Uses of Beryllium As a result of beryllium’s unusual physical properties, such as its high melting point, high electrical conduc-tivity, high heat capacity, and oxidation resistance, be-
Trang 1percent for a total of about $10.7 million This
indus-try began in Belgium in 1807 when the British started
a blockade of cane sugar from the Caribbean during
the Napoleonic Wars With cane sugar unavailable,
beet sugar began to be the sugar of choice throughout
Napoleonic Europe The sugar production capital of
Belgium is Tienen, which hosts a large sugar-beet
pro-cessing factory that was founded in 1836 This factory
and related sugar production facilities owned by the
Raffinerie Tirlemontoise Group employ nearly two
thousand people This company owns three other
Belgian sugar factories, in Brugelette, Genappe, and
Wanze
Beer
Monks in Belgium began brewing beer sometime
dur-ing the Middle Ages There are more than one
hun-dred breweries scattered throughout Belgium, with
about eight hundred standard types of beer produced
These range from light through dark types of beer;
Belgians brew and export nearly every type of beer
possible Often, each type of beer is served in its own
distinctive glass, which is said to enhance the flavor
of that particular type of beer Though Belgium is
famous for many kinds of beer, it is possibly most
fa-mous for lambic beer, which is made in an ancient
brewing style This style depends on a spontaneous
natural fermentation process after ingredients are
ex-posed to the wild yeasts and bacteria native to the
Senne Valley, located south of Brussels This unusual
fermentation process produces a drink that is
natu-rally effervescent or sparkling, which is then aged, up
to two or three years, to improve its taste Much like
champagne (only produced in a certain region in
France) or Madeira (only produced on a certain
is-land owned by Portugal), the title of “lambic beer”
can only be given to this type of beer brewed in the
small Pajottenland region of Belgium Nearly half of
the beer brewed in Belgium is exported, mostly to
Canada, France, Germany, Italy, Spain, the United
States, and the United Kingdom
Chocolate
During the seventeenth century, when the Low
Coun-tries were ruled by Spain, Spanish conquistadores
brought cacao beans back from the New World to the
region that is now Belgium By 1840, the Berwaerts
Company had begun to sell Belgian chocolates that
were quite popular However, not until the nineteenth
century, when King Leopold II colonized the Belgian
Congo in 1885 and discovered cacao tree fields there, did Belgian chocolatiers begin to manufacture Bel-gian chocolates on a large scale At the beginning of the 1900’s, there were at least fifty chocolate makers in Belgium In 1912, Jean Neuhaus created a process for making a chocolate shell that could be filled with any number of fillings, something he called a “praline,” making Belgian chocolates even more popular Bel-gium produces more than 156,000 metric tons of chocolate each year, has more than two thousand chocolate shops throughout the country, and hosts about three hundred different chocolate companies Many of the original chocolate-making companies— such as Godiva, Leonidas, Neuhaus, and Nirvana— are still in operation today, and many of them still make chocolates by hand, using original equipment, high-quality ingredients, and Old World manufactur-ing techniques Chocolate shops in Belgium offer tast-ings, much like wineries, and host chocolate festivals, workshops, tours, and demonstrations There is a mu-seum dedicated to chocolate, the Musée du Cacao et
du Chocolat, near the Grand Place, the town square
in Brussels Belgium’s European Union neighbors (particularly France, Germany, and the United King-dom) are the biggest importers of Belgian chocolate
Pharmaceuticals Belgium has become a world leader in the pharma-ceutical industry, employing nearly thirty thousand people and accounting for about 10 percent of all Bel-gian exports Major pharmaceutical companies head-quartered in Belgium include UCB, Solvay, Janssen Pharmaceutica, Omega Pharma, Oystershell NV, and Recherche et Industries Thérapeutiques Private in-vestment in research and development in the phar-maceutical industry is at about 40 percent, which is nearly twice the average of other European compa-nies The pharmaceutical industry is also heavily sup-ported by the Belgian government, which offers tax incentives for pharmaceutical research and develop-ment The United States has imported about $2.3 bil-lion annually in medicinal, dental, and pharmaceuti-cal products from Belgium, which accounts for about
