Potential benefits to fisheries and biodiversity of the Chagos Archipelago/British Indian Ocean Territory as a no-take marine reserve     

Koldewey HJ  Curnick D  Harding S  Harrison LR  Gollock M 《Marine pollution bulletin》2010,60(11):1906-1915

On 1st April 2010, the British Government announced designation of the British Indian Ocean Territory - or Chagos Archipelago - as the world’s largest marine protected area (MPA). This near pristine ocean ecosystem now represents 16% of the worlds fully protected coral reef, 60% of the world’s no-take protected areas and an uncontaminated reference site for ecological studies. In addition these gains for biodiversity conservation, the Chagos/BIOT MPA also offers subsidiary opportunities to act as a fisheries management tool for the western Indian Ocean, considering its size and location. While the benefits of MPAs for coral-reef dwelling species are established, there is uncertainty about their effects on pelagic migratory species. This paper reviews the increasing body of evidence to demonstrate that positive, measurable reserve effects exist for pelagic populations and that migratory species can benefit from no-take marine reserves.  相似文献   

Lagrangian particle tracking of a toxic dinoflagellate bloom within the Tampa Bay estuary   总被引：1，自引：0，他引：1  

Heather Havens  Mark E. Luther  Steven D. Meyers  Cynthia A. Heil 《Marine pollution bulletin》2010,60(12):2233-2241

A coastal risk assessment system simulates the basic physical mechanisms underlying contaminant transport in Tampa Bay. This risk assessment system, comprised of a three-dimensional numerical circulation model coupled to a Lagrangian particle tracking model, simulates the transport and dispersion of a toxic dinoflagellate bloom. Instantaneous velocity output from the circulation model drives the movement of particles, each representing a fraction of a K. brevis bloom, within the model grid cells. Hindcast simulations of the spatial distribution of the K. brevis bloom are presented and compared with water sample concentrations collected during the peak of the bloom. Probability calculations, herein called transport quotients, allow for rapid analysis of bay-wide K. brevis transport showing locations most likely to be impacted by the contaminant. Maps constructed from the transport quotients provide managers with a bay-wide snapshot of areas in Tampa Bay most at risk during a hazardous bloom event.  相似文献   

Visualizing geomorphology: improving communication of data and concepts through engagement with the arts          下载免费PDF全文

Stephen Tooth  Heather A. Viles  Ant Dickinson  Simon J. Dixon  Anna Falcini  Hywel M. Griffiths  Harriet Hawkins  Jessica Lloyd‐Jones  Julian Ruddock  Varyl R. Thorndycraft  Brian Whalley 《地球表面变化过程与地形》2016,41(12):1793-1796

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Extensive soft-sediment deformation and peperite formation at the base of a rhyolite lava: Owyhee Mountains,SW Idaho,USA     

Charlotte E. McLean  David J. Brown  Heather J. Rawcliffe 《Bulletin of Volcanology》2016,78(6):42

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Post-settlement alteration of spatial patterns of soft shell clam (<Emphasis Type="Italic">Mya arenaria</Emphasis>) recruits     

Heather?L.?HuntEmail author  D.?Archie McLean  Lauren?S.?Mullineaux 《Estuaries and Coasts》2003,26(1):72-81

To examine the roles of settlement and early post-settlement processes in patterns of recruitment of the soft shell clamMya arenaria, abundance of juvenileMya at three intertidal sites in Barnstable Harbor, Massachusetts, was monitored over two settlement seasons. Two peaks of settlement occurred in 1998 (July and September) and one peak was recorded in June 1999, indicating that a late season settlement event is not a consistent feature at this site. Abundance of recent settlers (i.e., early recruits, < 1 week past settlement) varied significantly among the tidal flats (sites) that were separated by hundreds of meters to kilometers, but not among plots meters apart. Differences in abundance of settlers likely resulted in these differences in early-recruit abundance among sites. Settlement was greatest at the site with the greatest variability in flow speed. Sites also differed to some extent in their sediment characteristics and macrofaunal assemblages, which may influence larval substrate choice. Between-site differences in abundance ofMya decreased after settlement. The rate of decline of abundance varied among cohorts and sites. Comparison of abundance of recent settlers (up to 145,000 m⁻²) to that of juveniles > 3-mm shell length at the end of the settlement season (up to 60 m⁻²) indicated large losses of individuals during the early post-settlement period. This study demonstrates that spatial patterns inMya abundance can change substantially during the early post-settlement period, and that high mortality rates can result in cohorts contributing little to the population size even when rates of settlement are high.  相似文献   

