The role of gear technologists in supporting an ecosystem approach to fisheries   总被引：2，自引：0，他引：2  

Jennings  Simon; Revill  Andrew S. 《ICES Journal of Marine Science》2007,64(8):1525-1534

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Halogenation processes linked to red wood ant nests (<Emphasis Type="Italic">Formica</Emphasis> spp.) and tectonics     

Gabriele M. Berberich  Tobias Sattler  Dietrich Klimetzek  Simon A. Benk  Martin B. Berberich  Daniela Polag  Heinz Friedrich Schöler  Elliot Atlas 《Journal of Atmospheric Chemistry》2017,74(2):261-281

We investigated and evaluated the occurrence of fault zone tracer gases (CO₂, He, Rn), volatile organohalogens (CH₃Cl, CHCl₃, CHBr₃), alkanes and limonene in soil and nest gases of red wood ants (RWA) in comparison to ambient air, in a seismically active area. In this new approach, we compared RWA-free areas to RWA-areas by combining different investigation and analytical methods. In soil gas, the fault zone tracer gas Rn was surprisingly highly correlated to limonene, suggesting a combination of biotic production of limonene and abiotic degassing of Rn in a seismically active area; moderate correlations were found with trihalomethanes and other halocarbons. In RWA nests a variety of elevated concentrations of haloforms were found, while remaining below the atmospheric background values in RWA-free areas. The evidence of CHCl₃ in RWA nests is the first record. Its average concentrations in nests of F. rufa and F. polyctena were up to 3 fold higher than atmospheric background and up to 28–70 fold higher compared to e.g. volcanic emissions being considered as one of its main geogenic sources. Thus, RWA nests could possibly be an additional source for CHCl₃ liberation. Consequently, apart from RWA being bioindicators for seismically active degassing faults, they might also be used as bioindicators for CHCl₃ formation in forest soils. Although we cannot yet differentiate between a geogenic/abiotic and a biotic formation. RWA nests will have to be reconsidered for halocarbon formation in future quantifications of geochemical cycles at global scale, since they impact organic soil chemistry through biotic and/or abiotic pathways. Therefore, further larger-scale research in different tectonic settings but also in well-known CHCl₃ “hot spot” study areas such as the Klosterhede area (Denmark) should focus directly on gas sampling from confirmed active fault systems. Nests of other ant species should be addressed to compare seasonal, diurnal and nocturnal variations of degassing procedures in relation to earth tides, different geologic settings, and tectonic events such as earthquakes and on quantifying the fluxes to the atmosphere.  相似文献   

Azimuthal structures in the wind and chromosphere of the herbig Ae star ab aur. preliminary results from the MUSICOS 1992 campaign     

C. Catala  T. Böhm  J. -F. Donati  T. Simon  A. Welty  E. Houdebine  L. Huang  S. Jiang  D. Zhai  J. Neff  B. H. Foing  K. Ghosh  J. Butler  A. Collier-Cameron  J. Baudrand  J. Czarny  B. Carter  D. Rees  M. Semel  G. Cutispoto  M. Rodonò 《Solar physics》1994,155(1):185-193

MUSICOS (for MUlti-SIte COntinuous Spectroscopy) is an international project to facilitate and organize world-wide multi-site campaigns in high resolution spectroscopy, in view of obtaining a complete time coverage of various types of variable stellar phenomena.In the framework of this project a vast spectroscopic campaign was organized in December 1992, involving 8 sites well distributed in longitude around the Earth. The observations concerned three scientific programs, among which was the study of azimuthal structures in the wind and chromosphere of the pre-Main-Sequence Herbig Ae star AB Aur.The Hei 5876 line of AB Aur, which is formed in the expanding chromosphere of this star, in the innermost parts of its wind, was monitored at a resolution of 30000, nearly continuously for about 4 days. A spectacular variability of this line was discovered, the profile changing from pure emission to a composite profile including a deep absorption component in the course of a few hours. This variability can be the signature of azimuthal structures in the wind of AB Aur.We present the data collected during the campaign, and discuss possible interpretations of the spectacular variations of the Hei 5876 line.ESA/VILSPAUniversity of British Columbia CanadaBased on observations obtained during the MUSICOS 92 MUlti-SIte COntinuous Spectroscopic campaign from the National Solar Observatory McMath/Pierce 1.5 m, University of Hawaii 2.2 m, Beijing Observatory Xinglong 2.16 m, La Palma 4.2 m William Herschel Telescope, and Observatoire de Haute-Provence 1.52 m telescopes.Presented at the Cosmic Winds and the Heliosphere Conference in Tucson, Arizona, U.S.A., October 18–22, 1993.Visiting Astronomer, Kitt Peak National Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.Visiting Astronomer National Solar Observatory, National Optical Astronomy Observatories, which is operated by the Association of Universities for Research in Astronomy, Inc., under cooperative agreement with the National Science Foundation.  相似文献   