16 percent of all exports from Belgium to the United States
Textiles Since the thirteenth century, Belgium has been known as the home of master textile producers The famous Unicorn Tapestries or “The Hunt of the
Trang 2corn” series on display at The Cloisters, a part of the
Metropolitan Museum of Art in New York, is thought
to have been woven in Brussels sometime around
1495-1505 (when that area was still part of the
Nether-lands) The Flanders, or Flemish, region of Belgium is
still home to many lace-making artists, particularly in
the area of Bruges, which is the home of bobbin lace;
however, lace is also still produced in Brussels and
Mechelen This industry can be traced back to the
fif-teenth century, when Charles V decreed that lace
making was to be taught in the schools and convents
of the Belgian provinces to provide girls with a source
of income, as lace was popular on collars and cuffs for
clothing of both sexes at that time Lace is still
pro-duced in Belgium by lace artisans in their homes, one
piece at a time, and, thus, is a source of artistic lace
rather than high-production lace There is even a
mu-seum dedicated solely to lace, the Musée du Costume
et de la Dentelle, located near the Grand Place Other
textile production, including cotton, linen, wool, and
synthetic fibers, is concentrated in Ghent, Kortrijk,
Tournai, and Verviers, where carpets and blankets are
manufactured
Other Resources
As mentioned above, Belgium has few natural
re-sources, and its economy depends on importing raw
materials, processing those materials, manufacturing,
and exporting a finished product However, in
addi-tion to sugar processing, there are a few agricultural
resources grown and exported by Belgian farmers
These include fruits, vegetables, grains (wheat, oats,
rye, barley, and flax), tobacco, beef, veal, pork, and
milk
Other industries in which Belgian workers are
in-volved in processing imported goods that are then
ex-ported are motor vehicles and other metal products,
scientific instruments, chemicals (fertilizers, dyes,
plas-tics), glass, petroleum, textiles, electronics, and
pro-cessed foods and beverages, such as the beer and
chocolate described above
Marianne M Madsen
Further Reading
Binneweg, Herbert Antwerp, the Diamond Capital of the
World Antwerp: Federation of Belgian Diamond
Bourses, 1993
Blom, J H C., and Emiel Lamberts History of the Low
Countries New York: Berghahn Books, 2006.
Hieronymus, Stan Brew Like a Monk: Trappist, Abbey,
and Strong Belgian Ales and How to Brew Them
Boul-der, Colo.: Brewers, 2005
Kockelbergh, Iris, Eddy Vleeschdrager, and Jan
Wal-grave The Brilliant Story of Antwerp Diamonds
Ant-werp: MIM, 1992
Mommen, Andre The Belgian Economy in the Twentieth Century New York: Routledge, 1994.
Parker, Philip M The 2007 Import and Export Market for Unagglomerated Bituminous Coal in Belgium San
Diego, Calif.: ICON Group International, 2006
Sparrow, Jeff Wild Brews: Culture and Craftsmanship in the Belgian Tradition Boulder, Colo.: Brewers, 2005 Wingfield, George Belgium Edgemont, Pa.: Chelsea
House, 2008
Witte, Els, Jan Craeybeckx, and Alain Maynen Politi-cal History of Belgium: From 1830 Onwards Brussels:
Free University of Brussels Press, 2008
Web Sites Belgium: A Federal State http://www.diplomatie.be/en/belgium U.S Department of State
Background Note: Belgium http://www.state.gov/r/pa/ei/bgn/2874.htm See also: Coal; Diamond; Sugars; Textiles and fab-rics
Beryllium
Category: Mineral and other nonliving resources
Where Found The element beryllium is believed to occur in the Earth’s igneous rocks to the extent of 0.0006 per-cent It does not occur in its free state in nature; it is found only in minerals The leading producers are the United States, China, and some African countries
Primary Uses Beryllium has a number of important industrial and structural applications Its widest use is in the prep-aration of alloys used in the manufacture of watch springs, welding electrodes, hypodermic needles, den-tures, and molds for casting plastics Metallic beryl-lium is used to make windows in X-ray tubes because
