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1.
Melchor Gonzlez-Dvila J. Magdalena Santana-Casiano Demetrio de Armas Jos Escnez Miguel Suarez-Tangil 《Marine Chemistry》2006,99(1-4):177
Measurements of surface partial pressure of CO2 and water column alkalinity, pHT, nutrients, oxygen, fluorescence and hydrography were carried out, south of the Canary Islands during September 1998. Cyclonic and anticyclonic eddies were alternatively observed from the northwestern area to the central area of the Canary Islands. Nutrient pumping and vertical uplifting of the deep chlorophyll maximum by cyclonic eddies were also ascertained by upward displacement of dissolved inorganic carbon. A model was applied to determine the net inorganic carbon balance in the cyclonic eddy. The fluxes were determined considering both the diffusive and convective contributions from the upward pumping and the corresponding horizontal transport of water outside the area. An increase in the total inorganic carbon concentration in the upper layers inside the eddy field of 133 mmol C m− 2 d− 1 was determined. The upward flux of inorganic carbon decreased the effect of the increased primary production on the carbon dioxide chemistry. The reduced fCO2 inside the cyclonic eddy, 15 μatm lower than that observed in non-affected surface water, was explained by thermodynamic aspects, biological activity, eddy upward pumping and diffusion and air–sea water exchange effects. 相似文献
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Iuliana Armaş Florin Vartolomei Florica Stroia Livioara Braşoveanu 《Natural Hazards》2014,70(2):995-1017
The study is a deterministic-based approach on landslide susceptibility. The purpose of the paper is to create quantitative susceptibility maps by joining the one-dimension infinite slope stability model with a raster-based GIS (ILWIS) and taking into account the spatial distribution of input parameters. A landslide-prone area, with relative homogeneous geology and geomorphology, located in the Subcarpathian sector of the Prahova River, Romania, was selected for the study. There are frequent problems caused by active landslides in the studied area, especially in years with heavy precipitation, often causing destruction of houses and roads situated on the slopes (1992, 1997, and 2005). Detailed surveys covering a 7-year period provided the necessary input data on slope parameters, hydrological components, and the geotechnical background. Two simulations were used: one on dry soil conditions and one on fully saturated soil conditions. A third test was based on the level of the groundwater table mapped in summer 2008. Detailed analyses were particularly focused on landslides to compare predicted results with actual results using field measurements. The model is very suitable for use in raster GIS because it can calculate slope instability on a pixel basis, each raster cell being considered individually. The drawback of the model is the highly detailed data of input parameters. Despite this disadvantage, in conclusion, the usefulness of slope stability models on a large-scale basis was emphasized under infinitely high failure plain conditions and lithological homogeneity. 相似文献
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Franco MA Viñas L Soriano JA de Armas D González JJ Beiras R Salas N Bayona JM Albaigés J 《Marine pollution bulletin》2006,53(5-7):260-271
The distribution of aliphatic and aromatic hydrocarbons was determined in surface sediments collected at 36 stations along the Galicia continental shelf (NW Spain), following the Prestige oil spill. Sampling was performed in December 2002, just after the accident, and in February and September 2003. Concentrations of PAHs (summation operator 13 parent components) were in the range of 0.9-422 microg/kgdw, the highest values being close to coastal urban areas (e.g. Pontevedra and A Coru?a), whereas in the stations of the area most heavily impacted by the spill (off Costa da Morte) concentrations were in the range of 14.8-89.6 microg/kgdw, with a certain predominance of alkylated compounds, which may suggest a mixture of petrogenic and pyrolytic sources. The detailed study of petrogenic molecular markers (e.g. steranes and triterpanes) showed the occurrence of an old (weathered) petrogenic chronic pollution in the shelf sediments but not of the Prestige oil, with the possible exception of few stations in the area of Costa da Morte. This was attributed to the heavy nature of the spilled oil that was barely