Environmental Encyclopedia

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Environmental Encyclopedia 3

Free riders

In March 2002, Parliament cast non-binding opinion

votes on the options. The House of Commons voted for a

ban. The House of Lord voted for licensed hunting. After

the vote, Rural Affairs Minister Alun Michael said that the

government would try to find a common ground before

trying to legislate fox hunting. The process of trying to reach

agreement was expected to take six months at most.

Fox hunting in other countries

The Scottish Parliament banned hunting in February

of 2002. The ban was to take effect on Aug, 1, 2002. The

Countryside Alliance announced plans to legally challenge

that ruling.

Fox hunting is legal in the following countries: Ireland,

Belgium, Portugal, Italy, and Spain. Hunting with hounds

is banned in Switzerland. In the United States, the MFHA

was established in 1907. In March of 2002, the MFHA

reported that there were 171 organized hunt clubs in North

America.

[Liz Swain]

ESOURCES

OOKS

Pool, Daniel. What Jane Austen Ate and Charles Dickens Knew: From Fox

Hunting to Whist—The Facts of Daily Life in Nineteenth-Century Enland.

Carmichael, CA: Touchstone Books, 1994.

Robards, Hugh J. Foxhunting in England, Ireland, and North America.

Lanham, MD: Derrydale Press, 2000.

Thomas, Joseph B., and Mason Houghland. Hounds and Hunting Through

the Ages. Lanham, MD: Derrydale Press, 2001.

RGANIZATIONS

British Government Committee of Inquiry into Hunting with Dogs in

England and Wales, , England Email: huntingwithdogs@defra.gsi.gov.uk,

<http://www.huntinginquiry.gov.uk/mainsections/huntingframe.htm>

Countryside Alliance, The OldTown Hall, 367 Kensington Road, London

SE11 4PT, England (011) 44-020-7840-9200, Fax: (011) 44-020-7793-

8899, Email: info@countryside-alliance.org, <http://www.countryside-

alliance.org>

International Fund for Animal Welfare, 411 Main Street, P.O. Box 193,

Yarmouth Port, MA USA 02675 (508) 744-2000, Fax: (508) 744-2009,

Toll Free: (800) 932-4329, Email: info@iafw.org, <http://www.iafw.org>

Masters of Foxhounds Association, Morven Park, P.O. Box 2420, Leesburg,

VA USA 20177 Email: office@mfha.com, <http://www.mfha.com>

Nottingham Hunt Saboteurs, The Sumac Centre, 245 Gladstone Street,

Nottingham NG7 6HX, England

Free riders

A free rider, in the broad sense of the term, is anyone who

enjoys a benefit provided, probably unwittingly, by others.

In the narrow sense, a free rider is someone who receives

the benefits of a cooperative venture without contributing

to the provision of those benefits. A person who does not

participate in a cooperative effort to reduce

air pollution

597

by driving less, for instance, will still breathe cleaner air—

and thus be a free rider—if the effort succeeds.

In this sense, free riders are a major concern of the

theory of collective action. As developed by economists and

social theorists, this theory rests on a distinction between

private and public (or collective) goods. A public good differs

from a private good because it is indivisible and nonrival. A

public good, such as clean air or national defense, is indivisi-

ble because it cannot be divided among people the way food

or money can. It is nonrival because one person’s enjoyment

of the good does not diminish anyone else’s enjoyment of

it. Smith and Jones may be rivals in their desire to win a

prize, but they cannot be rivals in their desire to breathe

clean air, for Smith’s breathing clean air will not deprive

Jones of an equal chance to do the same.

Problems arise when a public good requires the cooper-

ation of many people, as in a campaign to reduce

pollution

or conserve resources. In such cases, individuals have little

reason to cooperate, especially when cooperation is burden-

some. After all, one person’s contribution—using less

gaso-

line

or electricity, for example—will make no real difference

to the success or failure of the campaign, but it will be a

hardship for that person. So the rational course of action is

to try to be a free rider who enjoys the benefits of the

cooperative effort without bearing its burdens. If everybody

tries to be a free rider, however, no one will cooperate and

the public good will not be provided. If people are to prevent

this from happening, some way of providing selective or

individual incentives must be found, either by rewarding

people for cooperating or punishing them for failing to coop-

erate.

