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Encyclopedia - Britannica Online Encyclopedia (71011) / Spread Betting
Explore the updated online encyclopedia from Encyclopaedia Britannica with hundreds of thousands of articles, biographies, videos and photos along with access to the Britannica Student Encyclopedia, Britannica Concise Encyclopedia, and Merriam-Webster's Dictionary & Thesaurus.
Antiochus
III.) The Romans won a difficult war with King
Nabis of Sparta. Like Philip, Nabis kept his
throne, but he was not allowed to dominate other cities in southern
Greece and so provided a balance of power with Rome's ally, the
Achaean League.
In 194 all Roman troops were withdrawn from Greece, where
Flamininus was given divine honours. In Rome he celebrated an
unprecedented three-day triumph (Livy 34.52), and the Greeks
erected a bronze statue with a Greek inscription for him.
Flamininus's success was built on an ambiguity. For Greeks the
proclamation of freedom meant self-rule, but in Roman law a freed
slave (libertus) became the client of his former master and
still owed his patron respect and political obedience.
In 193 Antiochus was invited into Greece by the Aetolians, still
smarting from the frustration of their ambitions by Flamininus.
When Antiochus refused to withdraw, Flamininus announced that
Rome's next mission was the liberation of the Greek cities of Asia.
The victorious war was fought by Scipio Africanus
and his brother, but Flamininus remained active in diplomacy,
rewarding his friends of the Achaean League and annexing Zacynthus
for Rome. He was elected censor for 189.
In 183 he was sent on a diplomatic mission to negotiate a peace
treaty with Prusias I of Bithynia. (Prusias had remained neutral
during Rome's war with Antiochus only to see control of Phrygia
given to Rome's ally Eumenes II of Pergamum.)
Flamininus not only confirmed the transfer of Phrygia to Pergamum,
but he also demanded the surrender of Hannibal,
who had served Prusias against Rome, because he had served
Antiochus. Hannibal committed suicide rather than surrender to the
Romans. Flamininus worked with the Senate to name
Demetrius, Philip's younger son, as his heir
instead of his older son, Perseus. According to Polybius, Philip
was shown a letter from Flamininus promising Demetrius the throne
(though the Roman historian Livy expresses his belief that the
letter was forged), and Philip reluctantly put Demetrius to death
(181). This diplomatic failure was the last that was heard of
Flamininus until his death in 174.
Flamininus developed the policy of turning the cities, leagues, and
kingdoms of the Hellenistic world into the clients of Rome and of
himself, a policy that became the basis of the Roman hegemony of
the Mediterranean. The Greeks were freed, but, like Roman freedmen,
they were expected to follow Rome's explicit instructions and even
implicit hints. Flamininus initially won almost unbounded devotion
by his charm, intelligence, and knowledgeable admiration for Greek
culture, but in the end he aroused hostility by his unscrupulous
interference in Greek politics. By both his strengths and faults,
he laid the foundation for the Roman domination of the Greek world.
