On the Stability Regions of the Trojan Asteroids

The orbits of fictitious bodies around Jupiter’s stable equilibrium points L ₄ and L ₅ were integrated for a fine grid of initial conditions up to 100 million years. We checked the validity of three different dynamical models, namely the spatial, restricted three body problem, a model with Sun, Jupiter and Saturn and also the dynamical model with the Outer Solar System (Jupiter to Neptune). We determined the chaoticity of an orbit with the aid of the Lyapunov Characteristic Exponents (=LCE) and used also a method where the maximum eccentricity of an orbit achieved during the dynamical evolution was examined. The goal of this investigation was to determine the size of the regions of motion around the equilibrium points of Jupiter and to find out the dependance on the inclination of the Trojan’s orbit. Whereas for small inclinations (up to i=20°) the stable regions are almost equally large, for moderate inclinations the size shrinks quite rapidly and disappears completely for i>60^°. Additionally, we found a difference in the dynamics of orbits around L ₄ which – according to the LCE – seem to be more stable than the ones around L ₅.     

Clustering evolution between z=1 and today

We present results of an investigation of clustering evolution of field galaxies between a redshift of z ∼ 1 and the present epoch. The current analysis relies on a sample of ∼ 14000 galaxies in two fields of the COMBO 17 survey. The redshift distribution extends to z ∼ 1. The amplitude of the three-dimensional correlation function can be estimated by means of the projected correlation function w(r _p ). The validity of the deprojection was tested on the Las Campanas Redshift Survey (LCRS). In a flat cosmology with non-zero cosmological constant for bright galaxies (M _B ≤-18) the clustering growth is proportional to (1+z) ^-2. However, the measured clustering evolution clearly depends on Hubble type. While locally the clustering strength of early type galaxies is equal to that of the bright galaxies, at high redshifts they are much stronger clustered, and thus the clustering has to evolve much more slowly. This revised version was published online in August 2006 with corrections to the Cover Date.     

High-resolution210Pb dating of Lake Constance sediments: Stable lead in Lake Constance

Two sediment cores (BO90/13b and BO90/17b) from Lake Constance were investigated by-spectrometry for²¹⁰Pb,¹³⁴Cs,¹³⁷Cs,²⁴¹Am,²³⁴Th, and other members of the²³⁸U decay chain. The sediments were dated using the constant-flux model for²¹⁰Pb, and accumulation rates were determined. These range from 0.04 to 0.65g/cm ²/yr (BO90/13b) and 0.04 to 0.8g/cm ²/yr (BO90/17b), respectively. The mean accumulation rate amounts to 0.16g/cm ²/yr for both cores. The cores had already been dated by lamination counting and reconstruction of high-water events at the Limnological Institute at Constance, so that a very precise time scale was available. Both ages derived are in agreement within statistical error up to 1900, which means dating with the constant-flux model for²¹⁰Pb was confirmed up to that age. The position of the maxima of bomb cesium and americium confirm the stratigraphic and²¹⁰Pb datings. With²⁴¹Am a further radioactive isotope is available, which can, due to the half-life of²⁴¹Pu (t _1/2=14.4yr) be detected now by-spectrometry and can serve as an additional time indicator, the maximum being dated at 1963. By applying the various time scales, the depth profiles of stable lead and zinc of core BO90/13b were dated. Both heavy metals show a very significant maximum located beneath the layer of the maxima of bomb cesium and americium, showing that these maxima are older than those of the bomb isotopes. It is remarkable in this context that the maximum of zinc concentration occurs a little later than that of stable lead. Similar concentration profiles are observable in core BO90/17b and other, older sediment cores (CS6-CS10) on a transect across the lake. In contrast to a former assumption, the depth profile of stable lead in Lake Constance sediments does not reflect the anthropogenic gasoline lead emissions into the atmosphere for Germany, their maximum being dated at 1971.     