Phase-reversed seabed reflections in seismic data: examples related to mud volcanoes from the South Caspian Sea     

Robert J. Evans  Simon A. Stewart  Richard J. Davies 《Geo-Marine Letters》2007,27(2-4):203-212

The sediment–water interface is usually marked by an increase in acoustic impedance and is therefore displayed in a seismic section as a positive polarity reflection. Here, we use the term “seabed phase reversal” to describe areas of seafloor which are instead expressed as a negative polarity reflection in seismic data. We describe in detail a number of examples of seafloor phase reversals and use a simple one-dimensional geophysical model to test the hypothesis that they are the result of the presence of gas within the seafloor sediment. Our examples are all related to seismically imaged mud volcanoes located within the South Caspian Sea. Sections of phase-reversed seafloor at the summit area of these volcanoes have been mapped to reveal the existence of seafloor mud pools (salses) and recently erupted mud flows which show a strong similarity to smaller-scale features at onshore volcanoes in Azerbaijan. Synthetic geophysical modelling indicates that under the physical conditions likely to occur when the seabed sediment is gas-bearing, the seafloor will be expressed as a strong negative polarity reflection. Unlike other indicators of seafloor gas, such as pockmarks, which merely record the transient expulsion of fluids from sedimentary basins, seafloor phase reversals indicate the presence of gas in marine sediment at the time of survey acquisition. They therefore are of significance to engineering and site survey operations as well as the identification of biological communities and gas flux calculations.  相似文献   

Editorial: integrating local landscape management in a globalised world – practices and pathways     

Simon Swaffield  Jørgen Primdahl 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2016,116(1):1-4

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Pathways to sustainable landscape management: peer recognition as an indicator of effective ‘soft’ actions     

Simon Swaffield  Henry Winchester 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2016,116(1):14-23

New Zealand is a food producer and exporter that combines neoliberal policy with performance-based environmental management, using ‘soft’ governance and actions where possible. Voluntary environmental farm awards are analysed to identify the landscape management activities recognised as best practice by peers at a farm level. Results highlight the importance of whole farm system management. However, the efficacy of reliance upon voluntary mechanisms is coming under increasingly critical scrutiny, as environmental conditions in intensive agricultural landscapes continue to decline. The research question this poses is whether whole farm plans can be practically and formally connected in three concurrent ways – to supply chain management, and to statutory planning frameworks and environmental regulations and to local landscape co-management – while still maintaining flexibility of action for the farmer.  相似文献   

How Central Asian Orogeny Evolves: New Insights from End-Permian to Middle Triassic Magmatic Record along the Solonker Suture Zone     

LI Shan  CHUNG Sunlin  Simon A. WILDE  WANG Tao  XIAO Wenjiao  GUO Qianqian 《《地质学报》英文版》2016,90(5):1907-1908

正Objective The modern Earth is characterized by two types of orogens:collisional orogen and accretionary orogen.It is widely accepted that the Central Asian Orogenic Belt(CAOB)is made up of widespread multiple ancient archipelagos.It has been recognized as a non-collisional orogen,contrasting with the archetypical AlpineHimalayan-type collisional orogens.Although the CAOB is  相似文献   

Incorporating movement in species distribution models: how do simulations of dispersal affect the accuracy and uncertainty of projections?     

Paul Holloway  Jennifer A. Miller  Simon Gillings 《International journal of geographical information science》2016,30(10):2050-2074

Species distribution models (SDMs) are one of the most important GIScience research areas in biogeography and are the primary means by which the potential effects of climate change on species’ distributions and ranges are investigated. Dispersal is an important ecological process for species responding to changing climates, however, SDMs and their subsequent spatial products rarely reflect accessibility to any future suitable environment. Dispersal-related movement can be confounded by factors that vary across landscapes and climates, as well as within and among species, and it has therefore remained difficult to parametrise in SDMs. Here we compared 20 models that have previously been used (or have the potential to be used) to represent dispersal processes in SDM to predict future range shifts in response to climate change. We assessed the different dispersal models in terms of their accuracy at predicting future distributions, as well as the uncertainty associated with their predictions. Atlas data for 50 bird species from 1988 to 1991 in Great Britain were treated as base distributions (t₁), with the species–environment relationships extrapolated (using three commonly used statistical methods) to 2008–2011 (t₂). Dispersal (in the form of the 20 different models) was simulated from the base distribution (t₁) to 2008–2011 (t₂). The results were then combined and used to identify locations that were both abiotically suitable (obtained from the statistical methods) and accessible (obtained from the dispersal models). The accuracy of these coupled projections was assessed with the 2008–2011 atlas data (the observed t₂ distribution). There was substantial variation in the accuracy of the different dispersal models, and in general, the more restrictive dispersal models (e.g. fixed rate dispersal) resulted in lower accuracy for the metrics which reward correct prediction of presences. Ensemble models of the dispersal methods (generated by combining multiple projection outcomes) were created for each species, and a new Ensemble Agreement Index (EAI), which ranges from 0 (no agreement among models) to 1 (full agreement among models) was developed to quantify uncertainty among the projections. EAI values ranged from 0.634 (some areas of disagreement and therefore medium uncertainty among dispersal models) to 0.999 (large areas of agreement and low uncertainty among dispersal models). The results of this research highlight the importance of incorporating dispersal and also illustrate that the method with which dispersal is simulated greatly impacts the projected future distribution. This has important implications for studies aimed at predicting the effects of changing environmental conditions on species’ distributions.  相似文献   

