Reduced sulfur and iron species in anoxic water column of meromictic crater Lake Pavin (Massif Central, France)

The vertical distribution of reduced sulfur species (RSS including H₂S/HS⁻, S⁰, electroactive FeS) and dissolved Fe(II) was studied in the anoxic water column of meromictic Lake Pavin. Sulfide concentrations were determined by two different analytical techniques, i.e. spectophotometry (methylene blue technique) and voltammetry (HMDE electrode). Total sulfide concentrations determined with methylene blue method (∑H₂S_MBRS) were in the range from 0.6 µM to 16.7 µM and were substantially higher than total reduced sulfur species (RSS_V) concentrations determined by voltammetry, which ranged from 0.1 to 5.6 μM. The observed difference in the sulfide concentrations between the two methods can be assigned to the presence of FeS colloidal species.Dissolved Fe was high (> 1000 µM), whereas dissolved Mn was only 25 µM, in the anoxic water column. This indicates that Fe is the dominant metal involved in sulfur redox cycling and precipitation. Consequently, in the anoxic deep layer of Lake Pavin, “free” sulfide, H₂S/HS⁻, was low; and about 80% of total sulfide detected was in the electroactive FeS colloidal form. IAP calculations showed that the Lake Pavin water column is saturated with respect to FeS_am phase. The upper part of monimolimnion layer is characterized by higher concentrations of S(0) (up to 3.4 µM) in comparison to the bottom of the lake. This behavior is probably influenced by sulfide oxidation with Fe(III) oxyhydroxide species.     

The influence of the limestone-quarry Čertovy schody (Czech Republic) on the precipitation chemistry and atmospheric deposition

Atmospheric precipitation samples were collected in the Bohemian Karst (30 km SW from Prague, Czech Republic) at six localities in the vicinity of the limestone-quarry Čertovy schody during years 1996–2003. Samples were analyzed for major components (Na⁺, K⁺, Mg²⁺, Ca²⁺, F⁻, Cl⁻, NO₃⁻, HCO₃⁻, SO₄²⁻) and trace metals (Cu, Mn, Fe, Zn, Pb, Be, As, Sr, Cd, Al, Cr). Deposition fluxes were calculated from more than 10 000 elemental analyses of samples collected monthly. The fluxes of monitored substances show temporal and spatial variability. The most marked attribute is the strong affection by local emission sources confirmed by the investigation of seasonal variability, temporal trend and correlation analysis.     

Distribution of riverine sediment chemistry on the shelf,slope and rise of the Gulf of Papua

The tectonically active islands of the Indo-Pacific Archipelago deliver much sediment to the ocean margins. In the Gulf of Papua on the south coast of Papua New Guinea (PNG), the chemical composition of surface sediment from grab samples indicates that Fly River muds are dispersed to the north and east, where they are joined by sediment plumes from the other large rivers along the south coast of PNG. This is the likely source of terrestrial sediment on the Papuan Plateau and the northern Coral Sea Abyssal Plain. The sediment is transported through submarine troughs and canyons offshore, far to the east of the riverine inputs. Immediately south and 30–50 km offshore from the Fly and Purari deltas is a platform of algal and reef carbonate materials, containing little or no terrestrial surface sediment.     

The shock waves and the magnetic field in the corona above the active region on February 17–28, 1969

In this paper the situation above the large active region which passed across the solar disc between February 17 and 28, 1969 is considered. Five dynamical spectra of type II radio bursts registered by CSIRO and by Weissenau Observatory were used. After the elaboration of dynamical spectra, the parameters of shock waves and the values of magnetic field in corona were determined. The magnetic field was obtained using two methods. In the first method the connection between the velocity of shock front and the velocity of the Alfvén waves was used. In the second method the dependence of the frequency split upon the value of the magnetic field was applied.     

