Spatial Discontinuities in Support for Hydraulic Fracturing: Searching for a “Goldilocks Zone”

Recent research suggests that those located closer to energy development are, on average, more supportive of this development. However, case studies in specific locations reveal additional nuance. In a case study of Bakken Shale residents, Junod et al. identified a “Goldilocks Zone” of unconventional oil and gas development (UOGD) acceptance—an area on the periphery of development that is “just right” because residents feel close enough to receive economic benefits but far enough away to avoid negative impacts. We explore whether this Goldilocks Zone extends nationally by combining geocoded public opinion data (N?=?23,154) with UOGD locations. Using multilevel regression modeling, we find that respondents located within 115?km of newly active UOGD are more supportive of hydraulic fracturing while those located within 115–305?km are comparatively less supportive. While we do not uncover a national-level Goldilocks Zone, our work highlights innovative approaches for examining spatial relationships in energy development opinion.     

Strontium Isotope Analysis of Kimberlitic Groundmass Perovskite via LA-MC-ICP-MS

Strontium isotopic composition is a potentially powerful tracer in studies of kimberlitic rocks but the results from even the most carefully collected and stringently prepared bulk-rock samples are still hampered by contamination and alteration effects. Here we describe a LA-MC-ICP-MS technique which can obtain accurate, high precision Sr_i ratios from 50–150 μm kimberlitic groundmass perovskite without requiring time-consuming mineral separation procedures. Since perovskite is a robust magmatic phase with an extremely low Rb/Sr ratio, the effects of late-stage crustal contamination, post-emplacement alteration and age correction are minimised and results are more representative of primary melt compositions, while additionally preserving powerful grain-scale spatial and textural information. We demonstrate that the adopted protocol overcomes isobaric interferences from Kr⁺, Rb⁺, Er²⁺ and Yb²⁺, and that Ca dimers and Ca argides do not detectably affect the quality of ⁸⁷Sr/⁸⁶Sr ratios produced. To illustrate the utility of the technique, contrasting bulk-rock and in situ perovskite results from eleven Proterozoic kimberlites are documented.     

Deprotonation energies of a model fulvic acid. I. Carboxylic acid groups

A model Suwannee fulvic acid (SFA [Leenheer, J.A., 1994. In: Baker, L.A. (Ed.), Chemistry of Dissolved Organic Matter in Rivers, Lakes and Reservoirs. Advances in Chemistry Series, vol. 237. American Chemical Society]) was energy minimized in various deprotonation states using semi-empirical methods. The structures were minimized in the isolated SFA phase and SFA with 60 water molecules to mimic the first solvation sphere. The relative energies of deprotonation were calculated at four carboxylic acid sites with Hartree-Fock (HF/6-31G(d)) and density functional theory (B3LYP/6-31G(d)) methods. Comparisons were made between the theoretical methods and states of solvation. Isolated and solvated models resulted in different relative deprotonation orders. The energy changes calculated for removing a H⁺ from a given carboxylic acid group as a function of overall model molecule charge are large enough to explain the large variations of carboxyl group pK_as in dissolved natural organic matter. Analysis of the SFA structure as a function of molecular charge is also discussed.     

Methylmercury cycling in sediments on the continental shelf of southern New England

Exposure of humans to monomethylmercury (MMHg) occurs primarily through consumption of marine fish, yet there is limited understanding concerning the bioaccumulation and biogeochemistry of MMHg in the biologically productive coastal ocean. We examined the cycling of MMHg in sediments at three locations on the continental shelf of southern New England in September 2003. MMHg in surface sediments is related positively to inorganic Hg (Hg(II) = total Hg − MMHg), the geographical distribution of which is influenced by organic material. Organic matter also largely controls the sediment-water partitioning of Hg species and governs the availability of dissolved Hg(II) for methylation. Potential gross rates of MMHg production, assayed by experimental addition of ²⁰⁰Hg to intact sediment cores, are correlated inversely with the distribution coefficient (K_D) of Hg(II) and positively with the concentration of Hg(II), most probably as HgS⁰, in 0.2-μm filtered pore water of these low-sulfide deposits. Moreover, the efflux of dissolved MMHg to overlying water (i.e., net production at steady state) is correlated with the gross potential rate of MMHg production in surface sediments. These results suggest that the production and efflux of MMHg from coastal marine sediments is limited by Hg(II), loadings of which presumably are principally from atmospheric deposition to this region of the continental shelf. The estimated diffusive flux of MMHg from the shelf sediments averages 9 pmol m⁻² d⁻¹. This flux is comparable to that required to sustain the current rate of MMHg accumulation by marine fish, and may be enhanced by the efflux of MMHg from near-shore deposits contaminated more substantially with anthropogenic Hg. Hence, production and subsequent mobilization of MMHg from sediments in the coastal zone may be a major source of MMHg to the ocean and marine biota, including fishes consumed by humans.     