The free rider problem posed by public goods helps

to illuminate many social and political difficulties, not the

least of which are environmental concerns. It may explain

why voluntary campaigns to reduce driving and to cut energy

use so often fail, for example. As formulated in Garrett

Hardin’s

Tragedy of the Commons

, moreover, collective

action theory accounts for the tendency to use common

resources—grazing land, fishing banks, perhaps the earth

itself—beyond their

carrying capacity

. The solution, as

Hardin puts it, is “mutual coercion, mutually agreed upon”

to prevent the overuse and destruction of vital resources.

Without such action, the desire to ride free may lead to

irreparable ecological damage.

[Richard K. Dagger]

ESOURCES

OOKS

Hardin, R. Collective Action. Baltimore: Johns Hopkins University Press,

1982.

Olson, M. The Logic of Collective Action. New York: Schocken Books, 1971.

Environmental Encyclopedia 3

Freon

ERIODICALS

Hardin, G. “The Tragedy of the Commons.” Science 162 (December 13,

1968): 1243–48.

Freon

The generic name for several

chlorofluorocarbons

(CFCs)

widely used in refrigerators and air conditioners, including

the systems in houses and cars. Freon—comprised of

chlo-

rine

, fluorine, and

carbon

atoms—is a non-toxic gas at

room temperature. It is environmentally significant because

it is extremely long-lived in the

atmosphere

, with a typical

residence time

of 70 years. This long life-span permits

CFCs to disperse, ultimately reaching the

stratosphere

mi (30 km) above the earth’s surface. Here, high energy

photons in sunlight break down freon, and chlorine atoms

liberated during this process participate in other chemical

reactions that consume

ozone

. The final result is to decrease

the stratospheric ozone layer that shields the earth from

damaging

ultraviolet radiation

. Under the 1987 Montreal

Protocol, 31 industrialized countries agreed to phase out

CFC freon production. Freon substitutes use

bromine

atoms to replace the chlorine atoms, providing a substitute

refrigeration compound that appears less damaging, al-

though considerably more expensive and less energy efficient.

Fresh water ecology

The study of fresh water habitats is called

limnology

, com-

ing from the Greek word limnos, meaning “pool, lake, or

swamp.” Fresh water habitats are normally divided into two

groups: the study of standing bodies of water such as lakes

and ponds (called lentic ecosystems) and the study of rivers,

streams, and other moving sources of water (called lotic

ecosystems). Another important area that should be included

is fresh water

wetlands

The historical roots of limnology go back to F. A.

Forel, who studied Lake Geneva, Switzerland, in the late

1800s and E. A. Birge and C. Juday, who studied lakes in

Wisconsin in the early 1900s. More recently, the modern

“father” of limnology can arguably be attributed to G. Evelyn

Hutchinson, who died in 1991 after teaching at Yale Univer-

sity for more than 40 years. Among his prolific writings are

four treatises on limnology which offer the most detailed

descriptions of lakes that have been published.

Fresh water

ecology

is an intriguing field because of

the great diversity of aquatic habitats. For example, lakes

can be formed in different ways: volcanic origin such as

Crater Lake, Oregon; tectonic (earth movement) origin like

Lake Tahoe

in California/Nevada and

Lake Baikal

in Sibe-

ria; glacially-derived lakes like the

Great Lakes

or smaller

598

kettle hole or cirque lakes; oxbow lakes which form as rivers

change their meandering paths; and human-created reser-

voirs. Aquatic habitats are strongly influenced by the sur-

rounding

watershed

, and lakes in the same geographic area

tend to be of the same origin and have similar

water quality

Lakes are characteristically non-homogeneous. Physi-

cal, chemical, and biological factors contribute to both hori-

zontal and vertical zonations. For example, light penetration

creates an upper photic (lighted) zone and a deeper aphotic

(unlit) zone.

Phytoplankton

(microscopic algae such as dia-

toms, desmids, and filamentous algae) inhabit the

photic

zone

and produce oxygen through

photosynthesis

. This

creates an upper productive area called the trophogenic (pro-

ductive) zone. The deeper area where

respiration

prevails

is called the tropholytic (unproductive) zone.

