Carbon mineralization and carbonate preservation in modern cold-water coral reef sediments on the Norwegian shelf

Cold-water coral ecosystems are considered hot-spots of biodiversity and biomass production and may be a regionally important contributor to carbonate production. The impact of these ecosystems on biogeochemical processes and carbonate preservation in associated sediments were studied at Røst Reef and Traenadjupet Reef, two modern (post-glacial) cold-water coral reefs on the Mid-Norwegian shelf. Sulfate and iron reduction as well as carbonate dissolution and precipitation were investigated by combining pore-water geochemical profiles, steady state modeling, as well as solid phase analyses and sulfate reduction rate measurements on gravity cores of up to 3.25 m length. Low extents of sulfate depletion and dissolved inorganic carbon (DIC) production, combined with sulfate reduction rates not exceeding 3 nmol S cm−3 d−1, suggested that overall anaerobic carbon mineralization in the sediments was low. These data showed that the coral fragment-bearing siliciclastic sediments were effectively decoupled from the productive pelagic ecosystem by the complex reef surface framework. Organic matter being mineralized by sulfate reduction was calculated to consist of 57% carbon bound in CH2O groups and 43% carbon in -CH2- groups. Methane concentrations were below 1 μM, and failed to support the hypothesis of a linkage between the distribution of cold-water coral reefs and the presence of hydrocarbon seepage. Reductive iron oxide dissolution linked to microbial sulfate reduction buffered the pore-water carbonate system and inhibited acid-driven coral skeleton dissolution. A large pool of reactive iron was available leading to the formation of iron sulfide minerals. Constant pore-water Ca2+, Mg2+ and Sr2+ concentrations in most cores and decreasing Ca2+ and Sr2+ concentrations with depth in core 23–18 GC indicated diagenetic carbonate precipitation. This was consistent with the excellent preservation of buried coral fragments

An analysis of groundwater use to aquifer potential yield in Illinois

"December 24, 2003."Printed from URL.Includes bibliographical references (p. 12-13).LimitedDuplicate of http://hdl.handle.net/2142/8947. Having two copies visible in search and browse is confusing to users

Vulnerability of Illinois nature preserves to potential ground-water contamination volume I: methodology and initial assessment

"Prepared for Illinois Nature Preserves Commission.""March 1997."The Illinois Nature Preserves Commission (INPC) was created by the Illinois Natural Areas Preservation Act in 1963 (ch. 105, para. 701 et. seq.), with the mission to "assist...landowners in protecting high quality natural areas and habitats of endangered and threatened species in perpetuity, through voluntary dedication of such lands into the Illinois Nature Preserves System." Dedication as a nature preserve provides strong legal protection. For example, penalties for damaging a nature preserve range from a Class A misdemeanor to $10,000 per day in civil penalties. As of December 1996, the Illinois Nature Preserve System consisted of 261 nature preserves that encompass more than 35,000 acres (14,200 hectares) in 73 of the 102 Illinois counties. A significant threat to nature preserves (and other areas with high quality natural communities) is adjacent land use. Variability in adjacent land use generally depends on preserve size and location. Frequently, many different land uses surround a single nature preserve. Potential ground-water contaminant sources include: dumping within or near a preserve, residential septic systems, roads where deicers are used, agricultural fields or feedlots, leaking impoundments or storage tanks, and certain industrial and commercial activities. Unfortunately, the lack of baseline data at most preserves prevents the detection of water quality degradation from off-site activities. During this study, methods were developed and utilized to assess nature preserve sensitivity and vulnerability to potential ground-water contamination. First, a shallow ground-water sensitivity map of the state (1:500,000) was prepared using GIS techniques. It predicts the potential for movement of contaminants from the surface into shallow ground water based on soil leaching characteristics and depth to the uppermost aquifer. Two hundred seven nature preserves were screened, and nearly half of them were categorized as having high or very high sensitivity to ground-water contamination. Second, site surveys were conducted at the 85 nature preserves, which were expected to be most sensitive to ground-water contamination. Hydrologic, geologic, and land-use information was collected for the sites and surrounding areas prior to the surveys. These data were used during the surveys and can be used for future interpretations and comparisons. Roughly 30% of the sites were classified as having moderate-to-high or high vulnerability. The development and use of a field evaluation form facilitated site surveys and the subsequent entry of field data into an electronic database. These types of surveys should be conducted at all nature preserves to provide a standard set of background information for future decision making. Third, the geology and hydrology of Spring Grove Fen Nature Preserve in McHenry County were characterized in greater detail. Test drilling was conducted and 10 observation wells were installed. A total of 64 sets of ground-water and surface water samples were collected between August 1995 and October 1996 and analyzed for a minimum of 35 constituents. Increased chloride concentrations (up to 121 mg/L) were observed in and upgradient of the preserve. Use of deicers on nearby roads may be responsible for an increase in chloride of over 500% at well SG-1a. Low concentrations of alachlor metabolites (< 3 &#956;g/L) were seen in observation wells and in Nippersink Creek. Low concentrations of triazine residues (< 1 &#956;g/L) were also seen in Nippersink Creek. Chemical data at Spring Grove Fen supports the assessment of the site being highly vulnerable to contamination. This type of chemical sampling is important to establish existing water quality at preserves for comparison to future conditions. Information collected during this study is intended to facilitate petitions for state designation of ground water associated with a nature preserve as a Special Resource Ground Water. As stated in the Illinois Administrative Code (Title 35, Part 620.230), Special Resource Ground Water is: a) "demonstrably unique...," or b) "vital for a particularly sensitive ecological system...," or c) "groundwater that contributes to a dedicated nature preserve...." Such a designation may then provide an additional level of protection against destruction or degradation of nature preserves

