The effects of fishing on sharks, rays, and chimaeras (chondrichthyans), and the implications for marine ecosystems   总被引：16，自引：4，他引：16  

Stevens  J. D.; Bonfil  R.; Dulvy  N. K.; Walker  P. A. 《ICES Journal of Marine Science》2000,57(3):476-494

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Diatom blooms and copepod responses: Paradigm or paradox?     

Bruce W. Frost 《Progress in Oceanography》2005,67(3-4):283

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Spatial heterogeneity of epibenthos on artificial reefs: fouling communities in the early stages of colonization on an East Australian shipwreck     

Simon J. Walker  Thomas A. Schlacher  & Monika A. Schlacher-Hoenlinger 《Marine Ecology》2007,28(4):435-445

Artificial reefs are spatially complex habitats and serve as good model systems to study patterns of community succession and the response of epibiota to environmental clines over small spatial scales. Here, we quantified spatial heterogeneity in community composition and diversity of fouling communities across a number of environmental gradients that included water depth, surface orientation of habitats, exposure to currents, and shelter. Assemblage structure was quantified by spatially replicated photo transects on a recently scuttled large navy ship off the East Australian coast, lying in 27 m of water. A rich assemblage of epifauna had colonized the wreck within a year, dominated by barnacles, sponges and bryozoans. Community structure varied significantly over small spatial scales of meters to tens of meters. Depth, surface orientation and exposure were the major environmental drivers. Assemblages were substantially less diverse and abundant on the deepest (23 m near the seafloor) part of the hull with residual antifouling paint, on sheltered surfaces inside the wreck, and on the sediment‐laden horizontal surfaces. Overall, the wrecks’ habitat complexity corresponds with small‐scale heterogeneity in the fouling communities. This study supports the notion that wrecks enhance local diversity and biomass within the habitat mosaic of their location, and habitat complexity may be an important mechanism for this, as demonstrated by the large spatial variability in the assemblages documented here.  相似文献   

Estrogenic responses of larval sunshine bass (Morone saxatilis x M. Chrysops) exposed to New York City sewage effluent     

Todorov JR  Elskus AA  Schlenk D  Ferguson PL  Brownawell BJ  McElroy AE 《Marine environmental research》2002,54(3-5):691-695

To determine the estrogenicity of effluents from sewage treatment plants (STPs) to larval fish, 2-day-old sunshine bass were exposed to effluents from three STPs serving New York City (NYC), varying in size and treatment level. Estrogenic response was evaluated by measuring vitellogenin (VTG) and estrogen receptor (ER) expression in cytosolic fractions of whole body homogenates. Concentrations of the presumptive endocrine disruptors in the effluents were also measured. VTG and ER levels in sewage-exposed fish were 3-5 times that observed in controls. Combined concentrations of estradiol and estrone ranged from 5 to 13 ng/l and nonylphenol-ethoxylate metabolites (NPEOs: 4-nonylphenol, and 1-, 2-, and 3-nonylphenol-ethoxylates) ranged from 180 to 470 microg/l in chlorinated effluent. Results indicate that both ER and VTG can be used as biomarkers for endocrine disruption in larval fish, and that 4-day exposure to sewage effluent is sufficient to elicit significant expression of these markers in sunshine bass larvae. The extremely higher concentrations of NPEOs found in effluent relative to hormones (approximately 40,000-fold) indicates that surfactant metabolites may be contributing significantly to the estrogenic effects observed.  相似文献   

Measurement of water particle velocities in waves     

Brendan P. Mcnamee  Bruce B. Sharp  Leonard K. Stevens 《Applied Ocean Research》1983,5(1):49-53

Water surface profiles and horizontal and vertical water particle velocity components have been measured to investigate the properties of intermediate depth waves generated in the laboratory. The data has been compared with linear wave theory. It was found that linear theory predicted the attenuation of velocity field with depth successfully and that it overestimates both components of velocity slightly.  相似文献   

Local buckling strength of ring stiffened cylindrical shells under external pressure     

A.J. Reis  A.C. Walker 《Applied Ocean Research》1983,5(2):56-62

The paper presents a non-linear buckling analysis of ring stiffened cylindrical shells subject to external pressure. The collapse pressure is calculated by assuming failure to occur when the material reaches a plastic stress state defined by the Ilyushin criterion. It is shown in the paper that use of the non-linear theory can reduce the estimated first yield by up to 25% in comparison to the linear buckling analysis used up to now. Comparison of predicted failure loads are in good agreement with the lower bound of test results.  相似文献   

Long-term changes in ray populations in the North Sea   总被引：2，自引：3，他引：2  

Walker  P. A.; Heessen  H. J. L. 《ICES Journal of Marine Science》1996,53(6):1085-1093

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An altered carrying capacity of the Benguela upwelling ecosystem for African penguins (Spheniscus demersus)     

Crawford  Robert J. M.; Underhill  Les G.; Upfold  Leshia; Dyer  Bruce M. 《ICES Journal of Marine Science》2007,64(3):570-576

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Accelerated relative sea-level rise and rapid coastal erosion:: testing a causal relationship for the Louisiana barrier islands   总被引：1，自引：0，他引：1  

Jeffrey H. List  Asbury H. Sallenger Jr.  Mark E. Hansen  Bruce E. Jaffe 《Marine Geology》1997,140(3-4):347-365

The role of relative sea-level rise as a cause for the rapid erosion of Louisiana's barrier island coast is investigated through a numerical implementation of a modified Bruun rule that accounts for the low percentage of sand-sized sediment in the eroding Louisiana shoreface. Shore-normal profiles from 150 km of coastline west of the Mississippi delta are derived from bathymetric surveys conducted during the 1880s, 1930s and 1980s. An RMS difference criterion is employed to test whether an equilibrium profile form is maintained between survey years. Only about half the studied profiles meet the equilibrium criterion; this represents a significant limitation on the potential applicability of the Bruun rule. The profiles meeting the equilibrium criterion, along with measured rates of relative sea-level rise, are used to hindcast shoreline retreat rates at 37 locations within the study area. Modeled and observed shoreline retreat rates show no significant correlation. Thus, in terms of the Bruun approach, relative sea-level rise has no power for hindcasting (and presumably forecasting) rates of coastal erosion for the Louisiana barrier islands.  相似文献   

Contemporary ocean and coastal management issues in Australia and New Zealand: an overview     

Bruce W. Davis 《Ocean & Coastal Management》1996,33(1-3)

The past decade has witnessed an unprecedented increase in the number of international treaties, conventions and agreements dealing with maritime issues and oceans governance. Most nations are attempting to cope with this expanding agenda at a time of fiscal constraint, competing environmental demands and the emergence of a new global strategic, political and economic order. However, similar issues do not always lead to similar outcomes. Australia and New Zealand share some common oceanic and coastal management problems, but variations in response arise from geographical differences, constitutional provisions, political style and administrative arrangements. This paper provides a brief overview of contemporary maritime issues and attempted solutions in both nations.  相似文献