

Description: The study of fluid inclusions in high-grade rocks is especially challenging as the host minerals have been normally subjected to deformation, recrystallization and fluid-rock interaction so that primary inclusions, formed at the peak of metamorphism are rare. The larger part of the fluid inclusions found in metamorphic minerals is typically modified during uplift. These late processes may strongly disguise the characteristics of the “original” peak metamorphic fluid. A detailed microstructural analysis of the host minerals, notably quartz, is therefore indispensable for a proper interpretation of fluid inclusions. Cathodoluminescence (CL) techniques combined with trace element analysis of quartz (EPMA, LA-ICPMS) have shown to be very helpful in deciphering the rock-fluid evolution. Whereas high-grade metamorphic quartz may have relatively high contents of trace elements like Ti and Al, low-temperature re-equilibrated quartz typically shows reduced trace element concentrations. The resulting microstructures in CL can be basically distinguished in diffusion patterns (along microfractures and grain boundaries), and secondary quartz formed by dissolution-reprecipitation. Most of these textures are formed during retrograde fluid-controlled processes between ca. 220 and 500 °C, i.e. the range of semi-brittle deformation (greenschist-facies) and can be correlated with the fluid inclusions. In this way modified and re-trapped fluids can be identified, even when there are no optical features observed under the microscope.

Description: We report new examples of Cenozoic cold-seep communities from Colombia, Cuba, the Dominican Republic, Trinidad, and Venezuela, and attempt to improve the stratigraphic dating of Cenozoic Caribbean seep communities using strontium isotope stratigraphy. Two seep faunas are distinguished in Barbados: the late Eocene mudstone-hosted 'Joes River fauna' consists mainly of large lucinid bivalves and tall abyssochrysoid gastropods, and the early Miocene carbonate-hosted 'Bath Cliffs fauna' containing the vesicomyid Pleurophopsis, the mytilid Bathymodiolus and small gastropods. Two new Oligocene seep communities from the Sinú River basin in Colombia consist of lucinid bivalves including Elongatolucina, thyasirid and solemyid bivalves, and Pleurophopsis. A new early Miocene seep community from Cuba includes Pleurophopsis and the large lucinid Meganodontia. Strontium isotope stratigraphy suggests an Eocene age for the Cuban Elmira asphalt mine seep community, making it the oldest in the Caribbean region. A new basal Pliocene seep fauna from the Dominican Republic is characterized by the large lucinid Anodontia (Pegophysema). In Trinidad we distinguish two types of seep faunas: the mudstone-hosted Godineau River fauna consisting mainly of lucinid bivalves, and the limestone-hosted Freeman's Bay fauna consisting chiefly of Pleurophopsis, Bathymodiolus, and small gastropods; they are all dated as late Miocene. Four new seep communities of Oligocene to Miocene age are reported from Venezuela. They consist mainly of large globular lucinid bivalves including Meganodontia, and moderately sized vesicomyid bivalves. After the late Miocene many large and typical 'Cenozoic' lucinid genera disappeared from the Caribbean seeps and are today known only from the central Indo-Pacific Ocean. We speculate that the increasingly oligotrophic conditions in the Caribbean Sea after the closure of the Isthmus of Panama in the Pliocene may have been unfavorable for such large lucinids because they are only facultative chemosymbiotic and need to derive a significant proportion of their nutrition from suspended organic matter.

Description: Open-Access Publikationsfonds 2015

Description: Normalograptus kufraensis sp. nov. occurs as monospecific assemblages in the Tanezzuft Formation at the western margin of the Kufra Basin (Jabal Eghei), southern Libya. These graptolites have parallel-sided rhabdosomes with long, straight virgellae, climacograptid thecae and a full straight median septum. N. kufraensis is intermediate between Ordovician graptolites from the N. angustus (Perner) lineage and the younger sister species N. ajjeri (Legrand) and N. arrikini Legrand. N. kufraensis differs from these taxa as follows: it is broader than N. angustus; it has greater thecal spacing than N. ajjeri or N. arrikini. A table comparing measurements of N. kufraensis with 44 other Normalograptus taxa differentiates it from other members of this morphologically conservative group. Even though N. angustus and N. ajjeri are very long-ranging graptolites, a stratophenetic approach suggests that the specimens from Jabal Eghei may be of late Hirnantian or younger age. The faunal composition and preservation suggests these graptolites occupied the ‘cratonic invader’ biotope. The stratigraphic succession records deglacial flooding and fluctuating of redox in the Tanezzuft Formation, with the graptolites indicating a short-lived interval of anoxia.

