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121.
The environmental, socioeconomic and cultural significance of glaciers has motivated several countries to regulate activities on glaciers and glacierized surroundings. However, laws written to specifically protect mountain glaciers have only recently been considered within national political agendas. Glacier Protection Laws (GPLs) originate in countries where mining has damaged glaciers and have been adopted with the aim of protecting the cryosphere from harmful activities. Here, we analyze GPLs in Argentina (approved) and Chile (under discussion) to identify potential environmental conflicts arising from law restrictions and omissions. We conclude that GPLs overlook the dynamics of glaciers and could prevent or delay actions needed to mitigate glacial hazards (e.g. artificial drainage of glacial lakes) thus placing populations at risk. Furthermore, GPL restrictions could hinder strategies (e.g. use of glacial lakes as reservoirs) to mitigate adverse impacts of climate change. Arguably, more flexible GPLs are needed to protect us from the changing cryosphere.  相似文献   
122.
123.
Use of the genus Artemia in ecotoxicity testing   总被引:1,自引:0,他引:1  
Information related to varied uses of several species of the genus Artemia (commonly known as brine shrimp), is dispersed among literature from several scientific areas, such as Ecology, Physiology, Ecotoxicology, Aquaculture and Genetics. The present paper reviews information related to Artemia that may be considered relevant for ecotoxicity testing. Integration of different areas of scientific knowledge concerning biology, life cycle and environmental needs of Artemia is of crucial importance when considering the interpretation of results drawn from tests involving this genus. Furthermore, this paper provides suggestions to overcome problems related to toxicity assessment with the use of Artemia as test organism in bioassays, under the scope of estuarine, marine and hypersaline environments. Aspects related to variability in results, adoptable toxicity end-points, culture conditions, characteristics of species and strains, influence of geographical origins over physiological features and responses to exposure to chemical agents are considered.  相似文献   
124.
125.
One of the most important sources of solid waste in the Mediterranean Basin ecosystem originated from the phosphate fertilizer industries, which discharge phosphogypsum (PG) directly into aquatic environments or are stacked on stockpiles. The present study investigates metal release from PG under the influence of variable pH, increasing PG mass content, and complexing organic matter ligands. Major ions from PG leachates, grain size and charge, main functional groups along with metal leachability (Pb, Cd, Cr, Cu, and Zn) were determined using ion chromatography, laser diffraction, zetameter, Fourier transform infrared spectroscopy, and atomic absorption spectroscopy, respectively. The complete dissolution of PG recorded is at 2 g/L. Saturation and supersaturation with respect to PG may occur at concentrations of 3 and 4 g/L, respectively, revealing a clustering phenomenon leading to heavy metal encapsulation within the aggregates. Organic ligands such as citrate may trigger the cationic exchange within the PG suspension leading to ion release. As these factors are considered as specific process involving the release of contaminants from PG during storage under natural conditions, this study could set the foundations for PG remediation in aquatic environment. Organic ligands under controlled pH conditions could be utilized in treating fertilizer industrial wastes by taking into consideration the particularity of the receiving area, thus decreasing metal hazardous impact on natural media.  相似文献   
126.
Environmental Science and Pollution Research - The port regions of the Amazon are subject to environmental impacts high shipping traffic. In October 2015, a cargo ship containing 5000 oxen sank in...  相似文献   
127.
Myrmecophytes offer plant-ants a nesting place in exchange for protection from their enemies, particularly defoliators. These obligate ant–plant mutualisms are common model systems for studying factors that allow horizontally transmitted mutualisms to persist since parasites of ant–myrmecophyte mutualisms exploit the rewards provided by host plants whilst providing no protection in return. In pioneer formations in French Guiana, Azteca alfari and Azteca ovaticeps are known to be mutualists of myrmecophytic Cecropia (Cecropia ants). Here, we show that Azteca andreae, whose colonies build carton nests on myrmecophytic Cecropia, is not a parasite of AztecaCecropia mutualisms nor is it a temporary social parasite of A. alfari; it is, however, a temporary social parasite of A. ovaticeps. Contrarily to the two mutualistic Azteca species that are only occasional predators feeding mostly on hemipteran honeydew and food bodies provided by the host trees, A. andreae workers, which also attend hemipterans, do not exploit the food bodies. Rather, they employ an effective hunting technique where the leaf margins are fringed with ambushing workers, waiting for insects to alight. As a result, the host trees’ fitness is not affected as A. andreae colonies protect their foliage better than do mutualistic Azteca species resulting in greater fruit production. Yet, contrarily to mutualistic Azteca, when host tree development does not keep pace with colony growth, A. andreae workers forage on surrounding plants; the colonies can even move to a non-Cecropia tree.  相似文献   
128.