dispersed in the water column and mainly stranded on the coast or sedimented in the form of oil patches. The addition of increasing amounts of fuel oil to a representative sediment sample showed that the molecular indices were indicative of the presence of the Prestige oil when the amount was above 1g/kg of sediment. The toxicity of selected samples (showing the higher PAH concentrations) was tested using the bivalve embryogenesis bioassay. Embryogenesis success reached high values in all cases (80-88%, with 86% in the control), indicating a lack of toxicity in the sediments and supporting the conclusion that the patchiness of the fuel eventually reaching the seafloor reduced its impact on the benthic communities of the Galician shelf. 相似文献
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Semi-arid ecosystems are privileged sites to address the effects of plant interactions on community structure and dynamics because environmental conditions are demanding and may change quickly, altering in significant ways the balance between positive and negative effects among neighboring plants. Plant interaction processes have been well documented in the semi-arid region of Southeast Spain over the last 15 years. In this article we review the growing body of research on plant–plant interactions available from this area, highlighting its importance in increasing our knowledge on this field of study. This review has been organized in five sections, i) facilitation mechanisms; ii) the nurse effect; iii) the balance of interactions and environmental, ontogenic, temporal, and spatial gradients; iv) the effects of facilitation on biodiversity; and, v) facilitation and ecosystem functioning. Mechanisms of facilitation in these systems are relatively well known, but not completely explored. In these environments competition, mainly for water, is intense between neighbors and switches in intensity from belowground to aboveground as productivity increases. By contrast, facilitation may decrease quickly with increasing productivity, although the balance between facilitation and competition is not fully understood, and is further complicated because shifts can also be driven by factors such as life history or physiology of interacting species. Positive interactions are critical for maintaining biodiversity in some ecosystems in SE Spain, but their role as a driver of ecosystem functioning is less clear. Research on plant–plant interactions in this region has been highly influential and has contributed to our overall understanding of plant community dynamics. Despite the important progress achieved during the last 15 years, there is still substantial scope for exploring the effects of plant interactions at the ecosystem level, and their role as modulators of disturbances such as the current global environmental change. 相似文献
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Perception of flood risk in Danube Delta,Romania 总被引：1，自引：1，他引：0
For exposed and vulnerable communities, the perception of natural risk is an essential link in the analysis of man–environment
coping relationship and also an important parameter in the quantification of complex vulnerability as a central predictive
variable in the risk equation. The topic of flood risk in related perception is of considerable interest, as some recently
published papers have proven (Messner and Meyer 2005, 2006; Raaijmakers et al. 2008). The aim of the current study is to reveal the conscious and unconscious attitudes towards the flood risk for the inhabitants
of the Danube Delta/Romania. These attitudes, defined by different degrees of psychological vulnerability, represent the background
for a series of psycho-behavioural patterns that generate certain adjustment mechanisms and strategies. Application of a specially
designed questionnaire and the statistical analysis of the results revealed two psychological factors as essential in establishing
the psychosocial vulnerability degree of the interviewed subjects: (i) an internal control factor and (ii) an external control
factor. The persons characterized by inner control have a significantly reduced general anxiety level in comparison to individuals
with the control factor placed externally. As confidence diminishes, it increases the tendency of the individual to rely on
the external factors for support and security. The lack of resources (indicating lower resilience) and mistrust in the support
given emphasizes non-adaptive behaviours.
相似文献
| Iuliana ArmaşEmail: |
7.