E. Badian
Roman general and statesman To cite this page: (Greek: Dogs' Heads ), ancient range of hills in Thessaly, Greece, 7 miles (11 km) west of modern V los. It was the site of the victory (197 BC) that ended the Second Macedonian War when the Romans under Titus Quinctius Flamininus defeated Philip V of Macedon. The combat engaged about 26, 000 men on each side. The outcome hung in the balance, each side prevailing on its ... Nabis last ruler (207 192) of an independent Sparta. Nabis carried on the revolutionary tradition of Kings Agis IV and Cleomenes III. Since ancient accounts of him are mainly abusive, the details of his laws remain obscure, but it is certain that he confiscated a great deal of property and enfranchised many helots (Spartan serfs). He undoubtedly was not the monster depicted by ... Philip V king of Macedonia from 221 to 179, whose attempt to extend Macedonian influence throughout Greece resulted in his defeat by Rome. His career is significant mainly as an episode in Rome's expansion. The son of Demetrius II and his wife Phthia (Chryseis), the young prince was adopted, after his father's death in 229, by his half-cousin Antigonus Doson, who took the throne. ... Roman expansion in the eastern Mediterranean from the ancient Rome article Just before the Second Punic War, Rome had projected its power across the Adriatic Sea against the Illyrians. As noted, Philip V of Macedon in turn had joined the Carthaginians for a time during the war in an attempt to stem the tide of Roman expansion but had agreed to terms of peace with Rome's allies, the Aetolians, in 206 and then with Rome in the Peace of Phoenice of ... Britannica online encyclopedia article on Max Muller: German scholar of comparative language, religion, and mythology. M uuml;ller's special areas of interest were Sanskrit philology and the religions of India. born Dec. 6, 1823, Dessau, duchy of Anhalt [Germany] died Oct. 28, 1900, Oxford, Eng. Photograph:Max M ller Max M ller Courtesy of the Curator of the Senior Common Room, Christ Church, Oxford in full Friedrich Max M ller German scholar of comparative language, religion, and mythology. M ller's special areas of interest were Sanskrit philology and the religions of India. Special Offer! Activate a FREE trial to Britannica Online, your complete (re)search engine for when you need to be right. Life and chief works The son of Wilhelm M ller, a noted poet, Max M ller was educated in Sanskrit, the classical language of India, and other languages in Leipzig, Berlin, and Paris. He moved to England in 1846 and settled in Oxford in 1848, where he became deputy professor of modern languages in 1850. He was appointed professor of comparative philology in 1868 and retired in 1875. M ller was instrumental in editing and translating into English some of the most significant religious texts of Asia. Especially noteworthy are his edition of the great collection of Sanskrit hymns the Rigveda, Rig-Veda-samhit : The Sacred Hymns of the Br hmans (6 vol., 1849 74); his work as editor of the 51-volume series of translations The Sacred Books of the East; and his initial editorial efforts for the series Sacred Books of the Buddhists. In addition, M ller was an important early proponent of a study that he called the science of religion ; indeed, some credit him with founding that study. His most important writings on the subject include Essays on the Science of Religion (1869), vol. 1 of Chips from a German Workshop; Introduction to the Science of Religion (1873); and Lectures on the Origin and Growth of Religion (1878). German scholar Muller, Hermann Joseph American geneticist best remembered for his demonstration that mutations and hereditary changes can be caused by X rays striking the genes and chromosomes of living cells. His discovery of artificially induced mutations in genes had far-reaching consequences, and he was awarded the Nobel Prize for Physiology or Medicine in 1946. Henotheism, or kathenotheism from the monotheism article Henotheism (from Greek heis theos, one god ) a belief in worship of one god, though the existence of other gods is granted also called kathenotheism (Greek kath hena theon, one god at a time ) which literally implies worship of various gods one at a time has gone out of fashion as a term. It was introduced by the eminent 19th-century philologist and scholar in ... Darmesteter, James French scholar noted for ancient Iranian language studies, especially his English and French translations of the Avesta, the sacred scripture of Zoroastrianism. More results 1 Student Encyclopedia Britannica articles, specially written for elementary and high school students Planck, Max (1858 1947). Awarded the Nobel prize for physics in 1918, German physicist Max Planck is best remembered as the originator of the quantum theory (see Quantum Mechanics). His work helped usher in a new era in theoretical physics and revolutionized the scientific community's understanding of atomic and subatomic processes. Britannica online encyclopedia article on speed skiing: competitive skiing event in which racers equipped with special short skis, skintight suits, and aerodynamic helmets compete to achieve the fastest speed on a steep, straight, and meticulously prepared track. A dangerous pastime, it is frequently billed as the fastest nonmotorized sport on earth. Special Offer! Activate a FREE trial to Britannica Online Pollution is a special case of habitat destruction; it is chemical destruction rather than the more obvious physical destruction. Pollution occurs in all habitats land, sea, and fresh water and in the atmosphere. Global warming, which is discussed separately