Geochemical mass balance for lithium, boron, and strontium in the Gulf of Papua, Papua New Guinea (project TROPICS)

A mass balance has been calculated for the elements Li, B, and Sr in the Gulf of Papua from sampling undertaken during 1993 to 1999. Parameters measured included Fly, Kikori, and Purari River inputs of dissolved and particulate phases, removal flux to sediment traps at the base of the continental shelf slope, and century-scale accumulation rates in shelf and slope sediments (derived from excess ²¹⁰Pb profiles in sediment cores). About 91% of river input Li was in particulate form, and there was conservative behavior of dissolved Li in the salinity gradient of the estuaries. Li accumulation rate in inner-shelf sediments was slightly less than river inputs, suggesting that more than 90% of Li river inputs were trapped in rapid aluminosilicate mud accumulation zones of the inner shelf (<50-m depth). Li removal rate to sediment traps at the base of the slope at ∼1000-m water depth was an order of magnitude smaller than the inner-shelf sedimentation. Export of Li to deep water Coral Sea was estimated to be 1.2 × 10⁸ mol yr⁻¹, and this amount is equivalent to the riverine dissolved Li annual supply rate. About 66% of river input of B was in the particulate phase, and low dissolved B concentrations in freshwater were conservatively mixed with higher concentrations of B in seawater across the salinity gradient. Removal of B to inner-shelf sediments was about 83% of the total river input, indicating a small export of B (1.2 × 10⁸ mol yr⁻¹) to the Coral Sea. About half of the dissolved B input from rivers is sorbed to particles and trapped in inner-shelf sediments. Only 24% of river input of Sr was in particulate form, and low freshwater concentrations of dissolved Sr were conservatively mixed with higher concentrations of Sr in seawater across the salinity gradient. Only 20% of total river inputs of Sr were buried in shelf sediments, and there was a large export (7.3 × 10⁸ mol yr⁻¹) of Sr off the shelf to the Coral Sea. A sediment core from a rapidly accumulating mud deposition zone of the inner shelf shows twofold sympathetic variations in Li, B, and Sr/Ca supply rates over 200- to 1000-yr time intervals.     

Environmental observations in the Gulf of Gdansk and Pomeranian Bay following the summer flood of 1997

Summary In July and at the beginning of August 1997 a study was undertaken in the Gulf of Gdańsk and Pomeranian Bay to follow the immediate effects of the flood which occurred within the Polish rivers — Wisla and Odra — drainage areas. The study included measurements and observations of meteorological and hydrodynamic parameters, basic physico-chemical variables, certain persistent organic pollutants as well as heavy metals and the level of sanitary pollution. The paper presents an overview of environmental conditions in the bays, based on hydrochemical data, subsequent to the inflow of the flood crests. Results of biological investigations, carried out solely in the Pomeranian Bay, on phytoplankton abundance, biomass, species composition and Zooplankton diversity are also presented in the paper. The results of measurements were evaluated in comparison with long-term (1979–1996) monitoring data and control measurements carried out in the last decade of August. It was found out that the impact of flood water was restricted to internal areas of both bays and the negative environmental effects appeared only locally.

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Umweltuntersuchungen in der Danziger und der Pommerschen Bucht nach der Sommerflut 1997

Zusammenfassung Im Juli und Anfang August 1997 fand in der Danziger und in der Pommerschen Bucht eine Untersuchung mit dem Ziel statt, die unmittelbaren Auswirkungen der Flut, die sich in den Einzugsgebieten der polnischen Flüsse Weichsel und Oder ereignet hatte, festzustellen. Die Untersuchung umfa?te Messungen und Beobachtungen meteorologischer, hydrodynamischer und physisch-chemischer Parameter, bestimmter best?ndiger organischer Schadstoffe sowie Messungen von Schwermetallen und Messungen zum Grad der Verunreinigungen durch Colibakterien. Die Arbeit gibt einen überblick über Umweltbeeintr?chtigungen in den betroffenen Gebieten im Anschlu? an den Einstrom des Hochwassers basierend auf hydrochemischen Daten. Ergebnisse biologischer Untersuchungen in der Pommerschen Bucht, speziell auf den Gehalt an Phytoplankton, Biomasse und deren Zusammensetzung sowie auf Zooplanktonvielfalt, werden gezeigt. Die Ergebnisse der Messungen wurden im Vergleich mit Daten aus Langzeitreihen (1979–1996) und Kontrollmessungen in der letzten Dekade des August bewertet. Es wurde festgestellt, da? der Einflu? des Hochwassers sich auf die inneren Gebiete beider Buchten beschr?nkte und negative Umweltver?nderungen nur lokal auftraten.

