Acid leaching of ash and coal: Time dependence and trace element occurrences

The leaching of coal and coal/asphaltite/wood-ashes in sulfuric acid (pH 1.0, 25 °C, S/L, 1:10) was studied as a function of time; acid consumption and extracted metal concentrations are presented. Whole coals consumed acid rapidly during the first few minutes, followed by slow acid consumption. Wood-, lignite-, and asphaltite-ashes consumed acid in two stages, the rapid phase extending < 30 min and the slow phase extended up to 10 days. The rapid phase was dominated by the dissolution of Ca, K and Mg ions for wood-ash, by Ca, Al and Mg ions for lignite-ash and Ca and Mg ions for asphaltite-ash. The sulfur concentration in solution and the concentrations of Ca, Fe, K, Mg, Na, P, Al and Mn in the aqueous phase verified the neutralizing capacity of the untreated ashes as well as the formation of insoluble sulfates in the residues. The slow phase kinetics differed for different fuels and exhibited leaching of several abundant elements—Fe, Al, K, Na and Mn. Trace elements (Ba, Cd, Co, Cr, Cu, Mo, Ni, Pb, Th, U, V, Zn) sometimes required up to 32 h for maximal extraction from ashes. Suggestions are presented regarding the chemical nature of trace elements in the untreated coals and ashes and suitable residence times for economical industrial processes. We think it possible to combine bacteriological oxidation of sulfidic concentrates of acid leaching from ash of various qualities or even whole coals.     

Chromium uptake by giant reed under rhizobacterial inhibition

The role of rhizospheric microbes of giant reed (Arundo donax L.) in Cr uptake from hydroponic culture was investigated. The control group was exposed to Cr in range of 25–100 mg L^?1 containing a control itself (with no metal addition). The experimental group received same Cr treatments, but in addition was exposed to antibiotic treatment in order to inhibit rhizospheric bacteria. The range of Cr accumulated in the roots was 3–7.65 mg L^?1; in stem it ranged 2.15–42.4 mg kg^?1; while in leaves, the range of Cr content was 13.7–15 mg kg^?1. Overall, Cr uptake in A. donax (without rhizobacterial inhibition) was root < leaf < stem. However, the amount of Cr uptake in plants with rhizobacterial inhibition was significantly less (~4.6-folds in 100 mg L^?1 Cr treatment) than those without such inhibition clearly highlighting that rhizobacterial inhibition decreased the Cr uptake. The experimental results clearly demonstrated that the inhibition of the rhizobacterial populations had great influence on the Cr uptake. However, Cr uptake could not be completely inhibited as some metal uptake was observed after the rhizobacterial inhibition although it was significantly less than the Cr uptake of plants without such inhibition.     

Relatedness between contemporary and subfossil cladoceran assemblages in Turkish lakes

Cladocerans are valuable indicators of environmental change in lakes. Their fossils provide information on past changes in lake environments. However, few studies have quantitatively examined the relationships between contemporary and sub-fossil cladoceran assemblages and no investigations are available from Mediterranean lakes where salinity, eutrophication and top-down control of large-bodied cladocerans are known to be important. Here we compared contemporary Cladocera assemblages, sampled in summer, from both littoral and pelagic zones, with their sub-fossil remains from surface sediment samples from 40 Turkish, mainly shallow, lakes. A total of 20 and 27 taxa were recorded in the contemporary and surface sediment samples, respectively. Procrustes rotation was applied to both the principal components analysis (PCA) and redundancy analysis (RDA) ordinations in order to explore the relationship between the cladoceran community and the environmental variables. Procrustes rotation analysis based on PCA showed a significant accord between both littoral and combined pelagic–littoral contemporary and sedimentary assemblages. RDA ordinations indicated that a similar proportion of variance was explained by environmental variation for the contemporary and fossil Cladocera data. Total phosphorus and salinity were significant explanatory variables for the contemporary assemblage, whereas salinity emerged as the only significant variable for the sedimentary assemblage. The residuals from the Procrustes rotation identified a number of lakes with a high degree of dissimilarity between modern and sub-fossil assemblages. Analysis showed that high salinity, deep water and high macrophyte abundance were linked to a lower accord between contemporary and sedimentary assemblages. This low accord was, generally the result of poor representation of some salinity tolerant, pelagic and macrophyte-associated taxa in the contemporary samples. This study provides further confirmation that there is a robust relationship between samples of modern cladoceran assemblages and their sedimentary remains. Thus, sub-fossil cladoceran assemblages from sediment cores can be used with confidence to track long-term changes in this environmentally sensitive group and in Mediterranean lakes, subjected to large inter-annual variation in water level, salinity and nutrients.     

Molecular approach to the chemical characterization of fish-exuded kairomone: a Fourier transform infrared spectroscopic study

Diel vertical migration (DVM) bioassay-guided Fourier transform infrared spectroscopy can be a prominent non-destructive and innovative approach for ecological studies. During the characterization of the nature of the fish-exuded kairomone, the peak area results from the spectroscopic analysis of the control, fish-conditioned (F) and temperature incubated fish-conditioned (IF) treatments of the DVM bioassays demonstrated that there was a strong correlation between the alterations of the amine N–H, amide II, amide IV and CH₃ asymmetric vibrations, suggesting that both N–H and CH₃ molecules may be main components of the fish-exuded kairomone cocktail. The IF treatment, which showed similar results with the control treatment, supported that the kairomone is inactivated by bacterial biodegradation. The seasonal variations in the peak areas of the N–H and CH₃ bands suggested that DVM response varied seasonally, where migration response developed quickly in warmer seasons. The peak area of the amine N–H band of the F and IF treatments relative to control conditions can be used as an ideal indicator of the absence or presence and the promptness of migration, at all seasons.     