of its high degree of transparency Finally, beryllium
Trang 3compounds have various uses in glass manufacture, in
aircraft spark plugs, and as ultra-high-frequency radar
insulators
Technical Definition
Beryllium (abbreviated Be), atomic number 4,
be-longs to Group II of the periodic table of the elements
and is one of the rarest and lightest structural metals
It has four naturally occurring isotopes and an
aver-age atomic weight of 9.0122
Description, Distribution, and Forms
Pure beryllium is a steel-gray, light, hard, and brittle
metal that becomes ductile at higher temperatures
and may be rolled into a sheet Beryllium burns with a
brilliant flame, but it becomes oxidized easily and
forms a protective coating of the oxide Beryllium has
a density of 1.85 grams per cubic centimeter, a
melt-ing point of 1,285° Celsius, and a boilmelt-ing point of
2,970° Celsius
Among the elements, ber yllium ranks
thirty-second in order of abundance Like lithium, it is
usu-ally isolated from silicate minerals It is believed that
its nucleus, like the nucleus of lithium and boron, is
destroyed by high-energy protons in the Sun and
other stars As a result it cannot survive the hot, dense
interiors of the stars, where elements are formed,
which accounts for its low abundance At least fifty
beryllium-containing minerals are known, but only
beryl and bertrandite—which contain up to 15
per-cent beryllium oxide and whose clear varieties are the
gems aquamarine and emerald—are the major
pro-ducers of the metal The richest beryllium-containing
ore deposits are pegmatite varieties of granite rocks
Many beryllium compounds have properties that
re-semble those of aluminum compounds Beryllium
ox-ide absorbs carbon dioxox-ide readily and is moisture
sensitive Beryllium hydroxide is a gelatinous
precipi-tate that is easily soluble in acid All beryllium halides
are easily hydrolyzed by water and emit hydrogen
halides
History
Beryllium was discovered as an oxide by Louis-Nicolas
Vauquelin during an analysis of emerald in 1798 and
was originally named glucinum because of the sweet
taste of its salts It was first isolated as a free metal by
Friedrich Wöhler and Antoine Bussy, who reduced
be-ryllium chloride with potassium metal
Obtaining Beryllium Beryllium ore is usually converted to a more reactive compound, such as beryllium fluoride, which is then electrolyzed with magnesium The element is inert with respect to water
Beryllium exists in the atmosphere of urban and coal-burning neighborhoods in much greater quanti-ties than in rural areas Dry dust, fumes, and aqueous solutions of the metal compounds are toxic, creating dermatitis, and inhaling them produces the effects of phosgene gas Its toxicity is believed to result from the substitution of the smaller beryllium atoms for mag-nesium atoms in enzymes, which are the biochemical catalysts
Uses of Beryllium
As a result of beryllium’s unusual physical properties, such as its high melting point, high electrical conduc-tivity, high heat capacity, and oxidation resistance, be-ryllium serves as a component in alloys of elements such as copper, where it adds a high tensile strength to
Aerospace 10%
Electrical components 22.5%
Electronic components 62.5%
Other 5%
Source:
Historical Statistics for Mineral and Material Commodities in the United States
U.S Geological Survey, 2005, beryllium statistics, in
T D Kelly and G R Matos, comps.,
, U.S Geological Survey Data Series 140 Available online at http://pubs.usgs.gov/ds/2005/140/.
U.S End Uses of Beryllium
Trang 4the metal The added beryllium is no more than 3
per-cent of the alloy Beryllium’s ability to transmit X rays
seventeen times more effectively than aluminum
makes it useful in cases where high-intensity X-ray
beams are needed
Soraya Ghayourmanesh
Web Sites
U.S Department of Labor: Occupational
Safety and Health Administration
Safety and Health Topics: Beryllium
http://www.osha.gov/SLTC/beryllium/
U.S Geological Survey
Minerals Information: Beryllium Statistics and
Information
http://minerals.usgs.gov/minerals/pubs/
commodity/beryllium/
See also: Alloys; Boron; China; Lithium; Nuclear
en-ergy; United States
Bessemer process
Category: Obtaining and using resources
The Bessemer process was the first method for produc-ing large quantities of inexpensive steel.
