The occurrence of bisulfite-aldehyde addition products in fog- and cloudwater

Elevated concentrations of S(IV) and formaldehyde were observed in fog- and cloudwater at sites in California. The highest concentrations (up to 3 mM S(IV) and 0.7 mM CH₂O) were measured at Bakersfield, during a prolonged period of repeated fog. In Bakersfield [S(IV)] generally exceeded [CH₂O], while in the Los Angeles area the reverse was observed. The lowest concentrations of both species were observed at marine and high altitude sites away from local emissions. Equilibrium computations indicate that high concentrations of S(IV) cannot be achieved without the formation of S(IV)-RCHO adducts.     

IV. Stratigraphie Die fazielle Einstufung fossilführender Sedimente

Ohne Zusammenfassung     

Gyromagnetic remanence acquired by greigite (Fe3S4) during static three-axis alternating field demagnetization

A magnetic study was carried out on lacustrine sediments from the Zoigê basin, Tibetan Plateau, in order to obtain a better understanding of palaeoclimatic changes there. Gyromagnetic remanence (GRM) acquisition is unexpectedly observed during static three-axis alternating field (AF) demagnetization in about 20 per cent of a large number of samples. X-ray diffraction (XRD) analysis on a magnetic extract clearly shows that greigite is the dominant magnetic mineral carrier. Scanning electron microscopy (SEM) reveals that the greigite particles are in the grain size range of 200–300  nm, possibly in the single-domain state. Greigite clumps of about 3  μm size are sealed by silicates. Fitting of XRD peaks yields a crystalline coherence length of about 15  nm, indicating that the particles seen in the SEM are polycrystalline.
  GRM intensities of most samples are of the same order as the NRM, while others show much stronger GRM although their magnetic properties are similar. Variation of the demagnetization sequence confirms that GRM is mainly produced perpendicular to the AF direction. The anisotropy direction can be derived from GRM, but more systematic studies are needed for detailed conclusions. An attempt to correct for GRM failed due to high GRM intensities and because smaller GRM acquisition was also found along the demagnetization axis. Behaviours of acquisition and AF demagnetization of GRM are comparable with those of NRM, ARM, IRM, indicating fine grain sizes of remanence carriers.     

Emission of Biogenic Volatile Organic Compounds: An Overview of Field, Laboratory and Modelling Studies Performed during the `Tropospheric Research Program' (TFS) 1997–2000

The present paper summarises results on the emission of biogenicvolatile organic compounds (BVOC) achieved within the frame of thenational `German Tropospheric Research Programme' (TFS) between 1997 and2000. Field measurements were carried out at the meteorologicalmonitoring station `Hartheimer Wald' located in the vicinity of Freiburg(upper Rhine valley), Germany, within a pine plantation dominated byScots pine (Pinus sylvestris L.). The measured BVOC emissionrates were used to determine the daily and seasonal variation of BVOCemission and its dependence on important meteorological and plantphysiological parameters. In parallel, laboratory experiments usingyoung trees of pine (P. sylvestris), poplar (Populustremula ×P. alba) and pedunculate oak (Quercusrobur L.) were performed, and the influence of abiotic (e.g.,light, temperature, seasonality, flooding) factors on the biosynthesisand emission of BVOC was quantified. Based on these data, emissionalgorithms were evaluated and a process-oriented numerical model for thesimulation of the isoprene emission by plants was developed. Inaddition, newly calculated land use and tree species distributions wereused for the calculation of an actual BVOC emission inventory ofGermany.     

Identification of greigite in lake sediments and its magnetic significance

Detailed rock magnetic investigations and mineralogical analysis were conducted on lacustrine sediments recovered from Zoigê Basin, eastern Tibetan Plateau. Greigite, with fine and homogenous grain size, is found as a main magnetic carrier, which is suspected to be of biochemical origin. In contrast to some reports, greigite within the sediments is not oxidized even after exposure to air for a few years, which could be due to the fact that greigite is sealed by silicate.     

