923 resultados para Bay of Fundy


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Atlantic herring (Clupea harengus) is an ecologically and economically valuable species in many food webs, yet surprisingly little is known about the variation in the nutritional quality of these fish. Atlantic herring collected from 2005 through 2008 from the Bay of Fundy, Canada, were examined for variability in their nutritional quality by using total lipid content (n=889) and fatty acid composition (n=551) as proxies for nutritional value. A significant positive relationship was found between fish length and total lipid content. Atlantic herring also had significantly different fatty acid signatures by age. Fish from 2005 had significantly lower total lipid content than fish from 2006 through 2008, and all years had significantly different fatty acid signatures. Summer fish were significantly fatter than winter fish and had significantly different fatty acid signatures. For all comparisons (ontogenetic, annual, and seasonal) percent concentrations of omega-3, -6, and long-chain monounsaturated fatty acids were the most important for distinguishing between the fatty acid signatures of fish. This study underscores the importance of quantifying variation in prey quality synoptically with prey quantity in food webs over ontogenetic and temporal scales when evaluating the effect of prey nutritional quality on predators and on modeling trophic dynamics.

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The upper Bay of Fundy is a critical stopover site for Semipalmated Sandpipers (Calidris pusilla) during their fall migration. However, little is known about factors that influence selection of feeding and roosting sites by these birds, or the extent to which birds move between different sites during their time in the region. Using radio-telemetry, we studied movement patterns, examined habitat use, and tested hypotheses associated with factors influencing foraging and roost-site selection. Movements of radio-tagged sandpipers were tracked in the upper Bay of Fundy in August 2004 and 2005. In 2004, sandpipers from the Minas Basin, Nova Scotia and Chignecto Bay, New Brunswick and Nova Scotia, were tracked, and in 2005, sandpipers were tracked only in Chignecto Bay. Sandpipers were highly mobile in both the Minas Basin 2004 and Chignecto Bay 2005, making daily movements of up to 20 km between foraging and roosting sites, although very little movement was detected in Chignecto Bay in 2004. Migrating sandpipers appeared to select foraging sites based on relative safety, as measured by distance to cover, provided that these sites offered an adequate food supply. Similarly, roosting sandpipers preferred sites that were far from nearby trees that might offer cover to predators. This preference for safe sites became more apparent later in their stay in the Bay of Fundy, when birds were heavier and, therefore, possibly more vulnerable to predation. Semipalmated Sandpipers appear to be flexible during their time in the upper Bay of Fundy, displaying year-to-year and site-to-site variability in movement and mudflat usage. Therefore, multiple, synchronized population counts should be conducted at known roost sites in order to more accurately estimate Semipalmated Sandpiper abundance in this region. Furthermore, in a highly dynamic system where food can be variable, landscape features such as distance to cover may be important factors to consider when selecting candidate sites for shorebird conservation measures.

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Added t.-p.: Moore, J. B. International adjudications, ancient and modern ... Modern series. vol. VI.

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Mode of access: Internet.

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This layer is a georeferenced raster image of the untitled, historic nautical chart: [A chart of the Island of Grand Manan, Passamaquody Bay & River]. The map is [sheet 47] from the Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England, from surveys taken by Samuel Holland and published by J.F.W. Des Barres, 1781. Scale [ca. 1:50,000]. This layer is image 1 of 4 total images of the four sheet source map, representing the northeast portion of the map. Covers coastline from Blacks Harbour to Haggertys Cove, New Brunswick, Canada and portion of Bay of Fundy. The image is georeferenced to the surface of the earth and fit to the 'World Mercator' (WGS 84) projected coordinate system. All map collar information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows coastal features such as harbors, inlets, rocks, channels, points, coves, shoals, islands, and more. Includes also selected land features such as cities and towns, buildings. Depths shown by soundings. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection. The entire Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England has been scanned and georeferenced as part of this selection.

