957 resultados para Atlantic Coast


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A new species, Cheiriphotis petronioi sp. nov., is described from the Brazilian coast. This species is recognizable amongst its congeners by the carpus of adult male gnathopod 2 not fused with propodus and the palm acute and uropod 1 of adult males without a group of apical setae between rami. Specimens studied herein were collected between 23º and 34ºS (Brazil - São Paulo and Rio Grande do Sul) from 16 to 38 m depth. An updated key to all species of the genus is provided.

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The present study provided information extending the known geographical distribution of three species of majoid crabs, the epialtids Acanthonyx dissimulatus Coelho, 1993, Epialtus bituberculatus H. Milne Edwards, 1834, and E. brasiliensis Dana, 1852. Specimens of both genera from different carcinological collections were studied by comparing morphological characters. We provide new data that extends the geographical distributions of E. bituberculatus to the coast of the states of Paraná and Santa Catarina (Brazil), and offer new records from Belize and Costa Rica. Epialtus brasiliensis is recorded for the first time in the state of Rio Grande do Sul (Brazil), and A. dissimulatus is reported from Quintana Roo, Mexico. The distribution of A. dissimulatus, previously known as endemic to Brazil, has a gap between the states of Espírito Santo and Rio de Janeiro. However, this restricted southern distribution is herein amplified by the Mexican specimens.

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The objective of this work was to present an updated checklist of the currently known fishes in the Paranaguá Estuarine Complex (PEC) and provides comments on conservation status for the treated species. We used a large dataset derived from a pool of studies which have been conducted within there along the last 30 years. Each study was based on monthly samplings and conducted in several estuarine habitat; thus, the pool covers practically all estuarine habitats and takes into account the seasonal cycle in the system. The PEC ichthyofauna represents a mixture between that fauna typical from the tropical Brazilian coast and that with affinities of temperate Argentinean and Uruguayan zones. The PEC harbors a rich fish fauna of 213 species, inserted in the families that are common along the Brazilian coast. Only a minor part (8%) of the PEC fish fauna was evaluated as regards the conservation status, mostly because of the lack of basic biological and ecological information for most species. Despite part of the among-estuaries differences are due to different and incomplete sampling efforts, the richness in the PEC is surprisingly higher than other systems in Brazil and around world, which emphasize the importance of the region for global biodiversity conservation.

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The study of organic pollution in estuaries is very relevant as they are transitional zones, which control the fluxes of water, nutrients, particles and organisms from and to the continental margins, rivers and oceans. The aims of this study are:(1) to evaluate organic pollution in coastal sediments of Montevideo, Río de la Plata Estuary by a multi-biomarker approach, (2) to identify major sources of organic pollutants through qualitative analysis using molecular indices, (3) to assess the relative contribution of different sources of hydrocarbons through quantitative source apportionment employing (PCA/MLR) as chemometric technique. Sampling surveys were carried out in July 2009, January 2010 and March 2011 in 37 stations along the middle portion of the Río de la Plata Estuary across the coast of Montevideo. In each station surface (0–2 cm depth) sediment samples were taken with a 0.05 m2 van Veen grab. The Soxhlet extracted organic compounds included aliphatic hydrocarbons (AHs) and steroids, analysed by gas chromatograph with flame ionization detector (GC-FID), linear alkylbenzenes (LABs) and polycyclic aromatic hydrocarbons (PAHs) quantified by gas chromatograph with mass spectrometer (GC/MS). All biomarkers presented the highest concentrations in the stations of Montevideo Bay indicating high levels of organic pollution. The combination of molecular indices and the chemometric technique showed that major sources of AHs and PAHs are petroleum inputs and combustion, due to oil transport and refinement, harbour activities and vehicular emissions.Major sources of LABs and steroids are urban and domestic sewage. Identification, quantification and source assignment of those organic compounds are very important to assess pollution and to give tools to help minimize the inputs into the environment

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[EN] We apply an inverse model to a hydrographic cruise that completely closes the Canary Islands to investigate their effect on the water masses transports. Most central waters are transported south between the eastern islands and the African coast, with 2.5 Sv out of a total of 3.5 Sv. Intermediate waters are effectively blocked by the islands passages, with Mediterranean/Antarctic waters predominantly found north/south of the islands, and most deep waters loop around the archipelago plateau. A process model upholds the existence of intense two-way exchange between central and intermediate waters along the eastern passage, with vertical velocities of order 10 m s.

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[EN] The reproductive phenology of three species of Gelidiales, Gelidium canariense, Gelidium arbuscula and Pterocladiella capillacea, was analysed seasonally for a period of one year in two localities on the West coast of Tenerife Atlantic Ocean, Canary Islands, Spain. Considerations are provided on sex ratio, maximum length and branch order of uprights and on the length of the thalli for each sexual and asexual phase of the Canary Islands populations. The three species were characterized by a high percentage of tetrasporophytes, while female and male gametophytes have been observed only in little proportion. Only G. canariense showed gametophytes in all seasons while the occurrence of gametophytes in G. arbuscula and Pterocladiella capillacea demonstrated a clear seasonality.

