The role of negative CO2 emissions for reaching 2 °C—insights from integrated assessment modelling     

Detlef P. van Vuuren  Sebastiaan Deetman  Jasper van Vliet  Maarten van den Berg  Bas J. van Ruijven  Barbara Koelbl 《Climatic change》2013,118(1):15-27

Limiting climate change to 2 °C with a high probability requires reducing cumulative emissions to about 1600 GtCO₂ over the 2000–2100 period. This requires unprecedented rates of decarbonization even in the short-run. The availability of the option of net negative emissions, such as bio-energy with carbon capture and storage (BECCS) or reforestation/afforestation, allows to delay some of these emission reductions. In the paper, we assess the demand and potential for negative emissions in particular from BECCS. Both stylized calculations and model runs show that without the possibility of negative emissions, pathways meeting the 2 °C target with high probability need almost immediate emission reductions or simply become infeasible. The potential for negative emissions is uncertain. We show that negative emissions from BECCS are probably limited to around 0 to 10 GtCO₂/year in 2050 and 0 to 20 GtCO₂/year in 2100. Estimates on the potential of afforestation options are in the order of 0–4 GtCO₂/year. Given the importance and the uncertainty concerning BECCS, we stress the importance of near-term assessments of its availability as today’s decisions has important consequences for climate change mitigation in the long run.  相似文献   

New evidences of hydrothermal fluids circulation at the Devonian Kess Kess mounds,Hamar Laghdad (eastern Anti‐Atlas,Morocco)     

Fulvio Franchi  Barbara Cavalazzi  Catherine Pierre  Roberto Barbieri 《Geological Journal》2015,50(5):634-650

New evidences based on a combination of field and laboratory investigations reinforce the hypotheses that the circulation of warm fluids has remarkably contributed to the origin and development of the Devonian Kess Kess mounds of the Hamar Laghdad Ridge (eastern Anti‐Atlas, Morocco). The limestones of the Hamar Laghdad Ridge were deposited above a structural high generated by calc‐alkaline volcanic activity that has probably fuelled the circulation of warm fluids throughout the overlying carbonate units. The geological and palaeontological attributes described throughout the succession of the Hamar Laghdad Ridge (from the Lochkovian to Frasnian intervals) are interpreted as the result of hydrothermal processes related to a volcanic system. In particular, these attributes seem consistent with a chemo‐physical environment fuelled by the circulation of warm and late magmatic fluids. These attributes include a very low oxygen stable isotope signature (δ¹⁸O ~ −10‰) for carbonates. Evidences for a late magmatic fluid circulation consist of volcanic glass and pyroclasts replacement with hydrothermal minerals such as quartz, anatase and clinochlore. Fluids circulating through veins and pores into sediments, and venting to the seafloor, probably induced the formation of cavities where monospecific trilobite communities were detected. The partially silicified trilobite remains are associated with traces of goethite. This iron‐bearing oxide mineral is also present in the upper part of the Hamar Laghdad Ridge. All these attributes are here interpreted as possible evidences for a low‐temperature hydrothermal venting system active during the Lochkovian–Frasnian time span. This study combines an updated revision with new petrographic, geological and geochemical results aimed at providing an overall framework on the origin and early diagenesis of the Devonian succession of Hamar Laghdad. Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   

Metal distribution in sediment cores from São Paulo State Coast, Brazil     

Silva PS  Damatto SR  Maldonado C  Fávaro DI  Mazzilli BP 《Marine pollution bulletin》2011,62(5):1130-1139

Ten sediment core samples with lengths ranging from 35 to 100 cm were collected in the Baixada Santista region and analyzed to determine As, Br, Co, Cr, Cs, Fe, Rb, Sb, Ta, Th, U, Zn and rare earths (Sc, Ce, Eu, La, Lu, Nd, Sm, Tb and Yb) level concentrations using instrumental neutron activation analysis (INAA). The studied region is located in the southeastern coast of São Paulo State and is comprised of a densely urbanized area, the largest industrial complex of the country, with a predominance of petrochemical and fertilizer plants. It is also home to Brazil’s most important and busiest port. The conclusions found that the As, La, Sm, Ne, Ce, Eu, Hf, Ta, Th, and U elements have a high background level in the region and that Fe and Zn were the main indicators of anthropogenic contribution in the sediments.  相似文献   

Arsenic in sediments, groundwater, and streamwater of a glauconitic Coastal Plain terrain, New Jersey, USA—Chemical “fingerprints” for geogenic and anthropogenic sources     

Julia L. Barringer  Pamela A. Reilly  Dennis D. Eberl  Alex E. Blum  Jennifer L. Bonin  Robert Rosman  Barbara Hirst  Marzooq Alebus  Kimberly Cenno  Miroslawa Gorska 《Applied Geochemistry》2011,26(5):763-776