Description: Karst aquifers are characterized by highly conductive conduit flow paths embedded in a less conductive fissured and fractured matrix, resulting in strong permeability contrasts with structured heterogeneity and anisotropy. Groundwater storage occurs predominantly in the fissured matrix. Hence, most mathematical karst models assume quasi-steady-state flow in conduits neglecting conduitassociated drainable storage (CADS). The concept of CADS considers storage volumes, where karst water is not part of the active flow system but hydraulically connected to conduits (for example karstic voids and large fractures). The disregard of conduit storage can be inappropriate when direct water abstraction from karst conduits occurs, e.g., largescale pumping. In such cases, CADS may be relevant. Furthermore, the typical fixed-head boundary condition at the karst outlet can be inadequate for water abstraction scenarios because unhampered water inflow is possible. The objective of this work is to analyze the significance of CADS and flow-limited boundary conditions on the hydraulic behavior of karst aquifers in water abstraction scenarios. To this end, the numerical discrete-continuum model MODFLOW-2005 Conduit Flow Process Mode 1 (CFPM1) is enhanced to account for CADS. Additionally, a fixed-head limited-flow (FHLQ) boundary condition is added that limits inflow from constant head boundaries to a user-defined threshold. The effects and the proper functioning of these modifications are demonstrated by simplified model studies. Both enhancements, CADS and FHLQ boundary, are shown to be useful for water abstraction scenarios within karst aquifers. An idealized representation of a large-scale pumping test in a karst conduit is used to demonstrate that the enhanced CFPM1 is able to adequately represent water abstraction processes in both the conduits and the matrix of real karst systems, as illustrated by its application to the Cent Fonts karst system.

Description: Organic molecules, such as pharmaceuticals, agro-chemicals and pigments, frequently form several crystal polymorphs with different physicochemical properties. Finding polymorphs has long been a purely experimental game of trial-and-error. Here we utilize in silico polymorph screening in combination with rationally planned crystallization experiments to study the polymorphism of the pharmaceutical compound Dalcetrapib, with 10 torsional degrees of freedom one of the most flexible molecules ever studied computationally. The experimental crystal polymorphs are found at the bottom of the calculated lattice energy landscape, and two predicted structures are identified as candidates for a missing, thermodynamically more stable polymorph. Pressure-dependent stability calculations suggested high pressure as a means to bring these polymorphs into existence. Subsequently, one of them could indeed be crystallized in the 0.02 to 0.50 GPa pressure range and was found to be metastable at ambient pressure, effectively derisking the appearance of a more stable polymorph during late-stage development of Dalcetrapib.

Description: While components of the pathway that establishes left-right asymmetry have been identified in diverse animals, from vertebrates to flies, it is striking that the genes involved in the first symmetry-breaking step remain wholly unknown in the most obviously chiral animals, the gastropod snails. Previously, research on snails was used to show that left-right signaling of Nodal, downstream of symmetry breaking, may be an ancestral feature of the Bilateria [1, 2]. Here, we report that a disabling mutation in one copy of a tandemly duplicated, diaphanousrelated formin is perfectly associated with symmetry breaking in the pond snail. This is supported by the observation that an anti-formin drug treatment converts dextral snail embryos to a sinistral phenocopy, and in frogs, drug inhibition or overexpression by microinjection of formin has a chirality-randomizing effect in early (pre-cilia) embryos. Contrary to expectations based on existingmodels [3–5],wediscovered asymmetric gene expression in 2- and 4-cell snail embryos, preceding morphological asymmetry. As the formin-actin filament has been shown to be part of an asymmetry-breaking switch in vitro [6, 7], together these results are consistent with the view that animals with diverse body plans may derive their asymmetries from the same intracellular chiral elements [8].

