Environmental factors influencing aggregation of manta rays (Manta birostris) off the northeastern coast of the Yucatan Peninsula          下载免费PDF全文

Ana Hacohen‐Domené  Raúl O. Martínez‐Rincón  Felipe Galván‐Magaña  Natalí Cárdenas‐Palomo  Jorge Herrera‐Silveira 《Marine Ecology》2017,38(3)

Manta rays inhabit tropical, subtropical and temperate waters. Aggregation sites of manta rays have been recognized worldwide, but the reasons for this behavior are still poorly understood. This study describes environmental factors influencing aggregation sites of the giant manta ray (Manta birostris) off the northeastern coast of the Yucatan Peninsula. Observations of manta rays were obtained from scientific surveys conducted during 2006–2011. Environmental data were obtained from satellite imagery. The maximum entropy (Maxent) method for habitat modeling was used to determine the effects of environmental conditions on the species and predict suitable habitat for manta rays in this region. Primary productivity and distance to the coast were the most influential variables, suggesting that aggregation occurs in highly productive coastal waters. The distribution of manta rays predicted by the Maxent model showed that the most suitable habitat within the study area is located off the northeastern coast of the Yucatán Peninsula, more precisely, northeast of Isla Holbox and northwest of Isla Contoy. Seasonal patterns of distribution suggest that the most suitable conditions are present from July through September.  相似文献   

Superposition of tectonic structures leading elongated intramontane basin: the Alhabia basin (Internal Zones,Betic Cordillera)     

Martínez-Martos  Manuel  Galindo-Zaldivar  Jesús  Martínez-Moreno  Francisco José  Calvo-Rayo  Raquel  Sanz de Galdeano  Carlos 《International Journal of Earth Sciences》2017,106(7):2461-2471

International Journal of Earth Sciences - The relief of the Betic Cordillera was formed since the late Serravallian inducing the development of intramontane basins. The Alhabia basin, situated in...  相似文献   

Soil contamination by metals with high ecological risk in urban and rural areas     

F. B. V. da Silva  C. W. A. do Nascimento  P. R. M. Araújo  F. L. da Silva  L. H. V. Lima 《International Journal of Environmental Science and Technology》2017,14(3):553-562

Industrial development, intensive agriculture and fast urbanization have caused the metal contents of soils to increase to many times the allowable limits. To assess this impact on urban and rural soils, we quantified the Cd, Cr, Cu, Pb, Ni and Zn contents of 258 soil samples from the Recife metropolitan region (RMR). The objectives of the study were to estimate the probability of ecological risk, to determine the spatial pattern of the metals’ accumulation in the soil and to identify potential sources for the metals using a multivariate geostatistical approach. Mean concentrations of Zn, Cr, Pb, Cu, Ni and Cd in soils were 65.2, 17.9, 16.5, 12.8, 6.3 and 1.5 mg kg^?1, respectively. The results demonstrated that the Cd was anthropogenic in origin, the Cr and Ni were lithogenic (natural) in origin and the Cu, Pb and Zn were mixed in origin. Cd contaminated 91% of the samples; the median content of Cd (1.4 mg kg^?1) was three times the quality reference value for soil. The Cd contents of sugarcane fields exceeded the allowable limit (3.0 mg kg^?1) for agricultural areas. The spatial variability of the metals in the RMR showed that metallurgy, cement production, vehicle exhaust and vehicular traffic were the main sources of metals in urban areas, while phosphate-based fertilizers were the main sources in rural areas. More than 80% of the metropolitan region surveyed in the study was at moderate to high ecological risk.  相似文献   

Seismic Characteristics of the Vulcanian Explosions from the 2003–2005 Eruption at Colima Volcano,Mexico     

Francisco Javier Núñez-Cornú  Juan Manuel Espíndola  Fidencio Alejandro Nava Pichardo  Carlos Suárez-Plascencia 《Pure and Applied Geophysics》2016,173(10-11):3513-3524

  相似文献   

P-Wave Velocity Tomography from Local Earthquakes in Western Mexico     

Juan A. Ochoa-Chávez  Christian R. Escudero  Francisco J. Núñez-Cornú  William L. Bandy 《Pure and Applied Geophysics》2016,173(10-11):3487-3511

  相似文献   

Seismic Anisotropy and Mantle Flow Driven by the Cocos Slab Under Southern Mexico     

Leslie A. Bernal-López  Berenice R. Garibaldi  Gerardo León Soto  Raúl W. Valenzuela  Christian R. Escudero 《Pure and Applied Geophysics》2016,173(10-11):3373-3393