On the potential of plant species invasion influencing bio‐geomorphologic landscape formation in salt marshes

Species invasions are known to change biotic and abiotic ecosystem characteristics such as community structure, cycling of materials and dynamics of rivers. However, their ability to alter interactions between biotic and abiotic ecosystem components, in particular bio‐geomorphic feedbacks and the resulting landscape configuration in tidal wetlands, such as tidal channels have not yet been demonstrated. We studied the impact of altered bio‐geomorphic feedbacks on geomorphologic features (i.e. tidal wetland channels), by comparing proxies for channel network geometry (unchanneled flow lengths, fractal dimension) over time between non‐invaded and invaded salt marsh habitats. The non‐invaded habitats (the south of eastern Chongming Island, Yangtze estuary, China) show little change in network geometry over time with a tendency for an increased drainage density. The invaded site (salt marshes in the north of eastern Chongming Island invaded by the exotic plant species Spartina alterniflora) showed a decreasing tendency in channel drainage density throughout and after the species invasion. This suggests that species invasions might not only affect biotic ecosystem characteristics, but also their ability to change bio‐geomorphic feedback loops, potentially leading to changes in existing geomorphologic features and therefore landscape configuration. Our results further suggest that the species invasion also altered sediment composition. Based on observations we propose a mechanism explaining the change in channel drainage density by an alteration in plant properties. The physical and physiological characteristics of the invading species Spartina alterniflora clearly differ from the native species Scirpus mariqueter, inducing different bio‐geomorphic feedback loops leading to the observed change in salt marsh channel configuration. Copyright © 2016 John Wiley & Sons, Ltd.     

Beiträge zur Dynamik der Biomasse in Oxydationsteichen. Teil 3: Untersuchungen an der Teichanlage Greifswald-Ladebow nach Einsatz einer Kreiselbelüftungsanlage

The wastewater treatment is carried out in two parallel pond groups: South–9200 m³/d, 1748 kg/d BOD₅, preliminary clarifier (1.1 ha, 22000 m³), three ponds (9.8 ha, 88000 m³), naturel aeration; North ?5700 m³/d, 2394 kg/d BOD₅, Imhoff tank, three ponds (7.9 ha, 71000 m³), the pond 1 artificially aerated by gyroscopic units. The different loads of 15.9 and 33.7 g/m³ d BOD₅ results in rates of removal of 11.2 and 22.5 g/m³d BOD₅, resp. Therefore, the efficiency of the naturally aerated system is higher than that of the artificially aerated system. In the aerated system mainly the bacterial growth is promoted, a typical algal state being achieved only slowly, whereas the naturally aerated system gains a summer-time algal maximum in the ponds 2 and 3, which is accompanied already by zooplankton populations. In the dynamics of the biomass development, the higher efficiency of the four-stage, naturally aerated system is especially obvious.     

GGR Critical Review of Analytical Developments in 2006–2007

In 2005 the Geostandards and Geoanalytical Research editorial team, in the true spirit of scientific endeavour, embarked on an experiment of our own. We decided to trial a new kind of review, somewhat different from those more typically observed in journals, and one that would provide readers with a summary of analytical developments across a broad range of topics appropriate to the Earth sciences. The first contribution of this kind appeared in 2005, and reported on developments in 2003 (Hergt et al. 2005). The second, this time a biennial review, was published in 2006 and reported on highlights of the 2004 and 2005 literature (Hergt et al. 2006). Based on reprint requests, positive remarks at conferences and strong citations we consider the experiment a resounding success and proudly present here the third in this series. This comprises six individual review sections that cover the main analytical technologies and topical application fields in geoanalysis and geochemistry, including geological and environmental reference materials, ICP‐thermal and secondary ionisation‐mass spectrometry, as well as neutron activation analysis, X‐ray fluorescence and atomic absorption spectrometry.     