SMART-1 after lunar capture: First results and perspectives   总被引：1，自引：0，他引：1  

B. H. Foing  G. D. Racca  A. Marini  E. Evrard  L. Stagnaro  M. Almeida  D. Koschny  D. Frew  J. Zender  D. Heather  M. Grande  J. Huovelin  H. U. Keller  A. Nathues  J. L. Josset  A. Malkki  W. Schmidt  G. Noci  R. Birkl  L. Iess  Z. Sodnik  P. McManamon 《Journal of Earth System Science》2005,114(6):689-697

SMART-1 is a technology demonstration mission for deep space solar electrical propulsion and technologies for the future. SMART-1 is Europe’s first lunar mission and will contribute to developing an international program of lunar exploration. The spacecraft was launched on 27th September 2003, as an auxiliary passenger to GTO on Ariane 5, to reach the Moon after a 15-month cruise, with lunar capture on 15th November 2004, just a week before the International Lunar Conference in Udaipur. SMART-1 carries seven experiments, including three remote sensing instruments used during the mission’s nominal six months and one year extension in lunar science orbit. These instruments will contribute to key planetary scientific questions, related to theories of lunar origin and evolution, the global and local crustal composition, the search for cold traps at the lunar poles and the mapping of potential lunar resources  相似文献   

Sources of Sr and implications for weathering of limestone under tallgrass prairie, northeastern Kansas     

Heather K. Wood  G.L. Macpherson   《Applied Geochemistry》2005,20(12):4195

Grasslands of north-central Kansas are underlain by carbonate aquifers and shale aquitards. Chemical weathering rates in carbonates are poorly known, and, because large areas are underlain by these rocks, solute fluxes are important to estimating global weathering rates. Grasslands exist where the amount of precipitation is extremely variable, both within and between years, so studies in grasslands must account for changes in weathering that accompany changes in precipitation. This study: (1) identifies phases that dominate chemical fluxes at Konza Prairie Biological Station (KPBS) and Long-Term Ecological Research Site, and (2) addresses the impact of variable precipitation on mineral weathering. The study site is a remnant tallgrass prairie in the central USA, representing baseline weathering in a mid-temperate climate grassland.Groundwater chemistry and hydrology in the 1.2 km² watershed used for this study suggest close connections between groundwater and surface water. Water levels fluctuate seasonally. High water levels coincide with periods of precipitation plus low evapotranspiration rather than during precipitation peaks during the growing season. Precipitation is concentrated before recharging aquifers, suggesting an as yet unquantified residence time in the thin soils.Groundwater and surface water are oversaturated with respect to calcite within limitations of available data. Water is more dilute in more permeable aquifers, and water from one aquifer (Morrill) is indistinguishable from surface water. Cations other than Ca co-vary with each other, especially Sr and Mg. Potassium and Si co-vary in all aquifers and surface water, and increases in concentrations of these elements are the best indicators of silicate weathering at this study site. Silicate-weathering indices correlate inversely to aquifer hydraulic conductivity.⁸⁷Sr/⁸⁶Sr in water ranges from 0.70838 to 0.70901, and it decreases with increasing Sr concentration and with increasing silicate-weathering index. Carbonate extracted from aquifer materials, shales, soil, and tufa has Sr ranging from about 240 (soil) to 880 ppm (Paleozoic limestone). ⁸⁷Sr/⁸⁶Sr ranges from 0.70834 ± 0.00006 (limestone) to 0.70904 ± 0.00019 (soil). In all cases, ⁸⁷Sr/⁸⁶Sr of aquifer limestone is lower than ⁸⁷Sr/⁸⁶Sr of groundwater, indicating a phase in addition to aquifer carbonate is contributing solutes to water.Aquifer recharge controls weathering: during periods of reduced recharge, increased residence time increases the total amount of all phases dissolved. Mixing analysis using ⁸⁷Sr/⁸⁶Sr shows that two end members are sufficient to explain sources of dissolved Sr. It is proposed that the less radiogenic end member is a solution derived from dissolving aquifer material; longer residence time increases its contribution. The more radiogenic end member solution probably results from reaction with soil carbonate or eolian dust. This solution dominates solute flux in all but the least permeable aquifer and demonstrates the importance that land-surface and soil-zone reactions have on groundwater chemistry in a carbonate terrain.  相似文献   