Zooplankton

(microscopic invertebrates such as cladocerans, copepods,

and rotifers) and

nekton

(free-swimming animals such as

fish) inhabit both of these zones. The boundary area where

oxygen produced from photosynthesis equals that consumed

through respiration is called the compensation depth. Near-

shore areas where light penetrates to the bottom and aquatic

macrophytes such as cattails and bulrushes grow, are called

the

littoral zone

. This is typically the most productive area,

and it is more pronounced in ponds than in lakes. Open

water areas are called the limnetic zone, where most

plank-

ton

inhabit. Some

species

of zooplankton are found more

concentrated in deeper waters during the day and in greater

numbers in the upper waters during the night. One explana-

tion for this vertical

migration

is that these zooplankton,

often large and sometimes pigmented, are avoiding visually-

feeding planktivorous fish. These zooplankton are thus able

to feed on phytoplankton in the trophogenic zone during

periods of darkness, and then swim to deeper waters during

daylight hours. Phytoplankton are also adapted for existence

in the limnetic zone. Some species are quite small in size

(less than 20 microns in diameter and called nannoplankton),

allowing them to be competitive at

nutrient

uptake due to

their high surface-to-volume ratio. Other groups form large

colonies, often with spines, lessening the negative impacts

of herbivory and sinking. Blue-green algae produce oils that

help them float on or near the water’s surface. Some are

able to fix atmospheric

nitrogen

(called

nitrogen fixation

giving them a competitive advantage in low-nitrogen condi-

tions. Other species of blue-greens produce toxic

chemicals

making them inedible to herbivores. There have even been

reports of cattle deaths following ingestion of water with

dense growths of these algae.

Lakes can be isothermal (uniform temperature from

top to bottom) during some times of the year, but during

the summer months they are typically thermally stratified

with an upper, warm layer called the epilimnion (upper lake),

and a colder, deeper layer called the hypolimnion (lower

Environmental Encyclopedia 3

Fresh water ecology

lake). These zones are separated by the metalimnion, which

is determined by the depths with a temperature change of

more than 1°C per meter depth, called the

thermocline

The summer temperature

stratification

creates a density

gradient that effectively prevents mixing between zones.

Wind is another physical factor that influences aquatic

habitats, particularly in lakes with broad surface areas ex-

posed to the main direction of the wind, called fetch. Strong

winds can produce internal standing waves called seiches

that create a rocking motion in the water once the wind

dies down. Other types of wind-generated water movements

include Ekman spirals and Langmuir cells. Deep or chemi-

cally-stratified lakes that never completely mix are called

meromictic. Lakes in tropical regions that mix several times

a year are called polymictic. In regions with severe winters

resulting in ice covering the surface of the lake, mixing

normally occurs only during the spring and fall when the

water is isothermal. These lakes are called dimictic, and the

mixing process is called overturn. People living downwind

of these lakes often notice a rotten egg smell caused by the

release of

hydrogen

sulfide. This gas is a product of benthic

(bottom-dwelling) bacteria that inhabit the

anaerobic

muds

of productive lakes (discussed below in more detail).

Lakes that receive a low-nutrient input remain fairly

unproductive, and are called

oligotrophic

(low nourished).

These lakes typically have low concentrations of phytoplank-

ton, with diatoms being the main representative. Moderately

productive lakes are called mesotrophic. Eutrophic (well

nourished) lakes receive more nutrient input and are there-

fore more productive. They are typically shallower than oli-

gotrophic lakes and have more accumulated bottom sedi-

ments that often experience summer anoxia. These lakes

have an abundance of algae, particularly blue-greens (Cynao-

bacteria) which are often considered nuisance algae because

they float on the surface and out-compete the other algae

for nutrients and light.

Most lakes naturally age and become more productive

over time; however, large, deep lakes may remain oligotro-

phic. The maturing process is called eutrophication and it

is regulated by the input of nutrients which are needed by

the algae for growth. Definitive limnological studies done

in the 1970s concluded that

phosphorus

is the key limiting

nutrient in most lakes. Thus, the accelerated input of this

chemical into streams, rivers, and eventually lakes by excess

fertilization, sewage input (both human and animal), and

erosion

is called

cultural eutrophication

. Much debate

and research has been spent on how to slow down or control

this process. One interesting management tool is called bio-

manipulation, in which piscivorous (fish-eating) fish are

added to lakes to consume planktivorous (plankton-eating)

fish. Because the planktivores are visual feeders on the largest

prey, this allows higher numbers of large zooplankton to

599

thrive in the water, which consume more phytoplankton,

particularly non-toxic blue-green algae. A more practical

approach to controlling cultural eutrophication is by limiting

the nutrient

into our bodies of water. Although

this isn’t easy, we must consider ways of limiting excessive

uses of fertilizers, both at home and on farms, as well as

more effectively regulating the release of treated sewage into

rivers and lakes, particularly those which are vulnerable to

eutrophication. Another lake management tool is to aerate

the bottom (hypolimnetic) water so that it remains oxygen-

ated. This keeps iron in the oxidized state (Fe

), which

chemically binds with phosphate (PO

) and prevents it from

being available for algal uptake. Lakes that have anoxic bot-

tom water keep iron in the reduced state (Fe

), and phos-

phate is released from the

sediment

into the water. Fall

and spring turnover then returns this limiting nutrient to

the photic zone, promoting high algal growth. When these

organisms eventually die and sink to the bottom,

decom-

posers

use up more oxygen, and we get a “snow ball” effect.

