Immuno-localisations (GSSP) of subcellular accumulation sites of phenanthrene, aroclor 1254 and lead (Pb) in relation to cytopathologies in the gills and digestive gland of the mussel Mytilus edulis     

Einsporn S  Koehler A 《Marine environmental research》2008,66(1):185-186

Cell and tissue pathology of both, gill and digestive tissue, has been the subject of many studies for the elucidation of contaminant-induced biological effects. In the present study, cellular pathological alterations were linked to subcellular sites of chemical accumulation in gills and digestive gland tissues. For this purpose, mussels (Mytilus edulis) were exposed to the organic contaminants aroclor 1254 (PCB) (20 microg/L), phenanthrene (PAH) (150 microg/L) or the metal lead (Pb) (2.5mg/L). The localization of chemicals at the subcellular level was analysed by an antibody-based detection system (GSSP) by the use of commercially available antibodies specifically directed against the chemicals. Pathological changes were analysed in parallel in identical samples by transmission electron microscopy. After exposure to the different contaminants, cell organelles such as mitochondria, the endo-lysosomal system as well as endoplasmic reticulum showed clear evidence of chemically-induced alterations. Large numbers of crystalloid inclusions were found in mitochondria and in autophagic lysosomes as well as multi-lamellated whorls after PAH and aroclor exposure. Immunocytochemical detection of the chemicals showed their accumulation inside of various cell organelles such as lysosomes, mitochondria, and nuclei. Additionally, chemicals were localized in association to membranes, cilia and microvilli of gill and digestive gland cells. Furthermore, the chitinous rod and mucus secretions of gill epithelial cells were positively labelled for contaminants indicating their role in protection. Localization of contaminants by immuno-detection in combination with pathological diagnosis gives insights into the cellular targets of chemical attack.  相似文献   

International Young Scientists’ perspective on global change issues     

Sonja Wipf  Francisco J. Meza 《Climatic change》2009,94(1-2):1-4

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Continuous 60-year stable isotopic and earth-alkali element records in a modern laminated tufa (Jaruga,river Krka,Croatia): Implications for climate reconstruction     

Sonja Lojen  Andrej Trkov  Janez Ščančar  Juan A. Vázquez-Navarro  Neven Cukrov 《Chemical Geology》2009,258(3-4):242-250

A continuous 60-year record (1938–1998) of stable isotope compositions of carbon and oxygen, as well as trace metal (Mg, Sr, Ba) concentrations in a laminated calcite crust precipitated in a short artificial tunnel on a non-equilibrium groundwater-fed karstic river is presented. Chemical and isotopic records have been compared to hydrometeorological data, available for the last 48 years. An attempt is made to relate isotopic and geochemical variations in the crust to environmental parameters, such as temperature, precipitation and changes in vegetation cover, as well as to postdepositional recrystallisation of the older crust material. Isotopic composition of the crust is largely influenced by non-equilibrium precipitation, which favours the incorporation of isotopically depleted C and O into the carbonate. Furthermore, because of the complicated hydrological situation, there is no observable correlation between the stable oxygen isotope composition of water and temperature. The result is that the ¹⁸O isotopic thermometers overestimate the measured precipitation temperatures. Temperatures calculated from Mg/Ca ratios of water and the carbonate match the δ¹⁸O palaeotemperatures within ± 2.4 °C in the older part of the crust, precipitated before the onset of industrial pollution of the river. It was demonstrated that the application of Mg palaeothermometry in natural systems, where the Mg/Ca ratio of water is influenced not only by temperature, but also by other environmental parameters such as precipitation, surface runoff, groundwater retention time and anthropogenic influences, is subject to a large uncertainty, up to 10 °C.  相似文献   

Isotopic fractionation and reaction kinetics between Cr(III) and Cr(VI) in aqueous media     

Sonja Zink  Ronny Schoenberg  Michael Staubwasser 《Geochimica et cosmochimica acta》2010,74(20):5729-125

The redox-sensitive stable isotope geochemistry of chromium bears the potential to monitor the attenuation of chromate pollution and to investigate changes in environmental conditions in the present and the past. The use of stable Cr isotope data as a geo-environmental tracer, however, necessitates an understanding of the reaction kinetics and Cr fractionation behaviour during redox transition and isotope exchange. Here, we report stable chromium isotope fractionation data for Cr(VI) reduction, Cr(III) oxidation and isotopic exchange between soluble Cr(III) and Cr(VI) in aqueous media. The reduction of Cr(VI) to Cr(III) with H₂O₂ under strongly acidic conditions shows a near-equilibrium isotope fractionation of Δ^53/52Cr_{(Cr(III)-Cr(VI))} of −3.54 ± 0.35‰. At pH neutrality, however, the reduction experiments show a kinetic isotope fractionation Δ^53/52Cr_{(Cr(III)-Cr(VI))} of −5‰ for the extent of reduction of up to 85% of the chromium. The oxidation of Cr(III) to Cr(VI) in alkaline media, using H₂O₂ as the oxidant, cannot be explained by a single, unidirectional reaction. Our experiments indicate that the involvement of the unstable intermediates Cr(IV) and Cr(V) and their disproportionation during redox reactions between Cr(III) and Cr(VI) influence the overall fractionation factor, depending on the prevailing pH conditions and the reaction rates. No detectable isotope exchange between soluble Cr(VI) and Cr(III) species at pH values of 5.5 and 7 was revealed over a timescale of days to weeks. This means that, at least within such a time frame, the isotopic composition of Cr(VI) in a natural system will not be influenced by equilibration with any Cr(III) and thus reveal the true extent of reduction, given that the Cr isotope composition of the source Cr(VI) and the fractionation factor for the prevailing conditions are known.  相似文献   

