An overview of Calanus helgolandicus ecology in European waters     

Delphine Bonnet  Anthony Richardson  Andrew Hirst  Martin Edwards  Rabea Diekman  Luis Valdes  Juan Carlos Molinero  Wulf Greve  Aitor Albaina  Serena Fonda Umani  Antonina dos Santos  Susan Robinson 《Progress in Oceanography》2005,65(1):1-53

We review current knowledge and understanding of the biology and ecology of the calanoid copepod Calanus helgolandicus in European waters, as well as provide a collaborative synthesis of data from 18 laboratories and 26 sampling stations in areas distributed from the northern North Sea to the Aegean and Levantine Seas. This network of zooplankton time-series stations has enabled us to collect and synthesise seasonal and multi-annual data on abundance, body size, fecundity, hatching success and vertical distribution of C. helgolandicus. An aim was to enable comparison with its congener Calanus finmarchicus, which has been studied intensively as a key component of European and north east Atlantic marine ecosystems. C. finmarchicus is known to over-winter at depth, whereas the life-cycle of C. helgolandicus is less well understood. Overwintering populations of C. helgolandicus have been observed off the Atlantic coast between 400 and 800 m, while in the Mediterranean there is evidence of significant deep-water populations at depths as great as 4200 m. The biogeographical distribution of C. helgolandicus in European coastal waters covers a wide range of habitats, from open ocean to coastal environments, and its contribution to mesozooplankton biomass ranges from 6% to 93%. Highest abundances were recorded in the Adriatic and off the west coast of Spain. C. helgolandicus is generally found in 9-20 °C water, with maximum abundances from 13-17 °C. In contrast, C. finmarchicus is found in cooler water between 0 and 15 °C, with peak abundances from 0 to 9 °C. As water has warmed in the North Atlantic over recent decades, the range of C. helgolandicus and its abundance on the fringes of its expanding range have increased. This review will facilitate development of population models of C. helgolandicus. This will not only help answer remaining questions but will improve our ability to forecast future changes, in response to a warming climate, in the abundance and distribution of this important species.  相似文献   

Echinoderms in an anchialine cave in Mexico     

Luis M. Mejía-Ortíz  Germán Yánez  & Marilú López-Mejía 《Marine Ecology》2007,28(S1):31-34

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Bimodal back-arc alkaline magmatism after ridge subduction: Pliocene felsic rocks from Central Patagonia (47°S)     

Felipe Espinoza  Diego Morata  Mireille Polv  Yves Lagabrielle  Ren C. Maury  Christle Guivel  Joseph Cotten  Herv Bellon  Manuel Surez 《Lithos》2008,101(3-4):191-217

Volumetrically minor microsyenites, alkali microgranite and related trachytic dykes intrude early Pliocene OIB-like alkali basaltic and basanitic flows of the Meseta del Lago Buenos Aires in Central Patagonia (47°S–71°30′W), and occur together with scarce trachytic lava flows. Whole-rock K–Ar ages between 3.98 and 3.08 Ma indicate that the emplacement of these felsic rocks occurred more or less synchronously with that of the post-plateau basaltic sequence that they intrude, during a bimodal mafic–felsic magmatic episode devoid of intermediate compositions. Chemically, these rocks have A₁-type granitoid affinities and are characterized by high silica and alkali contents (60–68 wt.% SiO₂; 8.7–10.8 wt.% Na₂O + K₂O), major and trace elements patterns evidencing evolution by low-pressure fractional crystallization, and Sr and Nd isotopic signatures similar to those of coeval basalts ((⁸⁷Sr/⁸⁶Sr)_o = 0.70488–0.70571; (¹⁴³Nd/¹⁴⁴Nd)_o = 0.512603–0.512645). Nevertheless, some of them have the most radiogenic Sr values ever reported for a magmatic rock in the Meseta and even in the whole Neogene Patagonian Plateau Lavas province ((⁸⁷Sr/⁸⁶Sr)_o = 0.70556–0.70571; (¹⁴³Nd/¹⁴⁴Nd)_o = 0.512603–0.512608). In addition, very high contents of strongly incompatible elements in the most evolved rocks, together with Sr isotopic ratios higher than those of coeval basalts, suggest the occurrence of open-system magmatic processes. Continuous fractional crystallization from a primitive basaltic source, similar to post-plateau coeval basalts, towards alkali granites combined with small rates of assimilation of host Jurassic tuffs (AFC) in a shallow magmatic reservoir, best explains the geochemical and petrographic features of the felsic rocks. Therefore, A₁-type magmatic rocks can be generated by open-system crystallization of deep asthenospheric melts in back-arc tectonic settings.

