1,721,112 research outputs found
Ecologia applicata - Per un uso consapevole dell'aria, dell'acqua e del suolo
No full textIn una società che misura il benessere collettivo in base alla crescita del Prodotto Interno Lordo e dei consumi è necessario che si diffonda una maggior consapevolezza dei limiti oggettivi delle risorse naturali e della capacità del pianeta di sostenere la vita. Occorre favorire una riflessione critica sulle numerose pratiche insostenibili che caratterizzano questa nostra epoca e promuovere lo sviluppo di comportamenti individuali più coerenti con la salvaguardia dell'ambiente e delle risorse naturali. Questo manuale affronta i temi dell'Ecologia Applicata in una prospettiva interdisciplinare, dando adeguato risalto anche agli aspetti normativi, socio-economici ed alle applicazioni pratiche, prefiggendosi il duplice obiettivo di contribuire alla formazione di tecnici e ricercatori capaci di analizzare e fornire adeguate soluzioni ai molti problemi ambientali e quello di reindirizzare la società verso forme di sviluppo più sostenibili
Environmental contamination in Antarctic ecosystems
No full textAlthough the remote continent of Antarctica is perceived as the symbol of the last great wilderness, the human presence in the Southern Ocean and the continent began in the early 1900s for hunting, fishing and exploration, and many invasive plant and animal species have been deliberately introduced in several sub-Antarctic islands. Over the last 50 years, the development of research and tourism have locally affected terrestrial and marine coastal ecosystems through fuel combustion (for transportation and energy production), accidental oil spills, waste incineration and sewage. Although natural "barriers" such as oceanic and atmospheric circulation protect Antarctica from lower latitude water and air masses, available data on concentrations of metals, pesticides and other persistent pollutants in air, snow, mosses, lichens and marine organisms show that most persistent contaminants in the Antarctic environment are transported from other continents in the Southern Hemisphere. At present, levels of most contaminants in Antarctic organisms are lower than those in related species from other remote regions, except for the natural accumulation of Cd and Hg in several marine organisms and especially in albatrosses and petrels. The concentrations of organic pollutants in the eggs of an opportunistic top predator such as the south polar skua are close to those that may cause adverse health effects. Population growth and industrial development in several countries of the Southern Hemisphere are changing the global pattern of persistent anthropogenic contaminants and new classes of chemicals have already been detected in the Antarctic environment. Although the Protocol on Environmental Protection to the Antarctic Treaty provides strict guidelines for the protection of the Antarctic environment and establishes obligations for all human activity in the continent and the Southern Ocean, global warming, population growth and industrial development in countries of the Southern Hemisphere will likely increase the impact of anthropogenic contaminants on Antarctic ecosystems. (C) 2008 Elsevier B.V. All rights reserved
Terrestrial ecosystems of the Antarctic Peninsula and their responses to climate change and anthropogenic impacts
Full text linkAntarctica and the Southern Ocean are unique natural laboratories where organisms adapted to extreme environmental conditions have evolved in isolation for millions of years. These unique biotic communities on Earth are facing complex climatic and environmental changes. Terrestrial ecosystems in the Antarctic Peninsula Region (APR) have experienced the highest rate of climate warming and, being the most impacted by human activities, are facing the greatest risk of detrimental changes. This review provides an overview of the most recent findings on how biotic communities in terrestrial ecosystems of the Antarctic Peninsula Region (APR) are responding and will likely respond to further environmental changes and direct anthropogenic impacts. Knowledge gained from studies on relatively simple terrestrial ecosystems could be very useful in predicting what may happen in much more complex ecosystems in regions with less extreme temperature changes. The rapid warming of the APR has led to the retreat of glaciers, the loss of snow and permafrost and the increase of ice-free areas, with a consequent enhancement of soil-forming processes, biotic communities, and food web complexity. However, most human activity is concentrated in APR coastal ice-free areas and poses many threats to terrestrial ecosystems such as environmental pollution or disturbances to soil communities and wildlife. People who work or visit APR may inadvertently introduce alien organisms and/or spread native species to spatially isolated ice-free areas. The number of introduced non-indigenous species and xenobiotic compounds in the APR is likely to be greater than currently documented, and several biosecurity and monitoring activities are therefore suggested to Antarctic national scientific programs and tourism operators to minimize the risk of irreversible loss of integrity by the unique terrestrial ecosystems of APR
ANTARCTIC ECOSYSTEMS. Environmental Contamination, Climate Change, and Human Impact
No full textlibro n°175 della collana "Ecological Studies
Determination of metal deposiition patterns by epiphytic lichens
No full textThe use of epiphytic lichens as quantitative monitors of airborne heavy metals needs a standardization of collection, analytical procedures and of data elaboration. Evidence is given of a patterned metal accumulation in lichens and for the foliose species, the analysis of the outermost edge of the thallus is suggested. Moreover, the raw concentrations of metals must be normalized to the earth’s crustal abundance, as lichens entrap atmospheric particulates which are mostly constituted by soil and rock dust suspended by wind. © 1989, Taylor & Francis Group, LLC. All rights reserved
Trace metals in Antarctica related to climate change and increasing human impact
