Aluminium in Lake Cuicocha,Ecuador, an Andean Crater Lake: Filterable,Gelatinous and Microcrystal Al Occurrence

In Lake Cuicocha watershed, a young caldera lake, soils consist of volcanic deposits with a high SiO₂ and Al₂O₃ content; these andisols are in an early stage of development; and in drainage water from the watershed, aluminium concentrations reach 15.0 μmol L⁻¹. Total aluminium concentrations in Lake Cuicocha water raises up to 7.2 μmol L⁻¹, with nearly 70% occurring as filterable Al at neutral to weak alkaline conditions. Al polymerization to gelatinous aggregates of a few hundred micrometres in diameter as well as the occurrence of Al microcrystals like gibbsite as an ageing product of gelatinous Al polymers was noted in the lake water. The gelatinous Al leads to the formation of larger aggregates resulting in flocs of bacteria, algae, microorganisms and detritus.     

Hydrochemical characterisation of ground and surface water at Dörtyol/Hatay/Turkey

The degradation of ground water quality due to human activities is a widespread environmental problem. Furthermore, coastal aquifers are threatened by sea water intrusion as a result of increasing water exploitation. The investigation area near Dörtyol is located at the Mediterranean coast, southern Turkey, and dominated by agricultural land use. Drinking, domestic and agricultural purposes require different amounts of uncontaminated water. In this study the hydrogeological characteristics of the coastal plain were investigated. Discharge and ground water level measurements as well as geological investigations were undertaken in field in addition to anion and cation analyses of ground and surface water. The results show geological and anthropogenic influence on ground and surface water composition. In spite of a large number of wells in the coastal area sea water intrusion was not detected. With the goal of devising sustainable water use regulations, more emphasis and research needs to be directed to the long-term observation of ground and surface water quality as well as the detailed investigation of hydraulic characteristics of the local aquifer.     

The continent-ocean transition at the southeastern margin of the South China Sea

The South China Sea formed by magma-poor, or intermediate volcanic rifting in the Paleogene. We investigate the structure of the continent-ocean transition (COT) at its southern margin, off NW Palawan between the continental blocks of Reed Bank and the islands of Palawan and Calamian. Several surveys, recorded by the BGR from 1979 to 2008, established a comprehensive database of regional seismic lines, accompanied with magnetic and gravity profiles.We interpret two major rifted basins, extending in the NE direction across the shelf and slope, separated by a structural high of non volcanic origin.The continent-ocean transition is interpreted at the seaward limit of the continental crust, when magnetic spreading anomalies terminate some 80-100 km farther north. The area in between displays extensive volcanism - as manifest by extrusions that occasionally reach and cut the seafloor, by dykes, and by presumed basaltic lava flows - occurring after break-up.The COT is highly variable along the NW Palawan slope: One type shows a distinct outer ridge at the COT with a steep modern seafloor relief. The other type is characterised by rotated fault blocks, bounded by listric normal faults ramping down to a common detachment surface. Half-grabens developed above a strongly eroded pre-rift basement. The seafloor relief is smooth across this other type of COT.We suggest the pre-rift lithospheric configuration had major influence on the formation of the COT, besides transfer zones. Volcanic domains, confined to the north of competent crustal blocks correlate with the style of the COT.Gravity modelling revealed an extremely thinned crust across the shelf. We propose a depth-dependent extension model with crust being decoupled from mantle lithosphere, explaining the discrepancy of subsidence observed across the South China Sea region.     