Definition
In the 1850’s, Henry Bessemer, looking for a way to improve cast iron, stumbled upon a way to make a new kind of steel By blowing air through molten iron in a crucible, he was able to burn off the carbon and many harmful impurities, and then the iron was heated to the point that it could be poured into molds Bessemer eventually learned to add Spiegeleisen, a manganese-rich cast iron, to the molten iron after the carbon and impurities were burned off The manga-nese countered the effects of the remaining traces of oxygen and sulfur, while the carbon (always present in cast iron) helped create the properties of steel
The Bessemer converter, on display at England’s Science Museum, was used for steel production and is recognized as an important invention
of the Industrial Revolution (SSPL via Getty Images)
Trang 5Prior to the late 1850’s, there were two common
iron-based construction materials One was cast iron, an
impure, brittle, high-carbon material used in
col-umns, piers, and other load-bearing members The
other was wrought iron, a workable, low-carbon
mate-rial used in girders, rails, and other spans The word
“steel” usually referred to a custom material produced
in very small quantities by adding carbon to
high-quality wrought iron
Bessemer’s resulting product, which came to be
known as “mild steel,” proved to be reliable and
dura-ble Because of these qualities, and because it could
be produced in large quantities, mild steel quickly
found widespread use in rails, ship plates, girders, and
many other applications, often replacing wrought
iron
Brian J Nichelson
See also: Iron; Manganese; Metals and metallurgy;
Steel
Biodiversity
Category: Ecological resources
Scientist Walter G Rosen coined the term
“biodiver-sity” in 1986 for the National Forum on Biodiversity;
the term was popularized later by the biologist Edward
O Wilson Biodiversity includes the variations and
associated processes within and among organisms It
is linked to the stability and predictability of ecosystems
and can be measured through the numbers and
compo-sition of species.
Background
Conservation was a priority in the United States in the
late 1800’s and early 1900’s, but efforts were driven by
the mistaken beliefs that there were regions
un-touched by humanity and that humans were not part
of nature Intensified use of lands leading up to and
during World War II hastened the loss of species and
wilderness areas The science of ecology was
emerg-ing but “natural” ecosystems were hard to identify
Thus, conservation efforts in the 1960’s and 1970’s
fo-cused on the preservation of particular species in
or-der to preserve biodiversity and led to passage of the
Endangered Species Preservation Act in 1966
Politi-cal support for protecting the environment and biodi-versity spread globally, leading to the 1992 Earth Sum-mit, in which representatives of 175 nations met in Rio
de Janeiro, Brazil As of 2009, all countries present at the summit, except the United States, had ratified the agreements All participating countries were expected
to identify, monitor, and report on various aspects of biodiversity within their borders; help deteriorating regions recover; include indigenous peoples in dis-cussions of biodiversity; and educate citizens about the importance of biodiversity Preservation of origi-nal habitats was preferred over off-site recovery ef-forts
Recognizing and Measuring Biodiversity Biodiversity can be subdivided for analysis into a nested hierarchy of four levels (genetic, population
or species, community or ecosystem, and landscape or region) or it can be studied in terms of composition (genetic constituency, species and relative propor-tions in a community, and kinds and distribution of habitats and communities), structure (patterns, se-quence, and organization of constituents), and func-tion (evolufunc-tionary, ecological, hydrological, geologi-cal, and climatic processes responsible for the patterns of biodiversity) Diversity likely enhances sta-bility of the ecosystem, defined as the physiochemical setting associated with a community of living organ-isms in complex, multifaceted interactions Biodiver-sity is one characteristic of an ecosystem, and the sim-plest measure of diversity is the number of types of organisms (usually species or another group of organ-isms in the Linnaean classification system) Alpha di-versity is the number of types of organisms relative to abundance, and beta diversity is a relative measure of how much an ecosystem adds to a region
Species richness measures are typically favored in conservation planning as a proxy for overall level of biodiversity However, there are many definitions of species, and species can be hard to identify no matter what one’s theoretical biases (whether one prefers to explain species change by differing contributions of the evolutionary mechanisms of natural selection, mutation, genetic drift, and gene flow operating slowly and gradually over time or by relatively rapid means during more dramatic environmental shifts) Species exist as ecological mosaics and include a vari-ety of phenotypes that evolve as local environments change The variety of phenotypes within a species is another kind of diversity, named disparity; species
Trang 6number and species disparity are not necessarily
cor-related Phenotypes are altered or transformed as a
function of phenotypic plasticity, adaptation, and