No full textMetals are natural constituents of the abiotic and biotic components of all ecosystems, and under natural conditions they are cycled within and between the geochemical spheres - the atmosphere, lithosphere, hydrosphere, and biosphere - at quite steady fluxes. In the second half of the twentieth century, the huge increase in energy and mineral consumption determined anthropogenic emissions of several metals exceeding those from natural sources, e.g., volcanoes and windborne soil particles. In the Northern Hemisphere, the biogeochemical cycles of Pb, Cd, Zn, Cu, and other metals were significantly altered, even in Arctic regions. On the contrary, available data on trace metal concentrations in abiotic matrices from continental Antarctica, summarized in this review, suggest that the biogeochemical cycle of Pb is probably the only one that has been significantly altered by anthropogenic emissions in Antarctica and elsewhere in the Southern Hemisphere, especially in the period 1950-1975. Environmental contamination by other metals from anthropogenic sources in Antarctica itself can generally only be detected in snow samples taken within a range of a few kilometers or several hundred meters from scientific stations. Local metal pollution from human activities in Antarctica may compromise studies aimed at assessing the biogeochemical cycle of trace elements and the effects of global climate change. Thus, this review focuses on concentrations of metals in atmospheric particulate, snow, surface soils, and freshwater from the Antarctic continent and surface sediments and seawater from the Southern Ocean, which can plausibly be regarded as global background values of trace elements. These baselines are also necessary in view of the construction of new stations, the expansion of existing facilities to support research, and the growth of tourism and fisheries. Despite difficulties in making comparisons with data from other remote areas of the world, concentrations of trace metals in most samples of atmospheric particulates, snow, ice, soils, and marine sediments from Antarctica can be taken as global background levels. Comparison between the results of trace element surveys in marine waters of the Southern Ocean and in other seas is practically impossible. The upwelling or subduction of water masses, the seasonality in ice cover and in phytoplankton biomass, the low fallout of atmospheric dust, and many other peculiar characteristics of the Southern Ocean make concentrations of trace metals in surface waters quite variable in space and time. The depletion of nutrients in surface waters, which is a regular feature of many marine environments, rarely occurs in the Southern Ocean. Waters in some regions are characterized by very low concentrations of Fe and Mn, whereas in others the content of Cd is relatively high at the beginning of summer and may decrease about one order of magnitude during the phytoplankton bloom. Although in most Antarctic coastal ecosystems the input of metals from geochemical and anthropogenic sources and from long-range transport is negligible, concentrations of Cd in the waters and biota may be higher than in waters and related species of organisms from polluted coastal areas. Like the Southern Ocean, Antarctic lakes have many peculiar characteristics. They are often perennially ice covered and without outlet, and their water, which is gained only from short-term melting of snow and glaciers in summer, is lost mainly by sublimation of surface ice. Several lakes are distinctly stratified: the water under the ice may be cool, rich in oxygen, and among the cleanest and clearest of natural waters, whereas water near the bottom becomes anoxic, tepid, and richer in major and trace elements. Considering the specificity of Antarctic environments, to evaluate the extent and consequences of global changes and increasing human activities in Antarctica itself, research on the biogeochemistry of trace metals and monitoring programs should be implemented. © Springer-Verlag 2000
Trace elements in terrestrial plants. An Ecophysiological Approach to Biomonitoring and Biorecovery
No full textlibr
Trace element composition of vegetation and the possible incidence of soil contamination of samples
No full textSamples of olive leaves, the lichen Parmelia perlata (from the same trees) and the moss Scleropodium purum were collected in relatively uncontaminated areas of Calabria and Tuscany (Italy). Total concentrations of Al, Ba, Cd, Cr, Cu, Fe, Hg, Mn, Ni, Pb and Zn were determined in unwashed samples. Concentrations of lithophilic elements in mosses collected at the same samplings were higher in dry and barren environments, whereas in lichens they where significantly higher at the end of the dry season. These variations were probably due to the quantities of soil particles trapped in the samples. The normalization of raw concentrations to soil composition is advisable before making comparisons, assessing baseline concentrations and calculating patterns of trace element fallout over large areas. © 1996
Changes of major ion concentrations in melting snow and terrestrial waters from northern Victoria Land, Antrctica
No full textConcentrations of major ions (Cl-, NO3-, SO42-, Na+, K+, Mg2+, Ca2+) were measured in melting snow and water samples from streams and lakes in ice-free areas throughout northern Victoria Land. Most ions in snow and terrestrial water derive from the marine environment and their concentrations are extremely variable in space and time, especially in water systems without melting snow and ice. The distance from the sea, snow sublimation, changes in water inflow, evaporative concentrations, weathering and drainage processes in the catchment, nesting seabirds and aquatic microbiota. are among factors which most influence ion composition variability. Comparisons with data from twelve years ago in the same lakes indicate that the warming trend detected at Terra Nova Bay station during this period did not affect the biogeochemistry of water systems. Waters from a lake which recently experienced a lowering of the water level showed a remarkable increase in SO42- concentrations. We hypothesized that the differential mobility of sulphate salts in the Antarctic soils, the biosynthesis of sulphur compounds in the lake, and the progressive decrease of the water volume are factors involved in the increase of SO42- concentrations
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