Thus, productive lakes can become more eutrophic with

time, and may eventually develop into hypertrophic (overly

productive) systems.

Lotic ecosystems differ from lakes and ponds in that

currents are more of a factor and primary production inputs

are generally external (allochthonous) instead of internal

(autochthonous). Thus, a river or stream is considered a

heterotrophic

ecosystem

along most of its length. Gradients

in physical and chemical parameters also tend to be more

horizontal than vertical in running water habitats and organ-

isms living in lotic ecosystems are specially adapted for sur-

viving in these conditions. For example, trout require higher

amounts of

dissolved oxygen

, and are primarily found in

relatively cold, fast-moving water with low nutrient input.

Carp are able to tolerate warmer, slower, more productive

bodies of running water. Darters are fish that quickly dart

back and forth behind rocks in the bottom of fast-moving

streams and rivers as they feed on aquatic insects. Many of

these insects are shredders and

detritivores

on the organic

material like leaves that enter the water. Other groups spe-

cialize by scraping algae and bacteria off rocks in the water.

Recently, ecologists have begun to take a greater inter-

est in studying fresh water wetlands. These areas are defined

as being inundated or saturated by surface or ground water

for most of the year, and therefore having characteristic

wetland vegetation. Although some people consider these

areas a nuisance and prefer them being drained, ecologists

realize that they are valuable habitats for migrating water

fowl. They also serve as major “adsorptive” areas for nutri-

ents, which are particularly useful around sewage lagoons.

We must therefore take greater care in preserving these

habitats.

[John Korstad]

Environmental Encyclopedia 3

Friends of the Earth

ESOURCES

OOKS

Horne, A. J., and C. R. Goldman. Limnology. New York: McGraw

Hill, 1994.

Hutchinson, G.E. A Treatise on Limnology. vol. 1: Geography, Physics, Chem-

istry; vol. 2: Introduction to Lake Biology and Limnoplankton; vol. 3: Limnolog-

ical Botany; vol. 4: The Zoobenthos. New York: Wiley, 1993.

Smith, R. L. Ecology and Field Biology. 4th ed. New York: Harper Col-

lins, 1996.

Wetzel, R. Limnology. 2nd ed. Philadelphia: Saunders, 1983.

Friends of the Earth

Friends of the Earth (FOE) is a public interest environmen-

tal group committed to the

conservation

, restoration, and

rational use of the

environment

. Founded by David Brower

and other militant environmentalists in San Francisco in

1969, FOE works on the local, national, and international

levels to prevent and reverse

environmental degradation

and to promote the wise use of

natural resources

FOE has an international membership of one million.

Its particular areas of interest include

ozone layer deple-

tion

greenhouse effect

, toxic chemical safety,

coal

mining,

coastal and ocean

pollution

, the destruction of tropical for-

ests,

groundwater

contamination, corporate accountability,

and

nuclear weapons

production. In addition to its efforts

to influence policy and increase public awareness of environ-

mental issues, FOE’s ongoing activities include the operation

of the Take Back the Coast Project and the administration

of the Oceanic Society. Over the years, FOE has published

numerous books and reports on various topics of concern to

environmentalists.

FOE was originally organized to operate internation-

ally and now has national organizations in some 63 countries.

In several of these, most notably the United Kingdom, FOE

is considered to be the best-known and most effective

public

interest group

concerned with environmental issues.

The organization has changed its strategies consider-

ably over the years, and not without considerable controversy

within its own ranks. Under Brower’s leadership, FOE’s

tactics were media-oriented and often confrontational,

sometimes taking the form of direct political protests, boy-

cotts, sit-ins, marches, and demonstrations. Taking a

holistic

approach

to the environment, the group argued that funda-

mental social change was required for lasting solutions to

many environmental problems.

