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601.
A yearly maximum sea level simulator for Stockholm is presented. The simulator combines extreme sea level estimates and mean sea level rise projections into a joint probabilistic framework. The framework can be used, for example, to assess the risk that new structures placed at the current minimum allowed height above the sea level can become flooded in the future. Such assessments can be used to underpin future building free levels, which would be a great improvement over the much more arbitrary criteria in use today. Another strong point of the framework is that it can be used to quantify the influence of uncertainties in mean sea level projections, estimates of sea level extremes and future emission scenarios on the risk of flooding. For Stockholm mean sea level uncertainty is found to be much more important than extreme sea level uncertainty. The framework is also set-up to test adaptation measures. It is found that protections that are built once the mean sea level has risen above some given threshold can be very efficient. Lastly, the framework is embedded into a simple decision problem that can be used to calculate risk/reward ratios for land development as a function of height above today’s mean sea level.  相似文献   
602.
Abstract:  Mollusks are the group most affected by extinction according to the 2007 International Union for Conservation of Nature (IUCN) Red List, despite the group having not been evaluated since 2000 and the quality of information for invertebrates being far lower than for vertebrates. Altogether 302 species and 11 subspecies are listed as extinct on the IUCN Red List. We reevaluated mollusk species listed as extinct through bibliographic research and consultation with experts. We found that the number of known mollusk extinctions is almost double that of the IUCN Red List. Marine habitats seem to have experienced few extinctions, which suggests that marine species may be less extinction prone than terrestrial and freshwater species. Some geographic and ecologic biases appeared. For instance, the majority of extinctions in freshwater occurred in the United States. More than 70% of known mollusk extinctions took place on oceanic islands, and a one-third of these extinctions may have been caused precipitously by introduction of the predatory snail Euglandina rosea. We suggest that assessment of the conservation status of invertebrate species is neglected in the IUCN Red List and not managed in the same way as for vertebrate species .  相似文献   
603.
During recent decades anthropogenic activities have dramatically impacted the Black Sea ecosystem. High levels of riverine nutrient input during the 1970s and 1980s caused eutrophic conditions including intense algal blooms resulting in hypoxia and the subsequent collapse of benthic habitats on the northwestern shelf. Intense fishing pressure also depleted stocks of many apex predators, contributing to an increase in planktivorous fish that are now the focus of fishing efforts. Additionally, the Black Sea's ecosystem changed even further with the introduction of exotic species. Economic collapse of the surrounding socialist republics in the early 1990s resulted in decreased nutrient loading which has allowed the Black Sea ecosystem to start to recover, but under rapidly changing economic and political conditions, future recovery is uncertain.  相似文献   
604.
Gorgonian corals are long-lived, slow-growing marine species dominating Mediterranean rocky bottoms. Endowed with complex morphologies they give a structure to the whole community, moreover, being efficient suspension feeders, they play a key role in plankton-benthos energy flow and CO2CO2 storage. Thus, the structure and the development of benthic, hard bottom communities are linked to gorgonian survival. The red coral Corallium rubrum (L. 1758) is a precious gorgonian endemic to the Mediterranean Sea. Harvested and traded world-wide since ancient times red coral is a clear example of overexploited marine resource. This species is structured into self-seeding, genetically differentiated populations, some of which, living in the shallower part of the species bathymetric distribution, was recently affected by anomalous mortality events linked to global climate change. The co-occurrence of overharvesting and mass mortality could dramatically affect such populations. Demographic population models, widely applied by conservation biologists to check population viability and to project population trends over time are fundamental to foster survival of such populations matching harvesting to population growth rates. Therefore we set out a dynamic model of a genetically differentiated red coral population living in shallow waters. This population is characterised by small/young, crowded colonies and high recruitment rate. On the basis of the size–age structure determined for this population, a static life-history table, in which survival and reproduction coefficients of the different size–age classes were reported, has been set out. Demographic data were included in a non-linear, discrete, age-structured dynamic model, based on a Leslie-Lewis transition matrix. Our field data indicate that the recruits-to-larvae ratio is actually density-dependent. Such dependence, positive for low and negative for high density values, was included into the model and the effect of colonies of different size–age classes on recruits-to-larvae ratio was considered to be proportional to the number of polyps they have. We applied such model to simulate the trends of the studied population under different increases of survival and life-span. As some populations of gorgonians actually show the dominance of sparse, big/old colonies and low recruitment rate, while others are characterised by crowded, small/young colonies and high recruitment rate, we simulated the shift from the former to the latter structure increasing survival and life-span. Our results suggest that a dramatic mortality increase of bigger–older colonies (due, in the case of red coral to overfishing) could have determined the population structure we found.  相似文献   
605.
The simultaneous accounting of effects of natural and anthropogenic changes within a common framework calls for the development of new comprehensive tools capable of integrating biological processes that span a huge range of scales, from viruses to fishes, in addition to their interactions with physical–chemical environmental properties, i.e. End-to-End models.  相似文献   
606.
