Water pollution is the contamination of natural water bodies by chemical, physical, radioactive or pathogenic microbial substances. Adverse alteration of water quality presently produces large scale illness and deaths, accounting for approximately 50 million deaths per year worldwide, most of these deaths occurring in Africa and Asia. In China, for example, about 75 percent of the population (or 1.1 billion people) are without access to clean drinking water. Widespread consequences of water pollution upon ecosystems include species mortality, biodiversity reduction and loss of ecosystem services. Some water pollution may occur from natural causes such as sedimentation from severe rainfall events; however, natural causes, including volcanic eruptions and algae blooms from natural causes constitute a minute amount of the instances of worldwide water pollution. The most problematic of water pollutants are microbes that induce disease, since their sources may be construed as natural, but a preponderance of these instances result from human intervention in the environment (such as discharge of raw sewage) or human overpopulation phenomena. One of the chief causes of water pollution is agricultural activity where tillage practices, fertilizer, pesticide and herbicide use create massive amounts of sedimentation and chemical discharge to natural waters. Industrial discharges, by contrast, have been greatly mitigated in Western Countries, but remain a significant issue in developing countries.
[Raul Perianez is the lead author of this article]
Heavy metal distributions in the Gulf of Cadiz are generated chiefly by coastal riverine discharge, and thus...
OrcaLast Updated on 2014-04-16 15:11:43Orcinus orca, or simply orca, is in fact the largest of the dolphins within the order of cetaceans. This species of marine mammal, also commonly known as the killer whale, is easily identified by its black and white coloration; the underside is white with white patches behind the eyes and a greyish white area called a saddle-patch behind the dorsal fin. The shape of the saddle is unique in each animal, and can help to identify individuals. The dorsal fin is also used to recognize individuals. Male orcas have the tallest dorsal fin known in the animal kingdom, measuring up to six feet high in mature males. Females have shorter, more curved dorsal fins.
Kingdom: Anamalia (Animals)
Class:------ Mammalia... More »
Indus River Delta-Arabian Sea mangrovesLast Updated on 2013-10-17 23:48:27
The Indus River Delta-Arabian Sea mangroves ecoregion represents a mangrove habitat that is adapted to some of the most extreme temperatures and salinity conditions in the Indo-Pacific region. As a transition from the marine to freshwater and terrestrial systems, mangroves provide critical habitat for numerous species of fishes and crustaceans that are adapted to live among the tangled mass of pneumatophores, the roots that reach up from the muddy, anaerobic substrate to obrain the supply of oxygen for the mangrove trees.
This ecoregion lies at the delta of the Indus River, which originates in the Tibetan Plateau and flows through the northwestern part of India and into the arid Thar Desert in Pakistan before finally emptying into the Arabian Sea. There are high salinity levels in the sloughs because of the high evaporation rates and the salts that are washed down by the river,... More »
Amur RiverLast Updated on 2013-09-30 16:59:28The Amur River, considered the Earth's tenth largest watercourse, has its headwaters in western Manchuria and mouth at the Strait of Tartary, which connects the Sea of Japan with the Okhotsk Sea. Much of its length defines the border between Russia and China.
Although the generally level topography has made this basin vulnerable to heavy exploitation by agriculture, the region boasts many endemic species of fish, and its wetlands are important to a number of species of rare and endangered birds.
The Amur River became contaminated by a massive toxic release on the Chinese side of the catchment basin in 2005, which effects still linger to the current time. Similarly there are extensive deposits of mercury in Amur River sediments, residual from the central planning poor management practises of the communist Soviet era.
The length of the Amur River is 2825 kilometers, a river... More »
PollutionLast Updated on 2013-09-22 22:58:20Pollution is environmental contamination that results in harm or death to living organisms. Most pollution is in the form of chemical additions to air, water or soil; however, in modern times starting in the mid-twentieth century noise and light have been considered as pollution sources. Most pollution is man-made, with natural fluctuations in atmospheric composition, surface water bodies and soil considered temporal gyrations in the Earth's natural history. The chief driver of pollution is the massive growth in human population, which induces the proximate causes of intensive agriculture and extraordinary industrial output. The United Nations and the Blacksmith Institute are two prominent organisations that tabulate locales of the greatest pollution intensity; while their listings do not correspond precisely, the overlap countries that both entities agree are the worst polluted... More »
Black SeaLast Updated on 2013-09-21 16:00:44The Black Sea is a Mediterranean sea, centered at approximately 35o E and 44o N; it is considered the world’s largest inland water basin, although technically it is connected to the world's oceans via the Bosporus and the Dardanelles.
It has a surface area of about 461,000 km2 and a volume of 537,000 km3 with a mean depth of around 1200 to 1300 metres (m), although depths greater than 2000 m are common in the central basin.
The western part of the Black Sea is a wide shelf that gradually narrows to the south and breaks at around 100-150 m. In the rest of the basin the shelf doesn’t exceed 10 to 15 kilometres in width. It is connected to the Sea of Marmara via the narrow (760 m wide) and shallow (27.5 m maximum depth) Bosporus Straits, and further connects to the Mediterranean Sea via the long and narrow Dardanelles. It is also connected to the Sea of Azov to... More »
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