نتایج جستجو برای: anthropogenic causes
تعداد نتایج: 275384 فیلتر نتایج به سال:
Environmental pollution nowadays is a big concern. Anthropogenic activities have altered the environment significantly throughout the world like mining, industry and agriculture. This causes an increase in the Lead(Pb), Cadmium(Cd), Arsenic(As) content of soil and water, thus contaminating them. The increased uptake of these metals by plants influences the natural contents of vegetables and thu...
Ecosystems in the Caspian Sea region have been heavily modified by anthropogenic activities, mainly as a result of changes in the water flow and degradation of the water quality in the ecosystems. Changes in the regional environment have influenced regional economies, particularly obvious in the impacts on fish stocks. Using the methodology developed in the GIWA project, experts in the region c...
Reports of declining amphibian populations in many parts of the world are numerous, but supporting long-term census data are generally unavailable. Census data from 1979 to 1990 for three salamander species and one frog species at a breeding pond in South Carolina showed fluctuations of substantial magnitude in both the size of breeding populations and in recruitment of juveniles. Breeding popu...
There is increasing evidence that air pollution contributes to the burden of chronic disease and premature mortality, particularly from cardiovascular and respiratory causes. Action now urgently required to mitigate climate change has the potential co-benefit of improving air quality and reducing the chronic disease burden. Fossil fuel combustion, primarily from motor vehicles and energy genera...
The International Geosphere Biosphere Program sponsored by the International Council of Scientific Unions is directing attention to geophysical and biological change as influenced by human modifications in global energy and mass exchanges. Geographers in the Soviet Union and the United States have joined in critical appraisal of their experience in studying environmental change. This initial re...
Ecological data from land surveys from 1811 for the 100,000-acre Connecticut Tract in western New York were transcribed and then analyzed using ArcGIS and IDRISI GIS software. The surveys contained both witness tree data and line descriptions, which were analyzed for species composition and community type. Results illustrate that many changes have occurred in species composition. Possible cause...
Human health concerns and the dissemination of anthropogenic substances with unknown consequences are the reasons most often given why disposal of municipal sewage sludge in landfills or using the organic waste as biofuel is preferable to land application. But no "fertilizer" causes more nitrogen pollution than sludge when applied according to Virginia law. Poultry litter is the only other "fer...
The underlying causes of late-Holocene climate variability in the tropics are incompletely understood. Here we report a 1,500-year reconstruction of climate history and glaciation in the Venezuelan Andes using lake sediments. Four glacial advances occurred between anno Domini (A.D.) 1250 and 1810, coincident with solar-activity minima. Temperature declines of -3.2 +/- 1.4 degrees C and precipit...
Biological invasions are a major global environmental and economic problem. Analysis of the San Francisco Bay and Delta ecosystem revealed a large number of exotic species that dominate many habitats in terms of number of species, number of individuals and biomass, and a high and accelerating rate of invasion. These factors suggest that this may be the most invaded estuary in the world. Possibl...
Corals live in a symbiotic life with single-celled algae, zooxanthelle. Anthropogenic threats and natural threat-mediated stress destabilize the photosynthetic electron transport chain resulting in an increased production of reactive oxygen species (ROS) in symbiont algae and causes coral bleaching. In this review, the early warn‐ ing system and biomarkers for oxidative damages in corals are ex...
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