FOE eventually moved away from confrontational tac-

tics and towards a new emphasis on lobbying and legislation,

which helped provoke the departure of Brower and some of

the group’s more radical members. FOE began downplaying

several of its more controversial stances (for example, on the

control of nuclear weapons) and moved its headquarters from

600

San Francisco to Washington, D.C. More recent controver-

sies have concerned FOE’s endorsement of so-called

green

products

and its acceptance of corporate financial contribu-

tions.

FOE remains committed, however, to most of its orig-

inal goals, even if it has foresworn its earlier illegal and

disruptive tactics. Relying more on the technical competence

of its staff and the technical rationality of its arguments than

on idealism, FOE has been highly successful in influencing

legislation and in creating networks of environmental, con-

sumer, and human rights organizations worldwide. Its publi-

cations and educational campaigns have been quite effective

in raising public consciousness of many of the issues with

which FOE is concerned.

[Lawrence J. Biskowski]

ESOURCES

RGANIZATIONS

Friends of the Earth, 1025 Vermont Ave. NW, Washington, D.C. USA

20005 (202) 783-7400, Fax: (202) 783-0444, Email: foe@foe.org, <http://

www.foe.org>

Frogs

Frogs are amphibians belonging to the order anura. The

anuran group has nearly 2,700

species

throughout the world

and includes both frogs and toads. The word anura means

“without a tail,” and the term applies to most adult frogs.

The anura are distinguished from tailed amphibians (uro-

deles) such as salamanders because the latter retain a tail as

an adult.

One of the most studied and best understood frogs is

the northern leopard frog, Rana pipiens. This species is well-

known to most children, to people who love the outdoors,

and to scientists. Leopard frogs live throughout much of

the United States as well as Canada and northern Mexico.

Inhabiting a diverse array of environmental conditions, the

order anura exhibits an impressive display of anatomical

and behavioral variations among its members. Despite such

diversity, the leopard frog is often used as a model that

represents all members of the group.

Leopard frogs mate in the early spring. The frogs

deposit their eggs in jelly-like masses. These soft formless

clumps may be seen in temporary ponds where frogs are

common. Early embryonic development occurs within the

jelly mass after which the eggs hatch releasing small swim-

ming tadpoles. The tadpoles feed on algal periphyton, fine

organic

detritus

, and yolk reserves through much of the

spring and early summer. Next, metamorphosis begins a few

weeks or up to two years after the eggs is hatched depending

Environmental Encyclopedia 3

Frogs

of the species. Metamorphosis is the process whereby am-

phibious tadpoles lose their gills and tails and develop arms

and legs. The process of metamorphosis is complex and

involves not only the loss of the tail and the development

of limbs, but also a fundamental reorganization of the gut.

For example, in the leopard frog, the relatively long intestine

of the vegetarian tadpole is reorganized to form the short

intestine of the carnivorous adult frog because nutrients are

more difficult to extract from plant sources. Additionally,

metamorphosis profoundly changes the method of

respira-

tion

in the leopard frog. As the animal loses it gills, air-

breathing lungs are formed and become functional. A signifi-

cant portion of respiration and gas exchange will occur

through the skin of the adult frog. When metamorphosis

of a tadpole is complete, the result is a terrestrial, insect-

eating, air-breathing frog.

Frogs are important tolls for biological learning and

research. Many students first encounter vertebrate anatomy

with the dissection of an adult leopard frog. Consequently

physiologists have used frogs for the study of muscle contrac-

tion and the circulation of blood which is easily seen in the

webbing between the toes of a frog. Embryologists have

used frogs for study because they lay an abundance of eggs.

A mature R. pipiens female may release 3,000 or more eggs

during a single spawning. Frog eggs are relatively large and

abundant which simplifies manipulation and experimenta-

tion. Another anuran, the South African clawed frog, Xeno-

pus laevis, is useful in research because it can be cultivated

to metamorphosis easily and can be bred any time of year.

For these reasons, frogs emerge as extremely useful labora-

tory test animals that provide valuable information about

human biology.

Frogs and biomedical research

Many biological discoveries have been made or en-

hanced by using frogs. For example, the role of sperm in

development was studied in the late 1700s in frogs. Amphib-

ians in general, including frogs, have significantly more de-

oxyribonucleic

acid

(DNA) per cell than do other chordates.