below (see Global change), is one consequence of the increasing pollution of the atmosphere by emissions of carbon dioxide and other gases. Special Offer! Activate a FREE trial to Britannica Online, your complete (re)search engine for when you need to be right. Pollution is a global-scale problem, no less so for rivers and marine life. Wastes are often dumped into rivers, and they end up in estuaries and coastal habitats, regions that support the most diverse shallow-water ecosystems and the most productive fisheries. Rivers receive pollution directly from factories that dump a wide variety of wastes into them. They also receive runoff, which is rainwater that has passed over and through the soil while moving toward the rivers. In fact, water entering rivers after it has been used for irrigation has passed through the soil more than once first as runoff, which is then returned to the land for irrigation, whereupon it soaks through the soil again. Some polluted river water eventually reaches freshwater wetlands. In the case of the Florida Everglades, runoff from the agricultural areas upstream adds unwanted nutrients to an ecosystem that is naturally nutrient-poor. As it does so, the vegetation changes, and species not common in the Everglades begin to take over the natural habitats. Other polluted waters reach estuaries on the way to the oceans; estuaries are among the most polluted ecosystems on Earth. On entering the oceans, the polluted waters can harm the ecosystems there. The Mississippi River, for example, drains a basin of more than 3 million square km (1.2 million square miles), delivering its water, sediments, and nutrients and other pollutants into the northern Gulf of Mexico. Fresh water is less dense than salt water and floats on top. This upper layer contains the nitrogen and phosphorus fertilizers that have run off croplands, and they fertilize the ocean's phytoplankton, causing excessive population growth. As the masses of phytoplankton die, sink, and decompose, they deplete the water's oxygen. Bottom dwellers such as shrimp, crabs, starfish, and marine worms suffocate and die, creating a dead zone. Such conditions also occur in Europe's Baltic, Adriatic, and Black seas. The Baltic has gone from being naturally nutrient-poor and diverse in species to being nutrient-rich and degraded in its ecosystems within a few decades. In the Adriatic Sea, rising nutrient levels have generated a large increase in phytoplankton. Nutrients in the runoff flowing into the Black Sea seem to be contributing factors in the invasion and subsequent massive increase since the 1980s of the comb jelly Mnemiopsis leidyi. This has caused the decline of native species and fisheries. Similar nutrient enrichment has led to increasing frequencies of toxic blooms of microscopic organisms such as Pfiesteria piscicida in the eastern United States, a dinoflagellate that kills fish and has been reported to cause skin rashes and other maladies in humans. Rising levels of pollution may have also contributed to a wave of outbreaks of diseases affecting marine life. Caribbean coral reefs have been particularly affected, with successive waves of disease propagating throughout the region in recent decades. The result has been large declines in two species of major reef-building corals, Acropora cervicornis and A. palmata, and the herbivorous sea urchin Diadema antillarum. Their combined loss has transformed Caribbean reefs from high-coral, low-algae ecosystems to high-algae, low-coral ones. The latter type of ecosystems support far fewer species. 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Pollution"... 74 Encyclop dia Britannica articles, from the
full 32 volume encyclopedia Wildlife
Conservation from the The Environment
article In January 2001 Mexico's former environment
secretary Julia Carabias Lillo received the J. Paul Getty Wildlife
Conservation Prize from the World Wildlife Fund (WWF). Carabias
Lillo (seeBiographies) was credited with doubling the
protected-habitat system in Mexico. Thirty years of conservation
effort were rewarded in March when the birth of a male golden
tamarin ...
Despite numerous conservation efforts in 1997, evidence pointed to
a continued decline in almost all species worldwide. The 1996 Red
List of Threatened Animals issued by the International Union for
Conservation of Nature and Natural Resources identified 5, 205
species in danger of extinction. In tropical forests alone, for
example, biologists estimated that three species ...
Conservation problems from the Europe
article Pressure on space, hunting, either for sport or to
protect crops, the pollution of sea waters and fresh waters, and
the contamination of cropland have so reduced many animal species
that strong efforts are now being made to preserve those threatened
with extinction, in such refuges where they still, precariously,
live.
from the water article Unlike many of the world's
natural resources, water is a replenishable resource (see
Rainfall). However, it is vitally important that humans conserve
water and help to maintain the quality of water by discontinuing
practices that contaminate and pollute the supply faster than it
can replenish itself. (See also Conservation.) Water
Pollution from the pollution, environmental
article
Since the beginning of civilization, water has been used to carry
away unwanted refuse. Rivers, streams, canals, lakes, and oceans
are currently used as receptacles for every imaginable kind of
pollution. Water has the capacity to break down or dissolve many
materials, especially organic compounds, which decompose during
prolonged contact with bacteria and enzymes. Waste ...
