Hotel managed marine reserves: A willingness to pay survey

The 2003 Marine Parks Congress recommended networks of marine reserves to be established covering 20–30% of habitats by 2012. Most marine reserves are, however, failing to meet their objectives, the main reason being attributed to lack of funding. In light of the growing need for effectively managed marine reserves, a survey ascertaining tourists' support and willingness to pay extra to stay at reserves managed by the private sector – Hotel Managed Marine Reserves (HMMRs) was conducted at Whale Island Resort, Vietnam. A total of 97.5% support HMMR, 86.3% were willing to pay, the median amounting to US$9.6/room/night, or 10% of the average room rate, equaling US$67,277 at 60% occupancy.     

Hydrogen suppresses UO2 corrosion

Release of long-lived radionuclides such as plutonium and caesium from spent nuclear fuel in deep geological repositories will depend mainly on the dissolution rate of the UO₂ fuel matrix. This dissolution rate will, in turn, depend on the redox conditions at the fuel surface. Under oxidative conditions UO₂ will be oxidised to the 1000 times more soluble UO_2.67. This may occur in a repository as the reducing deep groundwater becomes locally oxidative at the fuel surface under the effect of α-radiolysis, the process by which α-particles emitted from the fuel split water molecules. On the other hand, the groundwater corrodes canister iron generating large amounts of hydrogen. The role of molecular hydrogen as reductant in a deep bedrock repository is questioned. Here we show evidence of a surface-catalysed reaction, taking place in the H₂-UO₂-H₂O system where molecular hydrogen is able to reduce oxidants originating from α-radiolysis. In our experiment the UO₂ surface remained stoichiometric proving that the expected oxidation of UO_2.00 to UO_2.67 due to radiolytic oxidants was absent. As a consequence, the dissolution of UO₂ stopped when equilibrium was reached between the solid phase and U⁴⁺ species in the aqueous phase. The steady-state concentration of uranium in solution was determined to be 9 × 10⁻¹² M, about 30 times lower than previously reported for reducing conditions. Our findings show that fuel dissolution is suppressed by H₂. Consequently, radiotoxic nuclides in spent nuclear fuel will remain immobilised in the UO₂ matrix. A mechanism for the surface-catalysed reaction between molecular hydrogen and radiolytic oxidants is proposed.     

Importance of vegetation type for mercury sequestration in the northern Swedish mire, Rödmossamyran

Even if mires have proven to be relatively reliable archives over the temporal trends in atmospheric mercury deposition, there are large discrepancies between sites regarding the magnitude of the anthropogenic contribution to the global mercury cycle. A number of studies have also revealed significant differences in mercury accumulation within the same mire area. This raises the question of which factors, other than mercury deposition, affect the sequestration of this element in peat. One such factor could be vegetation type, which has the potential to affect both interception and retention of mercury. In order to assess how small-scale differences in vegetation type can affect mercury sequestration we sampled peat and living plants along three transects on a northern Swedish mire. The mire has two distinctly different vegetation types, the central part consists of an open area dominated by Sphagnum whereas the surrounding fen, in addition to Sphagnum mosses, has an understory of ericaceous shrubs and a sparse pine cover. A few main patterns can be observed in our data; (1) Both peat and Sphagnum-mosses have higher mercury content (both concentration and inventory) in the pine-covered fen compared to the open Sphagnum area (100% and 71% higher for peat and plants, respectively). These differences clearly exceed the 33% difference observed for lead-210, which is considered as a good analogue for atmospheric mercury deposition. (2) The differences in mercury concentration between peat profiles within a single vegetation type can largely be attributed to differences in peat decomposition. (3) When growing side by side in the open Sphagnum area, the moss species Sphagnum subsecundum has significantly higher mercury concentrations compared to S. centrale (24 ± 3 and 18 ± 2 ng Hg g⁻¹, respectively). Based on these observations we suggest that species composition, vegetation type and decomposition can affect the mercury sequestration in a peat record, and that any changes in these properties over time, or space, have the potential to modify the mercury deposition signal recorded in the peat.     

Ellipsoidal quadtrees for indexing of global geographical data

Systems for landscape visualization and geographical data handling require methods for efficient data access. Retrieval of data from large geographical databases, ten to thousands of Gbytes, is usually optimized with spatial indexing mechanisms. The simplest form of spatial indexing is achieved by dividing the database into congruent grid cells. The subsequent subdivision of the grid cells can be based on so-called quadtrees. Quadtrees for two-dimensional division and subdivision are appropriate for cartographical data. A geographical database, with objects stored in geocentric or geodetic (geographical) co-ordinates, requires indexing mechanisms that take into account the shape of the Earth. In this paper, we present a method for indexing of geographical data, named Ellipsoidal Quadtrees (EQT). In contrast to other global indexing methods, EQT is based on the Earth ellipsoid and not a spherical approximation. EQT division and subdivision make it possible to divide the Earth surface into a mesh of quadrangles with equal areas. We will demonstrate that EQT is flexible. It can be used for indexing databases of various sizes, including national and global databases. Tests on real data show that the performance of EQT is good.     

Reactive monazite and robust zircon growth in diatexites and leucogranites from a hot,slowly cooled orogen: implications for the Palaeoproterozoic tectonic evolution of the central Fennoscandian Shield,Sweden

Monazite in melt-producing, poly-metamorphic terranes can grow, dissolve or reprecipitate at different stages during orogenic evolution particularly in hot, slowly cooling orogens such as the Svecofennian. Owing to the high heat flow in such orogens, small variations in pressure, temperature or deformation intensity may promote a mineral reaction. Monazite in diatexites and leucogranites from two Svecofennian domains yields older, coeval and younger U–Pb SIMS and EMP ages than zircon from the same rock. As zircon precipitated during the melt-bearing stage, its U–Pb ages reflect the timing of peak metamorphism, which is associated with partial melting and leucogranite formation. In one of the domains, the Granite and Diatexite Belt, zircon ages range between 1.87 and 1.86 Ga, whereas monazite yields two distinct double peaks at 1.87–1.86 and 1.82–1.80 Ga. The younger double peak is related to monazite growth or reprecipitation during subsolidus conditions associated with deformation along late-orogenic shear zones. Magmatic monazite in leucogranite records systematic variations in composition and age during growth that can be directly linked to Th/U ratios and preferential growth sites of zircon, reflecting the transition from melt to melt crystallisation of the magma. In the adjacent Ljusdal Domain, peak metamorphism in amphibolite facies occurred at 1.83–1.82 Ga as given by both zircon and monazite chronology. Pre-partial melting, 1.85 Ga contact metamorphic monazite is preserved, in spite of the high-grade overprint. By combining structural analysis, petrography and monazite and zircon geochronology, a metamorphic terrane boundary has been identified. It is concluded that the boundary formed by crustal shortening accommodated by major thrusting.