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31.
O'Leary BC Smart JC Neale FC Hawkins JP Newman S Milman AC Roberts CM 《Marine pollution bulletin》2011,62(12):2642-2648
We analysed the extent to which European politicians have adhered to scientific recommendations on annual total allowable catches (TACs) from 1987 to 2011, covering most of the period of the Common Fisheries Policy (CFP). For the 11 stocks examined, TACs were set higher than scientific recommendations in 68% of decisions. Politically-adjusted TACs averaged 33% above scientifically recommended levels. There was no evidence that the 2002 reform of the CFP improved decision-making, as was claimed at the time. We modelled the effects of such politically-driven decision-making on stock sustainability. Our results suggest that political adjustment of scientific recommendations dramatically increases the probability of a stock collapsing within 40 years.In 2012 European fisheries policy will undergo a once-a-decade reform. Ten years ago radical reforms were promised but the changes failed to improve sustainability. It is likely that the 2012 reform will be similarly ineffective unless decision-making is changed so that catch allocations are based on science rather than politics. 相似文献
32.
Kenneth C. Carroll Fiona L. Jordan Edward P. Glenn W. Jody Waugh Mark L. Brusseau 《Journal of Hydrology》2009,378(1-2):72-81
Several methods for characterizing the occurrence and rate of nitrate attenuation were tested at a field site near Monument Valley, Arizona. Spatial and temporal nitrate concentration data collected from a transect of monitoring wells located along the plume centerline were analyzed to evaluate the overall rates of natural attenuation. The occurrence and rate of denitrification was evaluated through microcosm experiments, nitrogen isotopic fractionation analysis, and solute-transport modeling. First-order denitrification-rate coefficients calculated with each method were comparable. In addition, the composite natural attenuation rate coefficient was similar to the denitrification-rate coefficients, which suggests that microbially induced decay primarily controls nitrate attenuation at the site. This research highlights the benefits associated with a multiple-method approach for the characterization of natural attenuation. 相似文献
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34.
Fiona?V.?FoleyEmail author Simon?Turner Tracy?Rushmer John?T.?Caulfield Nathan?R.?Daczko Paul?Bierman Matthew?Robertson Craig?D.?Barrie Adrian?J.?Boyce 《Contributions to Mineralogy and Petrology》2014,168(3):1048
Subduction-related Quaternary volcanic rocks from Solander and Little Solander Islands, south of mainland New Zealand, are porphyritic trachyandesites and andesites (58.20–62.19 wt% SiO2) with phenocrysts of amphibole, plagioclase and biotite. The Solander and Little Solander rocks are incompatible element enriched (e.g. Sr ~931–2,270 ppm, Ba ~619–798 ppm, Th ~8.7–21.4 ppm and La ~24.3–97.2 ppm) with MORB-like Sr and Nd isotopic signatures. Isotopically similar quench-textured enclaves reflect mixing with intermediate (basaltic-andesite) magmas. The Solander rocks have geochemical affinities with adakites (e.g. high Sr/Y and low Y), whose origin is often attributed to partial melting of subducted oceanic crust. Solander sits on isotopically distinct continental crust, thus excluding partial melting of the lower crust in the genesis of the magmas. Furthermore, the incompatible element enrichments of the Solander rocks are inconsistent with partial melting of newly underplated mafic lower crust; reproduction of their major element compositions would require unrealistically high degrees of partial melting. A similar argument precludes partial melting of the subducting oceanic crust and the inability to match the observed trace element patterns in the presence of residual garnet or plagioclase. Alternatively, an enriched end member of depleted MORB mantle source is inferred from Sr, Nd and Pb isotopic compositions, trace element enrichments and εHf ? 0 CHUR in detrital zircons, sourced from the volcanics. 10Be and Sr, Nd and Pb isotopic systematics are inconsistent with significant sediment involvement in the source region. The trace element enrichments and MORB-like Sr and Nd isotopic characteristics of the Solander rocks require a strong fractionation mechanism to impart the high incompatible element concentrations and subduction-related (e.g. high LILE/HFSE) geochemical signatures of the Solander magmas. Trace element modelling shows that this can be achieved by very low degrees of melting of a peridotitic source enriched by the addition of a slab-derived melt. Subsequent open-system fractionation, involving a key role for mafic magma recharge, resulted in the evolved andesitic adakites. 相似文献
35.
Fiona WILLIAMSON Rob ALLAN Guoyu REN Tsz-cheung LEE Wing-hong LUI Hisayuki KUBOTA Jun MATSUMOTO Jürg LUTERBACHER Clive WILKINSON Kevin WOOD 《大气科学进展》2018,35(8):899-904
正1.Introduction Historic instrumental weather observations,made on land or at sea from as early as the 17th century(e.g.,Camuffo et al.,2010),are integral to extending our understanding of the decadal and centennial variations of Earth’s climate and for comparison with paleo-proxy data.The potential of such data is shown to best effect when used in dynamical 4D global 相似文献
36.