Conservation and Restoration from the
museum and gallery article The preservation of a cultural
heritage is the most ancient of a museum's functions. Conservation
is the job of protecting the collection as a whole against damage
or alteration by such environmental causes as pollution, light, or
humidity; chemical and biological processes; and human
carelessness. Restoration is concerned with repairing specific
objects or returning them ...
Britannica online encyclopedia article on conservation,
Introduced species: The case histories previously discussed often
implicate introduced species as a cause of species extinctions.
Humans have spread species deliberately as they colonized new
areas, just one example being the Polynesians as they settled the
eastern Pacific Islands. New Yorkers in the 1890s wanted all the
birds in Shakespeare's works to inhabit the city's Central Park,
and they introduced the starling (Sturnus vulgaris) to North
America as a consequence. Through the centuries hunters have
demanded exotic birds and mammals to shoot, fishermen have wanted
challenging fish, and gardeners have wanted beautiful flowers.
Nonetheless, the consequences in some cases have been devastating.
Cacti and the shrub Lantana camara, for example, which were
introduced as ornamental plants, have destroyed huge areas of
grazing land worldwide.
AIDS Guam crow kingfisher flycatcher rail fantail white-eye
dove honeyeater swiftlet Islands domestic cat chestnut chestnut
blight stifftail article 176 Shopping
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conservation Introduced species
Encyclop dia Britannica Article
Page 26 of 61 Print Page Print Article E-mail Article Cite
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The pathology of extinction Factors that cause extinction
Introduced species
Photograph:Common starling (Sturnus vulgaris).
Common starling (Sturnus vulgaris).
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Cygni first star whose distance from Earth (about 11
light-years) was measured (by Friedrich Wilhelm Bessel in 1838).
The star is a visual binary the ... 9to5, National
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Britannica online encyclopedia article on human genome: all of
the approximately three billion base pairs of deoxyribonucleic acid
(DNA) that make up the entire set of chromosomes of the human
organism. The human genome includes the coding regions of DNA,
which encode all the genes (about 25, 000) of the human organism,
as well as the noncoding regions of DNA, which do not encode any
genes. By 2003 the DNA sequence of the entire human genome was
known.
Social impacts of human genome research Print this Table of
Contents Linked Articles polymerase chain reaction article
176 Shopping New! Britannica Book of the
Year The Ultimate Review of 2007. 2007 Britannica
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still unrivaled.
Special Offer! Activate a FREE trial to
Britannica Online, your complete (re)search engine
for when you need to be right. The human genome, like the genomes
of all other living animals, is a collection of long polymers of
DNA. These polymers are maintained in duplicate copy in the form of
chromosomes in every human cell and encode in their sequence of
constituent bases (guanine [G],
adenine [A], thymine [T], and
cytosine [C]) the details of the molecular and
physical characteristics that form the corresponding organism. The
sequence of these polymers, their organization and structure, and
the chemical modifications they contain not only provide the
machinery needed to express the information held within the genome
but also provide the genome with the capability to replicate,
repair, package, and otherwise maintain itself. In addition, the
genome is essential for the survival of the human organism; without
it no cell or tissue could live beyond a short period of time. For
example, red blood cells (erythrocytes), which
live for only about 120 days, and skin cells,
which on average live for only about 17 days, must be renewed to
maintain the viability of the human body, and it is within the
genome that the fundamental information for the renewal of these
cells, and many other types of cells, is found.
The human genome is not uniform. Excepting identical (monozygous)
twins, no two humans on Earth share exactly the
same genomic sequence. Further, the human genome is not static.