Untersuchungen zur Adsorption von Spuren hydrolysierbarer Metallionen an Oberflächen

In static laboratory experiments there are determined quantities influencing the adsorption of selected metal ions on different surfaces (base metals, glass of instruments, quartz glass, plastic materials, precious metals). A great dependence on pH, ionic species, ionic concentration, material as well as temperature and presence of complexing agents is observed. Processes are proposed or confirmed by which the losses of material during the trace analysis are reduced.     

Granites and migmatites of the Damara belt,South West Africa. Petrography and melting experiments

In the central area of the early paleozoic Damara belt migmatites and some types of granites (sensu lato) crop out. Conventional petrographic data were collected and melting experiments were carried out with 63 samples of such rocks. Based on these data, migmatite genesis can be classified as follows:

1. Formation by partial melting and separation of more liquid and more crystalline fractions, the melting behaviour of these fractions has to be principally similar then.
2. Formation by injection of “geologically liquid” crystal-melt mixes into rocks of (incidentally) similar or (more frequently) dissimilar melting behaviour.
3. Formation by partial melting of metasediments of originally different composition. The method is applied and demonstrated for outcrops with complicated interrelations and it is shown that temperature estimates are possible thereby (670° to 710° at 4–5 kb H₂O pressure in the central Damara belt).

     

Effective precipitation in southern Spain ( 266 to 46 ka) based on a speleothem stable carbon isotope record

We present the longest-duration directly dated terrestrial palaeoclimate record from the western Mediterranean region: a flowstone speleothem from Gitana Cave, southeast Spain. The main phase of growth was 274 to 58 ka, dated by multi-collector inductively coupled plasma mass spectrometry (MC-ICPMS) U-series methods. Effective precipitation, which we consider primarily responsible for flowstone calcite δ¹³C variations, measured at 300 μm resolution, was higher during interglacials associated with marine oxygen isotope stages (MIS) 7 and 5, and lower during glacial MIS 6. There is a close correspondence between speleothem δ¹³C and sea surface temperature (SST) estimates from adjacent Atlantic Ocean cores during MIS 6, which implies that oceanic conditions are critical in controlling the western Mediterranean terrestrial moisture balance during glacial periods. Other features of our record, such as the sequence of termination II warming/moistening between approximately 133 and 127 ka, including a “pause” around 130–128 ka, and the lagged termination of MIS 5 warm intervals (5e, 5c and 5a) are similar to other terrestrial records within the Mediterranean basin, indicating climate synchroneity along the northern Mediterranean coast. The Gitana cave region also may have been a refugium for temperate species during short-lived cold/arid periods during MIS 5.     

Investigating the transport dynamics and the properties of bedload material with a hydro‐acoustic measuring system

This article deals with the following two questions. Are acoustic measurements in running waters appropriate for a highly resolved investigation of the bedload transport? Which characterizations of the bedload regarding mass and shape are possible via the acoustic signals? The signals were recorded by means of data recorders (Tascam Inc. DAP1 Portable Data Recorder) and hydrophones (International Transducer Corp. ITC‐4001 A). The ITC‐4001 is a shallow water omnidirectional transducer containing a flexural disc transducer utilizing Channelite‐5400 ceramics mounted in a rugged corrosion‐resistant housing. These hydrophones were screwed onto the bottom side of stainless steel plates, serving as a contact surface for the bedload in motion above them. After more than 100 series of tests in the laboratory, which indicated the basic relations between the dimension, shape and weight of the bedload and the resulting signal, field tests of the measuring system were conducted. By artificially produced flood waves in the small brooks Riverisbach, Olewiger Bach and by a winter flood wave in the River Moselle, it is possible to elaborate similar structures of the signal course of the bedload movement. The highest transport rates can be observed at the beginning of the increasing limbs and behind the peaks of the waves. At the beginning of the waves, the increasing transport power of the water and the loose material can be considered as the cause for this result. The high stream velocity behind the wave peaks explains the increase in the bedload transport so that material from the channel beds is unfastened and will be mobilized. The characterization of the bedload regarding the shape and mass is still limited regarding the field measurements and could be solved only for homogeneous grain sizes and single stones under laboratory conditions. Copyright © 2007 John Wiley & Sons, Ltd.