We approach the problem of the evolution of bird migration by asking whether migration evolves towards new breeding areas or towards survival areas in the non-breeding season. Thus, we avoid the ambiguity of the usually discussed “southern-home-theory” or “northern-home-theory”. We argue that migration evolved in birds that spread to seasonal habitats through gradual dispersal to enhance survival during the non-breeding season; this in contrast to the alternative idea suggesting that migration evolved towards new breeding areas to increase reproductive success. Our synthesis is based on the threshold model explaining how migratory traits can change rapidly through microevolutionary processes. Our model brings former theories together and explains how bird migration, with the appropriate direction and time program, evolves through selection after genetically non-directed events such as dispersal and colonization. The model does not need the former untested assumptions such as competition as a reason for migration and for the disappearance of sedentary populations or higher reproductive success in temperate breeding areas. Our theory offers answers to questions such as how birds with a southern origin may gradually reach northern latitudes, why migration routes may follow historical expansion routes and why birds leave an area for the non-breeding season and move back instead of breeding on their wintering grounds. The theory proposes gradual change through selection and not sudden changes such as long distance dispersal or mutations and can be applied to migration at all latitudes and in all directions. The scenario provides a reasonable concept to understand most of the existing migratory phenomena on the basis of the ecology and genetics of migratory behaviour.  相似文献   
129.
Several factors can affect occupational accident frequency, namely economical factors, technologies used (low automation, discontinuous operating) job design, organization of work/environmental conditions and human factors. In particular, technological advances in industrial activities can give rise to improvement in productivity and in occupational health and safety, but not necessarily simultaneously. The beginning of the container transport dates back to 50 years ago, but while containerization changed everything, from ships and ports to patterns of global trade, its impact on work injuries was not explored at all. The aim of this paper is to investigate the relationship between work organization, job experience, productivity and occupational accidents, from the starting of the container expansion to nowadays, considering Genoa port (Italy), one of the largest of the Mediterranean Sea. In order to minimize possible reporting biases, such as underreporting or reclassification to a lower level of severity, injury statistics are elaborated starting from data collected directly on-site, from internal accident or medical-aid reports. An in-depth statistical analysis on occupational injuries in the years 1980–2006 is carried out, with reference to frequency indexes, mechanism of injury and material causes. The increase of container-ships traffic and, consequently, the sharp change in port infrastructure involved a rapid modification also in the work organization, with particular reference to the number and characteristics of workforce (decrease from 5783 to nearly 1000 employees and increase of low experience workers from 28% to 74%). The striking high percentage increase of young or low experienced workers in handling container (and performing correlated new tasks) caused a remarkable increase of the risk for occupational injuries. In the studied port, we recorded an increase of the frequency index (injuries per hundred thousand hours worked) from 13.0 to 29.7. It results that the increased expansion of shipping container utilization is not connected to a correspondent human factor safety implementation. Main risk factors are pointed out, revealing an increase of accidents due to transport vehicle (+8.3%) and a reduction of accidents caused by substance or materials (?4.5%). These factors show a statistical significant correlation with the new job tasks. Consideration of these findings may enable managerial solutions and workplace organization interventions for the prevention of injuries and safety performance improvement in port activities.  相似文献   
130.
Because group-hunting arboreal ants spread-eagle insect prey for a long time before retrieving them, these prey can be coveted by predatory flying insects. Yet, attempting to rob these prey is risky if the ant species is also an effective predator. Here, we show that trying to rob prey from Azteca andreae workers is a fatal error as 268 out of 276 potential cleptobionts (97.1?%) were captured in turn. The ant workers hunt in a group and use the “Velcro?” principle to cling firmly to the leaves of their host tree, permitting them to capture very large prey. Exceptions were one social wasp, plus some Trigona spp. workers and flies that landed directly on the prey and were able to take off immediately when attacked. We conclude that in this situation, previously captured prey attract potential cleptobionts that are captured in turn in most of the cases.  相似文献   
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