Subtle and sometimes not so subtle changes arise with startling
frequency. Some of these changes are neutral or even advantageous;
these are passed from parent to child and eventually become
commonplace in the population. Other changes may be detrimental,
resulting in reduced survival or decreased fertility of those
individuals who harbour them; these changes tend to be rare in the
population. The genome of modern humans, therefore, is a record of
the trials and successes of the generations that have come before.
Reflected in the variation of the modern genome is the range of
diversity that underlies what are typical traits of the human
species. There is also evidence in the human genome of the
continuing burden of detrimental variations that sometimes lead to
disease.
Knowledge of the human genome provides an understanding of the
origin of the human species, the relationships between
subpopulations of humans, and the health tendencies or disease
risks of individual humans. Indeed, in the past 20 years knowledge
of the sequence and structure of the human genome has
revolutionized many fields of study, including
medicine, anthropology, and
forensics. With technological advances that enable
inexpensive and expanded access to genomic information, the amount
of and the potential applications for the information that is
extracted from the human genome is extraordinary.
Role of the human genome in research
Video:Specific segments of DNA are amplified
(copied) in a laboratory using polymerase chain reaction
Specific segments of DNA are amplified (copied) in a laboratory
using polymerase chain reaction Encyclop dia
Britannica, Inc. Since the 1980s there has been an explosion in
genetic and genomic research. The combination of the discovery of
the polymerase chain reaction, improvements in DNA
sequencing technologies, advances in bioinformatics (mathematical
biological analysis), and increased availability of faster, cheaper
computing power has given scientists the ability to discern and
interpret vast amounts of genetic information from tiny samples of
biological material. Further, methodologies such as fluorescence in
situ hybridization (FISH) and comparative genomic hybridization
(CGH) have enabled the detection of the organization and copy
number of specific sequences in a given genome.
Understanding the origin of the human genome is of particular
interest to many researchers since the genome is indicative of the
evolution of humans. The public availability of full or almost full
genomic sequence databases for humans and a multitude of other
species has allowed researchers to compare and contrast genomic
information between individuals, populations, and species. From the
similarities and differences observed, it is possible to track the
origins of the human genome and to see evidence of how the human
species has expanded and migrated to occupy the planet.
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Encyclop dia Britannica articles, from the full 32 volume
encyclopedia human genome all of the
approximately three billion base pairs of deoxyribonucleic acid
(DNA) that make up the entire set of chromosomes of the human
organism. The human genome includes the coding regions of DNA,
which encode all the genes (about 25, 000) of the human organism,
as well as the noncoding regions of DNA, which do not encode any
genes. By 2003 the DNA sequence of the ...
Human Genome Project an international
collaboration that successfully determined, stored, and rendered
publicly available the sequences of almost all the genetic content
of the chromosomes of the human organism, otherwise known as the
human genome. Human Genome Project:Road Map for
Science and Medicine Certain to rank among the all-time
landmarks of human technical achievement, the completion of a rough
draft of the sequence of the human nuclear genome was announced in
June 2000. Its significance and ramifications for science and
society are both broad and profound, and, as with any empowering
technical advance, the challenge that now faces humanity, both as
individuals ...
Origins of the human genome from the
human genome article Comparisons of specific DNA sequences
between humans and their closest living relative, the chimpanzee,
reveal 99 percent identity, although the homology drops to 96
percent if insertions and deletions in the organization of those
sequences are taken into account. This degree of sequence variation
between humans and chimpanzees is only about 10-fold greater than
that seen ...
football (soccer) -- Britannica Online Encyclopedia
Britannica online encyclopedia article on football (soccer):
game in which two teams of 11 players, using any part of their
bodies except their hands and arms, try to maneuver the ball into
the opposing team's goal. Only the goalkeeper is permitted to
handle the ball and may do so only within the penalty area
surrounding the goal. The team that scores more goals wins.