     

Sediment and trace element depositional history from the Ajkwa River estuarine mangroves of Irian Jaya (West Papua), Indonesia

Radiotracer ²¹⁰Pb and contaminant copper were used to estimate sediment accumulation rates in 4 cores from the Ajkwa River estuary and mangrove tidal channels in western Irian Jaya. Mass accumulation rates (4.5–13 kg dry wt m⁻² yr⁻¹) were within the envelope of expectations for a region of high rainfall, great river catchment relief, and rapid tectonic uplift of mountains. Copper accumulation rates were enhanced 40 fold in surface sediments, compared to pre-1950 sections of the sediment cores. These recent sediments with enhanced copper concentrations come from Freeport Indonesia mine tailings over the last 27 years. Variations in sediment core profiles of Al, Fe, and organic carbon were small, indicating no great change in bulk sediment composition. Sulfur concentrations decline toward the sediment surface, suggesting a decline in rates of microbial sulfate reduction. Enhanced sediment copper concentrations will be a useful tracer of sediment dispersal from the Ajkwa River estuary along this coast.     

Combining trace-element compositions, U–Pb geochronology and Hf isotopes in zircons to unravel complex calcalkaline magma chambers in the Upper Cretaceous Srednogorie zone (Bulgaria)

Precise U–Pb geochronology and Hf isotope tracing of zircon is combined with whole-rock geochemical and Sr and Nd isotope data in order to unravel processes affecting mafic to felsic calcalkaline magmas prior to and during their crystallization in crustal magma chambers along the southern border of Central Srednogorie tectonic zone in Bulgaria (SE Europe). ID-TIMS U–Pb dating of single zircons from felsic and mixed/mingled dioritic to gabbroic horizons of single plutons define crystallization ages of around 86.5–86.0, 85.0–84.5 and 82 Ma. Concordia age uncertainties are generally less than 0.3 Ma (0.35%–2σ), and as good as 0.08 Ma (0.1%), when the weighted mean ²⁰⁶Pb/²³⁸U value is used. Such precision allows the distinction of magma replenishment processes if separated by more than 0.6–1.0 Ma and when they are marked by newly saturated zircons. We interpret zircon dates from a single sample that do not overlap to reflect new zircon growth during magma recharge in a long-lived crustal chamber. Mingling/mixing of the basaltic magma with colder granitoid mush at mid- to upper-crustal levels is proposed to explain zircon saturation and fast crystallization of U- and REE-rich zircons in the hybrid gabbro.Major and trace-element distribution and Sr and Nd whole-rock isotope chemistry define island arc affinities for the studied plutons. Slab derived fluids and a sediment component are constrained as enrichment sources for the mantle wedge-derived magma, though Hf isotopes in zircon suggest crustal assimilation was also important. Inherited zircons, and their corresponding ε-Hf, from the hybrid gabbroic rocks trace the lower crust as possible source for enrichment of the mantle magma. These inherited zircons are about 440 Ma old with ε-Hf of − 7 at 82 Ma, whereas newly saturated concordant Upper Cretaceous zircons reveal mantle ε-Hf values of + 7.2 to + 10.1. The upper and middle crusts contribute in the generation of the granitoid rocks. Their zircon inheritance is Lower Palaeozoic or significantly older and crustal dominated with 82–85 Ma corrected ε-Hf values of − 28. The Cretaceous concordant zircons in the granitoids are mantle dominated with a ε-Hf values spreading from + 3.9 to + 7.