Reversal of eutrophication following sewage treatment upgrades in the New River Estuary, North Carolina     

Michael A. Mallin  Matthew R. McIver  Heather A. Wells  Douglas C. Parsons  Virginia L. Johnson 《Estuaries and Coasts》2005,28(5):750-760

The New River Estuary consists of a series of broad shallow lagoons draining a catchment area of 1,436 km², located in Onslow County, North Carolina. During the 1980s and 1990s it was considered one of the most eutrophic estuaries in the southeastern United States and sustained dense phytoplankton blooms, bottom water anoxia and hypoxia, toxic outbreaks of the dinoflagellatePfiesteria, and fish kills. High nutrient loading, especially of phosphorus (P), from municipal and military sewage treatment plants was the principal cause leading to the eutrophic conditions. Nutrient addition bioassay experiments showed that additions of nitrogen (N) but not P consistently yielded significant increases in phytoplankton production relative to controls. During 1998 the City of Jacksonville and the U.S. Marine Corps Base at Camp Lejeune completely upgraded their sewage treatment systems and achieved large improvements in nutrient removal, reducing point source inputs of N and P to the estuary by approximately 57% and 71%, respectively. The sewage treatment plant upgrades led to significant estuarine decreases in ammonium, orthophosphate, chlorophylla, and turbidity concentrations, and subsequent increases in bottom water dissolved oxygen (DO) and light penetration. The large reduction in phytoplankton biomass led to a large reduction in labile phytoplankton carbon, likely an important source of biochemical oxygen demand in this estuary. The upper estuary stations experienced increases in average bottom water DO of 0.9 to 1.4 mg l⁻¹, representing an improvement in benthic habitat for shellfish and other organisms. The reductions in light attenuation and turbidity should also improve the habitat conditions for growth of submersed aquatic vegetation, an important habitat for fish and shellfish.  相似文献   

Migration in a transitional economy: Beyond the planned and spontaneous dichotomy in Vietnam     

Heather Xiaoquan Zhang  P. Mick Kelly  Catherine Locke  Alexandra Winkels  W. Neil Adger 《Geoforum》2006,37(6):1066-1081

Migration is frequently portrayed as a negative force in its relationship with economic and social development. This negative perception is exhibited through describing population movements as either ‘forced’ (e.g. political and environmental refugees) or ‘voluntary’ movements (e.g. economic and uninhibited relocation). This paper examines the limitations of this conceptual dualism. It points out that the dualistic approach, widely used in the context of developing countries, simplifies a highly complex phenomenon by ignoring its essential heterogeneity and spatial and temporal dynamics. As such, it is limited in explaining and understanding the globally diversified, historically and politically contextualised situations. Focusing on the migratory experiences of contemporary Vietnam, the study identifies major patterns and trends of population mobility in the country in the past fifty years. It shows that despite the state’s continued attempts to reshape the spatial distribution of population over recent historical periods, the policy outcomes with respect to population mobility have been swayed as much by individuals and their families in pursuit of their own aspirations and livelihoods as by state plans. The Vietnam case has provided evidence of a much more complicated relationship between migration and livelihoods than the conceptual dichotomy assumes, and the opportunity for a richer set of policy options. We argue that the evidence from Vietnam, and elsewhere, warrants an integrated approach to studying migration, combining analysis at the macro- and micro-levels with the nexus lying at the critical decision-making point of the individual or household.  相似文献   

Climate change impacts on freshwater fish,coral reefs,and related ecosystem services in the United States     

Diana Lane  Russell Jones  David Mills  Cameron Wobus  Richard C. Ready  Robert W. Buddemeier  Eric English  Jeremy Martinich  Kate Shouse  Heather Hosterman 《Climatic change》2015,131(1):143-157

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