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41.
Robert S. Pomeroy Michael D. Pido John Francisco A. Pontillas Benjamin S. Francisco Alan T. White Eva Marie C. Ponce De Leon Geronimo T. Silvestre 《Marine Policy》2008
The live reef food fish (LRFF) trade has an estimated annual retail value of US$1 billion in the Asia-Pacific region and at least US$30 million in the Philippines. Palawan Province is the trade's center accounting for as much as 55% of the commodity's total export. Concern about the LRFF trade has caused the Palawan Provincial government to take action to regulate the trade. Four key policy options to address the short-term policy objective of developing a sustainable LRFF industry through the reduction of threats associated with destructive fishing and overfishing were proposed. These four policy options and associated analyses were presented to stakeholders at three separate policy consultations. The stakeholders reached a consensus that a regulated LRFF trade was the most sensible option. As a result, the Provincial Government of Palawan took action to enact “The Palawan Live Reef Fish Ordinance of 2006”, which provides for the sustainable and integrated regulation of the LRFF industry. This provincial ordinance will assist in crafting a national policy for the LRFF trade and may also be useful in revising the 1998 Philippine Fisheries Code. The key challenge is how to translate the ordinance provisions into effective on-the-ground actions. 相似文献
42.
Survey and Geographic Information System (GIS) data analysis describes the relative influence of biophysical and human variables on site choices made by marine farmers in New Zealand. Community conflicts have grown in importance in determining farm location and different government planning strategies leave distinct signature patterns. Recent legislation empowers local governments to choose among three strategies for future regional aquaculture development. This paper suggests each strategy could result in different spatial outcomes. Simulation modelling of the type described here can provide a better understanding of farmer responses to management approaches and the range of futures that could result from planning choices made today. 相似文献
43.
Sea-level rise is likely to cause significant changes in the morphodynamic state of beaches in the higher latitudes, resulting in steeper beaches with larger particle sizes. These physical changes have implications for beach invertebrate communities, which are determined largely by sediment particle size, and hence for ecosystem function. Previous studies have explored the relationships between invertebrate communities and environmental variables such as particle size, beach slope and exposure to wave action, and often these physical variables can be integrated in various indices of morphodynamic state. Most of these studies incorporated a full range of beach types that included wave-dominated surf beaches, where the wave action is harsh enough to enable reliable estimates of breaker height, a parameter included in several of the indices, and concluded that more dissipative beaches with gentler slopes and finer particle sizes often support a higher number of species and greater abundance than more reflective beaches. Whether these predictions remain valid for less wave-dominated beaches, where breaker height is more difficult to determine, is uncertain. In the present study, the abundance of meio- and macrofauna was quantified across a range of beaches in the UK, which are generally towards the lower energy end of the morphodynamic gradient, and their relationships with beach physical properties explored. No significant relationships were found between abundance and the standard morphodynamic indices, but significant relationships were found for both macro- and meiofaunal abundance when these indices were combined with an exposure index (derived from velocity, direction, duration and the effective fetch). All the relationships identified between abundance and combined morphodynamic indices indicated a higher abundance of both macro- and meiofauna on the more dissipative beaches. The reverse was however found for species richness. If predictions that accelerated sea-level rise will move beaches towards a more reflective morphodynamic state are correct, this could lead to declines in the abundance of meio- and macrofauna, with potential adverse consequences for ecosystem functioning. 相似文献
44.
45.
A. J. R. White 《Australian Journal of Earth Sciences》2013,60(4):551-555
Dehydration (vapour absent) partial melting reactions in the Earth's crust produce a hydrous granitic melt phase, new anhydrous minerals that are mostly pyroxenes, and new plagioclase more calcic than the initial plagioclase. These solid phases of the melt reaction are restite. If the restite is carried to high levels in the crust as a component of the magma, cooling and crystallisation to granite will result in back reactions in which the H2O in the melt phase is consumed and is not then available to form a hydrothermal solution. Even in magmas in which some restite has been removed there will be some back reaction and again less H2O. Only fractional crystallisation will enrich the H2O in the magma in sufficient amounts to form a substantial quantity of hydrothermal solution and possible mineralisation. 相似文献
46.
A riparian ecosystem downstream of a small dam in central Texas was instrumented for sap flow, soil moisture content, and stream level from 2001. Stable isotopes in water (D and 18O) were analysed from rainfall, stream, lake, and cored sapwood cellulose from cedar elm (Ulmus crassifolia). The isotope signature of water source to cedar elm was identified by back calculation starting with the water isotopes in cellulose, and accounting for leaf‐water evaporation and biological fractionation during cellulose synthesis. The estimated mean isotope of the source water to cedar elm was enriched above rainfall in similarity to stream water during 2002. Flow paths that may have contributed to estimated variability from regional base flow and recharge water were identified using the variably saturated HYDRUS‐2D model. Copyright © 2004 John Wiley & Sons, Ltd. 相似文献
47.