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This layer is a georeferenced raster image of the untitled, historic nautical chart: [A chart of the Island of Grand Manan, Passamaquody Bay & River]. The map is [sheet 48] from the Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England, from surveys taken by Samuel Holland and published by J.F.W. Des Barres, 1781. Scale [ca. 1:50,000]. This layer is image 2 of 4 total images of the four sheet source map, representing the southeast portion of the map. Covers portin of the coastline of Grand Manan Island, New Brunswick, Canada and Bay of Fundy. The image is georeferenced to the surface of the earth and fit to the 'World Mercator' (WGS 84) projected coordinate system. All map collar information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows coastal features such as harbors, inlets, rocks, channels, points, coves, shoals, islands, and more. Includes also selected land features such as cities and towns, buildings. Depths shown by soundings. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection. The entire Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England has been scanned and georeferenced as part of this selection.

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This layer is a georeferenced raster image of the untitled, historic nautical chart: [A chart of the Island of Grand Manan, Passamaquody Bay & River]. The map is [sheet 49] from the Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England, from surveys taken by Samuel Holland and published by J.F.W. Des Barres, 1781. Scale [ca. 1:50,000]. This layer is image 3 of 4 total images of the four sheet source map, representing the southwest portion of the map. Covers portions of the coastline of Grand Manan Island, New Brunswick, Canada, coast of northern Maine, and Bay of Fundy. The image is georeferenced to the surface of the earth and fit to the 'World Mercator' (WGS 84) projected coordinate system. All map collar information is also available as part of the raster image, including any inset maps, profiles, statistical tables, directories, text, illustrations, or other information associated with the principal map. This map shows coastal features such as harbors, inlets, rocks, channels, points, coves, shoals, islands, and more. Includes also selected land features such as cities and towns, buildings. Depths shown by soundings. This layer is part of a selection of digitally scanned and georeferenced historic maps from The Harvard Map Collection. The entire Atlantic Neptune atlas Vol. 3 : Charts of the coast and harbors of New England has been scanned and georeferenced as part of this selection.

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High-resolution data from the TRMM satellite shows that sea surface temperature (SST) cools by 3 degrees C under the tracks of pre-monsoon tropical cyclones in the north Indian Ocean. However, even the strongest post-monsoon cyclones do not cool the open north Bay of Bengal. In this region, a shallow layer of freshwater from river runoff and monsoon rain caps a deep warm layer. Therefore, storm-induced mixing is not deep, and it entrains warm subsurface water. It is possible that the hydrography of the post-monsoon north Bay favours intense cyclones.

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Simultaneous and collocated measurements of total and hemispherical backscattering coefficients (σ and β, respectively) at three wavelengths, mass size distributions, and columnar spectral aerosol optical depth (AOD) were made onboard an extensive cruise experiment covering, for the first time, the entire Bay of Bengal (BoB) and northern Indian Ocean. The results are synthesized to understand the optical properties of aerosols in the marine atmospheric boundary layer and their dependence on the size distribution. The observations revealed distinct spatial and spectral variations of all the aerosol parameters over the BoB and the presence of strong latitudinal gradients. The size distributions varied spatially, with the majority of accumulation modes decreasing from north to south. The scattering coefficient decreased from very high values (resembling those reported for continental/urban locations) in the northern BoB to very low values seen over near-pristine environments in the southeastern BoB. The average mass scattering efficiency of BoB aerosols was found to be 2.66 ± 0.1 m2 g−1 at 550 nm. The spectral dependence of columnar AOD deviated significantly from that of the scattering coefficients in the northern BoB, implying vertical heterogeneity in the aerosol type in that region. However, a more homogeneous scenario was observed in the southern BoB. Simultaneous lidar and in situ measurements onboard an aircraft over the ocean revealed the presence of elevated aerosol layers of enhanced extinction at altitudes of 1 to 3 km with an offshore extent of a few hundred kilometers. Back-trajectory analyses showed these layers to be associated with advection from west Asia and western India. The large spatial variations and vertical heterogeneity in aerosol properties, revealed by the present study, need to be included in the regional radiative forcing over the Bay of Bengal.