Early taphonomy of benthic foraminifera in Storfjorden ‘sea-ice factory’: the agglutinated/calcareous ratio as a proxy for brine persistence

The recurrent latent-heat polynya characterizing Storfjorden (Svalbard, Norway) triggers seasonal formation of thin first-year sea ice. This leads to the production of dense, salty, and corrosive brines that cascade towards the sea floor and mix with shelf waters. The bottom topography of the fjord is responsible for the retention of these dense waters in two central deep basins throughout the year. Recent studies show that living benthic foraminifera in Storfjorden are particularly affected by the persistence of brines on the sea floor, with a strong dominance of agglutinated (A) species and high degrees of dissolution of calcareous(C) faunas. Therefore, the A/C ratio, calculated on living faunas, was proposed as a proxy for brine persistence. In the present study we analyse the fossil faunas, found below the taphonomically active zone, to investigate the residual signal of the A/C proxy after the intense early taphonomic processes and challenge its applicability in sedimentary archives. Our results show that despite the generally high taphonomic loss inside the fjord, a high proportion of agglutinated species is still visible in fossil faunas at the stations experiencing regular and/or persistent presence of brine-enriched shelf waters. These results support the application of the A/C ratio in historical records to reconstruct the persistence of brines and indirectly the first-year sea ice formation in Storfjorden. This can be further applied to other Arctic fjords with similar settings and characterized by the production of brines during the winter–early spring season.     

Qualité des eaux du cours principal de la Medjerda (Tunisie et Algérie) et trois de ses affluents Nord

Résumé

Une étude a été effectuée dans la zone Nord-Ouest du bassin versant de la Medjerda avec pour objectif de fournir de nouvelles connaissances sur la qualité des eaux ainsi que sur le type de relation qui peut exister entre les variables physico-chimiques, bactériologiques et les indices de diversité/densité de la méiofaune. Les résultats montrent une dégradation de la qualité du cours principal de la Medjerda et de trois de ses affluents Nord (augmentation de la salinité, teneur en nitrate, matière organique, coliformes…). Les indices de diversité et d’équitabilité suivent cette évolution régressive des variables physico-chimiques et apportent de nouvelles connaissances sur le type et la qualité du sédiment.

Editeur Z.W. Kundzewicz ; Editeur associé B. Touaïbia     

Active tectonic and palaeoseismological features of the western section of Mustafakemalpaşa Fault; Bursa,NW Anatolia

The Mustafakemalpa?a Fault (MF), located among Manyas, Ulubat and Orhaneli faults, is a right lateral strike-slip and 47 km in length. The MF begins with a pressure ridge at the west and exhibits complex jog terminations at east ends in restraining left stepovers. The western section of the fault bounds Miocene and Quaternary units and continues towards ?lyasç?lar. The central segment of the fault, starts with approximately 750-m leftward stepover, exhibits a sinusoidal geometry between Kapakl?oluk and Kabulbaba. In this section, MF traverses mountainous terrain and cuts Ophiolite, Jurassic limestones and Miocene detritals, forming dextral faulting features and gaining reverse component. The eastern section exhibits left stepping en-echelon pattern and consists 2.5-km offset on the Orhaneli River. In this study, palaeoseismological findings related to the Holocene activity and active tectonic properties of the MF are presented. The trenches exposed mismatched stratigraphy, demonstrating evidence of events across the fault. We identified three events (before BC 2190, later AD 1425 and 1850) that have occurred during the past 4000 years. We suggest a long non-characteristic recurrence interval and ~0.7 mm/y slip-rate for MF, based on trench data and offset of the Late Pliocene drainage of Orhaneli River.     

Palaeozoic-Recent geological development and uplift of the Amanos Mountains (S Turkey) in the critically located northwesternmost corner of the Arabian continent

We have carried out a several-year-long study of the Amanos Mountains, on the basis of which we present new sedimentary and structural evidence, which we combine with existing data, to produce the first comprehensive synthesis in the regional geological setting. The ca. N-S-trending Amanos Mountains are located at the northwesternmost edge of the Arabian plate, near the intersection of the African and Eurasian plates. Mixed siliciclastic-carbonate sediments accumulated on the north-Gondwana margin during the Palaeozoic. Triassic rift-related sedimentation was followed by platform carbonate deposition during Jurassic-Cretaceous. Late Cretaceous was characterised by platform collapse and southward emplacement of melanges and a supra-subduction zone ophiolite. Latest Cretaceous transgressive shallow-water carbonates gave way to deeper-water deposits during Palaeocene-Eocene. Eocene southward compression, reflecting initial collision, resulted in open folding, reverse faulting and duplexing. Fluvial, lagoonal and shallow-marine carbonates accumulated during Late Oligocene(?)-Early Miocene, associated with basaltic magmatism. Intensifying collision during Mid-Miocene initiated a foreland basin that then infilled with deep-water siliciclastic gravity flows. Late Miocene-Early Pliocene compression created mountain-sized folds and thrusts, verging E in the north but SE in the south. The resulting surface uplift triggered deposition of huge alluvial outwash fans in the west. Smaller alluvial fans formed along both mountain flanks during the Pleistocene after major surface uplift ended. Pliocene-Pleistocene alluvium was tilted towards the mountain front in the west. Strike-slip/transtension along the East Anatolian Transform Fault and localised sub-horizontal Quaternary basaltic volcanism in the region reflect regional transtension during Late Pliocene-Pleistocene (<4 Ma).