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251.
Renée Katrin Bechmann Bodil Katrine Larsen Ingrid Christina Taban Per Møller 《Marine pollution bulletin》2010,60(11):2087-2098
Adult shrimps (Pandalus borealis) and their embryos were exposed to an oil-water dispersion (OWD) at concentrations of 0.015, 0.06 and 0.25 mg/L using a continuous flow system. Lysosomal membrane stability was analysed in haemocytes using the neutral red retention assay and an alkaline unwinding assay was used to measure DNA damage in hepatopancreas tissue. Exposure to oil induced concentration and time dependent biomarker responses in adult shrimps together with the accumulation of PAH in their tissues. Oil exposure of shrimp embryos caused increased mortality in the resultant larvae, even if the larvae were kept in clean water after hatching. There were minor differences observed in larval stage development times in the first part of the experiments. The fatty acid composition of embryos exposed to oil was different to that of non-exposed larvae. PAH tissue concentration and biomarker responses correlated to the reduced survival of the shrimp larvae. 相似文献
252.
Sven Fuchs Magdalena Thöni Maria Christina McAlpin Urs Gruber Michael Bründl 《Natural Hazards》2007,41(1):113-129
This paper demonstrates the application of cost effectiveness analysis and cost benefit analysis to alternative avalanche
risk reduction strategies in Davos, Switzerland. The advantages as well as limitations of such analysis for natural hazards
planning are discussed with respect to 16 avalanche risk reduction strategies. Scenarios include risk reduction measures that
represent the main approaches to natural hazards planning in Switzerland, such as technical, organisational, and land use
planning measures. The methodologies used outline how concepts and techniques from risk analysis, hazard mapping, Geographic
Information System, and economics can be interdisciplinary combined. The results suggest important considerations, such as
possible sources of uncertainty due to different choices in the calculation of cost effectiveness ratio and net present value.
Given the parameters and assumptions, it seems as if the current approach to avalanche risk reduction in the study area approximates
to economic and cost efficiency and serves the aim of reducing risk to human fatalities. 相似文献
253.
Structural and geochronological constraints on the tectonic evolution of the Dulong-Song Chay tectonic dome in Yunnan province, SW China 总被引:14,自引:1,他引:14
Dan-Ping Yan Mei-Fu Zhou Christina Yan Wang Bin Xia 《Journal of Asian Earth Sciences》2006,28(4-6):332-353
The Dulong-Song Chay tectonic dome lies on the border of China (SE Yunnan Province) and northern Vietnam, and consists of two tectonic and lithologic units: a core complex and a cover sequence, separated by an extensional detachment fault. These two units are overlain unconformably by Late Triassic strata. The core complex is composed of gneiss, schist and amphibolite. SHRIMP zircon U–Pb dating results for the orthogneiss yield an age of 799±10 Ma, which is considered to be the crystallization age of its igneous protolith formed in an arc-related environment. A granitic intrusion within the core complex occurred with an age of 436–402 Ma, which probably formed during partial closure of Paleotethys. Within the core complex, metamorphic grades change sharply from upper greenschist-low amphibolite facies in the core to low greenschist facies in the cover sequence. There are two arrays of foliation within the core complex, detachment fault and the cover sequence: S1 and S2. The pervasive S1 is the axial plane of intrafolial S0 folds. D1 deformation related to this foliation is characterized by extensional structures. The strata were structurally thinned or selectively removed along the detachment faults, indicating exhumation of the Dulong-Song Chay tectonic dome. The major extension occurred at 237 Ma, determined by SHRIMP zircon U–Pb and 39Ar/40Ar isotopic dating techniques. Regionally, simultaneous tectonic extension was associated with pre-Indosinian collision between the South China and Indochina Blocks. The S2 foliation appears as the axial plane of NW-striking S1 buckling folds formed during a compressional regime of D2. D2 is associated with collision between the South China and Indochina Blocks along the Jinshajiang-Ailao Shan suture zone, and represents the Indosinian deformation. The Dulong granites intruded the Dulong-Song Chay dome at 144±2, 140±2 and 116±10 Ma based on 39Ar/40Ar measurement on muscovite and biotite. The dome was later overprinted by a conjugate strike-slip fault and related thrust fault, which formed a vortex structure, contemporaneously with late Cenozoic sinistral movement on the Ailao Shan-Red River fault. 相似文献
254.