mi-gration, but there is no standard means of measuring
and comparing morphological difference within or
between species Which aspects of phenotype are of
interest will again depend on the aims of the
re-searcher
About 2 million species have been described, and
counts of the total number of species range from
5 million to 30 million However, monitored species
indicate that there have been dramatic declines
About 6,200 vertebrate species, 2,700 invertebrate
species, and at least 8,500 species of plants from
around the globe were identified as “threatened” in
2009 in the International Union for Conservation
of Nature (IUCN) Red List of Threatened Species
There is particularly intense interest in identifying
re-gions, called “hot spots,” where a large concentration
of species are experiencing especially high levels of extinctions About 44 percent of vascular plants and
35 percent of vertebrates except fish are found in twenty-five hot spots, representing only 1.4 percent of the Earth’s land surface Most are found in the trop-ics Habitats vary in their distribution of biodiversity, but the environments richest in species are tropical rain forests (primarily because of the impressive num-bers of insects), coral reefs, large tropical lakes, and maybe the deep sea Terrestrial habitats tend to be richest in species at lower elevations and in regions with plenty of rainfall In general, geologically and topographically complicated areas are also likely to have more species
All threatened species are at high risk for becom-ing extinct in their natural settbecom-ings because of human impacts that lead to fragmentation and devastation of habitats as well as the spread of nonnative species, the impact of big-business agriculture and forestry,
Rain forests such as El Yunque Caribbean Recreation Area in Puerto Rico are some of the most biodiverse places on Earth (AP/Wide World
Photos)
Trang 7tion, direct use of species, global climate change, and
destructive interference with ecosystem processes
Conserved areas are not enough to stop or reverse the
declines Selection of areas to conserve has been
hap-hazard, and most represent limited ecologies with the
poorest soils, steepest slopes, and highest elevations
Valuing Biodiversity
In the 1950’s, biologists assumed that increasing
bio-logical diversity stabilized ecosystems because any
sin-gle aspect of an ecosystem, if changed, should be less
disruptive the greater the level of complexity In the
1970’s, mathematical modeling of complex systems
confirmed that instability increased with biological
complexity, a view that was favored until the models
proved inadequate to describe all the varying aspects
of living ecosystems Nonequilibrium
(unpredict-able) processes also affected species diversity Thus,
interest continued in the relationship between
mea-sures of biodiversity and productivity, which was the
focus of much experimental research in artificial and
natural settings in the 1990’s However, few simple
as-sociations were found, making the outcome of a
dis-ruption to a particular ecosystem difficult to predict
Some diversity is not evident For example,
biodi-versity is partly determined by genes that may be
somewhat or fully expressed, depending on the
selec-tive demands of local conditions Gene expression is
also sensitive to developmental context as well as
se-lection pressures as the organism survives to
repro-duce The prior history of a lineage (phylogeny) is
also relevant Precipitous population declines can
re-duce genetic variability in a lineage, likely lowering its
flexibility in surviving environmental disturbances
Larger populations are more likely to inhabit more
diverse settings and to accumulate more genetic and
phenotypic diversity Longer-lived (older) systems
seem to accumulate more diversity and are better able
to maintain their integrity
Biological diversity can be assessed in terms of
di-versity among species within an ecosystem, their
vary-ing roles in food chains (trophic) networks, their
biogeochemical cycles, and the accumulation and
production of energy Low species diversity can mean
low productivity when, for example, one compares
deserts and tundra to tropical forests, or high
produc-tivity when evaluating energy subsidized agricultural
systems In addition, greater redundancy of species
with similar roles or functions produces a more stable
system that responds more adaptively to disruptions
The difficulty is that the “roles” and functions of vari-ous organisms within a particular local setting are hard to identify and measure, making the outcomes
of any specific disruptions challenging for planners to predict The stability of a system may mean stability of processes rather than continuity of the same group-ing of species
The Organization for Economic Co-operation and Development advocates the use of marketing strate-gies for increasing the types and levels of biodiversity worldwide There are five economically useful kinds
of biodiversity: direct extractive uses such as foods, plants, and animals of commercial value; direct nonextractive uses, including ecotourism, education, recreation, and extracting and making commercially useful plant products for new medications; indirect uses, as in the case of ecosystems that cleanse air and water, provide flood control, or maintain soil systems; option values or utility for future generations; and ex-istence or bequest values, or how much people are willing to pay to preserve biodiversity Support for bio-diversity will occur if benefits are made explicit and marketable in the global economy