Granulite sulphides as tracers of lower crustal origin and evolution: An example from the Slave craton, Canada     

Sonja Aulbach  Cristen Krauss  Robert A. Creaser  Thomas Stachel  Larry M. Heaman  Sergei Matveev  Thomas Chacko 《Geochimica et cosmochimica acta》2010,74(18):5368-5381

We carried out a detailed study of sulphide minerals, a ubiquitous mineral group in lower crustal mafic to peraluminous granulite xenoliths from the Diavik kimberlites, to assess their use in constraining the origin and tectonothermal evolution of the deep crust, and to obtain additional data on the composition of lower crust beneath ancient continents. Sulphides are overwhelmingly pyrrhotite with minor Ni (0.7-3.9 at.%), Co (0.1-0.7 at.%), and Cu contents (0.4-3.9 at.%). Sulphide modes in mafic granulites range from 0.14 to 0.55 vol%, translating into bulk rock S contents from ∼600 to 2000 ppm, similar to S contents in other mafic igneous rocks and indicating preservation of primary igneous S contents. In mafic granulites, Re and Os abundances in sulphides range from 42.5 to 726 ppb and 3.2 to 180 ppb, respectively, whereas those in peraluminous granulites are distinctly lower (36.1-282 ppb and 1.8-7.2 ppb, respectively), suggestive of Re and Os loss to fractionating sulphides in the more evolved precursors of these rocks.The significant within-sample variability of ¹⁸⁷Os/¹⁸⁸Os and correlation with ¹⁸⁷Re/¹⁸⁸Os indicates the preservation of primary Re-Os isotope systematics and time-integrated decay of the measured ¹⁸⁷Re. Within the large uncertainties inherent in the nature of the samples and technique, sulphides in some granulites may record major tectonothermal events in the central Slave craton spanning several billion years of evolution. Multiple generations of sulphide can occur in a single sample. These data attest to the heterogeneous composition and complex history of the Slave craton lower crust.  相似文献   

Is global warming affecting cave temperatures? Experimental and model data from a paradigmatic case study     

David Domínguez-Villar  Sonja Lojen  Kristina Krklec  Andy Baker  Ian J. Fairchild 《Climate Dynamics》2015,45(3-4):569-581

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Additionality revisited: guarding the integrity of market mechanisms under the Paris Agreement     

Axel Michaelowa  Wolfgang Obergassel  Sonja Butzengeiger 《Climate Policy》2013,13(10):1211-1224

ABSTRACT

The Paris Agreement requires mitigation contributions from all Parties. Therefore, the determination of additionality of activities under the market mechanisms of its Article 6 will need to be revisited. This paper provides recommendations on how to operationalize additionality under Article 6. We first review generic definitions of additionality and current approaches for testing of additionality before discussing under which conditions additionality testing of specific activities or policies is still necessary under the new context of the Paris Agreement, that is, in order to prevent increases of global emissions. We argue that the possibility of ‘hot air’ generation under nationally-determined contributions (NDCs) requires an independent check of the NDC’s ambition. If the NDC of the transferring country does contain ‘hot air’, or if the transferred emission reductions are not covered by the NDC, a dedicated additionality test should be required. While additionality tests of projects and programmes could continue to be done through investment analysis, for policy instruments new approaches are required. They should be differentiated according to type of policy instrument. For regulation, we suggest calculating the resulting pay-back period for technology users. If the regulation generates investments exceeding a payback period threshold, it could be deemed additional. Similarly, carbon pricing policies that generate a carbon price exceeding a threshold could qualify; for trading schemes an absence of over-allocation needs to be shown. The threshold should be differentiated according to country categories and rise over time.

Key policy insights

• Without additionality testing, market mechanisms under the Paris Agreements might lead to an international diffusion of ‘hot air’. To avoid this, an independent assessment of NDC ambition is in order. Otherwise, activities under the mechanisms need to undergo specific additionality tests.

• Additionality testing of projects and programmes should build on the experience developed under the Kyoto Protocol mechanisms.

• Bold approaches are needed for assessing additionality of policies. To avoid cumbersome assessment of all activities triggered by such policies, highly aggregated approaches are suggested, ranging from payback period thresholds for technologies mandated by regulation to minimum price levels triggered by carbon pricing policies. Over time, the stringency of threshold values should increase.

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A spatial approach to baseline and leakage in CDM forest carbon sinks projects     

Michael Dutschke  Sonja Butzengeiger  Axel Michaelowa 《Climate Policy》2013,13(5):517-530

Abstract

Forestry projects under the Clean Development Mechanism (CDM) face specific challenges with regard to determination of a baseline for carbon sequestration. We propose a semi-standardized approach called PARAPIA for calculation of a baseline that is built on the concept of a reference area around the project area whose land-use characteristics determine the baseline scenario. The land-use shares in the reference area are checked at each verification. Baseline carbon stocks are then derived ex post using the average carbon content of each land-use type. The reference area is between five and ten times larger than the project area. To determine indirect effects (the so-called ‘leakage’), a political influence area such as province or state is assessed with regards to migration flows due to the project and related emissions.  相似文献   

The climate sensitive zone along an altitudinal gradient in central Himalayan rivers: a useful concept to monitor climate change impacts in mountain regions     

Ram Devi Tachamo Shah  Subodh Sharma  Peter Haase  Sonja C. Jähnig  Steffen U. Pauls 《Climatic change》2015,132(2):265-278

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The disc evolution of V2051 Oph on decline from superoutburst     

Sonja Vrielmann  Warren Offutt 《Monthly notices of the Royal Astronomical Society》2003,338(1):165-175

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