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91.
The vegetation communities and spatial patterns on the Fire Island National Seashore are dynamic as the result of interactions with driving forces such as sand deposition, storm-driven over wash, salt spray, surface water, as well as with human disturbances. We used high spatial resolution QuickBird-2 satellite remote sensing data to map both terrestrial and submerged aquatic vegetation communities of the National Seashore. We adopted a stratified classification and unsupervised classification approach for mapping terrestrial vegetation types. Our classification scheme included detailed terrestrial vegetation types identified by previous vegetation mapping efforts of the National Park Service and three generalized categories of high-density seagrass, low-density seagrass coverages, and unvegetated bottom to map the submerged aquatic vegetation habitats. We used underwater videography, GPS-guided field reference photography, and bathymetric data to support remote sensing image classification and information extraction. This study achieved approximately 82% and 75% overall classification accuracy for the terrestrial and submnerged aquatic vegetations, respectively, and provided an updated vegetation inventory and change analysis for the Northeast Coastal and Barrier Network of the National Park Service. 相似文献
92.
An improved Ewing heat probe frame 总被引:3,自引:0,他引:3
The standard Ewing heat probe frame has been improved through the design of a new takedown model whose parts are held together by lynch pins. When a 600 lb (272 kg) unit of this type is taken apart, the heaviest single piece of the dismantled unit weighs only 75 lb (34 kg).This makes it feasible for one person to handle, transport, and assemble the new unit. A central, main support member of a heat probe using this frame can be suspended over the side of a research vessel while the heavier temperature recorder and ballast weights are attached by means of the quickaction lynch pins. This makes it possible to use this device on relatively small vessels which are not designed for coring work, having a minimum of free deck space and without launching platforms or hydraulic A-frame booms. 相似文献
93.
94.
Frank Rske 《Ocean Modelling》2006,11(3-4):235-297
A global dataset based on the ECMWF Re-Analyses (ERA) is presented that can be used as surface boundary conditions for ocean models with sea-ice components. The definition of these conditions is based on bulk formulae. To study the mean ocean circulation, a mean annual cycle on a daily basis was constructed from ERA for all relevant parameters including wind stress. Continental runoff is considered by using information about the catchment areas of the rivers and about the main drainage basins. The bulk formulae were extended by using sea ice concentration.To estimate meridional heat transports (MHT) and to avoid any drift in ocean model simulations, the heat and fresh water budgets have been closed by applying an inverse procedure to fine-tune the fluxes towards observed transports. To improve the MHTs on the Southern Hemisphere the winds and the short wave radiation at southern higher latitudes should be corrected. Furthermore, tests were performed concerning short wave radiation which was increased in the tropics and decreased in the subsidence zones.The heat and fresh water fluxes are assessed by using a scheme of Macdonald and Wunsch based on hydrographic sections. The net heat fluxes of ERA and of the forcing dataset are consistent with the heat flux divergences and convergences estimated by this scheme except for parts of the South Atlantic and the Indian Ocean sector of the Southern Ocean where none of these datasets is consistent with these estimates. In the subtropical South Indian Ocean the forcing dataset is consistent with these estimates while ERA are not. The flux components of ERA and the forcing dataset were compared to several observational datasets (SRB, SOC, HOAPS, GPCP, and CMAP). For each component, at least one of these datasets (especially HOAPS) supports the effects of the inverse procedure and the bulk formulae almost globally with some regional exceptions: short wave radiation in the tropical oceans and the subtropical North Atlantic, latent heat flux at higher latitudes, and precipitation in the northern North Atlantic.Comparisons to the NCAR/NCEP Re-Analyses (NRA) (versions 1 and 2) and the ECHAM model in place of ERA lead to similar results. In the North Atlantic the net heat fluxes of the model based datasets approach the hydrographic estimate with increasing resolution. Applied to any ocean/sea-ice model and compared to ERA, the forcing dataset would induce only a relative small net sea-surface buoyancy loss.A comparison of the forcing dataset to measurements made using one buoy deployed in the western Pacific warm pool and five buoys deployed in the subduction region of the Northeast Atlantic shows that at the site of the first buoy the net heat fluxes of the forcing dataset are in poorer agreement than those of ERA. At the sites of two subduction buoys both datasets show the same level of agreement within the error bars specified. At the sites of the three remaining subduction buoys the forcing dataset shows a marginal improvement on ERA. 相似文献
95.
96.
Jesper Raakjær Dao Manh Son Karl-Johan Stæhr Holger Hovgård Nguyen Thi Dieu Thuy Kristine Ellegaard Frank Riget Dang Van Thi Phung Giang Hai 《Marine Policy》2007
Vietnam is in the process of introducing adaptive management based on indicators and time-series to manage its marine fisheries. The development of indicator-based frameworks for fisheries management has accelerated in recent years. This article describes the suite of indicators being suggested or used in Vietnam including the data-collection system. The Vietnamese approach is supported by an institutional structure consisting of a multi-disciplinary advisory system to facilitate the process of using indicators and to introduce knowledge-based management. The article concludes by identifying current problems and weaknesses and by providing suggestions for future improvement of the system. 相似文献
97.
98.
This paper outlines the structure of the institutions involved in scientific and technological development in France. It points to new trends in French marine policy, and gives details of the country's offshore petroleum technology and nodule mining. 相似文献
99.
100.
Diet restriction induced autophagy: a lysosomal protective system against oxidative- and pollutant-stress and cell injury 总被引:1,自引:0,他引:1
Moore MN 《Marine environmental research》2004,58(2-5):603-607
Nutrient deprivation or dietary restriction (DR) confers protection against ageing and stress in many animals and induced lysosomal autophagy is part of this mechanism. The effects of dietary restriction on the toxicity of copper and the polycyclic aromatic hydrocarbon phenanthrene have been investigated in the common marine mussel Mytilus edulis. The findings show that DR-induced autophagy facilitates the recovery of the digestive gland (i.e., molluscan liver analogue) from cell injury caused by both copper and phenanthrene. It is inferred that DR-induced autophagy and lysosomal proteolysis results in improved cellular "housekeeping" through the more efficient removal of oxidatively and pollutant damaged proteins (e.g., protein carbonyls, protein adducts, etc.) and that this contributes to stress resistance. 相似文献