Description: djackso@uni-goettingen.de Specialty section: This article was submitted to Aquatic Microbiology, a section of the journal Frontiers in Marine Science Received: 31 October 2016 Accepted: 10 March 2017 Published: 28 March 2017 Citation: Germer J, Cerveau N and Jackson DJ (2017) The Holo-Transcriptome of a Calcified Early Branching Metazoan. Front. Mar. Sci. 4:81. doi: 10.3389/fmars.2017.00081 The Holo-Transcriptome of a Calcified Early Branching Metazoan Juliane Germer, Nicolas Cerveau and Daniel J. Jackson* Department of Geobiology, Georg-August University of Göttingen, Göttingen, Germany Symbiotic interactions are widespread throughout the animal kingdom and are increasingly recognized as an important trait that can shape the evolution of a species. Sponges are widely understood to be the earliest branching clade of metazoans and often contain dense, diverse yet specific microbial communities which can constitute up to 50% of their biomass. These bacterial communities fulfill diverse functions influencing the sponge’s physiology and ecology, and may have greatly contributed to the evolutionary success of the Porifera. Here we have analyzed and characterized the holo-transcriptome of the hypercalcifying demosponge Vaceletia sp. and compare it to other sponge transcriptomic and genomic data. Vaceletia sp. harbors a diverse and abundant microbial community; by identifying the underlying molecular mechanism of a variety of lipid pathway components we show that the sponge seems to rely on the supply of short chain fatty acids by its bacterial community. Comparisons to other sponges reveal that this dependency may be more pronounced in sponges with an abundant microbial community. Furthermore, the presence of bacterial polyketide synthase genes suggests bacteria are the producers of Vaceletia’s abundant mid-chain branched fatty acids, whereas demospongic acids may be produced by the sponge host via elongation and desaturation of short-chain precursors. We show that the sponge and its microbial community have the molecular tools to interact through different mechanisms including the sponge’s immune system, and the presence of eukaryotic-like proteins in bacteria. These results expand our knowledge of the complex gene repertoire of sponges and show the importance of metabolic interactions between sponges and their endobiotic microbial communities.

Description: Open-Access-Publikationsfonds 2017

Description: The Antarctic clam Laternula elliptica lives almost permanently below 0 °C and therefore is a valuable and tractable model to study the mechanisms of biomineralisation in cold water. The present study employed a multidisciplinary approach using histology, immunohistochemistry, electron microscopy, proteomics and gene expression to investigate this process. Thirty seven proteins were identified via proteomic extraction of the nacreous shell layer, including two not previously found in nacre; a novel T-rich Mucin-like protein and a Zinc-dependent metalloprotease. In situ hybridisation of seven candidate biomineralisation genes revealed discrete spatial expression patterns within the mantle tissue, hinting at modular organisation, which is also observed in the mantle tissues of other molluscs. All seven of these biomineralisation candidates displayed evidence of multifunctionality and strong association with vesicles, which are potentially involved in shell secretion in this species.

Description: The water column of the Landsort Deep, central Baltic Sea, is stratified into an oxic, suboxic, and anoxic zone. This stratification controls the distributions of individual microbial communities and biogeochemical processes. In summer 2011, particulate organic matter was filtered from these zones using an in situ pump. Lipid biomarkers were extracted from the filters to establish water-column profiles of individual hydrocarbons, alcohols, phospholipid fatty acids, and bacteriohopanepolyols (BHPs). As a reference, a cyanobacterial bloom sampled in summer 2012 in the central Baltic Sea Gotland Deep was analyzed for BHPs. The biomarker data from the surface layer of the oxic zone showed major inputs from cyanobacteria, dinoflagellates, and ciliates, while the underlying cold winter water layer was characterized by a low diversity and abundance of organisms, with copepods as a major group. The suboxic zone supported bacterivorous ciliates, type I aerobic methanotrophic bacteria, sulfate-reducing bacteria, and, most likely, methanogenic archaea. In the anoxic zone, sulfate reducers and archaea were the dominating microorganisms as indicated by the presence of distinctive branched fatty acids: archaeol and pentamethylicosane (PMI) derivatives, respectively. Our study of in situ biomarkers in the Landsort Deep thus provided an integrated insight into the distribution of relevant compounds and describes useful tracers to reconstruct stratified water columns in the geological record.

