ALBERT

Description: The repository concept for geological disposal of spent nuclear fuel in Sweden and Finland is planned to be constructed in sparsely fractured crystalline bedrock and with an engineered bentonite buffer to embed the waste canisters. An important stage in such a deep repository is the post-closure phase following the deposition and the backfilling operations when the initially unsaturated buffer material gets hydrated by the groundwater delivered by the natural bedrock. We use numerical simulations to interpret observations on buffer wetting gathered during an in situ campaign, the Bentonite Rock Interaction Experiment, in which unsaturated bentonite columns were introduced into deposition holes in the floor of a 417 m deep tunnel at the Äspö Hard Rock Laboratory in Sweden. Our objectives are to assess the performance of state-of-the-art flow models in reproducing the buffer wetting process and to investigate to which extent dependable predictions of buffer wetting times and saturation patterns can be made based on information collected prior to buffer insertion. This would be important for preventing insertion into unsuitable bedrock environments. Field data and modeling results indicate the development of a de-saturated zone in the rock and show that in most cases, the presence or absence of fractures and flow heterogeneity are more important factors for correct wetting predictions than the total inflow. For instance, for an equal open-hole inflow value, homogeneous inflow yields much more rapid buffer wetting than cases where fractures are represented explicitly thus creating heterogeneous inflow distributions. This article is protected by copyright. All rights reserved.

Description: The seasonal and spatial variability of dissolved Barium (Ba) in the Amundsen Gulf, southeastern Beaufort Sea, was monitored over a full year from September 2007 to September 2008. Dissolved Ba displays a nutrient-type behavior: the maximum water column concentration is located below the surface layer. The highest Ba concentrations are typically observed at river mouths, the lowest concentrations are found in water masses of Atlantic origin. Barium concentrations decrease eastward through the Canadian Arctic Archipelago. Barite (BaSO4) saturation is reached at the maximum dissolved Ba concentrations in the subsurface layer, whereas the rest of the water column is undersaturated. A three end-member mixing model comprising freshwater from sea-ice melt and rivers, as well as upper halocline water, is used to establish their relative contributions to the Ba concentrations in the upper water column of the Amundsen Gulf. Based on water column and riverine Ba contributions, we assess the depletion of dissolved Ba by formation and sinking of biologically bound Ba (bio-Ba), from which we derive an estimate of the carbon export production. In the upper 50 m of the water column of the Amundsen Gulf, riverine Ba accounts for up to 15% of the available dissolved Ba inventory, of which up to 20% is depleted by bio-Ba formation and export. Since riverine inputs and Ba export occur concurrently, the seasonal variability of dissolved Ba in the upper water column is moderate. Assuming a fixed organic carbon to bio-Ba flux ratio, carbon export out of the surface layer is estimated at 1.8 ± 0.45 mol C m−2 yr−1. Finally, we propose a climatological carbon budget for the Amundsen Gulf based on recent literature data and our findings, the latter bridging the surface and subsurface water carbon cycles.

Description: In this study the flows of chemical risk information for paint as a consumer product were investigated from a product chain perspective. The main method of research involved semi-structured interviews with Swedish manufacturers of paint and chemicals. In addition, retailers and consumers were interviewed. The flows of chemical risk information between actors within (e.g., manufacturers, retailers, and consumers) and outside (e.g., industry associations and regulators) the paint product chain are described. Because the European chemical legislation REACH (Registration, Evaluation, Authorization and restriction of CHemicals) plays a large role in the management of chemical risk information at companies, some consequences of REACH on actors in the paint product chain are described. Examples of such consequences are that importing of chemicals from non–European Union (EU) countries may be discouraged and that some low-volume chemicals may no longer be produced. However, manufacturers do not yet see these consequences as impediments to innovation. The results of this work show that chemical risk information is most comprehensive during the manufacturing steps of the product chain. This is due not only to tradition and industry initiatives, but also to REACH and other legislation. The results also illustrate the need for evaluation of how chemical risk information is used in different contexts and the importance of directing the right information at the right target group. Following legislative development, more specialized information is required in the safety data sheet (SDS), and because of this many manufacturers find it necessary to create simplified safety sheets that make the most pertinent safety and hazard information easily accessible to individuals that handle the chemicals in their factories. The study found that in creating the simplified safety sheets, the content and use of chemical risk information is evaluated and adjusted for presentation to this particular target group. It is evident that the Swedish Paint and Printing Ink Makers Association plays an important role in the interpretation of legal requirements and even in agreements for providing information that exceeds legal requirements.