Feeding strategies of deep-sea sub-Arctic macrofauna of the Faroe-Shetland Channel: Combining natural stable isotopes and enrichment techniques

The response of a sub-arctic, deep-sea macrofaunal community to a simulated food sedimentation event was studied by means of a stable isotope “pulse-chase” experiment. A food pulse was simulated by adding 500 mg C m⁻² of ¹³C-labelled diatoms, Chaetoceros radicans, to sediment cores retrieved from 1080 m in the Faroe-Shetland Channel. Carbon uptake by specific macrofaunal groups was quantified after 3 and 6 days of incubation. The carbon uptake of the dominant taxon (Polychaeta) was quantified at the genus-, and where possible, species-level, representing a data resolution that is rare in deep-sea tracer studies. The macrofaunal community reacted rapidly to the diatom addition, with 47% and 70% of the animals illustrating ¹³C-enrichment after 3 and 6 days, respectively. Approximately 95% of C uptake was located in the upper 2 cm due to the particularly shallow vertical distribution of the macrofaunal community and the nonexistent tracer subduction by burrowing species. Polychaetes of the families Ampharetidae and Cirratulidae were among the most heavily labelled with above background enrichment reaching 1300‰. Approximately 0.8 and 2.0 mg C m⁻² were processed by the macrofauna after 3 and 6 days, representing 0.2% and 0.4% of the added carbon, respectively. It was not possible to differentiate sub-surface deposit-feeding polychaetes from predator/scavenger- and omnivorous polychaetes using their natural ??¹⁵N signatures. However, the combination of natural abundance ??¹⁵N data and ¹³C-labelling experiments proved to be useful for elucidating trophic relations in deep-sea food webs. This study confirms that macrofauna play an active role in the short-term carbon cycling at bathyal depths even at sub-zero temperatures and highlights the need for detailed knowledge of the community structure in understanding carbon processing patterns and early diagenesis of organic matter in marine sediments.     

Deciphering an Archean mantle plume: Abitibi greenstone belt,Canada

The 2724–2722 Ma Stoughton-Roquemaure Group (SRG) of the Abitibi greenstone belt (the Archean Superior Province, Canada) is a ≤ 2 km thick komatiite–basalt succession intermittently exposed for about 50 km along strike. The ultramafic and mafic rocks occur mainly as pillowed, brecciated, and massive flows with well preserved spinifex textures in the komatiites. Volcanological, comparative stratigraphic and geochemical studies of the group along a volcanic marker horizon at the base of the succession allow the assessment of magma emplacement processes and mantle source rocks. Major feeder channels, secondary distributary tubes surrounded by pillowed flows with minor breccias and hyaloclastites display facies architecture of small volume flow fields (1–2 km³). Within the SRG, Al-depleted (ADK; Barberton-type) and Al-undepleted (AUK; Munro-type) komatiitic lavas are intercalated with tholeiitic basalt flows at a m- to 10s of m scale. Basalts and komatiites are inferred to be mantle plume-related; both rock types form two groups with characteristics of ADK and AUK including Al₂O₃/TiO₂ ~ 9–12 for ADK versus 17–22 for AUK, as well as (Gd/Yb)_n with > 1.3 versus ~ 1, respectively. The interdigitation of compositionally different flow units, limited extent of SRG volcanic rocks and facies architecture with the prevalence of small volume flows argue for a relatively small, heterogeneous mantle plume during the incipient stage of the evolution of the Archean Abitibi belt. Assuming that the scale of heterogeneities is comparable to the field expression of compositional changes and stratigraphy, it can be suggested that geochemical plume ‘layering’ is on 10s to 100s of m-scale. The evolution of this Archean mantle plume from inception to demise compares favorably with the Yellowstone hotspot which is assumed to have developed over 17 m.y. and had a diameter of about 300 km.     

Hydrogeological processes in seasonally frozen northern latitudes: understanding, gaps and challenges

The groundwater regime in seasonally frozen regions of the world exhibits distinct behavior. This paper presents an overview of flow and associated heat and solute transport processes in the subsurface, from the soil/vadose zone, through groundwater recharge to groundwater discharge processes in these areas. Theoretical developments, field studies and model development are considered. An illustrative conceptual model of the system is presented. From a groundwater perspective, the dominant effect is the extent of hydraulic isolation between the water above and that below the near-surface frozen zone. The spatial and temporal occurrences of this isolation are seasonally variable and may also be modified under a future changing climate. A good qualitative conceptual understanding of the system has been developed over numerous decades of study. A major gap is the inability to effectively monitor processes in the field, particularly unfrozen water content during freezing conditions. Modeling of field-scale behavior represents a major challenge, even while physically based models continue to improve. It is suggested that progress can be made by combining well-designed field experiments with modeling studies. A major motivation for improving quantification of these processes derives from the need to better predict the impacts of a future changing climate.     