Description: Open Access Publikationsfonds 2014

Description: About 60% of the European wetlands are located in the European part of Russia. Nevertheless, data on methane emissions from wetlands of that area are absent. Here we present results of methane emission measurements for two climatically different years from a boreal peatland complex in European Russia. Winter fluxes were well within the range of what has been reported for the peatlands of other boreal regions before, but summer fluxes greatly exceeded the average range of 5–80 mgCH4m−2 d−1 for the circumpolar boreal zone. Half of the measured fluxes ranged between 150 and 450 mgCH4m−2 d−1. Extrapolation of our data to the whole boreal zone of European Russia shows that theses emissions could amount to up to 2.7±1.1 TgCH4 a−1, corresponding to 69% of the annual emissions from European wetlands or 33% of the total annual natural European methane emission. In 2008, climatic conditions corresponded to the long term mean, whereas the summer of 2011 was warmer and noticeably drier. Counterintuitively, these conditions led to even higherCH4 emissions, with peaks up to two times higher than the values measured in 2008. As Russian peatlands dominate the areal extend of wetlands in Europe and are characterized by very high methane fluxes to the atmosphere, it is evident, that sound European methane budgeting will only be achieved with more insight into Russian peatlands.

Description: Soils act as sources and sinks for greenhouse gases (GHG) such as carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O). Since both storage and emission capacities may be large, precise quantifications are needed to obtain reliable global budgets that are necessary for land-use management (agriculture, forestry), global change and for climate research. This paper discusses exclusively the soil emissionrelated processes and their influencing parameters. It reviews soil emission studies involving the most important land-cover types and climate zones and introduces important measuring systems for soil emissions. It addresses current shortcomings and the obvious bias towards northern hemispheric data. When using a conservative average of 300 mg CO2e m−2 h−1 (based on our literature review), this leads to global annual net soil emissions of ≥350 Pg CO2e (CO2e = CO2 equivalents = total effect of all GHG normalized to CO2). This corresponds to roughly 21% of the global soil C and N pools. For comparison, 33.4 Pg CO2 are being emitted annually by fossil fuel combustion and the cement industry.

Description: The emplacement of the Mesoproterozoic Götemar Pluton into Paleoproterozoic granitoid host rocks of the Transscandinavian Igneous Belt is re-examined by microfabric analysis, including cathodoluminescence microscopy. Field data on the pluton-host rock system are used to strengthen the model. The Götemar Pluton, situated on the Baltic Shield of SE Sweden, is a horizontally zoned tabular structure that was constructed by the intrusion of successive pulses of magma with different crystal/melt ratios, at an estimated crustal depth of 4–8 km. Initial pluton formation involved magma ascent along a vertical dike, which was arrested at a mechanical discontinuity within the granitoid host rocks; this led to the formation of an initial sill. Subsequent sill stacking and their constant inflation resulted in deformation and reheating of existing magma bodies, which also raised the pluton roof. This multi-stage emplacement scenario is indicated by complex dike relationships and the occurrence of several generations of quartz (Si-metasomatism). The sills were charged by different domains of a heterogeneous magma chamber with varying crystal/melt ratios. Ascent or emplacement of magma with a high crystal/melt ratio is indicated by syn-magmatic deformation of phenocrysts. Complex crystallization fabrics (e.g. oscillatory growth zoning caused by high crystal defect density, overgrowth and replacement features, resorbed and corroded crystal cores, rapakivi structure) are mostly related to processes within the main chamber, that is repeated magma mixing or water influx.

Description: Background: The oxygen (d18O) and carbon (d13C) isotope compositions of bioapatite from skeletal remains of fossil mammals are well-established proxies for the reconstruction of palaeoenvironmental and palaeoclimatic conditions. Stable isotope studies of modern analogues are an important prerequisite for such reconstructions from fossil mammal remains. While numerous studies have investigated modern large- and medium-sized mammals, comparable studies are rare for small mammals. Due to their high abundance in terrestrial ecosystems, short life spans and small habitat size, small mammals are good recorders of local environments. Methodology/Findings: The d18O and d13C values of teeth and bones of seven sympatric modern rodent species collected from owl pellets at a single locality were measured, and the inter-specific, intra-specific and intra-individual variations were evaluated. Minimum sample sizes to obtain reproducible population d18O means within one standard deviation were determined. These parameters are comparable to existing data from large mammals. Additionally, the fractionation between coexisting carbonate (d18OCO3) and phosphate (d18OPO4) in rodent bioapatite was determined, and d18O values were compared to existing calibration equations between the d18O of rodent bioapatite and local surface water (d18OLW). Specific calibration equations between d18OPO4 and d18OLW may be applicable on a taxonomic level higher than the species. However, a significant bias can occur when bone-based equations are applied to tooth-data and vice versa, which is due to differences in skeletal tissue formation times. d13C values reflect the rodents’ diet and agree well with field observations of their nutritional behaviour. Conclusions/Significance: Rodents have a high potential for the reconstruction of palaeoenvironmental conditions by means of bioapatite d18O and d13C analysis. No significant disadvantages compared to larger mammals were observed. However, for refined palaeoenvironmental reconstructions a better understanding of stable isotope signatures in modern analogous communities and potential biases due to seasonality effects, population dynamics and tissue formation rates is necessary.