Managing Biodiversity Humans are part of an evolving lineage and are also part of global biodiversity Human population growth and the integration of rural, formerly isolated peo-ples into the global economic system have led to ex-tensive losses of human languages, worldviews, and knowledge about local ecologies and biodiversity No human group should be forced to live on the brink of starvation with high rates of mortality and be ex-cluded from discussions about their region’s biodiver-sity In addition, humans scrambling to survive also have suppressed immune systems and are vulnerable
to epidemic disease
Protection and adequate management of biodiver-sity require that humanity give up the typical short-term, immediate-needs perspective dominated by the most wealthy and politically influential interests and move in the direction of collaboration among diverse interests, including all levels of government, nongov-ernmental organizations, the public, industry, prop-erty owners, developers, and scientists representing academia, government, and industry The planning and associated decision making must include focus
on both public and private lands
Contemporary agricultural systems influence and are influenced by surrounding ecologies less affected
Trang 8by human activities Genetically modified plants may
introduce traits that can alter their “wilder” cousins
Agricultural biodiversity has also been declining at
precipitous rates because of reliance on fewer species
as large corporations homogenize and simplify
indus-trial agriculture with reliance on one (monocrop) or
just a few domesticated species All regions are
report-ing declines in mammal, bird, and insect pollinators
This loss of biodiversity in “wild” and “domestic”
ecol-ogies increases the susceptibility of these plants and
animals to virulent diseases that do not stop at
agricul-tural or naagricul-tural boundaries, threatening both
eco-nomic and political stability in affected regions
Conservation
Preservation of species in their natural (in situ)
set-tings involves legislation to protect species, setting
aside protected areas, and devising effective
manage-ment plans, all of which are expectations of the
agree-ment made at the Earth Summit A reserve may
in-clude a less disturbed core surrounded by buffer
zones that differ in the intensity of human use The
designs of reserves are influenced by the research and
theory of the discipline of ecology Larger protected
regions are better than smaller; closely placed blocks
of habitats are better than widely spaced blocks; and
interconnected zones are better than isolated ones
All planning must involve the local peoples living in
or adjacent to the protected regions
Many situations exist in which there is too much
disturbance by humans or the remnant population is
too small to survive under current conditions Thus,
the maintenance of these species in artificial ex situ
(off-site) conditions—such as zoos, aquariums,
botan-ical gardens, and arboretums—under human
super-vision becomes necessary Sometimes captive
colo-nies can be used to introduce species into the wild
Seed banks and sperm preservation are other ways to
conserve genetic diversity, an idea initially pushed by
Nikolai Ivanovich Vavilov in the early twentieth
cen-tury Gary P Nabhan advocates a means of increasing
the biodiversity of local plants and the resulting foods
in a sustainable manner by creating markets
patron-ized by restaurant chefs as well as home cooks for
lo-cally grown, traditional foods Many creative
strate-gies will be required to stop the declines in
biodiversity, which, over time, will most likely increase
the stability and predictability of the Earth’s living
re-sources
Joan C Stevenson
Further Reading
Chivian, Eric, and Andrew Bernstein Sustaining Life: How Human Health Depends on Biodiversity New
York: Oxford University Press, 2008
Cockburn, Andrew An Introduction to Evolutionary Ecology Illustrated by Karina Hansen Boston:
Blackwell Scientific, 1991
Farnham, Timothy J Saving Nature’s Legacy: Origins of the Idea of Biological Diversity New Haven, Conn.:
Yale University Press, 2007
Groves, Craig R Drafting a Conservation Blueprint: A Practitioner’s Guide to Planning for Biodiversity
Wash-ington, D.C.: Island Press, 2003
Jarvis, Devra I., Christine Padoch, and H David
Coo-per, eds Managing Biodiversity in Agricultural Ecosys-tems New York: Columbia University Press, 2007 Jeffries, Michael J Biodiversity and Conservation 2d ed.
New York: Routledge, 2006
Ladle, Richard J., ed Biodiversity and Conservation: Critical Concepts in the Environment 5 vols New York:
Routledge, 2009
Lévêque, Christian, and Jean-Claude Mounolou Bio-diversity New York: John Wiley and Sons, 2003 Louka, Elli Biodiversity and Human Rights: The Interna-tional Rules for the Protection of Biodiversity Ardsley,
N.Y.: Transnational, 2002
Lovejoy, Thomas E., and Lee Jay Hannah, eds Climate Change and Biodiversity New Haven, Conn.: Yale
University Press, 2005
Maclaurin, James, and Kim Sterelny What Is Biodiver-sity? Chicago: University of Chicago Press, 2008 Mann, Charles C Noah’s Choice: The Future of Endan-gered Species New York: Knopf, 1995.
