Geographic signatures of North American West Coast estuaries     

Robert Emmett  Roberto Llansó  Jan Newton  Ron Thom  Michelle Hornberger  Cheryl Morgan  Colin Levings  Andrea Copping  Paul Fishman 《Estuaries and Coasts》2000,23(6):765-792

West Coast estuaries are geologically young and composed of a variety of geomorphological types. These estuaries range from large fjords to shallow lagoons; from large to low freshwater flows. Natural hazards include E1 Niños, strong Pacific storms, and active tectonic activity. West Coast estuaries support a wide range of living resources: five salmon species, harvestable shellfish, waterfowl and marine birds, marine mammals, and a variety of algae and plants. Although populations of many of these living resources have declined (salmonids), others have increased (marine mammals). West Coast estuaries are also centers of commerce and increasingly large shipping traffic. The West Coast human population is rising faster than most other areas of the U.S. and Canada, and is distributed heavily in southern California, the San Francisco Bay area, around Puget Sound, and the Fraser River estuary. While water pollution is a problem in many of the urbanized estuaries, most estuaries do not suffer from poor water quality. Primary estuarine problems include habitat alterations, degradation, and loss; diverted freshwater flows; marine sediment contamination; and exotic species introductions. The growing West Coast economy and population are in part related to the quality of life, which is dependent on the use and enjoyment of abundant coastal natural resources.  相似文献   

The predictability of near-coastal currents using a baroclinic unstructured grid model   总被引：1，自引：1，他引：0  

Cheryl Ann Blain  Mustafa Kemal Cambazoglu  Robert S. Linzell  Kendra M. Dresback  Randall L. Kolar 《Ocean Dynamics》2012,62(3):411-437

A limited domain, coastal ocean forecast system consisting of an unstructured grid model, a meteorological model, a regional ocean model, and a global tidal database is designed to be globally relocatable. For such a system to be viable, the predictability of coastal currents must be well understood with error sources clearly identified. To this end, the coastal forecast system is applied at the mouth of Chesapeake Bay in response to a Navy exercise. Two-day forecasts are produced for a 10-day period from 4 to 14 June 2010 and compared to real-time observations. Interplay between the temporal frequency of the regional model boundary forcing and the application of external tides to the coastal model impacts the tidal characteristics of the coastal current, even contributing a small phase error. Frequencies of at least 3 h are needed to resolve the tidal signal within the regional model; otherwise, externally applied tides from a database are needed to capture the tidal variability. Spatial resolution of the regional model (3 vs 1 km) does not impact skill of the current prediction. Tidal response of the system indicates excellent representation of the dominant M ₂ tide for water level and currents. Diurnal tides, especially K ₁, are amplified unrealistically with the application of coarse 27-km winds. Higher-resolution winds reduce current forecast error with the exception of wind originating from the SSW, SSE, and E. These winds run shore parallel and are subject to strong interaction with the shoreline that is poorly represented even by the 3-km wind fields. The vertical distribution of currents is also well predicted by the coastal model. Spatial and temporal resolution of the wind forcing including areas close to the shoreline is the most critical component for accurate current forecasts. Additionally, it is demonstrated that wind resolution plays a large role in establishing realistic thermal and density structures in upwelling prone regions.  相似文献   

(Re)politicizing empowerment: Lessons from the South African wine industry     

Cheryl McEwan  David Bek 《Geoforum》2006,37(6):1021-1034

Despite being a poorly defined and vague concept, empowerment is currently of political and theoretical significance and nowhere more so than in South Africa, where it seen as central to post-apartheid transformation. This paper explores the ways in which empowerment has been understood, defined and deployed by post-apartheid governments in the context of a gradual shift from nation-building to neo-liberal governance. It examines the impact of legislation and government policy through a critical examination of empowerment initiatives in the wine industry. Drawing on research conducted in the Western Cape in 2004, the paper analyses how empowerment is interpreted and appropriated both within legislation and specifically within the wine industry. It explores what the wine industry reveals about the disempowering work of neo-liberalism, even as it is couched in the discourses of empowerment. Findings suggest that equating empowerment with economic empowerment threatens to reinforce structures of domination, rather than transforming them, while leaving power relations largely untouched. The case study reveals that until more radical understandings of power and empowerment are acknowledged and incorporated into government policies the failure to address broader issues of social and economic transformation will persist and policies aimed at the empowerment of marginalised individuals and communities will continue to have apparently pre-determined and depoliticised outcomes.  相似文献   

Stable isotope and trace element status of subsistence-hunted bowhead and beluga whales in Alaska and gray whales in Chukotka     

Dehn LA  Follmann EH  Rosa C  Duffy LK  Thomas DL  Bratton GR  Taylor RJ  O'Hara TM 《Marine pollution bulletin》2006,52(3):301-319

Tissues of bowhead, beluga, and gray whales were analyzed for Ag, Cd, Cu, Se, Zn, THg and MeHg (belugas only). Delta15N and delta13C in muscle were used to estimate trophic position and feeding habitat, respectively. Trace element concentrations in tissues were significantly different among whale species. Hepatic Ag was higher in belugas than bowheads and gray whales. Gray whales had lower Cd concentrations in liver and kidney than bowhead and belugas and a sigmoid correlation of Cd with length was noted for all whales. Renal and hepatic Se and THg were higher in belugas than in baleen whales. The hepatic molar ratio of Se:THg exceeded 1:1 in all species and was negatively correlated to body length. Hepatic and renal Zn in subsistence-harvested gray whales was lower than concentrations for stranded whales. Se:THg molar ratios and tissue concentrations of Zn may show promise as potential indicators of immune status and animal health.  相似文献