Mads Solgaard Thomsen Karen J. McGlathery Anna Christina Tyler 《Estuaries and Coasts》2006,29(3):465-473
We determined the distribution of macroalgae in Hog Island Bay, a shallow coastal lagoon in Virginia, USA, seasonally at 12
sites from 1998 to 2000 and at 3 representative sites from 2000 to 2002. We analyzed macroalgal biomass, taxonomic richness,
and abundance of two non-native species, the cryptic invaderGracilaria vermiculophylla and the conspicuousCodium fragile, with respect to season, location (mainland, mid lagoon, barrier island sites), and elevation (intertidal, subtidal). Taxonomic
richness, total algal biomass, and nonnative biomass peaked in the summer months when temperature and light availability were
highest. A few stress tolerant and ephemeral algae dominated the algal assemblage.G. vermiculophylla constituted 74% of the entire algal biomass, was the most abundant alga in all seasons, locations, and elevation levels,
and was positively correlated with taxonomic richness and abundance of filamentous species.Ulva curvata, Bryopsis plumosa, andC. fragile accounted for an additional 16% of the algal biomass. There are distinct habitats in Hog Island Bay that can be classified
into low diversity-low biomass regions near the mainland and barrier islands and high diversity-high biomass regions in the
open mid lagoon, where abundant shells for attachment and intermediate levels of water column nutrients and turbidity likely
create better growth conditions. Taxonomic richness and biomass were higher in subtidal than intertidal zones, presumably
due to lower desiccation stress. This study provides an example of how a single invasive species can dominate an entire assemblage,
both in terms of biomass (being most abundant in all seasons, locations, and tidal levels) and species richness (correlating
positively with epiphytic filamentous taxa). By adding hard-substratum structural complexity to a relatively homogenous soft-substratum
system,G. vermiculophylla increases substratum availability for attachment and entanglement of other algal species and enhances local diversity. Without
widespread and abundantG. vermiculophylla, taxa likePolysiphonia, Ceramium, Bryopsis, Ectocarpus, andChampia would likely be much less common. This study also highlights the importance of using DNA analysis of voucher specimens in
monitoring programs to accurately identify cryptic invaders. 相似文献
255.
256.
Susanna F. Jenkins Christina R. MagillK. John McAneney 《Journal of Volcanology and Geothermal Research》2007
Volcanic events comprising multiple eruptive stages are common in the historical and geological record and display activity of variable intensity ranging, in some cases, through to several centuries. To better understand the characteristics of such events globally, this study explores a database of historical events having Volcanic Explosivity Indices 4 or greater. The database was compiled for the most part from published and unpublished material provided by the Smithsonian Institution. The database was examined to find common statistical relationships, within and between the variables characterising multi-stage explosive events. 相似文献
257.
A brief review of ophiolites in China 总被引:7,自引:0,他引:7
Qi Zhang Christina Yan Wang Dunyi Liu Ping Jian Qing Qian Guoqing Zhou Paul T. Robinson 《Journal of Asian Earth Sciences》2008,32(5-6):308-324
Ophiolites are widely distributed in western, southwestern and northern China, where they fall into four principal age groups; Neoproterozoic, Early Paleozoic, Late Paleozoic and Mesozoic–Cenozoic. Neoproterozoic ophiolites are known only in the North Qinling orogenic belt, in NE Jiangxi Province and in western Sichuan Province. Phanerozoic ophiolites are grouped into the Paleo-Asian, Tethyan and Circum-Pacific series. The Paleo-Asian ophiolites crop out in the western and northern parts of China between the Siberian and North China Blocks, and range in age from early to late Paleozoic. All of these ophiolites are of the Franciscan (formerly Cordilleran) type and many are superimposed on one another, suggesting repeated accretion of arc assemblages in an environment similar to the present-day western Pacific Ocean. Mediterranean-type (formerly Tethyan-type) ophiolites are confined to SW China, particularly Tibet and Yunnan Province. Paleo-Tethyan ophiolites are characterized by MORB-type lavas and are typically bounded by old continental lithosphere, suggesting that they formed in small, intercontinental ocean basins. Neo-Tethyan ophiolites contain a range of lava types including MORB, IAT and boninite, indicating formation in a variety of suprasubduction zone (SSZ) environments. Circum-Pacific ophiolites occur sporadically in Taiwan and NE China, where they form tectonic mélanges composed mainly of metaperidotite, gabbro and basalt. 相似文献
258.