Description: Open-Access-Publikationsfonds 2012

Description: Slates are internationally known as roof and façade-cladding material since prehistoric times. The methods required to mine and manufacture these dimensional stones are relatively simple in comparison to those utilized in granitic dimensional stones. This has led to a worldwide rentable commercialization of slate in the last centuries and also to the development of characteristic cultural landscapes. In Uruguay several slates are mined and used in architecture, especially as façade cladding and floor slabs. The most important slates regarding their production and utilization are the dolomitic slates. These dolomitic slates are associated with the Neoproterozoic thrust and fold belt of the Dom Feliciano belt. Representative samples have been geochemically and petrographically characterized, as well as petrophysically and petromechanically analyzed. The petrophysical and petromechanical properties were investigated in a very systematic way with respect to the new European standards, showing values comparable to those registered for internationally known slates. Detailed structural and deposit analysis were carried out in Uruguay in order to evaluate the dolomitic slate deposits. The slates are linked to calc-silicate strata in a greenschist facies volcano-sedimentary sequence and the deposits are located in the limb of a regional fold, where bedding and cleavage are parallel. The main lithotype is a layered and fine-grained dolomitic slate with a quite diverse palette of colors: light and dark green, gray, dark gray, reddish and black. The mined slate is split into slabs 0.5–2 cm thick. In the past, the average production in Uruguay was around 4,000 tons/year and a historical maximum of 13,000 tons was reached in 1993 (Oyhantçabal et al. in Z dt Ges Geowiss 158(3):417–428, 2007). The oscillations in the regional demand were the cause of several flourishing and decay cycles in the activity, but our investigation shows a considerable volume of indicated resources and therefore a very good potential.

Description: During the first week of the 2011 El Hierro submarine eruption, abundant light-coloured pumiceous, high-silica volcanic bombs coated in dark basanite were found floating on the sea. The composition of the light-coloured frothy material (‘xeno-pumice’) is akin to that of sedimentary rocks from the region, but the textures resemble felsic magmatic pumice, leaving their exact mode of formation unclear. To help decipher their origin, we investigated representative El Hierro xeno-pumice samples using X-ray computed microtomography for their internal vesicle shapes, volumes, and bulk porosity, as well as for the spatial arrangement and size distributions of vesicles in three dimensions (3D). We find a wide range of vesicle morphologies, which are especially variable around small fragments of rock contained in the xeno-pumice samples. Notably, these rock fragments are almost exclusively of sedimentary origin, and we therefore interpret them as relicts an the original sedimentary ocean crust protolith(s). The irregular vesiculation textures observed probably resulted from pulsatory release of volatiles from multiple sources during xeno-pumice formation, most likely by successive release of pore water and mineral water during incremental heating and decompression of the sedimentary protoliths.

Description: Microstructure‐based finite-element analysis with a microcracking algorithm was used to simulate an actual degradation phenomenon of marble structures, i.e., microcracking. Both microcrack initiation and crack propagation were characterized, as were their dependence on lattice preferred orientation (LPO), grain shape preferred orientation (SPO), grain size, marble composition (calcite and dolomite) and grain‐boundary fracture toughness. Two LPOs were analyzed: a random orientation distribution function and an orientation distribution function with strong directional crystalline texture generated from a March–Dollase distribution. Three SPOs were considered: equiaxed grains; elongated grains and a mixture of equiaxed and elongated grains. Three different grain sizes were considered: fine grains of order 200 μm (only calcitic marble); medium size grains of order 1 mm (calcitic and dolomitic marbles); and large grains of order 2 mm (only dolomitic marble). The fracture surface energy for the grain boundaries, γig, was chosen to be 20 and 40 % of the fracture surface energy of a grain, γxtal, so that both intergranular and transgranular fracture were possible. Studies were performed on these idealized marble microstructures to elucidate the range of microcracking responses. Simulations were performed for both heating and cooling by 50 °C in steps of 1 °C. Microcracking results were correlated with the thermoelastic responses, which are indicators related to degradation. The results indicate that certain combinations of LPO, SPO, grain size, grain‐boundary fracture toughness and marble composition have a significant influence on the thermal-elastic response of marble. Microstructure with the smallest grain size and the highest degree of SPO and LPO had less of a tendency to microcrack. Additionally, with increasing SPO and LPO microcracking becomes more spatially anisotropic. A significant observation for all microstructures was an asymmetry in microcracking upon heating and cooling: more microcracking was observed upon cooling than upon heating. Given an identical microstructure and crystallographic texture, calcite showed larger thermal stresses than dolomite, had an earlier onset of microcracking upon heating and cooling, and a greater microcracked area at a given temperature differential. Thermal expansion coefficients with and without microcracking were also determined.