A multinuclear 1H, 13C and 11B solid-state MAS NMR study of 16- and 18-electron organometallic ruthenium and osmium carborane complexes

YesThe first 1H, 13C, 31P and 11B solid state MAS NMR studies of electron- deficient carborane-containing ruthenium and osmium complexes [Ru/Os(p-cym)(1,2-dicarba-closo-dodecaborane-1,2- dithiolate)] are reported. The MAS NMR data from these 16-electron complexes are compared to those of free carborane-ligand and an 18-electron triphenylphosphine ruthenium adduct, and reveal clear spectral differences between 16- and 18-electron organometallic carborane systems in the solid state.We thank the Swiss National Science Foundation (grant no. PA00P2-145308 to NPEB), the ERC (grant no. 247450 to PJS), EPSRC (grant no. EP/F034210/1) and EC COST Action CM1105 for support. JVH thanks EPSRC and the University of Warwick for partial funding of the solid state NMR infrastructure at Warwick, and acknowledges additional support obtained through Birmingham Science City: Innovative Uses for Advanced Materials in the Modern World (West Midlands Centre for Advanced Materials Project 2), with support from Advantage West Midlands (AWM) and partial funding by the European Regional Development Fund (ERDF)

Management of patients with biliary sphincter of Oddi disorder without sphincter of Oddi manometry