Collapse all Introduction History The
early years Professionalism International organization
Football around the world Regional traditions Europe North
and Central America and the Caribbean South America Africa Asia and
Oceania Spectator problems
Play of the game Equipment and field of play Fouls Rules
Strategy and tactics Additional Reading Print this Table of
Contents article 176
monebaggasse
Roman general and statesman To cite this page: (Greek: Dogs' Heads ), ancient range of hills in Thessaly, Greece, 7 miles (11 km) west of modern V los. It was the site of the victory (197 BC) that ended the Second Macedonian War when the Romans under Titus Quinctius Flamininus defeated Philip V of Macedon. The combat engaged about 26, 000 men on each side. The outcome hung in the balance, each side prevailing on its ... Nabis last ruler (207 192) of an independent Sparta. Nabis carried on the revolutionary tradition of Kings Agis IV and Cleomenes III. Since ancient accounts of him are mainly abusive, the details of his laws remain obscure, but it is certain that he confiscated a great deal of property and enfranchised many helots (Spartan serfs). He undoubtedly was not the monster depicted by ... Philip V king of Macedonia from 221 to 179, whose attempt to extend Macedonian influence throughout Greece resulted in his defeat by Rome. His career is significant mainly as an episode in Rome's expansion. The son of Demetrius II and his wife Phthia (Chryseis), the young prince was adopted, after his father's death in 229, by his half-cousin Antigonus Doson, who took the throne. ... Roman expansion in the eastern Mediterranean from the ancient Rome article Just before the Second Punic War, Rome had projected its power across the Adriatic Sea against the Illyrians. As noted, Philip V of Macedon in turn had joined the Carthaginians for a time during the war in an attempt to stem the tide of Roman expansion but had agreed to terms of peace with Rome's allies, the Aetolians, in 206 and then with Rome in the Peace of Phoenice of ... Britannica online encyclopedia article on Max Muller: German scholar of comparative language, religion, and mythology. M uuml;ller's special areas of interest were Sanskrit philology and the religions of India. born Dec. 6, 1823, Dessau, duchy of Anhalt [Germany] died Oct. 28, 1900, Oxford, Eng. Photograph:Max M ller Max M ller Courtesy of the Curator of the Senior Common Room, Christ Church, Oxford in full Friedrich Max M ller German scholar of comparative language, religion, and mythology. M ller's special areas of interest were Sanskrit philology and the religions of India. Special Offer! Activate a FREE trial to Britannica Online, your complete (re)search engine for when you need to be right. Life and chief works The son of Wilhelm M ller, a noted poet, Max M ller was educated in Sanskrit, the classical language of India, and other languages in Leipzig, Berlin, and Paris. He moved to England in 1846 and settled in Oxford in 1848, where he became deputy professor of modern languages in 1850. He was appointed professor of comparative philology in 1868 and retired in 1875. M ller was instrumental in editing and translating into English some of the most significant religious texts of Asia. Especially noteworthy are his edition of the great collection of Sanskrit hymns the Rigveda, Rig-Veda-samhit : The Sacred Hymns of the Br hmans (6 vol., 1849 74); his work as editor of the 51-volume series of translations The Sacred Books of the East; and his initial editorial efforts for the series Sacred Books of the Buddhists. In addition, M ller was an important early proponent of a study that he called the science of religion ; indeed, some credit him with founding that study. His most important writings on the subject include Essays on the Science of Religion (1869), vol. 1 of Chips from a German Workshop; Introduction to the Science of Religion (1873); and Lectures on the Origin and Growth of Religion (1878). German scholar Muller, Hermann Joseph American geneticist best remembered for his demonstration that mutations and hereditary changes can be caused by X rays striking the genes and chromosomes of living cells. His discovery of artificially induced mutations in genes had far-reaching consequences, and he was awarded the Nobel Prize for Physiology or Medicine in 1946. Henotheism, or kathenotheism from the monotheism article Henotheism (from Greek heis theos, one god ) a belief in worship of one god, though the existence of other gods is granted also called kathenotheism (Greek kath hena theon, one god at a time ) which literally implies worship of various gods one at a time has gone out of fashion as a term. It was introduced by the eminent 19th-century philologist and scholar in ... Darmesteter, James French scholar noted for ancient Iranian language studies, especially his English and French translations of the Avesta, the sacred scripture of Zoroastrianism. More