Oxygen isotope systematics of emerald: relevance for its origin and geological significance

Oxygen isotopic composition of emerald from 62 occurrences and deposits in the world reveals a wide range in δ¹⁸O (SMOW) between +6.2 and +24.7‰. The δ¹⁸O-values for each deposit are restricted and can be used to determine the origin of emerald from the world's most important producers. The δ¹⁸O-value of emerald appears to be a fingerprint of its origin, especially for gems of exceptional quality from Colombia (eastern emerald zone, δ¹⁸O = +16.8 ± 0.1‰; western emerald zone, δ¹⁸O = +21.2 ± 0.5‰), Afghanistan (δ¹⁸O = +13.5 ± 0.1‰), Pakistan (Swat-Mingora districts, δ¹⁸O = +15.7 ± 0.1‰), Brazil (Santa Terezinha de Goiás, δ¹⁸O = +12.2 ± 0.1‰; Quadrilatero Ferrifero, δ¹⁸O = +6.9 ± 0.4‰) and Zimbabwe (Sandawana, δ¹⁸O = +7.5 ± 0.5‰). Furthermore, the ¹⁸O-composition of emerald appears to be a good marker of its geological environment because the data suggest that host-rock-buffering of fluid δ¹⁸O is considerable during fluid-rock interaction. Received: 29 January 1998 / Accepted: 25 March 1998     

Mineralogy of the lunar crust: Results from Clementine

Abstract— The central peaks of 109 impact craters across the Moon are examined with Clementine ultraviolet-visible (UVVIS) camera multispectral data. The craters range in diameter from 40 to 180 km and are believed to have exhumed material from 5–30 km beneath the surface to form the peaks, including both upper and lower crustal rocks depending on whether craters have impacted into highlands or basins. Representative five-color spectra from spectrally and spatially distinct areas within the peaks are classified using spectral parameters, including “key ratio” (which is related to mafic mineral abundance) and “spectral curvature” (linked to absorption band shape, which distinguishes between low- and high-Ca pyroxene and olivine). The spectral parameters are correlated to mineralogical abundances, related in turn to highland plutonic rock compositions. The derived rock compositions for the various central peaks are presented in a global map. From these results, it is evident that the lunar crust is compositionally diverse, both globally and at local 100 m scales found within individual sets of central peaks. Although the central peaks compositions imply a crust that is generally consistent with previous models of crustal structure, they also indicate a more anorthositic crust than generally assumed, with a bulk plagioclase content of ～81%, evolving from “pure” anorthosite near the surface towards more mafic, low-Ca pyroxene-rich compositions with depth (comparable to anorthositic norite). Evidence for mafic plutons occurs in both highlands and basins and represent all mafic highland rock types. However, the lower crust is more compositionally diverse than the highlands, with both a greater range of rock types and more diversity within individual sets of central peaks.     

Automated facies identification by Direct Push-based sensing methods (CPT,HPT) and multivariate linear discriminant analysis to decipher geomorphological changes and storm surge impact on a medieval coastal landscape

In ad 1362, a major storm surge drowned wide areas of cultivated medieval marshland along the north-western coast of Germany and turned them into tidal flats. This study presents a new methodological approach for the reconstruction of changing coastal landscapes developed from a study site in the Wadden Sea of North Frisia. Initially, we deciphered long-term as well as event-related short-term geomorphological changes, using a geoscientific standard approach of vibracoring, analyses of sedimentary, geochemical and microfaunal palaeoenvironmental parameters and radiocarbon dating. In a next step, Direct Push (DP)-based Cone Penetration Testing (CPT) and the Hydraulic Profiling Tool (HPT) were applied at vibracore locations to obtain in situ high-resolution stratigraphic data. In a last step, multivariate linear discriminant analysis (LDA) was successfully applied to efficiently identify different sedimentary facies (e.g., fossil marsh or tidal flat deposits) from the CPT and HPT test dataset, to map the facies' lateral distribution, also in comparison to reflection seismic measurements and test their potential to interpolate the borehole and CPT/HPT data. The training dataset acquired for the key site from coring and DP sensing finally allows an automated facies classification of CPT/HPT data obtained elsewhere within the study area. The new methodological approach allowed a detailed reconstruction of the local coastal landscape development in the interplay of natural marsh formation, medieval land reclamation and storm surge-related land losses.