Javier Arístegui Eric D. Barton Paul Tett María F. Montero Mercedes García-Muoz Gotzon Basterretxea Anne-Sophie Cussatlegras Alicia Ojeda Demetrio de Armas 《Progress in Oceanography》2004,62(2-4):95
The variability in dissolved and particulate organic matter, plankton biomass, community structure and metabolism, and vertical carbon fluxes were studied at four stations (D1–D4), placed along a coastal-offshore gradient of an upwelling filament developed near Cape Juby (NW Africa). The filament was revealed as a complex and variable system in terms of its hydrological structure and distribution of biological properties. An offshore shift from large to small phytoplankton cells, as well as from higher to lower autotrophic biomass, was not paralleled by a similar gradient in particulate (POC) or dissolved (DOC) organic carbon. Rather, stations in the central part of the filament (D2 and D3) presented the highest organic matter concentrations. Autotrophic carbon (POCChl) accounted for 53% (onshore station, D1) to 27% (offshore station, D4) of total POC (assuming a carbon to chlorophyll ratio of 50), from which nano- and pico-phytoplankton biomasses (POCA < 10 μm) represented 14% (D1) to 79% (D4) of POCChl. The biomass of small hetrotrophs (POCH < 10 μm) was equivalent to POCA < 10 μm, except at D1, where small autotrophs were less abundant. Dark community respiration (Rd) in the euphotic zone was in general high, almost equivalent to gross production (Pg), but decreasing offshore (D1–D4, from 108 to 41 mmol C m−2 d−1). POC sedimentation rates (POCsed) below the euphotic zone ranged from 17 to 6 mmol C m−2 d−1. Only at D4 was a positive carbon balance observed: Pg−(Rd + POCsed) = 42 mmol C m−2 d−1. Compared to other filament studies from the NE Atlantic coast, the Cape Juby filament presented lower sedimentation rates and higher respiration rates with respect to gross production. We suggest that this is caused by the recirculation of the filament water, induced by the presence of an associated cyclonic eddy, acting as a trapping mechanism for organic matter. The export capacity of the Cape Juby filament therefore would be constrained to the frequency of the interactions of the filament with island-induced eddies. 相似文献
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Social vulnerability and seismic risk perception. Case study: the historic center of the Bucharest Municipality/Romania 总被引：3，自引：2，他引：1
Iuliana Armaş 《Natural Hazards》2008,47(3):397-410
Social vulnerability is as much a part of risk as building damage, hazard magnitude, and economic loss. Social vulnerability refers to the capacity of a human community exposed during the impact of a natural hazard event (in this case, an earthquake)
to resist, cope with, and recover from that impact. In the perspective of the 3rd millennium, we come to understand that the
most efficient and accessible way to reduce the pressure of natural risks is to reduce the vulnerability level of the human
communities exposed to that certain hazard. This study aims to test, in an exposed and vulnerable area, the relationship between
social vulnerability and the perception of the seismic risk. The research focuses only on the first level of social vulnerability,
defined as the ability of an individual within a household to recover from a natural hazard impact (Dwyer et al. 2004). A prevailing assumption was that social vulnerability influences the level of perception of the seismic risk, in an exposed, vulnerable area. To this end, two samples were used, different under the aspect of social vulnerability, in the context of the same residential
area. Social vulnerability was computed as a normalized composed index that includes the poverty ratio and the demographic
vulnerability ratio (depending on the age, gender, and education level indicators). The statistical processing has indicated
a significant difference in the high perception level for the two samples that were compared, in the sense that in the context
of an increased level of social vulnerability, people generally better acknowledge the seismic risk.
相似文献
| Iuliana ArmaşEmail: |
9.
J.D. Miranda C. Armas F.M. Padilla F.I. Pugnaire 《Journal of Arid Environments》2011,75(12):1302-1309
The structure and functioning of semi-arid ecosystems are strongly influenced by precipitation patterns. Water availability in such environments is highly pulsed, and discrete rainfall events interspersed with drought periods are important components of the annual water supply. Plant communities do not only respond to rainfall quantity, but also to variations in time, so that relatively small changes in rainfall frequency (i.e., pulsed inputs) may have strong effects on communities. Within the Mediterranean basin, climate change models forecast a decrease in mean annual precipitation and more extreme events (i.e., less rainy days and longer drought periods between events), along with seasonal changes. However, little is known on the consequences of these future precipitation changes on plant communities, especially in semi-arid environments. Here, we summarize the few experiments that have manipulated rainfall patterns in arid and semi-arid areas worldwide, and introduce the first results of a pioneer, long-term rainfall exclusion in the semi-arid southeast region of the Iberian Peninsula. The experiment is not only manipulating the amount of rainfall, but also its frequency and seasonal distribution in a grassland-shrubland in the Tabernas desert (Almería, Spain). This work monitored the effect of precipitation changes on different ecosystem processes for five years, at the species and community level, concluding that this plant community (as other communities studied in the same area) exhibited great resilience to changes in rainfall availability, likely caused by plant adaptation to large intra- and inter-annual precipitation variability. 相似文献
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