删除爱情

时间:2100年 他们结婚已经3年了. 他很爱她. 她认为他各方面都很好,她很愿意和他一起生活,直到永远.可是每当他们在一起亲热的时候,另一个他的影子就会出现……那是她的初恋情人.     

Hormone loads exported by a tile‐drained agroecosystem receiving animal wastes

Little is known regarding hormone export from tile‐drained agricultural fields despite the widespread presence of tile drains in the Midwestern United States. By intensively measuring water flow rates and hormone concentrations in four subsurface tile drains and three receiving ditches at a working Midwest farm, hormone fluxes and loads from the tile‐drained fields were quantified. Before and during the 17‐month study period (January 2009 – May 2010), the associated farm fields received various animal waste applications (beef, dairy, poultry, sheep, and swine). Hormones monitored included the estrogens17β‐ and 17α‐estradiol, estrone, and estriol; the natural androgens testosterone, and androstenedione; and the synthetic androgens 17β‐ and 17α‐trenbolone, and trendione. Hormone loads measured in the ditches for three drainage areas during the entire 17‐month study period were in ranges of 16–58 mg/ha for total estrogens, 6.8–19 mg/ha for natural androgens, and 4.2–44 mg/ha for synthetic androgens. Because higher hormone concentrations generally occurred during discrete periods of increased flow, high flow rates often were associated with a disproportionately high hormone flux. For example, 80% of total estrogens and natural androgens exported into the ditches occurred during only 9–26% of the study period, coinciding with the most significant storm events. In addition, hormone fluxes were highest during storm events that occurred shortly after animal waste applications. Therefore, to effectively reduce hormone loads exported to downstream aquatic ecosystems in the absence of any application reduction, the short periods during which high‐flow events occur must be targeted. Copyright © 2012 John Wiley & Sons, Ltd.     

Petrogenesis of the Dar al Gani (DaG) 1.1 Ma ejection-paired olivine-phyric shergottites and implications for ~470 Ma Martian volcanism

The Dar al Gani (DaG) olivine-phyric shergottites share mineralogical and geochemical characteristics, which confirm that these meteorites are derived from a single source. Bulk trace elements (La/Yb—0.12), in situ maskelynite ⁸⁷Sr/⁸⁶Sr (~0.7014) and redox estimates (FMQ ~ −2) indicate derivation from a depleted, reduced mantle reservoir; identical to all ~470 Ma shergottites ejected at 1.1 Ma. The DaG shergottites have been variably affected by terrestrial alteration, which precipitated carbonate along fractures and modified bulk-rock fluid mobile (e.g., Ba) elements. Nonetheless, sufficient data are available to construct a multi-stage formation model for the DaG shergottites and other 1.1 Ma ejection-paired shergottites that erupted at ~470 Ma. First, partial melting of a depleted mantle source occurred at 1540 ± 20°C and 1.2 ± 0.1 GPa, equivalent to > ~100 km depth. Then, initial crystallization in a staging chamber at ~85 km depth at the crust–mantle boundary took place, followed by magma evolution and variable incorporation of antecrystic olivine ± orthopyroxene. Subsequently, crystallization of olivine phenocrysts and re-equilibration of olivine antecrysts occurred within an ascending magma. Finally, magmas with variable crystal loads erupted at the surface, where varied cooling rates produced a range of groundmass textures. This model is similar to picritic flood basalt magmas erupted on Earth.