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trabajo realizado por Medina Alcaraz, C., Castro, J.J., Sosa, P. A.

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[EN]Coastal upwelling in the eastern margin and offshore curl-driven upwelling in the southeastern margin, make the subtropical Northeast Atlantic a region of major primary productivity. When examining a broad zonal area, from the coast to 40_W, we find that the upward transport of nutrients due to offshore curl-driven upwelling becomes the main control on productivity. Nevertheless, despite its relatively small zonal extension of about 100 km, coastal upwelling extends its impact towards the open ocean through offshore Ekman transport and convergence of the meridional flow at Cape Blanc (21_N).

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As an initial step in establishing mechanistic relationships between environmental variability and recruitment in Atlantic cod Gadhus morhua along the coast of the western Gulf of Maine, we assessed transport success of larvae from major spawning grounds to nursery areas with particle tracking using the unstructured grid model FVCOM (finite volume coastal ocean model). In coastal areas, dispersal of early planktonic life stages of fish and invertebrate species is highly dependent on the regional dynamics and its variability, which has to be captured by our models. With state-of-the-art forcing for the year 1995, we evaluate the sensitivity of particle dispersal to the timing and location of spawning, the spatial and temporal resolution of the model, and the vertical mixing scheme. A 3 d frequency for the release of particles is necessary to capture the effect of the circulation variability into an averaged dispersal pattern of the spawning season. The analysis of sensitivity to model setup showed that a higher resolution mesh, tidal forcing, and current variability do not change the general pattern of connectivity, but do tend to increase within-site retention. Our results indicate strong downstream connectivity among spawning grounds and higher chances for successful transport from spawning areas closer to the coast. The model run for January egg release indicates 1 to 19 % within-spawning ground retention of initial particles, which may be sufficient to sustain local populations. A systematic sensitivity analysis still needs to be conducted to determine the minimum mesh and forcing resolution that adequately resolves the complex dynamics of the western Gulf of Maine. Other sources of variability, i.e. large-scale upstream forcing and the biological environment, also need to be considered in future studies of the interannual variability in transport and survival of the early life stages of cod.

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Management plans to reduce human-caused deaths of North Atlantic right whales Eubalaena glacialis depend, in part, on knowing when and where right whales are likely to be found. Local environmental conditions that influence movements of feeding right whales, such as ultra-dense copepod patches, are unpredictable and ephemeral. We examined the utility of using the regional-scale mean copepod concentration as an indicator of the abundance of right whales in 2 critical habitats off the northeastern coast of the United States: Cape Cod Bay and Great South Channel. Right whales are usually found in Cape Cod Bay during the late winter and early spring, and in the Great South Channel during the late spring and early summer. We found a significant positive relationship between mean concentration of the copepod Calanus finmarchicus in the western Gulf of Maine and the frequency of right whale sightings in the Great South Channel. In Cape Cod Bay we found a significant positive relationship between the mean concentration of other copepods (largely Pseudocalanus spp. and Centropages spp.) and the frequency of right whale sightings. This information could be used to further our understanding of the environmental factors that drive seasonal movement and aggregation of right whales in the Gulf of Maine, and it offers a tool to resource managers and modelers who seek to predict the movements of right whales based upon the concentration of copepods.

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In this study four data quality flags are presented for automated and unmanned above-water hyperspectral optical measurements collected underway in the North Sea, The Minch, Irish Sea and Celtic Sea in April/May 2009. Coincident to these optical measurements a DualDome D12 (Mobotix, Germany) camera system was used to capture sea surface and sky images. The first three flags are based on meteorological conditions, to select erroneous incoming solar irradiance (ES) taken during dusk, dawn, before significant incoming solar radiation could be detected or under rainfall. Furthermore, the relative azimuthal angle of the optical sensors to the sun is used to identify possible sunglint free sea surface zones. A total of 629 spectra remained after applying the meteorological masks (first three flags). Based on this dataset, a fourth flag for sunglint was generated by analysing and evaluating water leaving radiance (LW) and remote sensing reflectance (RRS) spectral behaviour in the presence and absence of sunglint salient in the simultaneously available sea surface images. Spectra conditions satisfying "mean LW (700-950 nm) < 2 mW/m**2/nm/Sr" or alternatively "minimum RRS (700-950 nm) < 0.010/Sr", mask the most measurements affected by sunglint, providing efficient flagging of sunglint in automated quality control. It is confirmed that valid optical measurements can be performed 0° <= theta <= 360° although 90° <= theta <= 135° is recommended.