Description: In Uruguay commercial granite varieties comprise mafic rocks, granitoids, and syenitoids. There is a long tradition in Uruguay, as well as worldwide, of using dimensional stones in architecture and art, specially granitic ones. Some of the present applications of these dimensional stones are as façade cladding, countertops, and outdoor and indoor floor slabs. The color spectrum of the Uruguayan granitic dimensional stones varies from black to light gray, covering a wide variety of red and pink and minor greenish-gray. The décor of these granitic dimensional stones is mainly determined by their fabric, fundamentally the grain size and the color distribution between the different minerals that compose the rocks. In the present research the most important commercial granites were sampled to analyze their petrography and petrophysical properties. A detailed structural analysis has been performed in several deposits, as well as the application of the software 3D Block Expert for modeling the possible raw block size distribution. Other factors controlling the mining viability of the deposits were also studied (e.g., homogeneity/heterogeneity of color and décor) and the possible reserves were calculated.

Description: The old mining city of Guanajuato in middle Mexico preserves one of the most important historical legacies in colonial buildings, the UNESCO declared the city World Heritage Site in 1988. Practically all the colonial constructions were built with natural stones from the neighbourhood, of which stands a greenish to reddish vulcanite, called Loseros Tuff. Although the Loseros Tuff is widely used in historical buildings in the city. It shows significant deterioration and weathering effects, principally in the parts where the tuff shows a coarse grain size. The petrographic, petrophysical, mineralogical and geochemical properties of the Loseros Tuff were analysed in order to determine the causes, effects, behaviour and response to deterioration of this volcanic rock. The results of the investigations suggest that in addition to the parameters like the grain size and the porosity properties, the pore radii distribution is decisive for the effectiveness of porosity and the water transport into the rock. It is recognized that once the liquid water invades the rock the dissolution of the matrix occurs, which is accompanied by a sudden moisture expansion favoured by the newly formed secondary porosity and the high content of expandable clay minerals.

Description: A knowledge system (KS) is a knowledge that is unique to a given group of persons. This form of knowledge may have a local or natural origin and is linked to the community that has produced it. On the contrary, the core of mainstream science (MS) is the desire to profoundly understand processes, through sequential studies such as hypothesis formulation, experiment and prediction. Thus, KS is communitarian and MS is universal. KS can be understood and rendered universal through MS. In general, a process discovery (know-how) may be intuitive, accidental, conjectural or inspirational but outcomes should be predictable and repeatable as soon as the know-why is achieved by MS. This paper argues that the technology of using metallic iron for water treatment has all the characteristics of a KS and that promoters of this technology have deliberately rejected scientific arguments leading to the know-why of the fortuitous discovery. Consequently, the technology has developed into an impasse where controversial discoveries are reported on all relevant aspects. It is concluded that the integrity of science in endangered by this communitarian behaviour.

Description: Introduction Inter-specific comparisons of metazoan developmental mechanisms have provided a wealth of data concerning the evolution of body form and the generation of morphological novelty. Conversely, studies of intra-specific variation in developmental programs are far fewer. Variation in the rate of development may be an advantage to the many marine invertebrates that posses a biphasic life cycle, where fitness commonly requires the recruitment of planktonically dispersing larvae to patchily distributed benthic environments. Results We have characterised differences in the rate of development between individuals originating from a synchronised fertilisation event in the tropical abalone Haliotis asinina, a broadcast spawning lecithotrophic vetigastropod. We observed significant differences in the time taken to complete early developmental events (time taken to complete third cleavage and to hatch from the vitelline envelope), mid-larval events (variation in larval shell development) and late larval events (the acquisition of competence to respond to a metamorphosis inducing cue). We also provide estimates of the variation in maternally provided energy reserves that suggest maternal provisioning is unlikely to explain the majority of the variation in developmental rate we report here. Conclusions Significant differences in the rates of development exist both within and between cohorts of synchronously fertilised H. asinina gametes. These differences can be detected shortly after fertilisation and generate larvae of increasingly divergent development states. We discuss the significance of our results within an ecological context, the adaptive significance of mechanisms that might maintain this variation, and potential sources of this variation.