In Central Patagonia, these  3–4 Ma old alkaline intrusions occur aligned along a  N160–170 trending lineament, the Zeballos Fault Zone, stacking the morphotectonic front of one segment of the Patagonian Cordillera. Intrusion along this fault zone occurred during the onset of a new transtensional or extensional event in the area, related to major regional tectonics occurring in possible relation with the collision of one segment of the Chile Spreading Ridge with the trench.  相似文献   

Integration of climatic indices in an objective probabilistic model for establishing and mapping viticultural climatic zones in a region     

Francisco J. Moral  Francisco J. Rebollo  Luis L. Paniagua  Abelardo García  Fulgencio Honorio 《Theoretical and Applied Climatology》2016,124(3-4):1033-1043

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Accurate pressure gradient calculations in hydrostatic atmospheric models     

John J. Carroll  Luis R-Mendez-Nuñez  Saffet Tanrikulu 《Boundary-Layer Meteorology》1987,41(1-4):149-169

Most models of atmospheric flow which use the primitive equations require a diagnostic equation to determine local total pressure. In hydrostatic models, this equation is the vertically integrated hydrostatic equation. A frequently used approximation to this integration is to hold the temperature constant within model layers yielding a linear proportionality between p or (Exner's function) and z. This procedure yields static pressures with errors on the order of 10^–3mb.If terrain following coordinates are used, terms arise in the horizontal momentum equations involving the gradient of total pressure along the coordinate surface, less a correction for the variation of the hydrostatic pressure along a sloped surface. Erroneous horizontal accelerations are common in these models which result from spurious pressure gradients that are due to inaccurate computation of the static pressure. This error may be amplified if the computation of the slope correction term of the horizontal pressure gradient is not consistent with the method of calculating the total pressure.We derive a methodology to be used in the vertical pressure integrations that is exact if the potential temperature lapse rate is constant between integration limits. The method is applied to both the integration of the hydrostatic equation and the computation of the slope correction term in the horizontal pressure gradient. The method employs a fixed vertical grid and a dynamic one defined by the significant levels in the vertical temperature distribution. With this methodology, the error in calculation of the horizontal pressure gradient acceleration is greatly reduced, especially in situations where the isothermal surfaces are not parallel to the vertical coordinate surfaces. The problem of aliasing and the treatment of significant temperature levels is described.  相似文献   

DDTs in Balaenopterids (Cetacea) from the Chilean coast     

Silvio Pantoja  Luis Pastene  Jose Becerra  Mario Silva  Victor A. Gallardo 《Marine pollution bulletin》1984,15(12):451

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Casabianca formation: a Colombian example of volcanism-induced aggradation in a fluvial basin     

A. Carlos  P. Borrero  Jose Luis H. Naranjo 《Journal of Volcanology and Geothermal Research》1990,41(1-4)

The Upper Pliocene to Pleistocene Casabianca Formation is an assemblage of coarse-grained volcanogenic sediments derived from the Ruiz-Cerro Bravo volcanic axis, which were deposited on the west and east flanks of the middle Colombian Central Cordillera (5°–5°30′ N Lat.; 74°30′–76° W Long.).Facies assemblages, paleocurrent data, and geomorphic expression define four depositional settings: (1) an alluvial fan with debris-flow lobes represented by the Manizales fan in the western sector and the Fresno fan in the eastern sector, characterized by the facies assemblage of Gms, Gp and Gt; (2) valley fill deposits represented by the Arauca section at the west sector, characterized by the facies assemblage of Gms and Gi; (3) deposits produced by the diversion of the debris-flow and hyperconcentrated flood-flow deposits from the main channels into narrow effluent channels; represented by the Delgaditas and Manzanares-Marquetalia sections, in the eastern sector and characterized by the facies assemblage Gms and Gm(a); and (4) lateral accretion in gravelly, medium to high-sinuosity rivers, represented by the Casabianca-Villa Hermosa, Palo Cabildo-Falan, Lagunillas and Guali sections of the eastern sector, characterized by the facies assemblage Gms, Gp and Gt.Casabianca Formation deposition records the response of a semi-arid to tropical fluvial system to large, volcanism-induced sediment loads.  相似文献   

Model for the Processing and Estimation of Dual Frequency Echo Sounder Observations in Detailed Bathymetries   总被引：1，自引：0，他引：1  

