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21.
22.
We aim to show how some of the important interdisciplinary fixes or solutions to diverse problems observed in fisheries can complement each other. This can be achieved through methodical allocation of the rights pertaining to fisheries and simultaneous implementation of policy instruments to correct for market failures and equity concerns. We emphasize via a roadmap that there are some general principles that should be invoked when choosing between alternative structures of rights. Our examples from Sweden provide evidence of the flexibility of fishing rights and how they can be adapted to integrate fixes from different disciplines into practical fisheries management. 相似文献
23.
Bacteria and bovine faecal matter were introduced into cultures of pathogenic free‐living amoebae, with chlorine or chlorine dioxide. The bacteria and faeces were to simulate natural conditions for a more exacting test of disinfectant demand when compared to axenic conditions. Both chlorine and chlorine dioxide were effective disinfectants under all conditions tested. Axenically and monoxenically cultured amoebae were used, the latter exerted a greater disinfectant demand. 相似文献
24.
25.
Rosalind C. King Guillaume Backé Christopher K. Morley Richard R. Hillis Mark R.P. Tingay 《Marine and Petroleum Geology》2010
Recent GPS measurements demonstrate that NW Borneo undergoes 4–6 mm of plate-scale shortening a year, which is not accommodated by plate-scale structures. The only geological structure in NW Borneo described to accommodate on-going shortening is the Baram Delta System located on the outer shelf to basin floor. Delta toe fold-thrust belts are commonly thought to be caused by margin-normal compressional stresses generated by margin-parallel upslope gravitational extension. 相似文献
26.
Melissa M. Foley Benjamin S. Halpern Fiorenza Micheli Matthew H. Armsby Margaret R. Caldwell Caitlin M. Crain Erin Prahler Nicole Rohr Deborah Sivas Michael W. Beck Mark H. Carr Larry B. Crowder J. Emmett Duffy Sally D. Hacker Karen L. McLeod Stephen R. Palumbi Charles H. Peterson Helen M. Regan Mary H. Ruckelshaus Paul A. Sandifer Robert S. Steneck 《Marine Policy》2010
The declining health of marine ecosystems around the world is evidence that current piecemeal governance is inadequate to successfully support healthy coastal and ocean ecosystems and sustain human uses of the ocean. One proposed solution to this problem is ecosystem-based marine spatial planning (MSP), which is a process that informs the spatial distribution of activities in the ocean so that existing and emerging uses can be maintained, use conflicts reduced, and ecosystem health and services protected and sustained for future generations. Because a key goal of ecosystem-based MSP is to maintain the delivery of ecosystem services that humans want and need, it must be based on ecological principles that articulate the scientifically recognized attributes of healthy, functioning ecosystems. These principles should be incorporated into a decision-making framework with clearly defined targets for these ecological attributes. This paper identifies ecological principles for MSP based on a synthesis of previously suggested and/or operationalized principles, along with recommendations generated by a group of twenty ecologists and marine scientists with diverse backgrounds and perspectives on MSP. The proposed four main ecological principles to guide MSP—maintaining or restoring: native species diversity, habitat diversity and heterogeneity, key species, and connectivity—and two additional guidelines, the need to account for context and uncertainty, must be explicitly taken into account in the planning process. When applied in concert with social, economic, and governance principles, these ecological principles can inform the designation and siting of ocean uses and the management of activities in the ocean to maintain or restore healthy ecosystems, allow delivery of marine ecosystem services, and ensure sustainable economic and social benefits. 相似文献
27.
Previous stable isotope studies at Lizzies Basin revealed that metasedimentary rocks are 18O-depleted relative to protolith values, particularly in the lower parts of the section (Lower Zone) where the rocks are also
isotopically homogeneous on a scale of hundreds of meters (quartz δ18O=+9.0 to +9.6 per mil). In contrast, metasedimentary rocks at higher levels at Lizzies Basin (Upper Zone) are less 18O-depleted and more heterogeneous in δ18O. In order to understand more fully the isotopic evolution of this terrane, a series of detailed, meter-scale traverses across
various metamorphic and igneous lithologies were completed at Lizzies Basin, and at the structurally higher Angel Lake locality.
Traverses in the Lizzies Basin Lower Zone and in the lower parts of Angel Lake (Angel Lake Lower Sequence) across various
silicate lithologies, including abundant granitoids, reveal similar degrees of homogeneity, although the average δ18O values are higher at Angel Lake. In contrast, traverses which include substantial thicknesses of marble and calc-silicate
gneiss and very little granitoid have more heterogeneous quartz δ18O values (+11.9 to +13.4 per mil), and also have a higher average δ18O (+12.9 per mil), than observed elsewhere. The scale of 18O/16O homogeneity in quartz observed at Lizzies Basin and Angel Lake (meters to hundreds of meters) requires fluid-mediated isotope
exchange, which accompanied Tertiary metamorphism. There is a correlation between the degree of 18O-depletion in metasedimentary rocks, 18O/16O homogenization between lithologies, and the proportion of granitoids (leucogranites in particular) within any part of the
section, and a corresponding anticorrelation with the proportion of marble. This points to a causal relationship, whereby
the leucogranites (as well as the Tertiary hornblende diorite and biotite monzogranite) acted as both a relatively low-18O reservoir and a source of fluids to enhance exchange, while the marbles hindered isotope depletion and homogenization by
acting as relatively high-18O reservoirs and impermeable layers. Material balance calculations help delineate the plausible mechanisms of exchange between
granitoids and metasediments. Single-pass infiltration of magmatic fluids from the granitoids is not capable of reproducing
all of the observations. Fluid-mediated exchange by convective recirculation of magmatic fluids on a scale of meters is the
mechanism which explains all of the observations. The generalized model for the isotopic evolution of the East Humboldt Range
core complex provides an excellent opportunity to establish the main causes and controlling factors of 18O-depletion and 18O/16O homogenization during regional metamorphism.