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Hydrographic observations were taken along two coastal sections and one open ocean section in the Bay of Bengal during the 1999 southwest monsoon, as a part of the Bay of Bengal Monsoon Experiment (BOBMEX). The coastal section in the northwestern Bay of Bengal, which was occupied twice, captured a freshwater plume in its two stages: first when the plume was restricted to the coastal region although separated from the coast, and then when the plume spread offshore. Below the freshwater layer there were indications of an undercurrent. The coastal section in the southern Bay of Bengal was marked by intense coastal upwelling in a 50 km wide band. In regions under the influence of the freshwater plume, the mixed layer was considerably thinner and occasionally led to the formation of a temperature inversion. The mixed layer and isothermal layer were of similar depth for most of the profiles within and outside the freshwater plume and temperature below the mixed layer decreased rapidly till the top of seasonal thermocline. There was no barrier layer even in regions well under the influence of the freshwater plume. The freshwater plume in the open Bay of Bengal does not advect to the south of 16 degrees N during the southwest monsoon. A model of the Indian Ocean, forced by heat, momentum and freshwater fluxes for the year 1999, reproduces the freshwater plume in the Bay of Bengal reasonably well. Model currents as well as the surface circulation calculated as the sum of geostrophic and Ekman drift show a southeastward North Bay Monsoon Current (NBMC) across the Bay, which forms the southern arm of a cyclonic gyre. The NBMC separates the very low salinity waters of the northern Bay from the higher salinities in the south and thus plays an important role in the regulation of near surface stratification. (c) 2007 Elsevier Ltd. All rights reserved.

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Hydrographic observations were taken along two coastal sections and one open ocean section in the Bay of Bengal during the 1999 southwest monsoon, as a part of the Bay of Bengal Monsoon Experiment (BOBMEX). The coastal section in the northwestern Bay of Bengal, which was occupied twice, captured a freshwater plume in its two stages: first when the plume was restricted to the coastal region although separated from the coast, and then when the plume spread offshore. Below the freshwater layer there were indications of an undercurrent. The coastal section in the southern Bay of Bengal was marked by intense coastal upwelling in a 50 km wide band. In regions under the influence of the freshwater plume, the mixed layer was considerably thinner and occasionally led to the formation of a temperature inversion. The mixed layer and isothermal layer were of similar depth for most of the profiles within and outside the freshwater plume and temperature below the mixed layer decreased rapidly till the top of seasonal thermocline. There was no barrier layer even in regions well under the influence of the freshwater plume. The freshwater plume in the open Bay of Bengal does not advect to the south of 16 degrees N during the southwest monsoon. A model of the Indian Ocean, forced by heat, momentum and freshwater fluxes for the year 1999, reproduces the freshwater plume in the Bay of Bengal reasonably well. Model currents as well as the surface circulation calculated as the sum of geostrophic and Ekman drift show a southeastward North Bay Monsoon Current (NBMC) across the Bay, which forms the southern arm of a cyclonic gyre. The NBMC separates the very low salinity waters of the northern Bay from the higher salinities in the south and thus plays an important role in the regulation of near surface stratification. (c) 2007 Elsevier Ltd. All rights reserved.

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Buoy and satellite data show pronounced subseasonal oscillations of sea surface temperature (SST) in the summertime Bay of Bengal. The SST oscillations are forced mainly by surface heat flux associated with the active break cycle of the south Asian summer monsoon. The input of freshwater (FW) from summer rain and rivers to the bay is large, but not much is known about subseasonal salinity variability. We use 2002-2007 observations from three Argo floats with 5 day repeat cycle to study the subseasonal response of temperature and salinity to surface heat and freshwater flux in the central Bay of Bengal. About 95% of Argo profiles show a shallow halocline, with substantial variability of mixed layer salinity. Estimates of surface heat and freshwater flux are based on daily satellite data sampled along the float trajectory. We find that intraseasonal variability of mixed layer temperature is mainly a response to net surface heat flux minus penetrative radiation during the summer monsoon season. In winter and spring, however, temperature variability appears to be mainly due to lateral advection rather than local heat flux. Variability of mixed layer freshwater content is generally independent of local surface flux (precipitation minus evaporation) in all seasons. There are occasions when intense monsoon rainfall leads to local freshening, but these are rare. Large fluctuations in FW appear to be due to advection, suggesting that freshwater from rivers and rain moves in eddies or filaments.