The Gradenbach Observatory—monitoring deep-seated gravitational slope deformation by geodetic, hydrological, and seismological methods

The Gradenbach mass movement (GMM) is an example of DGSD (deep-seated gravitational slope deformation) in crystalline rocks of the Eastern Alps (12.85°E, 47.00°N). The main body of the GMM covers an area of 1.7 km² and its volume is about 120?×?10⁶ m³. A reconstruction of the deformation history yields a mean displacement of?～?22 m from 1962 to 2011. In 1965/66, 1975, 2001, and 2009 high sliding velocities, exceeding several meters per year, interrupt the quasi-stationary periods of slow movement (≤0.3 m/year). Since 1999 the displacement of the main body of the GMM has been observed by GPS. Time series of extensometer readings, precipitation, snow cover water equivalent, water discharge, and hydrostatic water level observed in boreholes were re-processed and are presented in this paper. Continuous recording of seismic activity by a seismic monitoring network at the GMM began in the summer of 2006. Deformation has been monitored since 2007 by an embedded strain rosette based on fiber optics technology and a local conventional geodetic deformation network. The velocity of the GMM could be modeled to a large extent by a quantitative relation to hydro-meteorological data. During the phase of high sliding velocity in spring 2009, the seismic activity in the area increased significantly. Several types of seismic events were identified with some of them preceding the acceleration of the main body by about 6 weeks. The potential inherent in the Gradenbach Observatory data to supply early warning and hazard estimation is discussed.     

Life cycle assessment of pyrolysis–gasification as an emerging municipal solid waste treatment technology

Waste-to-energy technologies are considered as one of the key waste treatment technologies due to their energy and heat recovery efficiencies from the waste. A number of research studies were accomplished to understand the potential environmental burdens from emerging waste treatment technologies such as pyrolysis–gasification (PG). The aim of this study was to examine the PG of municipal solid waste (MSW) treatment process through a life cycle assessment (LCA) method. The study also includes a comparative LCA model of PG and incineration to identify the potential environmental burdens from the existing (incineration) and emerging (PG) waste treatment technologies. This study focused on ten environmental impact categories under two different scenarios, namely: (a) LCA model of PG and (b) comparative LCA model of PG and incineration. The scenario (a) showed that PG had significant environmental burdens in the aquatic eco-toxicity and the global warming potential impact categories. The comparative scenario (b) of PG and incineration of MSW showed that PG had comparatively lower potential environmental burdens in acidification, eutrophication, and aquatic eco-toxicity. Both LCA models showed that the environmental burdens were mainly caused by the volume of the thermal gas (emissions) produced from these two technologies and the final residue to disposal. Therefore, the results indicate that the efficiency and environmental burdens of the emerging technologies are dependent on the emissions and the production of final residue to the landfill.     

Identification of waste management development drivers and potential emerging waste treatment technologies

Application and development of municipal solid waste treatment technology depends on various socio-economic and environmental factors. All those factors are work as development drivers for waste management systems. The study aims to identify key drivers from case studies of waste management development trend in Sweden. Social, economic and environmental drivers are identified and presented in this study. The study identifies personal behaviour, local waste management practice, consumption and generation of waste as the key social drivers. Resource value of waste, economic benefit from waste treatment facilities and landfill tax have been acknowledged as economic drivers for developing waste treatment technology. Moreover, global climate change, environmental movement and awareness have been working as environmental drivers for developing various waste treatment methods in Sweden. In addition, the study aims to analyse emerging waste treatment technologies based on a number of literature review and questionnaire survey. Dry composting, pyrolysis-gasification, plasma arc, and anaerobic digestion have been identified as potential emerging technologies for waste management systems in Sweden.