Description: Saturated fatty acids like palmitate induce endoplasmic reticulum (ER) stress in pancreatic beta-cells, an event linked to apoptotic loss of β -cells in type 2 diabetes. Sustained activation of the ER stress response leads to expression of growth arrest and DNA damage-inducible protein 34 (GADD34), a regulatory subunit of protein phosphatase 1. In the present study, we have used small interfering RNA in order to knockdown GADD34 expression in insulin-producing MIN6 cells prior to induction of ER stress by palmitate and evaluated its consequences on RNA-activated protein kinase-like ER-localized eIF2alpha kinase (PERK) signalling and apoptosis. Salubrinal, a specific inhibitor of eukaryotic initiation factor 2 α (eIF2 α ) dephosphorylation, was used as a comparison. Salubrinal treatment augmented palmitate-induced ER stress and increased GADD34 levels. Both GADD34 knockdown and salubrinal treatment potentiated the cytotoxic effects of palmitate as evidenced by increased DNA fragmentation and activation of caspase 3, with the fundamental difference that the former did not involve enhanced levels of GADD34. The data from this study suggest that sustained activation of PERK signalling and eIF2 α phosphorylation sensitizes insulin-producing MIN6 cells to lipoapoptosis independently of GADD34 expression levels. Copyright © 2014 John Wiley & Sons, Ltd.

Description: We report on measurements across an annual cycle of carbon dioxide system parameters in the polar mixed layer (PML) of the circumpolar flaw lead in the Amundsen Gulf, Arctic Ocean. From these and other properties (nitrate, S, T) of the PML, we found that biological processes (photosynthesis and respiration) accounted for about 50% of the monthly variations in the carbonate ion concentration, [CO32−] and Ω, the saturation state of these waters with respect to calcite (ΩCa) and aragonite (ΩAr). Vertical mixing and salinity changes had equal impacts over the annual cycle. The impact of sea ice meltwater resulted in decreasing Ω values in summer, but most of this change was offset by the Ω increase as a result of CO2 drawdown during biological photosynthesis.

Description: In austral summer, from December 2008 to January 2009, we investigated the sea-ice carbon dioxide (CO2) system and CO2 controls in the Amundsen and Ross Seas, Antarctica. We sampled seawater, brine and sea ice for the measurements of total alkalinity (AT), total inorganic carbon (DIC), pH, inorganic nutrients, particulate organic carbon (POC) and nitrogen (PON), chlorophyll a, pigments, salinity and temperature. Large variability in all measured parameters was observed in time and space due to the complex sea-ice dynamics. We discuss the controls of the sea-ice CO2 system, such as brine rejection, biological processes, calcium carbonate (CaCO3) precipitation/dissolution and CO2 exchange. Most (80 to 90%) of the DIC loss was due to brine rejection, which suggests that the sea ice acted as an efficient DIC sink from 0.8 and 2.6 mol m−2 yr−1 (9.6–31 g C m−2 yr−1). The remaining change in DIC was to a large extent explained by net biological production. The AT:DIC ratio in the sea ice was higher than in the under-ice water (UIW), with ratios reaching 1.7, which indicated CaCO3 precipitation and concomitant DIC loss in the sea ice. Elevated AT:DIC ratios and carbonate concentrations were also observed in the UIW, which reflect the solid CaCO3 rejected from the ice during melt. The potential for uptake of atmospheric CO2 in the mixed layer increased by approximately 56 μatm due to the combined effect of CaCO3 precipitation during ice formation, and ice melt in summer.