Thus, their chromosomes are large and easy to see with a

microscope. In addition, induced ovulation in frogs by pitu-

itary injection was developed during the early 1930s. Early

endocrinologists studied the role of the hormone thyroxine

(also found in human beings) in vertebrate development in

1912. The role of viruses in animal and human

cancer

receiving renewed interest—the first herpes

virus

known to

cause a cancer was the frog cancer herpes virus. Furthermore,

mammalian and human

cloning

, a controversial topic, has

its foundations in the cloning of frogs. The first vertebrate

ever cloned was Rana pipiens, in an experiment published

by Thomas King and Robert Briggs in 1952. As such, experi-

mentation with frogs has contributed greatly to biomedical

research.

601

Unfortunately, the future of amphibians, like the

northern leopard frog, appears to be jeopardized. Most am-

phibians in the world are frogs and toads. Since the 1980s,

scientists have noted a distinct decline in amphibian popula-

tions. Worldwide, over 200 species of amphibians have expe-

rienced recent population declines. At least 32 documented

species extinctions have occurred. Of the 242 native North

American amphibian species, the U.S. Nature Conservancy

has identified three species that are presumed to be extinct,

another three classified as possibly extinct, with an additional

38% categorized as vulnerable to

extinction

. According to

the United States

Fish and Wildlife Service

, there are four

frog species listed as endangered and three listed as

threatened.

The actual cause of the reductions in frog and amphib-

ian populations remains unclear, but many well-supported

hypotheses exist. One speculation is the run-off of

chemi-

cals

that poison ponds producing defective frogs that cannot

survive well. A second possibility is an increase in amphibian

disease caused by virulent pathogens. Viral and fungal infec-

tion of frogs has led to recent declines in many populations.

A third explanation involves parasitic infections of frogs

with flatworms, causing decreased survival. Another theory

blames atmospheric

ozone

depletion for frog decline. Yet

another implicates a toxic combination of intensified agricul-

ture,

drainage

habitat

, and predator changes as the

cause for the drastic declines in frog populations. While each

argument has merits of its own, it is unlikely that any single

cause can adequately explain all amphibian decline.

The poisoned pond hypothesis brought the issue of

frog population decline to the forefront. Several years ago,

students on a field trip at a pond near the Minnesota commu-

nity of Henderson discovered a number of frogs with ex-

tremely abnormal limbs. Some frogs had three or more hind

legs, some had fused appendages, and some had no legs at

all. Concerned with what they had found, their teacher,

Cindy Reinitz, and her students contacted the Minnesota

Pollution Control

Agency. Soon, state agency biologists and

officials from the University of Minnesota confirmed the

presence of many abnormal frogs at the site. The word

spread, and by late 1996, many sites in Minnesota were

known to have abnormal frogs.

Frog developmental abnormalities are not new to sci-

ence. What made the Minnesota case of frog malformations

different, however, was the extraordinary concentration of

abnormal frogs in an unusually large number of locations.

Concern became more urgent when abnormal animals also

were reported in several other states, then Canada, and finally

in Japan. Many of the abnormal frogs were found in agricul-

tural areas where large amounts of fertilizers and pesticides

were used.

Environmental Encyclopedia 3

Frogs

One reason for concern is that frogs and humans me-

tabolize toxic

xenobiotic

chemicals, such as fertilizers or

pesticides, in similar ways. Also, human beings and frogs

have very similar early developmental stages, which is why

frogs are used as model animals in embryology. Because of

this, worry exists regarding the potential for human develop-

mental abnormalities from such chemicals. Some of the

chemicals implicated in the frog malformations were reti-

noids. Retinoids are derivatives of vitamin A that are potent

and crucial hormonal regulators of vertebrate embryological

development. Numerous laboratory studies using retinoic

acid (a form of retinoid) have reproduced the abnormalities

seen in the Minnesota frogs, and the role of retinoids in the

regulation of genes involved in limb development is well-

characterized. Frog anatomical defects are regarded as a

warning sign for potential problems in humans exposed to

the same chemicals, since retinoic acid regulates human limb

development as well.

Disease is a growing problem for frogs. Recently, two

important frog pathogens have been identified and are sus-

pected to play a role in global frog decline. Iridiovirus, a

virus that commonly infects fish and insects, has now been

found to infect frogs. An aquatic fungus, chytrid, is also

implicated in frog decline. Infection with the fungus is called

chytridiomycosis. The chytrid fungus, Batrachochytrium den-

drobatidis, which normally resides in decaying plant material,

causes the degeneration of tadpole mouthparts. This results

in the death of post-metamorphic frogs, and is reportedly

involved in amphibian decline in

Australia

, Europe, and

recently in the Sierra Nevada region of California. In Austra-

lia the depletion of the frog population may have been caused

by a disease introduced through infected fish. The Australian

cane toad, Bufo marinus, may be responsible for spreading

a virus to other frogs outside its native range.