Received: 27 July 1993 / Accepted: 1 July 1994 相似文献
28.
Comprehensive risk assessments are fundamental to effective emergency management. These assessments need to identify the range
of hazards (or perils) an entity is exposed to and quantify the specific threats associated with each of those hazards. While
hazard identification is commonly, if not formally, conducted in most circumstances, specific threat analysis is often overlooked
for a variety of reasons, one of which is poor communication with subject matter experts. This poor communication is often
attributable to an adherence to scientific jargon and missed opportunities to simplify information. In Canada, for example,
earthquake hazard calculations have been readily available to engineers and scientists for decades. This hazard information,
however, is expressed in terms of peak ground accelerations (PGA) or spectral accelerations (SA) that are foreign concepts
to most emergency managers, community decision-makers and the public-at-large. There is, therefore, a need to more clearly,
simply and effectively express seismic hazard information to the non-scientific community. This paper provides crustal, sub-crustal
and subduction interface earthquake shaking probabilities, expressed as simple percentages for each of 57 locations across
Vancouver Island, British Columbia, Canada. Calculations present the likelihood of earthquake shaking on Vancouver Island
as the probabilities of exceeding each of three shaking intensity thresholds (“widely felt”; onset of “non-structurally damaging”
shaking; and onset of “structurally damaging” shaking) over four timeframes (10, 25, 50 and 100 years). Results are based
on the latest Geological Survey of Canada hazard models used for the 2010 national building code and are presented in both
tabular and graphic formats. This simplified earthquake hazard information is offered to aid local residents, organizations
and governments in understanding and assessing their risk and to encourage and facilitate sound earthquake preparedness funding
decisions. 相似文献
29.
Maria Schönbächler Mark Rehkämper Manuela A. Fehr Alex N. Halliday Bodo Hattendorf 《Geochimica et cosmochimica acta》2005,69(21):5113-5122
Stepwise dissolutions of the carbonaceous chondrites Orgueil (CI), Murchison (CM) and Allende (CV) reveal large nucleosynthetic anomalies for Zr isotopes that contrast with the uniform compositions found in bulk meteorites. Two complementary nucleosynthetic components are observed: one enriched and one depleted in s-process nuclides. The latter component, characterized by excess 96Zr, is most distinctive in the acetic acid leachate (up to ε96Zr ≈ 50). The excess decreases with increasing acid strength and the final leaching steps of the experiment are depleted in 96Zr and thus enriched in s-process nuclides. Presolar silicon carbide grains are likely host phases for part of the anomalous Zr released during these later stages. However, by mass balance they cannot account for the 96Zr excesses observed in the early leaching steps and this therefore hints at the presence of at least one additional carrier phase with significant amounts of anomalous Zr. The data provide evidence that average solar system material consists of a homogenized mixture of different nucleosynthetic components, which can be partly resolved by leaching experiments of carbonaceous chondrites. 相似文献
30.
Gold partitioning in melt-vapor-brine systems 总被引:5,自引:0,他引:5
Adam C. Simon Mark R. Frank Philip A. Candela Christoph A. Heinrich 《Geochimica et cosmochimica acta》2005,69(13):3321-3335
We used laser-ablation inductively coupled plasma mass spectrometry to measure the solubility of gold in synthetic sulfur-free vapor and brine fluid inclusions in a vapor + brine + haplogranite + magnetite + gold metal assemblage. Experiments were conducted at 800°C, oxygen fugacity buffered at Ni-NiO (NNO), and pressures ranging from 110 to 145 MPa. The wt% NaCl eq. of vapor increases from 2.3 to 19 and that of brine decreases from 57 to 35 with increasing pressure. The composition of the vapors and brines are dominated by NaCl + KCl + FeCl2 + H2O. Gold concentrations in vapor and brine decrease from 36 to 5 and 50 to 28 μg/g, respectively, and the calculated vapor:brine partition coefficients for gold decrease from 0.72 to 0.17 as pressure decreases from 145 to 110 MPa. These data are consistent with the thermodynamic boundary condition that the concentration of gold in the vapor and brine must approach a common value as the critical pressure is approached along the 800°C isotherm in the NaCl-KCl-FeCl2-HCl-H2O system.We use the equilibrium constant for gold dissolution as AuOH0, extrapolated from lower temperature and overlapping pressure range, to calculate expected concentrations of AuOH0 in our experimental vapors. These calculations suggest that a significant quantity of gold in our experimental vapors is present as a non-hydroxide species. Possible chloridogold(I) species are hypothesized based on the positively correlated gold and chloride concentrations in our experimental vapors. The absolute concentration of gold in our synthetic vapor, brine, and melt and calculated mass partition coefficients for gold between these physicochemically distinct magmatic phases suggests that gold solubility in aqueous fluids is a function of aqueous phase salinity, specifically total chloride concentration, at magmatic conditions. However, though we highlight here the effect of salinity, the combination of our data with data sets from lower temperatures evinces a significant decrease in gold solubility as temperature drops from 800°C to 600°C. This decrease in solubility has implications for gold deposition from ascending magmatic fluids. 相似文献