Fiona M. Smith 《Applied geography (Sevenoaks, England)》1997,17(4):355-369
Geopolitics and city restructuring are typically regarded as separate scales and processes: the international and national versus the local. The local politics of urban change in an east German city in the period after reunification question this divide. The ‘pathways’ approach to post-socialist transitions is utilized to illustrate how reunification is contested as much in neighbourhood restructuring and actions in response to incoming capital and the dominance of western legalpolitical norms as it is in national or international discourses and practices. Assumed divisions between East and West, professional and lay, and local and national are questioned. 相似文献
37.
A technique for identifying non‐visible basaltic tephra‐rich horizons of Younger Dryas (YD)/Greenland Stadial (GS) 1 age in northeast Atlantic sediments using rapid, non‐destructive magnetic measurements is presented. Three high‐resolution marine sediment cores have been studied in an E–W transect across the Hebridean margin: St Kilda Basin (MD95‐2007), Barra Fan (MD95‐2006) and Rockall Trough (MD04‐2822). Magnetic susceptibilities and remanent magnetisations were measured at contiguous 1 cm resolution on bulk sediments. In all three cores, an interval with higher proportions of hard magnetic minerals coincides with a clearly defined peak in basaltic tephra shard (>250 µm) counts, which can be constrained to the early part of the YD/GS1 based on faunal climate proxies. Electron microprobe analyses of the magnetically distinct basaltic tephra interval, in all three cores, displays the same major element geochemistry as published for the Vedde basaltic (I Tab. 1), i.e. sourced from the Icelandic volcano Katla. The identification of transitional alkalic basaltic tephras within marine sediments could potentially be facilitated by magnetic analysis as a useful chronostratigraphic screening tool. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
38.
Caroline A. Canham Clément Duvert Leah S. Beesley Michael M. Douglas Samantha A. Setterfield Fiona L. Freestone Steven Clohessy Robyn C. Loomes 《水文研究》2021,35(5):e14180
Riparian trees play a critical role in the ecological function of rivers, yet are threatened by anthropogenic change to the hydrological cycle. Identifying the sources of water used by riparian trees can inform sustainable water policy. We used isotopic analysis complemented by measurements of plant water relations to assess water sources for riparian trees at two sites with contrasting hydrogeological processes; one with an alluvial aquifer overlaying an aquitard, and one where fault-induced preferential pathways in the aquitard allowed the flow of deeper, older groundwater from a regional aquifer to the alluvium. At both sites, plant water potential, stomatal conductance, and plant water isotope composition in the xylem sap of riparian trees were collected from two landscape positions, the riverbank and floodplain. We used a Bayesian mixing model (MixSIAR) to assess differences in the proportion of water sources for sites and landscape positions. We found that xylem water isotope values differed between the two sites in line with their hydrogeological characteristics, with trees at the regional aquifer site using water sourced from the regional groundwater and trees at the site with only an alluvial aquifer present using a mixture of water sources, with no dominant source identified. Higher plant predawn water potential values at the regional site indicated greater water availability and support the inference that plants were using more groundwater at the regional site compared to the alluvial site. Trees closer to the river had higher isotope values, indicative of surficial water sources i.e. shallow soil water and river water. Our findings show that the water sources used by riparian trees reflect local hydrogeology and resource availability. Water managers should identify and protect plant water sources to ensure maintenance of riparian trees. 相似文献
39.
The first monograph of the British Silurian crinoids was published as early as 1839 and identified 14 species; over 120 are now known. The most productive horizon for both diversity of species and numbers of well‐preserved specimens is the Much Wenlock Limestone Formation at Dudley (Lower Silurian, Wenlock), a site of international significance. Other localities have produced fewer, but different species. Herein, we introduce the most important crinoid localities in the Llandovery to Ludlow of the British Isles, and figure some of the many beautiful and significant specimens that they have produced. 相似文献
40.
Christoph Zöckler Lera Miles Lucy Fish Annett Wolf Gareth Rees Fiona Danks 《Climatic change》2008,87(1-2):119-130
Climate change is expected to alter the distribution of habitats and thus the distribution of species connected with these
habitats in the terrestrial Barents Sea region. It was hypothesised that wild species connected with the tundra and open-land
biome may be particularly at risk as forest area expands. Fourteen species of birds were identified as useful indicators for
the biodiversity dependent upon this biome. By bringing together species distribution information with the LPJ-GUESS vegetation
model, and with estimates of future wild and domestic reindeer density, potential impacts on these species between the present
time and 2080 were assessed. Over this period there was a net loss of open land within the current breeding range of most
bird species. Grazing reindeer were modelled as increasing the amount of open land retained for nine of the tundra bird species. 相似文献