Nabhan, Gary Paul Where Our Food Comes From: Re-tracing Nikolay Vavilov’s Quest to End Famine
Wash-ington, D.C.: Island Press, 2009
Organization for Economic Co-operation and
Devel-opment Harnessing Markets for Biodiversity: Towards Conservation and Sustainable Use Paris: Author,
2003
Primack, Richard B Essentials of Conservation Biology.
4th ed Sunderland, Mass.: Sinauer Associates, 2006
Wilson, Edward O The Diversity of Life Cambridge,
Mass.: Belknap Press of Harvard University Press,
1992 Reprint New York: W W Norton, 1999
Zeigler, David Understanding Biodiversity Westport,
Conn.: Praeger, 2007
Trang 9Web Sites
Heritage Canada
The Canadian Biodiversity Web Site
http://canadianbiodiversity.mcgill.ca/english/
index.htm
U.S Geological Survey
Biodiversity
http://www.usgs.gov/science/science.php?term=92
See also: Animals as a medical resource; Biosphere
reserves; Conservation; Environmental degradation,
resource exploitation and; Genetic diversity; Land
management; Land-use planning; Nature
Conser-vancy; Plants as a medical resource; Population
growth; Species loss
Biofuels
Category: Energy resources
Where Found
Biofuels are made mainly from plant material such as
corn, sugarcane, or rapeseed Theoretically, biofuels
can be generated anywhere on Earth where living
or-ganisms can grow
Primary Uses
Biofuels such as ethanol and biodiesel are excellent
transportation fuels that are used as substitutes or
sup-plements for gasoline and diesel fuels Biofuels can
also be burned in electrical generators to produce
electricity Two biofuels are used in vehicles: ethanol
and biodiesel Biogas and methane are used mainly to
generate electricity Biomass was used traditionally to
heat houses
Technical Definition
Biofuels are renewable fuels generated from or by
or-ganisms They can be manufactured from this organic
matter and, unlike fossil fuels, do not require
millen-nia to be produced Since they are renewable, biofuels
are considered by many as potential future substitutes
for fossil fuels, which are nonrenewable and
dwin-dling Moreover, pollution from fossil fuels affects
public health and has been associated with global
cli-mate change, because burning them in engines
re-leases carbon dioxide (CO) into the atmosphere
Using biofuels as an energy source generates fewer pollutants and little or no carbon dioxide In addi-tion, the utilization of biofuels reduces U.S depen-dence on foreign oil
Description, Distribution, and Forms Over millions of years, dead organic matter—both plant and animal organisms—played a crucial role in the formation of fossil fuels such as oil, natural gas, and coal Since the nineteenth century, humans have increasingly depended on fossil fuels to meet energy needs As the supply of fossil fuels has diminished, humankind has begun looking for alternative en-ergy sources Thus, the use of biofuels—including ethanol, biodiesel, methane, biogas, biomass, biohy-drogen, and butanol—is increasing
Ethanol is a colorless liquid with the chemical for-mula C2H5OH Another name for ethanol is ethyl al-cohol, grain alal-cohol, or simply alcohol
Biodiesel is a diesel substitute obtained mainly from vegetable oils, such as soybean oil or restaurant greases It is produced by the transesterification of oils, a simple chemical reaction with alcohol (ethanol
or methanol), catalyzed by acids or bases (such as so-dium hydroxide) Transesterification produces alkyl esters of fatty acids that are biodiesel and glycerol (also known as glycerin)
Methane is a colorless, odorless, nontoxic gas with
Biofuel Energy Balances
The following table lists several crops that have been consid-ered as viable biofuel sources and several types of ethanol, as well as each substance’s energy input/output ratio (that is, the amount of energy released by burning biomass or ethanol, for each equivalent unit of energy expended to create the sub-stance).
Biomass/Biofuel
Energy Output per Unit Input
Oilseed rape (with straw) 9.21
Source: Data from the British Institute of Science in
Society.