Description: Open-Access-Publikationsfonds 2012

Description: The temporally and geographically scattered Phanerozoic record of methane-seep deposits hampers reconstruction of the evolution of life in chemosynthesis-based ecosystems. Unlike modern, Cenozoic, and late Mesozoic seeps, many of the known older seep deposits are typified by assemblages with profuse rhynchonellide brachiopods. Late Triassic (Norian) limestone bodies in eastern Oregon are enclosed in deep-water strata, extend laterally for up to a few hundred meters, and contain the dimerelloid rhynchonellide Halorella in rock-forming quantities. The analysis of two large limestone bodies in the Rail Cabin Member of the Vester Formation exposed near Graylock Butte, Grant County, Oregon, fosters the reconstruction of the paleoenvironmental setting of these unusual Halorella deposits, resulting in the first recognition of Triassic methane-seep deposits. The faunal assemblage includes few fossils other than Halorella. Although occasionally found at seeps, the recognized nuculanids are not seep-endemic bivalves. A Nucinella-like bivalve and a possible permophorid bivalve were likely endemic to this chemosynthesis-based environment; related bivalves lived at Jurassic and Cretaceous seeps. The superabundant, mostly articulated brachiopod shells are enclosed in a variety of micrites, including peloidal to clotted micrite. Early fibrous cement, forming banded and botryoidal crystal aggregates, preferentially occurs at the margin of the large limestone bodies but is scarce overall. Peloidal to clotted micrite and banded and botryoidal cement are common constituents of methane-seep limestones. Their negative d13C values as low as 36‰ reveal that carbonate formation was induced by the oxidation of methane. The presence of pyrobitumen (i.e., metamorphosed crude oil) in the limestones may indicate that the seepage fluids contained oil in addition to methane. Apart from the diagnostic 13C-depleted carbonate phases, mud injections recognized in one of the two limestone bodies also bear testament to former seepage activity.

Description: The degree of weathering in natural stones on buildings and sculptures has been determined for many years in numerous cases by means of ultrasonic measurements. Conclusions concerning the strength of the rock and the type of weathering can thus be drawn. This relationship has not been established for all rock types. Most of the progress utilizing this method has been made in the analysis of marbles, where an increasing degree of weathering shows lower ultrasonic velocities. In the present study, four Carrara marble samples showing similar rock fabrics, but with respect to weathering exhibit considerable differences are investigated. Porosity varies between 0.2 vol. % and ca. 2.4 vol. %, whereby with increasing porosity the pore radii changes as well. Parallel to this the ultrasonic velocities change in dry samples from about 5.5 to 1.6 km/s, respectively. Model calculations reveal that the velocity reduction is caused by cracks with an extremely small aspect ratio of about 0.005 or even less. After a specific loss of strength, however, solution processes can become active, which modify the microcracks and generate an opposite trend. In the process a strong porosity increase correlates to a relatively small velocity reduction. With the presence of water the Vp porosity weathering relationship experiences a considerable modification. Parallel to the reduction of the ultrasonic velocities, it was determined that the mechanical strength (compressive strength, flexural strength, etc.) as well as the static Young’s modulus is reduced almost equally by a progressive advancement of the weathering front. In one case study dealing with tensile strengths, it was clearly documented how tensile cracks develop and propagate in dependence of the rock fabric. The rock mechanical and ultrasonic velocity data were used for stability assessments applied to the marble statuaries from the Schlossbrücke in Berlin. Stability assessments of the sculpture group 4 reveal that some critical parts must be replaced due to safety reasons.