Glauconite-bearing deposits are found worldwide, but As levels have been determined for relatively few. The As content of glauconites in sediments of the Inner Coastal Plain of New Jersey can exceed 100 mg/kg, and total As concentrations (up to 5.95 μg/L) found historically and recently in streamwaters exceed the State standard. In a major watershed of the Inner Coastal Plain, chemical “fingerprints” were developed for streambed sediments and groundwater to identify contributions of As to the watershed from geologic and anthropogenic sources. The fingerprint for streambed sediments, which included Be, Cr, Fe and V, indicated that As was predominantly of geologic origin. High concentrations of dissolved organic C, nutrients (and Cl⁻) in shallow groundwater indicated anthropogenic inputs that provided an environment where microbial activity released As from minerals to groundwater discharging to the stream. Particulates in streamwater during high flow constituted most of the As load; the chemical patterns for these particulates resembled the geologic fingerprint of the streambed sediments. The As/Cr ratio of these suspended particles likely indicates they derived not only from runoff, but from groundwater inputs, because As contributed by groundwater is sequestered on streambed sediments. Agricultural inputs of As were not clearly identified, although chemical characteristics of some sediments indicated vehicle-related inputs of metals. Sediment sampling during dry and wet years showed that, under differing hydrologic conditions, local anthropogenic fingerprints could be obscured but the geologic fingerprint, indicating glauconitic sediments as an As source, was robust.  相似文献   

Spatial and temporal evolution of Cu-Zn mine tailings during dewatering     

Barbara L. Sherriff  D. Jared EtcheverryNikolay V. Sidenko  Jamie Van Gulck 《Applied Geochemistry》2011,26(11):1832-1842

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Towards improving ambient noise tomography using simultaneously curvelet denoising filters and SEM simulations of seismic ambient noise     

Laurent Stehly  Paul Cupillard  Barbara Romanowicz 《Comptes Rendus Geoscience》2011,343(8-9):591-599

The aim of this article is to investigate a possible way to improve ambient noise tomography by expanding the data base of useful cross-correlation measurements. We show that the curvelet transform makes it possible to compute synthetic noise correlations by simulating directly seismic ambient noise using the spectral element method. These synthetic correlations can in turn be used to identify surface waves and overtones even on correlations having a signal to noise ratio much lower than one. We hope that the possibility to compute SEM synthetic correlations and to extract more information from correlations will be useful to improve ambient noise tomography and monitoring.  相似文献   

The use of coarser taxonomy in the detection of long-term changes in polychaete assemblages     

Musco L  Mikac B  Tataranni M  Giangrande A  Terlizzi A 《Marine environmental research》2011,71(2):131-138

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Shifts in an epibenthic trophic web across a marine frontal area in the Southwestern Atlantic (Argentina)     

A. Cecilia Mauna  Florencia Botto  Barbara Franco  J. Matías Schwartz  E. Marcelo Acha  Mario L. Lasta  Oscar O. Iribarne 《Journal of Sea Research》2011,66(3):248-255

Marine benthic trophic relationships and food web structures may be influenced by benthic–pelagic coupling processes, which could also be intensified by the physical dynamics of marine fronts. In this work, we employed stable isotope (δ¹³C and δ¹⁵N) analysis to investigate the influence of the Southwest (SW) Atlantic shelf-break front (SBF; 38–39°S, 55–56°W; Argentina) on an epibenthic trophic web. Epibenthic organisms were sampled, at depths of ~ 100 m, with a non-selective dredge from a sandy bottom community located in frontal (F) and marginal (M) areas. The SBF position and the chlorophyll-a (chl-a) concentrations were inferred using satellite data of the sea surface temperature (SST) and satellite chl-a concentration, respectively. The most noticeable shifts in stable isotopes between the sampled areas were those of the Patagonian scallop, Zygochlamys patagonica (δ¹³C), and those of the sea urchin, Sterechinus agassizi (δ¹⁵N). Diet analyses inferred from stable isotopes and mixing models demonstrated that the dominant component of this community, Z. patagonica, had variable contributions to higher trophic levels between areas. More importantly, the epibenthic assemblage in F areas showed δ¹³C-enriched and δ¹⁵N-depleted isotopic signatures with respect to the M areas. Collectively, this evidence suggests that frontal dynamics promotes the accumulation of δ¹³C-enriched phytoplankton in the seabed in F areas, while in M areas the more degraded organic matter becomes more important in the trophic web, decreasing the δ¹⁵N isotopic signature of the assemblage. Therefore, the trophic web was sustained by fresher food in F areas than in M areas, demonstrating the role of frontal dynamics in the shaping of these communities.  相似文献   

Seeing the forest for the trees: Local-level resource use and forest restitution in postsocialist Bulgaria     

Barbara A. Cellarius 《GeoJournal》2001,55(2-4):599-606

Recent legislation for the restitution of ownership rights to, and subsequent management of, formerly privately owned forests in postsocialist Bulgaria has focused largely albeit not exclusively on the restored forests from the perspective of timber production, that is, `forest' equals `harvestable timber resource'. Using ethnographic data collected in rural Rhodope Mountain communities, this paper presents a local-level perspective on forests and forest use, including the meaning that forests hold for local residents as a source of non-timber forest products such as mushrooms and medicinal plants, of animal pasture, and of firewood for household heating and cooking. This local social perspective is then contrasted with the timber-resource focus of the forestry legislation and subsequent planning for forest use. The scale of forest ownership – in part a function of the restitution legislation – is also addressed in relation to the practicalities of resource management. Generally, the paper demonstrates a mismatch between the postsocialist forestry legislation and local practice and conditions with regard to forests and the natural resources therein. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

A fluid inclusion reconnaissance study of the Huanuni tin deposit (Bolivia), using LA-ICP-MS micro-analysis   总被引：1，自引：0，他引：1  

Barbara Müller  Rolf Frischknecht  Terry Seward  Christoph Heinrich  Willy Camargo Gallegos 《Mineralium Deposita》2001,36(7):680-688

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