Raúl Pereda García  Felipe Piña García  Julio Manuel De Luis Ruiz  Raúl Husillos Rodríguez 《Marine Geodesy》2016,39(3-4):305-320

The dataset acquired by an echo sounder generally comprises outliers and erroneous measurements which must be automatically processed. The main aim of this research is the development and validation of an algorithm which permits detecting outliers, estimating their real value from data acquired with a multifrequency echo sounder, and verifying the measure according to the desired accuracy. The process considers the nature of the seabed and improves the density and number of lectures without globally compromising the precision, but enhancing it in areas with anomalous measurements. Twenty-nine percent of this type of measurements, which would have been otherwise rejected, have been estimated.  相似文献   

Long‐term spatial dynamics in vegetated seascapes: fragmentation and habitat loss in a human‐impacted subtropical lagoon          下载免费PDF全文

Rolando O. Santos  Diego Lirman  Simon J. Pittman 《Marine Ecology》2016,37(1):200-214

Vegetated coastal seascapes exhibit dynamic spatial patterning, some of which is directly linked to human coastal activities. Human activities (e.g. coastal development) have modified freshwater flow to marine environments, resulting in significant changes to submerged aquatic vegetation (SAV) communities. Yet, very little is known about the spatially complex process of SAV habitat loss and fragmentation that affects ecosystem function. Using habitat mapping from aerial photography spanning 71 years (1938–2009) for Biscayne Bay (Florida, USA), we quantify both SAV habitat loss and fragmentation using a novel fragmentation index. To understand the influence of water management practices on SAV seascapes, habitat loss and fragmentation were compared between nearshore and offshore locations, as well as locations adjacent to and distant from canals that transport freshwater into the marine environment. Habitat loss and fragmentation were significantly higher along the shoreline compared with offshore seascapes. Nearshore habitats experienced a net loss of 3.31% of the total SAV mapped (2.57 km²) over the time series. While areas adjacent to canals had significantly higher SAV cover, they still experienced wide fluctuations in cover and fragmentation over time. All sites exhibited higher fragmentation in 2009 compared with 1938, with four sites exhibiting high fragmentation levels between the 1990s and 2000s. We demonstrate that freshwater inputs into coastal bays modify the amount of SAV and the fragmentation dynamics of SAV habitats. Spatial changes are greater close to shore and canals, indicating that these coastal developments have transformative impacts on vegetated habitats, with undetermined consequences for the provisioning of ecosystem goods and services.  相似文献   

Resource partitioning among air‐breathing marine predators: are body size and mouth diameter the major determinants?          下载免费PDF全文

Fabiana Saporiti  Stuart Bearhop  Damián G. Vales  Laura Silva  Lisette Zenteno  Mauricio Tavares  Enrique A. Crespo  Luis Cardona 《Marine Ecology》2016,37(5):957-969

Although the body size of consumers may be a determinant factor in structuring food webs, recent evidence indicates that body size may fail to fully explain differences in the resource use patterns of predators in some situations. Here we compared the trophic niche of three sympatric and sexually dimorphic air‐breathing marine predators (the South American sea lion, Otaria flavescens, the South American fur seal, Arctocephalus australis, and the Magellanic penguin, Spheniscus magellanicus) in three areas of the Southwestern Atlantic Ocean (Río de la Plata and adjoining areas, Northern Patagonia and Southern Patagonia), in order to assess the importance of body size and mouth diameter in determining resource partitioning. Body weight and palate/bill breadth were used to characterize the morphology of each sex and species, whereas the trophic niche was assessed through the use of stable isotope ratios of carbon and nitrogen. The quantitative method Stable Isotope Bayesian Ellipses in R (SIBER) was used to compute the area of the Bayesian ellipses and the overlap of the isotopic niches. The results showed that morphological similarity was significantly correlated with isotopic distance between groups within the δ¹³C–δ¹⁵N bi‐plot space in the Río de la Plata area, but not in Northern and Southern Patagonia. Furthermore, resource partitioning between groups changed regionally, and some morphologically distinct groups exhibited a large trophic overlap in certain areas, such as the case of male penguins and male sea lions in Southern Patagonia. Conversely, female sea lions always overlapped with the much larger males of the same species, but never overlapped with the morphologically similar male fur seals. These results indicate that body size and mouth diameter are just two of the factors involved in resource partitioning within the guild of air‐breathing predators considered here, and for whom – under certain environmental conditions – other factors are more important than morphology.  相似文献