Description: From sea-ice formation in November 2007 to onset of ice melt in May 2008, we studied the carbonate system in first-year Arctic sea ice, focusing on the impact of calcium-carbonate (CaCO 3 ) saturation states of aragonite (ΩAr) and calcite (ΩCa) at the ice-water interface (UIW). Based on total inorganic carbon (C T ) and total alkalinity (A T ), and derived pH, CO 2 , carbonate ion ([CO 3 2- ]) concentrations and Ω, we investigated the major drivers such as brine rejection, CaCO 3 precipitation, bacterial respiration, primary production and CO 2 -gas flux in sea ice, brine, frost flowers and UIW. We estimated large variability in sea-ice C T at the top, mid and bottom ice. Changes due to CaCO 3 and CO 2 -gas flux had large impact on C T in the whole ice core from March to May, bacterial respiration was important at the bottom ice during all months, and primary production in May. It was evident that the sea-ice processes had large impact on UIW, resulting in a five times larger seasonal amplitude of the carbonate system, relative to the upper 20 m. During ice formation, [CO 2 ] increased by 30 µmol kg-1, [CO 3 2- ] decreased by 50 µmol kg -1 , and the ΩAr decreased by 0.8 in the UIW due to CO 2 -enriched brine from solid CaCO 3 . Conversely, during ice melt, [CO 3 2- ] increased by 90 µmol kg -1 in the UIW, and Ω increased by 1.4 between March and May, likely due to CaCO 3 dissolution. We estimated that increased ice melt would lead to enhanced oceanic uptake of inorganic carbon to the surface layer.

Description: We performed measurements of carbon dioxide fugacity ( f CO 2 ) in the surface water under Arctic sea ice from January to June 2015 during the Norwegian young sea ICE (N-ICE2015) expedition. Over this period, the ship drifted with four different ice floes and covered the deep Nansen Basin, the slopes north of Svalbard and the Yermak Plateau. This unique winter-to-spring dataset includes the first winter-time under-ice water f CO 2 observations in this region. The observed under-ice f CO 2 ranged between 315 µatm in winter and 153 µatm in spring, hence was undersaturated relative to the atmospheric f CO 2 . Although the sea ice partly prevented direct CO 2 exchange between ocean and atmosphere, frequently occurring leads and breakup of the ice sheet promoted sea-air CO 2 fluxes. The CO 2 sink varied between 0.3 and 86 mmol C m −2 d −1 , depending strongly on the open-water fractions (OW) and storm events. The maximum sea-air CO 2 fluxes occurred during storm events in February and June. In winter, the main drivers of the change in under-ice water f CO 2 were dissolution of CaCO 3 (ikaite) and vertical mixing. In June, in addition to these processes, primary production and sea-air CO 2 fluxes were important. The cumulative loss due to CaCO 3 dissolution of 0.7 mol C m −2 in the upper 10 m played a major role in sustaining the undersaturation of f CO 2 during the entire study. The relative effects of the total f CO 2 change due to CaCO 3 dissolution was 38%, primary production 26%, vertical mixing 16%, sea-air CO 2 fluxes 16%, and temperature and salinity insignificant. This article is protected by copyright. All rights reserved.

Description: In order to investigate the effect of glacial water on the CO 2 system in the fjord, we studied the variability of the total alkalinity (A T ), total dissolved inorganic carbon (C T ), dissolved inorganic nutrients, oxygen isotopic ratio (δ 18 O), and freshwater fractions from the glacier front to the outer Tempelfjorden on Spitsbergen in winter 2012 (January, March and April) and 2013 (April) and summer/fall 2013 (September). The two contrasting years clearly showed that the influence of freshwater, mixing and haline convection affected the chemical and physical characteristics of the fjord. The seasonal variability showed the lowest calcium carbonate saturation state (Ω) and pH values in March 2012 coinciding with the highest freshwater fractions. The highest Ω and pH were found in September 2013, mostly due to CO 2 uptake during primary production. Overall, we found that increased freshwater supply decreased Ω, pH and A T . On the other hand, we observed higher A T relative to salinity in the freshwater end-member in the mild and rainy winter of 2012 (1142 µmol kg −1 ) compared to A T in 2013 (526 µmol kg −1 ). Observations of calcite and dolomite crystals in the glacial ice suggested supply of carbonate-rich glacial drainage water to the fjord. This implies that winters with a large amount of glacial drainage water partly provide a lessening of further ocean acidification, which will also affect the air-sea CO 2 exchange. This article is protected by copyright. All rights reserved.