U- and Th-decay series constraints on the timescales of crystal fractionation to produce the phonolite erupted in 2004 near Tristan da Cunha, South Atlantic Ocean     

Mark K. Reagan  Simon Turner  Kenneth W.W. Sims 《Geochimica et cosmochimica acta》2008,72(17):4367-4378

Phonolite pumice found floating offshore of Tristan da Cunha following intense seismic activity southeast of the island July 29-30, 2004 was analyzed for ²³⁸U- and ²³²Th-series nuclides to determine initial ²³⁰Th, ²²⁶Ra, ²¹⁰Pb, ²¹⁰Po, ²²⁸Ra, and ²²⁸Th activities. The initial (²¹⁰Po/²¹⁰Pb) value of 0.15 for the phonolite shows that, like most subaerial lavas, this subaqueous tephra degassed most of its ²¹⁰Po upon eruption. The (²³⁰Th/²³²Th) and (²³⁸U/²³²Th) values for the phonolite are similar to those of the trachyandesites erupted in 1961 from Tristan da Cunha. However, the relative activities of ²¹⁰Pb, ²²⁶Ra, and ²³⁰Th in the phonolite contrast with those of the trachyandesites, in that ²¹⁰Pb and ²³⁰Th are both strongly enriched with respect to ²²⁶Ra. In addition, the phonolite had a small deficit in ²²⁸Ra with respect to ²³²Th. The Ra deficits likely resulted from partitioning into feldspars and hornblende in a time frame that extended over several decades to a century. These disequilibria can be explained by crystal fractionation at a decreasing rate through time at an average of 3-5 × 10⁻³ year⁻¹. The calculated crystallization rate is about an order of magnitude faster than has been calculated for most other phonolites and trachytes, and about half that calculated for crystallization of the Makaopuhi lava lake. These data imply that the 2004 magma was not the differentiated cap of a much larger body that remained at depth. Instead, it was likely the residue of a relatively small body of more mafic magma that was injected into the crust southeast Tristan and underwent extensive and rapid crystal fractionation before it erupted.  相似文献   

Primordial compositions of refractory inclusions   总被引：1，自引：0，他引：1  

L. Grossman  S.B. Simon  M.H. Thiemens  R.W. Williams  T. Ding  R.N. Clayton  T.K. Mayeda 《Geochimica et cosmochimica acta》2008,72(12):3001-3021

Bulk chemical and O-, Mg- and Si-isotopic compositions were measured for each of 17 Types A and B refractory inclusions from CV3 chondrites. After bulk chemical compositions were corrected for non-representative sampling in the laboratory, the Mg- and Si-isotopic compositions of each inclusion were used to calculate its original chemical composition assuming that the heavy-isotope enrichments of these elements are due to Rayleigh fractionation that accompanied their evaporation from CMAS liquids. The resulting pre-evaporation chemical compositions are consistent with those predicted by equilibrium thermodynamic calculations for high-temperature nebular condensates, but only if different inclusions condensed from nebular regions that ranged in total pressure from 10⁻⁶ to 10⁻¹ bar, regardless of whether they formed in a system of solar composition or in one enriched in dust of ordinary chondrite composition relative to gas by a factor of 10 compared to solar composition. This is similar to the range of total pressures predicted by dynamic models of the solar nebula for regions whose temperatures are in the range of silicate condensation temperatures. Alternatively, if departure from equilibrium condensation and/or non-representative sampling of condensates in the nebula occurred, the inferred range of total pressure could be smaller. Simple kinetic modeling of evaporation successfully reproduces observed chemical compositions of most inclusions from their inferred pre-evaporation compositions, suggesting that closed-system isotopic exchange processes did not have a significant effect on their isotopic compositions. Comparison of pre-evaporation compositions with observed ones indicates that 80% of the enrichment in refractory CaO + Al₂O₃ relative to more volatile MgO + SiO₂ is due to initial condensation and 20% due to subsequent evaporation for both Types A and B inclusions.  相似文献