Another potential cause for the striking decline of frog

populations involves parasitism, the act of being a parasite.

Parasitism is a type of

symbiosis

in which a parasitic orga-

nism gains benefit from living within or upon a host orga-

nism. The host, in turn, gains no benefit, and in fact may

be harmed by the symbiosis. Scientists have discovered that

a parasitic trematode or flatworm is threatening many frog

populations. Trematode larvae erupt from snails inhabiting

ponds, which then infect frog tadpoles. Once inside the

tadpoles, the flatworm larvae multiply and physically scram-

ble developing limb bud cells in the hind quarters of the

tadpole. If the limb bud cells are not in their proper places,

malformations are the consequence. The result of such para-

sitism by flatworms is adult frogs with multiple legs or fused

legs. It is believed that the flatworms derive benefit from

the relationship because frogs with defective legs are easier

for birds to prey upon. Birds that eat infected frogs in-turn

602

become infected. The cycle is complete when bird droppings

littered with flatworm larvae are dropped into pond water.

A fourth possible explanation for the decline of frogs

involves ozone depletion. Some scientists believe that atmo-

spheric ozone loss has led to an increase in ultraviolet light

penetration to the surface of the earth. Frogs are exquisitely

sensitive to ultraviolet light. It is believed that due to in-

creased UV-B penetration, mutations in frogs has been in-

creased, resulting in limb malformations. Evidence for this

hypothesis exists in laboratory experiments that have been

able to reliably replicate the limb malformations observed

in the Minnesota ponds using UV-B radiation on experi-

mental frogs.

Many scientists believe, however, that multiple factors

are to blame for frog decline. They believe that synergy,

or the combination of many factors is the most plausible

explanation for the decrease in the number and diversity of

frogs.

Climate

change, urbanization, prolonged

drought

global warming, secondary

succession

, drainage of habitat

for housing developments,

habitat fragmentation

, intro-

duced predators, loss of territory, and the aforementioned

infectious and

poisoning

reasons may all simultaneously

contribute to the decline of frog populations worldwide.

Humans perpetuate the decline by

hunting

frogs for food.

Because the decrease in numbers and diversity of frogs is so

striking, conservationists are concerned that it is an early

indicator of the consequences of human progress and overpo-

pulation.

[Robert G McKinnell]

ESOURCES

OOKS

Behler, J. L., and F. W. King. National Audubon Society Field Guide to North

American Reptiles & Amphibians. New York: Alfred A. Knopf, Inc., 1997.

DiBerardino, M. A. Genomic Potential of Differentiated Cells. New York:

Columbia University Press, 1997.

Duellman, W. E., and L. Trueb. Biology of Amphibians. New York:

McGraw-Hill Book Company, 1986.

Gilbert, S. F. Development Biology. 5th ed. Sunderland, MA: Sinauer Associ-

ates, Inc., 1997.

Stebbins, R. C., and N. W. Cohen. A Natural History of Amphibians.

Princeton: Princeton University Press, 1995.

ERIODICALS

Carlson, D. L., L. A. Rollins-Smith, and R. G. McKinnell. “The Lucke

Herpesvirus Genome: Its Presence in Neoplastic and Normal Kidney Tis-

sue,” Journal of Comparative Pathology 110 (1995): 349–355.

Cheh, A. M., et al. “A Comparison of the Ability of Frog and Rat S-9

to Activate Promutagens in the Ames Test,” Environmental Mutagenesis 2

(1980): 487–508.

THER

CSIRO Australian Animal Health Laboratory. December 1995 [June 2002].

<http://www2.open.ac.uk/biology/froglog/FROGLOG-15-4.html>.

Environmental Encyclopedia 3

Fuel cells

Tennessee Wildlife Resources Agency. March 22, 2002 [cited June 2002].

<http://www.state.tn.us/twra/lifecyc.html>.

United State Fish and Wildlife Services, Division of Endangered Species. De-

cember 7, 2001 [cited June 2002]. <http://ecos.fws.gov/servlet/TESSSpec-

iesReport/generate>.