Description: Fabrics of Cambrian sedimentary dykes formed in Proterozoic granites of the Västervik area (Southeast Sweden) evidence repeated opening/filling and mineralisation/cementation events under varying conditions. Diagnostic features include (1) wall-parallel boundaries between epiclastic fillings and (2) early formed dyke sediments that appear as lithoclasts in subsequently formed sedimentary fillings. The psammitic components mostly consist of well-rounded quartz grains related to a coastal environment and fragments from the granitic host rock. Platy calcitic fragments embedded in the epiclastic matrix originally formed as microveins within already-lithified dyke sediments and the adjacent host rock. Convex downward-pointing, internal sagging structures, together with the preferred orientation of compositional boundaries and long axes of grains/rock fragments parallel to the dyke walls, are interpreted as the result of suction-controlled flow of unconsolidated fillings during episodes of downward dyke growth. Pressure solution of quartz grains are evidence of extensional phases with dyke propagation that were interrupted by phases of horizontal compression normal to the dyke walls. The N–S and NE–SW striking sedimentary dykes formed by opening of a pre-existing joint set during NW–SE oriented rifting during the Cambrian.

Description: Moisture expansion in natural building stones is considered one of the most important factors affecting their weathering and deterioration. The processes that may be responsible for the expansion under determinate relative humidity (hygric dilatation) and water-saturated conditions (hydric dilatation) are generally attributed to the presence of swellable clay minerals. In contrast to this assumption, our investigations show that moisture expansion also takes place in volcanic tuff building stones almost free from clay minerals. To provide a deeper understanding of the processes, swelling and deterioration were performed on 14 volcanic tuffs used as important building stones of different ages, compositions and weathering stages from Mexico, Germany and Hungary. The investigations undertaken include extensive chemical, petrophysical and fabric analyses. The samples show a wide range of effective porosity, microporosity, capillary water absorption, moisture expansion, and CEC values. High moisture expansion does not seem to depend on clay mineral content alone. We also observed that there is no significant effect on dilatation if clay minerals are present but only form a thin coat on the outer shell of bigger pores. Moreover, we identified a correlation between microporosity, average pore radius and moisture expansion. The investigations highlight the fact that moisture expansion cannot only be attributed to swellable clay minerals, and suggest that the presence and accumulation of micropores and their average radius and distribution play an important role for non-clay associated swelling intensity, which can most probably be attributed to the disjoining pressure.

Description: Static (or ‘normal’) grain growth, i.e. grain boundary migration driven solely by grain boundary energy, is considered to be an important process in polar ice. Many ice-core studies report a continual increase in average grain size with depth in the upper hundreds of metres of ice sheets, while at deeper levels grain size appears to reach a steady state as a consequence of a balance between grain growth and grain-size reduction by dynamic recrystallization. The growth factor k in the normal grain growth law is important for any process where grain growth plays a role, and it is normally assumed to be a temperature-dependent material property. Here we show, using numerical simulations with the program Elle, that the factor k also incorporates the effect of the microstructure on grain growth. For example, a change in grain-size distribution from normal to log-normal in a thin section is found to correspond to an increase in k by a factor of 3.5.

Description: Investigation by Raman spectroscopy of samples from different geological settings shows that the occurrence of TiO2 polymorphs other than rutile can hardly be predicted, and furthermore, the occurrence of anatase is more widespread than previously thought. Metamorphic pressure and temperature, together with whole rock chemistry, control the occurrence of anatase, whereas variation of mineral assemblage characteristics and/or fluid occurrence or composition takes influence on anatase trace element characteristics and re-equilibration of relict rutiles. Evaluation of trace element contents obtained by electron microprobe in anatase, brookite, and rutile shows that these vary significantly between the three TiO2 phases. Therefore, on the one hand, an appropriation to source rock type according to Nb and Cr contents, but as well application of thermometry on the basis of Zr contents, would lead to erroneous results if no phase specification is done beforehand. For the elements Cr, V, Fe, and Nb, variation between the polymorphs is systematic and can be used for discrimination on the basis of a linear discriminant analysis. Using phase group means and coefficients of linear discriminants obtained from a compilation of analyses from samples with well-defined phase information together with prior probabilities of groupings from a natural sample compilation, one is able to calculate phase grouping probabilities of any TiO2 analysis containing at least the critical elements Cr, V, Fe, and Nb. An application of this calculation shows that for the appropriation to the phase rutile, a correct-classification rate of 99.5% is obtained. Hence, phase specification by trace elements proves to be a valuable tool besides Raman spectroscopy.