  相似文献   

Identification of T-Waves in the Alboran Sea     

Enrique Carmona  Javier Almendros  Gerardo Alguacil  Juan Ignacio Soto  Francisco Luzón  Jesús M. Ibáñez 《Pure and Applied Geophysics》2015,172(11):3179-3188

  相似文献   

Slope instabilities triggered by the 11th May 2011 Lorca earthquake (Murcia,Spain): comparison to previous hazard assessments and proposition of a new hazard map and probability of failure equation     

Martín Jesús Rodríguez-Peces  Julián García-Mayordomo  José Jesús Martínez-Díaz 《Bulletin of Earthquake Engineering》2014,12(5):1961-1976

The Lorca Basin has been the object of recent research aimed at studying the phenomena of earthquake-induced landslides and its assessment in the frame of different seismic scenarios. However, it has not been until the 11th May 2011 Lorca earthquakes when it has been possible to conduct a systematic approach to the problem. In this paper we present an inventory of slope instabilities triggered by the Lorca earthquakes which comprises more than 100 cases, mainly rock and soil falls of small size (1–100  \(\hbox {m}^{3}\) ). The distribution of these instabilities is here compared to two different earthquake-triggered landslide hazard maps: one considering the occurrence of the most probable earthquake for a 475-years return period in the Lorca Basin \((\hbox {M}_{\mathrm{w}}=5.0)\) based on both low- and high-resolution digital elevation model (DEM); and a second one matching the occurrence of the \(\hbox {M}_{\mathrm{w}}=5.2\) 2011 Lorca earthquake, which was performed using the higher resolution DEM. The most frequent Newmark displacements related to the slope failures triggered by the 2011 Lorca earthquakes are lower than 2 cm in both the hazard scenarios considered. Additionally, the predicted Newmark displacements were correlated to the inventory of slope instabilities to develop a probability of failure equation. The fit seems to be very good since most of the mapped slope failures are located on the higher probability areas. The probability of slope failure in the Lorca Basin for a seismic event similar to the \(\hbox {M}_{\mathrm{w}}\) 5.2 2011 Lorca earthquake can be considered as very low (0–4 %).  相似文献   

Laboratory studies on the sputtering contribution to the sodium atmospheres of Mercury and the Moon     

Catherine A. Dukes  Wen-Yen Chang  Marcelo Famá  Raúl A. Baragiola 《Icarus》2011,212(2):463-469

To ascertain the importance of sputtering by solar wind ions on the formation of a sodium exosphere around Mercury and the Moon, we have irradiated with 4 keV He ions, the Na bearing tectosilicates: albite, labradorite, and anorthoclase, as well as adsorbed Na layers deposited on albite and on olivine (a neosilicate that does not contain Na). Sodium at the surface and near surface (<40 Å) was quantified with X-ray photoelectron spectroscopy before and after each irradiation to determine the depletion cross section. We measured a cross section for sputtering of Na adsorbed on mineral surfaces, σ_s ≈ 1 × 10^?15 cm² atom^?1. In addition, mass spectrometric analyses of the sputtered flux show that a large fraction of the Na is sputtered as ions rather than as neutral atoms. These results have strong implications for modeling the sodium population within the mercurian and the lunar exospheres.  相似文献   

Analysis of horizontal and vertical ring structure based on analytical model and satellite data: Application to the North Brazil Current Rings     

Raúl Cruz-Gómez  Julio Salcedo-Castro 《Ocean Science Journal》2013,48(2):161-172

A theoretical analysis of the principal oceanic ring parameters (tangential and angular velocities, shape function, horizontal and vertical scale of the ring) is described. The theoretical model consists of a reduced gravity model of the lens-like vortices with solid body rotation. The application of this approach is tested by comparison with data from the North Brazil Current Rings Experiment and remote sensing data. Specifically, we used the data corresponding to the surfaceintensified North Brazil Current ring (R-3) surveyed in February–March 1999, using direct velocity and hydrographical measurements. The theoretical model was used for evaluating the geometrical structure of the surface-intensified rings that produce remarkable signals in satellite data. The principal ring parameters from the model were compared with those from satellite data (altimetry and drifter information), which were estimated by using the method of minimization of the multivariable objective functions. Although the proposed model is linear in its conception, a good agreement was observed between the model and the primary characteristics of the observed rings. The model, however, allows for improvement in its assumptions, since its application is rather limited to intense ocean rings.  相似文献