results 1 Student Encyclopedia Britannica articles, specially written for elementary and high school students Planck, Max (1858 1947). Awarded the Nobel prize for physics in 1918, German physicist Max Planck is best remembered as the originator of the quantum theory (see Quantum Mechanics). His work helped usher in a new era in theoretical physics and revolutionized the scientific community's understanding of atomic and subatomic processes. Britannica online encyclopedia article on speed skiing: competitive skiing event in which racers equipped with special short skis, skintight suits, and aerodynamic helmets compete to achieve the fastest speed on a steep, straight, and meticulously prepared track. A dangerous pastime, it is frequently billed as the fastest nonmotorized sport on earth. Special Offer! Activate a FREE trial to Britannica Online Pollution is a special case of habitat destruction; it is chemical destruction rather than the more obvious physical destruction. Pollution occurs in all habitats land, sea, and fresh water and in the atmosphere. Global warming, which is discussed separately below (see Global change), is one consequence of the increasing pollution of the atmosphere by emissions of carbon dioxide and other gases. Special Offer! Activate a FREE trial to Britannica Online, your complete (re)search engine for when you need to be right. Pollution is a global-scale problem, no less so for rivers and marine life. Wastes are often dumped into rivers, and they end up in estuaries and coastal habitats, regions that support the most diverse shallow-water ecosystems and the most productive fisheries. Rivers receive pollution directly from factories that dump a wide variety of wastes into them. They also receive runoff, which is rainwater that has passed over and through the soil while moving toward the rivers. In fact, water entering rivers after it has been used for irrigation has passed through the soil more than once first as runoff, which is then returned to the land for irrigation, whereupon it soaks through the soil again. Some polluted river water eventually reaches freshwater wetlands. In the case of the Florida Everglades, runoff from the agricultural areas upstream adds unwanted nutrients to an ecosystem that is naturally nutrient-poor. As it does so, the vegetation changes, and species not common in the Everglades begin to take over the natural habitats. Other polluted waters reach estuaries on the way to the oceans; estuaries are among the most polluted ecosystems on Earth. On entering the oceans, the polluted waters can harm the ecosystems there. The Mississippi River, for example, drains a basin of more than 3 million square km (1.2 million square miles), delivering its water, sediments, and nutrients and other pollutants into the northern Gulf of Mexico. Fresh water is less dense than salt water and floats on top. This upper layer contains the nitrogen and phosphorus fertilizers that have run off croplands, and they fertilize the ocean's phytoplankton, causing excessive population growth. As the masses of phytoplankton die, sink, and decompose, they deplete the water's oxygen. Bottom dwellers such as shrimp, crabs, starfish, and marine worms suffocate and die, creating a dead zone. Such conditions also occur in Europe's Baltic, Adriatic, and Black seas. The Baltic has gone from being naturally nutrient-poor and diverse in species to being nutrient-rich and degraded in its ecosystems within a few decades. In the Adriatic Sea, rising nutrient levels have generated a large increase in phytoplankton. Nutrients in the runoff flowing into the Black Sea seem to be contributing factors in the invasion and subsequent massive increase since the 1980s of the comb jelly Mnemiopsis leidyi. This has caused the decline of native species and fisheries. Similar nutrient enrichment has led to increasing frequencies of toxic blooms of microscopic organisms such as Pfiesteria piscicida in the eastern United States, a dinoflagellate that kills fish and has been reported to cause skin rashes and other maladies in humans. Rising levels of pollution may have also contributed to a wave of outbreaks of diseases affecting marine life. Caribbean coral reefs have been particularly affected, with successive waves of disease propagating throughout the region in recent decades. The result has been large declines in two species of major reef-building corals, Acropora cervicornis and A. palmata, and the herbivorous sea urchin Diadema antillarum. Their combined loss has transformed Caribbean reefs from high-coral, low-algae ecosystems to high-algae, low-coral ones. The latter type of ecosystems support far fewer species. Copy and paste this code into your page
Flat areas of colour are bound by firm brush contours that contrast vibrantly with the rich texture of the hieroglyphic writing., Britannica Online Encyclopedia
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