By mainly targeting larger predatory fish, commercial fisheries have indirectly promoted rapid increases in densities of their prey; smaller predatory fish like sprat, stickleback and gobies. This process, known as mesopredator release, has effectively transformed many marine offshore basins into mesopredator-dominated ecosystems. In this article, we discuss recent indications of trophic cascades on the Atlantic and Baltic coasts of Sweden, where increased abundances of mesopredatory fish are linked to increased nearshore production and biomass of ephemeral algae. Based on synthesis of monitoring data, we suggest that offshore exploitation of larger predatory fish has contributed to the increase in mesopredator fish also along the coasts, with indirect negative effects on important benthic habitats and coastal water quality. The results emphasize the need to rebuild offshore and coastal populations of larger predatory fish to levels where they regain their control over lower trophic levels and important links between offshore and coastal systems are restored.  相似文献   
607.
Bisphenol A (BPA) is an endocrine disruptor (ED) that is abundant in the environment because of its extensive use in human-manufactured products. In this study, the BPA concentration was measured in the muscle and liver of five edible fish, characterized by different habitat and habits, caught in two different sites of the Tyrrhenian Sea (Italy). Our results show that: (i) fish livers are about 2.5 times more polluted than muscle; (ii) fish caught in the Gulf of Naples are more polluted than those from the Latium coasts, ranging from 1.2-fold more for White Bream to 6.6-fold for Grey Mullet; and (iii) the percentages of fish found to be BPA-polluted in the Gulf of Naples ranged from 73% (for Bass) to 90% (for Mullet), while the Latium fish range from 60% (for Bass) to 90% (for Mullet). These data indicate that consumers of fish caught in the Gulf of Naples are at a greater risk for BPA-induced endocrine pathologies compared to those who consume fish caught along the Latium coasts.  相似文献   
608.
Jönsson AM 《Ambio》2011,40(2):121-132
Scientific complexity and uncertainty is a key challenge for environmental risk governance and to understand how risks are framed and communicated is of utmost importance. The Baltic Sea ecosystem is stressed and exposed to different risks like eutrophication, overfishing, and hazardous chemicals. Based on an analysis of the Swedish newspaper Dagens Nyheter, this study discusses media representations of these risks. The results show that the reporting on the Baltic Sea has been fairly stable since the beginning of the 1990s. Many articles acknowledge several risks, but eutrophication receives the most attention and is also considered the biggest threat. Authorities, experts, organizations, and politicians are the dominating actors, while citizens and industry representatives are more or less invisible. Eutrophication is not framed in terms of uncertainty concerning the risk and consequences, but rather in terms of main causes.  相似文献   
609.
气相介质阻挡放电氧化降解酸性红88的机理   总被引:1,自引:0,他引:1  
为了有效处理难生物降解的染料废水,采用气相介质阻挡放电产生以羟基自由基为主的氧化性物质,对偶氮染料酸性红88(AR88)进行了氧化降解,并对放电过程中各化学效应对AR88降解的作用机理进行了分析。结果表明,当用相对湿度100%的空气为气源时,放电过程中生成的活性物种如OH·、O,和H2O2是引起放电过程中AR88氧化降解反应的主体,其中OH·在AR88的降解过程中起主要作用,O3参与了对AR88的氧化降解,H2O2对AR88的降解没有明显作用。采用GC/MS分析AR88的主要降解中间产物为萘磺酸、1,2-萘醌、1,2-苯并吡喃酮、萘酚和邻苯二甲酸。通过产物测定和前线电子密度理论,推测了降解途径。  相似文献   
610.
The Norwegian spring spawning (NSS) herring is an ecologically important fish stock in the Norwegian Sea, and with a catch volume exceeding one million tons a year it is also economically important and a valuable food source. In order to provide a baseline of the levels of contaminants in this fish stock, the levels of organohalogen compounds were determined in 800 individual herring sampled at 29 positions in the Norwegian Sea and off the coast of Norway. Due to seasonal migration, the herring were sampled where they were located during the different seasons. Concentrations of dioxins and dioxin-like PCBs, non-dioxin-like PCBs (PCB7) and PBDEs were determined in fillet samples of individual herring, and found to be relatively low, with means (min-max) of 0.77 (0.24-3.5) ng TEQ kg−1 wet weight (ww), 5.0 (1.4-24) μg kg−1 ww and 0.47 (0.091-3.1) μg kg−1 ww, respectively. The concentrations varied throughout the year due to the feeding- and spawning cycle: Starved, pre-spawning herring caught off the Norwegian coast in January-February had the highest levels and those caught in the Norwegian Sea in April-June, after further starvation and spawning, had the lowest levels. These results show that the concentrations of organohalogen compounds in NSS herring are relatively low and closely tied to their physiological condition, and that in the future regular monitoring of NSS herring should be made in the spawning areas off the Norwegian coast in late winter.  相似文献   
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