Trang 10the molecular formula CH4 It is the main chemical
component (70 to 90 percent) of natural gas, which
accounts for about 20 percent of the U.S energy
sup-ply Methane was discovered by the Italian scientist
Alessandro Volta, who collected it from marsh
sedi-ments and showed that it was flammable He called it
“combustible air.”
Biogas is a gas produced by the metabolism of
mi-croorganisms There are different types of biogas
One type contains a mixture of methane (50 to 75
per-cent) and carbon dioxide Another type comprises
primarily nitrogen, hydrogen, and carbon monoxide
(CO) with trace amounts of methane
Biomass is a mass of organisms, mainly plants, that
can be used as an energy source Plants and algae
con-vert the energy of the Sun and carbon dioxide into
en-ergy that is stored in their biomass Biomass, burning
in the form of wood, is the oldest form of energy used
by humans Using biomass as a fuel source does not
re-sult in net CO2emissions, because biomass burning
will release only the amount of CO2it has absorbed
during plant growth (provided its production and
harvesting are sustainable)
Molecular hydrogen (H2) is a colorless, odorless,
and tasteless gas It is an ideal alternative fuel to be
used for transportation because the energy content of
hydrogen is three times greater than in gasoline Also,
it is virtually nonpolluting and a renewable fuel Using
H2as an energy source produces only water; H2can be
made from water again A great number of
microor-ganisms produce H2from inorganic materials, such as
water, or from organic materials, such as sugar, in
re-actions catalyzed by enzymes Hydrogen produced by
microorganisms is called biohydrogen
Butanol (butyl alcohol) is a four-carbon alcohol
with the molecular formula C4H9OH Among other
types of biofuels, butanol has been the most
promis-ing in terms of commercialization It is another
alco-hol fuel but has higher energy content than ethanol
It does not pick up water as ethanol does and is not as
corrosive as ethanol but is more suitable for
distribu-tion through existing pipelines for gasoline However,
compared to ethanol, butanol is considered toxic It
can cause severe eye and skin irritation and
suppres-sion of the nervous system
History
The concept of biofuels is not new People have been
using biomass such as plant material to heat their
houses for thousands of years The idea of using
hy-drogen as fuel was expressed by Jules Verne in his
novel L’Île mystérieuse (1874-1875; The Mysterious Island,
1875) In 1900, Rudolf Diesel, the inventor of the die-sel engine, used peanut oil for his engine during the World Exhibition in Paris, France Henry Ford’s first (1908) car, the Model T, was made to run on pure eth-anol Later, the popularity of biofuels as a fuel source followed the “oil trouble times.” For example, bio-fuels were considered during the 1970’s oil embargo Early in the twenty-first century, concerns about global warming and oil-price increases reignited interest in biofuels In 2005, the U.S Congress passed the En-ergy Policy Act, which included several sections lated to biofuels In particular, this energy bill re-quired more research on biofuels, mixing ethanol with gasoline, and an increase in the production of cellulosic biofuels
Obtaining Biofuels Ethanol is produced mainly by the microbial fermen-tation of starch crops (such as corn, wheat, and bar-ley) or sugarcane In the United States, most of the ethanol is produced by the yeast (fungal) fermenta-tion of sugar from cornstarch Ethanol can be pro-duced from cellulose, the most plentiful biological material on Earth; however, current methods of con-verting cellulosic material into ethanol are inefficient and require intensive research and development ef-forts Ethanol can also be produced by chemical means from petroleum Therefore, ethanol that is produced by microbial fermentation is commonly re-ferred to as “bioethanol.”
In the United States, biodiesel comes mainly from soybean plants; in Europe, the world’s top producer
of biodiesel, it comes from canola oil Other vegeta-tive oils that have been used in biodiesel production are corn, sunflower, cottonseed, jatropha, palm oil, and rapeseed Another possible source for biodiesel production is microscopic algae (microalgae), the mi-croorganisms similar to plants
Methane is produced by microorganisms and is an integral part of their metabolism Biogas is produced during the anaerobic fermentation of organic matter
by a community of microorganisms (bacteria and ar-chaea) For practical use, methane and biogas are generated from wastewater, animal waste, and “gas wells” in landfills Biomass is produced naturally, in the forest, and agriculturally, from agricultural resi-dues and dung
No commercial biohydrogen production process