Atmospheric teleconnection mechanisms of extratropical North Atlantic SST influence on Sahel rainfall 总被引:1,自引:0,他引:1
Yuwei Liu John C. H. Chiang Chia Chou Christina M. Patricola 《Climate Dynamics》2014,43(9-10):2797-2811
Extratropical North Atlantic cooling has been tied to droughts over the Sahel in both paleoclimate observations and modeling studies. This study, which uses an atmospheric general circulation model (GCM) coupled to a slab ocean model that simulates this connection, explores the hypothesis that the extratropical North Atlantic cooling causes the Sahel droughts via an atmospheric teleconnection mediated by tropospheric cooling. The drying is also produced in a regional climate model simulation of the Sahel when reductions in air temperature (and associated geopotential height and humidity changes) from the GCM simulation are imposed as the lateral boundary conditions. This latter simulation explicitly demonstrates the central role of tropospheric cooling in mediating the atmospheric teleconnection from extratropical North Atlantic cooling. Diagnostic analyses are applied to the GCM simulation to infer teleconnection mechanisms. An analysis of top of atmosphere radiative flux changes diagnosed with a radiative kernel technique shows that extratropical North Atlantic cooling is augmented by a positive low cloud feedback and advected downstream, cooling Europe and North Africa. The cooling over North Africa is further amplified by a reduced greenhouse effect from decreased atmospheric specific humidity. A moisture budget analysis shows that the direct moisture effect and monsoon weakening, both tied to the ambient cooling and resulting circulation changes, and feedbacks by vertical circulation and evaporation augment the rainfall reduction. Cooling over the Tropical North Atlantic in response to the prescribed extratropical cooling also augments the Sahel drying. Taken together, they suggest a thermodynamic pathway for the teleconnection. The teleconnection may also be applicable to understanding the North Atlantic influence on Sahel rainfall over the twentieth century. 相似文献
259.
Geoffrey M. Morrison Sonia Yeh Anthony R. Eggert Christopher Yang James H. Nelson Jeffery B. Greenblatt Raphael Isaac Mark Z. Jacobson Josiah Johnston Daniel M. Kammen Ana Mileva Jack Moore David Roland-Holst Max Wei John P. Weyant James H. Williams Ray Williams Christina B. Zapata 《Climatic change》2015,131(4):545-557
260.
The Scoping Plan for compliance with California Assembly Bill 32 (Global Warming Solutions Act of 2006; AB 32) proposes a substantial reduction in 2020 greenhouse gas (GHG) emissions from all economic sectors through energy efficiency, renewable energy, and other technological measures. Most of the AB 32 Scoping Plan measures will simultaneously reduce emissions of traditional criteria pollutants along with GHGs leading to a co-benefit of improved air quality in California. The present study quantifies the airborne particulate matter (PM2.5) co-benefits of AB 32 by comparing future air quality under a Business as Usual (BAU) scenario (without AB 32) to AB 32 implementation by sector. AB 32 measures were divided into five levels defined by sector as follows: 1) industrial sources, 2) electric utility and natural gas sources, 3) agricultural sources, 4) on-road mobile sources and 5) other mobile sources. Air quality throughout California was simulated using the UCD source-oriented air quality model during 12 days of severe air pollution and over 108 days of typical meteorology representing an annual average period in the year 2030 (10 years after the AB 32 adoption deadline). The net effect of all AB 32 measures reduced statewide primary PM and NOx emissions by ~1 % and ~15 %, respectively. Air quality simulations predict that these emissions reductions lower population-weighted PM2.5 concentrations by ~6 % for California. The South Coast Air Basin (SoCAB) experienced the greatest reductions in PM2.5 concentrations due to the AB 32 transportation measures while the San Joaquin Valley (SJV) experiences the smallest reductions or even slight increases in PM2.5 concentrations due to the AB 32 measures that called for increased use of dairy biogas for electricity generation. The ~6 % reduction in PM2.5 exposure associated with AB 32 predicted in the current study reduced air pollution mortality in California by 6.2 %, avoiding 880 (560–1100) premature deaths per year for the conditions in 2030. The monetary benefit from this avoided mortality was estimated at $5.4B/yr with a weighted average benefit per tonne of $35 k/tonne ($23 k/tonne–$45 k/tonne) of PM, NOx, SOx, and NH3 emissions reduction. 相似文献