<p>Abstract</p> <p>Background</p> <p>The paucity of controlled data for the treatment of most biliary sphincter of Oddi disorder (SOD) types and the incomplete response to therapy seen in clinical practice and several trials has generated controversy as to the best course of management of these patients. In this observational study we aimed to assess the outcome of patients with biliary SOD managed without sphincter of Oddi manometry.</p> <p>Methods</p> <p>Fifty-nine patients with biliary SOD (14% type I, 51% type II, 35% type III) were prospectively enrolled. All patients with a dilated common bile duct were offered endoscopic retrograde cholangiopancreatography (ERCP) and sphincterotomy whereas all others were offered medical treatment alone. Patients were followed up for a median of 15 months and were assessed clinically for response to treatment.</p> <p>Results</p> <p>At follow-up 15.3% of patients reported complete symptom resolution, 59.3% improvement, 22% unchanged symptoms, and 3.4% deterioration. Fifty-one percent experienced symptom resolution/improvement on medical treatment only, 12% after sphincterotomy, and 10% after both medical treatment/sphincterotomy. Twenty percent experienced at least one recurrence of symptoms after initial response to medical and/or endoscopic treatment. Fifty ERCP procedures were performed in 24 patients with an 18% complication rate (16% post-ERCP pancreatitis). The majority of complications occurred in the first ERCP these patients had. Most complications were mild and treated conservatively. Age, gender, comorbidity, SOD type, dilated common bile duct, presence of intact gallbladder, or opiate use were not related to the effect of treatment at the end of follow-up (p > 0.05 for all).</p> <p>Conclusions</p> <p>Patients with biliary SOD may be managed with a combination of endoscopic sphincterotomy (performed in those with dilated common bile duct) and medical therapy without manometry. The results of this approach with regards to symptomatic relief and ERCP complication rate are comparable to those previously published in the literature in cohorts of patients assessed by manometry.</p

Mineralogical and geochemical analysis of Fe-phases in drill-cores from the Triassic Stuttgart Formation at Ketzin CO₂ storage site before CO₂ arrival

Reactive iron (Fe) oxides and sheet silicate-bound Fe in reservoir rocks may affect the subsurface storage of CO2 through several processes by changing the capacity to buffer the acidification by CO2 and the permeability of the reservoir rock: (1) the reduction of three-valent Fe in anoxic environments can lead to an increase in pH, (2) under sulphidic conditions, Fe may drive sulphur cycling and lead to the formation of pyrite, and (3) the leaching of Fe from sheet silicates may affect silicate diagenesis. In order to evaluate the importance of Fe-reduction on the CO2 reservoir, we analysed the Fe geochemistry in drill-cores from the Triassic Stuttgart Formation (Schilfsandstein) recovered from the monitoring well at the CO2 test injection site near Ketzin, Germany. The reservoir rock is a porous, poorly to moderately cohesive fluvial sandstone containing up to 2–4 wt% reactive Fe. Based on a sequential extraction, most Fe falls into the dithionite-extractable Fe-fraction and Fe bound to sheet silicates, whereby some Fe in the dithionite-extractable Fe-fraction may have been leached from illite and smectite. Illite and smectite were detected in core samples by X-ray diffraction and confirmed as the main Fe-containing mineral phases by X-ray absorption spectroscopy. Chlorite is also present, but likely does not contribute much to the high amount of Fe in the silicate-bound fraction. The organic carbon content of the reservoir rock is extremely low (<0.3 wt%), thus likely limiting microbial Fe-reduction or sulphate reduction despite relatively high concentrations of reactive Fe-mineral phases in the reservoir rock and sulphate in the reservoir fluid. Both processes could, however, be fuelled by organic matter that is mobilized by the flow of supercritical CO2 or introduced with the drilling fluid. Over long time periods, a potential way of liberating additional reactive Fe could occur through weathering of silicates due to acidification by CO2

Land conflict in peri-urban areas: Exploring the effects of land reform on informal settlement in Mexico

Peri-urban areas are often subject to intensive construction, through both formal and informal processes. As land transitions from rural to urban status, different land tenure and administration systems may come into conflict, leading to disputes, contestation and, in some cases, violence. However, little is known about the precise causes of peri-urban land conflict. In Mexico, peri-urban growth has historically proceeded peacefully, owing to the control exerted by a corporatist system of government, and the political use of land tenure regularisation. However, the effects of land reforms on transactions at the peri-urban fringe, in the context of wider processes of liberalisation, may be increasing vulnerability to conflict over land. This paper explores these issues through a case study of an irregular settlement on the peri-urban fringe of the provincial Mexican city of Xalapa, where contestations over informally developed land have escalated into violent encounters between groups of settlers and the state. The findings show that vulnerability to conflict in peri-urban areas can be attributed to the interaction of macro-level processes with local-level factors, including diverse claims, overlapping legal and governance frameworks and, critically, local power relations