Civil society is a critical arena both for exploring Sustainability itself and for sustaining trajectories towards it through innovation, experimentation and debate. Innovations can be mould breaking and can challenge local institutions. Concurrently, initiatives may be fragile due to the development of new working relationships, reliance on voluntary labour and goodwill, and dependence on grant funding. Here we examine different aspects of what it takes to sustain grassroots trajectories for ‘communal growing’, given the pressures that groups and intermediary organisations practicing and supporting this activity experience, and the consequential need to build qualities like ‘resilience’. Attending carefully to the definition of this otherwise slippery concept, a particular focus is given to how contrasting aspects of temporality and agency lead to divergent constructions of ‘resilience’ and strategies for sustaining growing. We draw on fieldwork that explores the practice and support of communal growing in East Sussex, England, and directly associated activities at a national level.We find important interdependencies between communal growing projects and the intermediary organisations supporting them. Additionally there is huge diversity within and between both projects and the organisations that support them, including with respect to the ends to which growing is seen as a means. These ends link growing initiatives – both antagonistically and synergistically – to food, education and health systems. This diversity can be seen positively as: a source of innovation; facilitating the open and bottom up nature of growing; and, enabling the securing of greater financial support for the endeavour. What is less clear is how this plays into framing and configuring communal growing specifically in relation to achieving a more Sustainable and localised food system. We discuss the conceptual and methodological implications of these empirically derived observations with regards future research on grassroots innovations. 相似文献
48.
49.
R. W. Parkinson T. C. Wang J. R. White J. R. David M. E. Hoffman 《Environmental Geology》1993,22(1):26-32
This project was designed to: (1) document the distribution and migration of organochlorine pesticide residues within marsh substrates of 18 St. Lucie County mosquito control impoundments located along the Indian River Lagoon estuary, and (2) evaluate the impact of water management techniques on residue mobility. Our results indicate that detectible concentrations of organochlorine compounds, applied between the late 1940s and early 1950s, are present in 16 of the 18 St. Lucie County mosquito control impoundments. These compounds are primarily restricted to the surficial, organic-rich wetland sediment, which, based upon geotechnical analysis, was exposed to the atmosphere at a time when the impoundments were subjected to pesticide treatment. Contaminated sediments are present below the surficial, organic-rich layer, suggesting that some vertical migration of pesticides has occurred. It is unlikely that leaching associated with the downward percolation of impounded water was responsible for this migration as pesticide residues were never detected within thein situ pore waters. An alternative explanation is that biological processes (e.g., rooting, burrowing) facilitated the downward flux of organochlorine compounds into sediment horizons not subjected to direct treatment. Eighty-eight surface water samples obtained from two impoundments subjected to contrasting water management techniques were analyzed for pesticide content. None of the surficial water samples collected in association with these impoundments contained detectible concentrations of organochlorine compounds. These samples were unfiltered and contained as much as 25 mg/1 of particulate organic matter. This suggests that the currently preferred management technique (RIM), which is designed to maintain water quality, limit mosquito production, and provide for ecological continuity, does not hydraulically mobilize pesticide residues into the Indian River Lagoon estuary. 相似文献
50.
Joseph Clancy White 《Contributions to Mineralogy and Petrology》1993,113(4):524-532
The textural relationships and structural states of optically isotropic labradorite from the Manicouagan, Quebec, impact structure have been examined by light (optical) and transmission electron (TEM) microscopy. Two distinct diaplectic glasses have been recognized based on their contrasting morphology, timing and the inferred modes of formation. The earliest isotropic bands and grain-scale isotropism (maskelynite) optically exhibit a gradational,in situ transformation from crystalline plagioclase with preservation of relict textures (twins, grain boundaries). The same transformation from crystalline to amorphous structure is observed in TEM to occur heterogeneously at scales on the order of the unit cell. The progressive transformation of optical properties reflects an increase in the volume fraction and eventual coalescence of these amorphous units. This maskelynite-type diaplectic glass is interpreted to form in the solid-state directly from crystalline material during the compressional phase of the shock wave. The other isotropic material occurs in spatially discrete tensiongashes and planar deformation features (PDFs) that overprint the maskelynite-type glass. This second type of diaplectic glass (PDF-type) is developed homogeneously within a given glass band and exhibits sharp crystal-glass boundaries, in contrast to the gradational boundaries of the maskelynite-type glass. PDF-type glass is interpreted to form by melting in tensional release zones during passage of the rarefaction wave. These observations emphasize the ability of naturally shocked rocks to preserve subtle evidence of variations in the shock process from highly transient events. 相似文献