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911.
Patterns in megabenthic assemblages on a seamount summit (Ormonde Peak,Gorringe Bank,Northeast Atlantic) 下载免费PDF全文
Manuela Ramos Iacopo Bertocci Fernando Tempera Gonçalo Calado Mónica Albuquerque Pedro Duarte 《Marine Ecology》2016,37(5):1057-1072
Gettysburg and Ormonde are two shallow peaks located on the Gorringe seamount about 200 and 240 km WSW off Cape St. Vincent (Portugal, NE Atlantic), within the Portuguese Economic Exclusive Zone. Despite the ecological importance of the biological assemblages on these peaks and the need to preserve seamounts as valuable habitats, no management plans have been yet implemented at this site, which only recently has been included in the list of Sites of Community Importance of Portugal. Video imagery collected using a ROV during the 2011 Oceana campaigns was used here to analyse qualitative and quantitative patterns of benthic assemblage composition at the summit of the seamount (between 30 and 230 m depth). The results suggest that Ormonde is a biologically important area made up of vulnerable marine ecosystem elements that change significantly with depth. These include: kelp beds, in the euphotic zone; encrusting coralline algal communities and solitary colonies or mixed associations of suspension‐feeders (scleractinians, gorgonians, antipatharians, encrusting demosponges and ascidians), at the lower limit of the euphotic zone; mixed coral gardens and erect sponges, in the disphotic zone; and dense sponge aggregations, on the upper slope. These results were further used to propose amendments to the European Nature Information System habitat classification as a tool to work towards resolving the seamounts management issue. The results also provide information on taxa and habitats with high ecological value and classified as threatened or vulnerable, which is essential for the implementation of the cornerstones of Europe's biodiversity conservation policy, namely the OSPAR Convention and the EU Habitats Directive. 相似文献
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Mário Pereira Fernando Veloso-Gomes José Lima Sérgio Oliveira 《Marine Georesources & Geotechnology》2016,34(7):617-629
This article describes the implementation of a monitoring system on the breakwater at the Funchal Port (Madeira Island, Portugal) for the purpose of understanding its dynamic behavior and the temporal evolution of structural health. The monitoring system focuses on the breakwater superstructure and aims to identify the evolution of damage on the breakwater and analyze the impact of cruise ships docking and undocking. The system includes the measurement of displacements through geodetic techniques using global navigation satellite systems and the measurement of vibrations using accelerometers. Ten observation campaigns were performed over almost 3 years. As the measured displacements during this period were less than 7.5 mm it can be concluded that, despite some visible cracks, the breakwater superstructure did not suffer significant structural changes. It was shown from the measured acceleration records that some of the main modal parameters could be identified, namely the main natural frequencies of the superstructure. Through an analysis of the natural frequencies progression over time, it will be possible to identify deterioration effects on the foundation and/or the superstructure. The comparison of natural frequencies identified could be useful to evaluate the impact of these events on structural health. 相似文献
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José Alfredo Ramos-Leal B. López-Álvarez G. Santacruz-De León O. Almanza-Tovar J. Morán-Ramírez D. A. Padilla-Reyes Z. I. González-Acevedo 《Arabian Journal of Geosciences》2016,9(19):736
The paper evaluates the quality of groundwater for agricultural use in Tierra Nueva, San Luis Potosi, Mexico, where the agricultural productivity zone presents problems of salinity soil. Twenty groundwater samples and 11 soil samples at 2 depths at each point were collected and analyzed. In this type of water quality study, Wilcox classification diagram and the method of Salinity Laboratory United States for the quality of agricultural land were used. However, in some cases, these rankings do not reflect the actual condition, as in the case of Tierra Nueva, where the soil is classified as normal while water is classified at intermediate good. To analyze the real conditions of soil and water quality indicators of water for agricultural use risk of salinization, sodium adsorption ratio, adsorption ratio magnesium, permeability index, sodium percentage, soluble sodium percentage, residual sodium carbonate, and Kelly ratio were used. Sodicity rates including sodium adsorption ratio indicate no problem in soil extract. However, 25% of water samples are dangerous, with levels ranging from medium to high. For indexes of sodium percentage, residual sodium carbonate, and Kelly ratio, a distribution of classes ranging from questionable to inadequate was applied. Salinity levels show that effective salinity has good classification; potential salinity (PS) is conditional and therefore not recommended; and osmotic potential and electrical conductivity are classified as high in saline water, which is an increasingly important problem. The combination of different indices emphasized serious problems of salinity conditions, particularly sodicity. 相似文献
916.
Air Quality Index Revisited from a Compositional Point of View 总被引:1,自引:0,他引:1
Eusebi Jarauta-Bragulat Carme Hervada-Sala Juan José Egozcue 《Mathematical Geosciences》2016,48(5):581-593
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An ecological classification of rocky shores at a regional scale: a predictive tool for management of conservation values 下载免费PDF全文
The ecological classification of coastal waters has become an important issue in ecosystem water quality assessment. Previous studies have suggested that abiotic variables seem to be a suitable alternative to biological data for classifying coastal areas at different scales. The study presented here proposes a downscaling methodology for the classification of coastal waters at a regional scale within the NE Atlantic based on standardized data and objective decision rules. Physical variables (temperature, wave exposure, tidal range and radiation) were selected because of their ecological role, availability and statistical decision rules. This information was based on satellite data and mathematical modelling of natural coastal processes. The N and NW Spanish coastline was subdivided into 41 20‐km segments that were classified according to physical variables using the self‐organizing map and k‐means algorithms. To validate the classification with biological data, 21 sites representing the entire range of physical typologies in the study area were simultaneously and consistently sampled. Intertidal macroalgae were identified in each of 10 quadrats of 50 × 50 cm for two to three transects per site, according to a stratified sampling procedure. The coverage of macroalgae was obtained by photographic analysis. The physical classification shows four typologies: Lower Rias, Upper Rias, West Cantabric and East Cantabric. Statistical analyses confirmed the ecological significance of these typologies at the tidal levels where seaweeds were the major structural element (lower and middle intertidal). According to the biological data, the greatest differences were found between the Upper Rias and the rest of the N and NW Iberian Peninsula coast. Thus, the classification methodology has potential application as a management tool. 相似文献
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Mª Carmen Ruiz-Delgado Jenyffer Vierheller Vieira Mª José Reyes-Martínez Carlos Alberto Borzone Juan Emilio Sánchez-Moyano Francisco José García-García 《Estuaries and Coasts》2016,39(4):1113-1121
A distinctive feature of sandy beaches is the stranded wrack, which represents a key element in the maintenance of their biodiversity and ecosystem function. However, these materials are commonly removed from beaches worldwide. In October–November 2012, a field experiment following an M-BACI design was conducted to assess the effect of wrack removal on sandhopper populations on two sandy beaches on the Atlantic southwest coast of Spain. The beaches, Levante (36°33′N, 6°13′W) and Cortadura (36°28′N, 6°15′W) differed in their morphodynamics (dissipative and intermediate, respectively) and in the dominant wrack sources (seagrasses vs. macroalgae). Wrack removal diminished the density of the sandhopper, Talitrus saltator, a dominant species in the supratidal zone especially under wrack, but the difference between impacted and control plots was short-lived (several days). Juvenile sandhoppers appeared more sensitive to this disturbance than adults, although this was found only at Levante. This study highlights the adaptability of this sandhopper to a single wrack removal event and shows that the magnitude of the effect is likely dependent on the particular characteristics of individual beaches. The consequences of frequent wrack removal from these beaches on sandhopper populations remain to be determined. 相似文献