Frontier economy

An economy similar to that which was prevalent at the

“frontier” of European settlement in North America in the

eighteenth and nineteenth centuries. A frontier economy is

characterized by relative scarcities (and high prices) of capital

equipment and skilled labor, and by a relative abundance

(and low prices) of

natural resources

. Because of these

factors, producers will look to utilize natural resources in-

stead of capital and skilled labor whenever possible. For

example, a sawmill might use a blade that creates large

amounts of wood waste since the cost of extra logs is less

than the cost of a better blade. The long-term environmental

effects of high natural resource use and

pollution

from

wastes are ignored since they seem insignificant compared

to the vastness of the natural resource base.

A frontier economy is sometimes contrasted with a

spaceship economy, in which resources are seen as strictly

limited and need to be endlessly recycled from waste

products.

Frost heaving

The lifting of earth by

soil

water as it freezes. Freezing

water expands by approximately nine percent and exerts a

pressure of about fifteen tons per square inch. Although this

pressure and accompanying expansion are exerted equally in

all directions, movement takes place in the direction of least

resistance

, namely upward. As a result, buried rocks, varying

from pebbles to boulders, can be raised to the ground surface;

small mounds and layers of soil can be heaved up; young

plants can be ripped from the earth or torn apart below

ground; and pavement and foundations can be cracked and

lifted. Newly planted tree seedlings, grass, and agricultural

crops are particularly vulnerable to being lifted by acicular

ice crystals during early fall and late spring frosts. Extreme

cases in cold climates at high latitudes or high elevation at

mid-latitudes result in characteristic patterned ground.

Fuel cells

Fuel cells produce energy through electrochemical reactions

rather than through the process of

combustion

. They con-

vert

hydrogen

and oxygen into electricity and heat. Fuel

cells are sometimes compared to batteries because, like bat-

603

teries, they have two electrodes, an anode and a cathode,

through which an electrical current flows into and out of

the cell. But fuel cells are fundamentally different electrical

devices from batteries since the latter simply store electrical

energy, while the former are a source of electrical energy.

In a fuel cell, chemical energy is converted directly

into electrical energy by means of an oxidation-reduction

reaction. The British physicist Sir William Grove developed

the fuel cell concept in 1839. A practical, working model

of the concept was not constructed until a century later,

however. The earliest fuel cells carried out this energy con-

version by means of the reaction between hydrogen gas

and oxygen gas, and formed water as a by-product. In this

chemical reaction, each hydrogen atom loses one electron

to an oxygen atom. The exchange of electrons, from hydro-

gen to oxygen, is what characterizes an oxidation-reduction

reaction. A fuel cell thus creates a pathway through which

electrons lost by hydrogen atoms must flow before they reach

oxygen atoms. The cell typically consists of four basic parts:

an anode, a cathode, an electrolyte, and an external circuit.

In the simplest fuel cell, hydrogen gas is pumped into

one side of the fuel cell where it passes into a hollow, porous

anode. At the anode, hydrogen atoms lose an electron to

hydroxide ions present in the electrolyte. The source hydrox-

ide ions is a solution of potassium hydroxide in water. The

electrons released in this reaction travel up the anode, out

of the fuel cell, and into the external circuit, which carries

the flow of electrons (an electric current) to some device

such as a light bulb where it can be used. Meanwhile, a

second reaction is taking place at the opposite pole of the

fuel cell. Oxygen gas is pumped into this side of the fuel

cell where it passes into the hollow, porous cathode. Oxygen

atoms pick up electrons from the cathode and react with

water in the electrolyte to regenerate hydroxide ions.

As a result of the two chemical reactions taking place

at the two poles of the fuel cell, electrons are removed from

hydroxide ions at the anode, passed through the external

circuit where they can be used to do work, returned to

the cell through the cathode, and then returned to water

molecules in the electrolyte. Meanwhile, oxygen and hydro-

gen are used up in the production of water. A fuel cell such

as the one described here should have a voltage of 1.23 volts

and a theoretical efficiency (based on the heat of combustion

of water) of 83%. The actual voltage of a typical hydrogen/

oxygen fuel cell normally ranges between 0.6 to 1.1 volts

depending on operating conditions.

Fuel cells have many advantages as energy sources.

They are significantly more efficient than energy sources

such as nuclear or fossil-fueled

power plants

. In addition,

a fuel cell is technically simple and lightweight. Also, the

product of the fuel cell reaction —water— is of course harm-

less to humans and the rest of the

environment

. Finally,

Environmental Encyclopedia 3

Fuel cells

both hydrogen and oxygen, the raw materials used in a fuel

cell, are abundant in

nature

. They can both be obtained

from water, the most common single compound on the

planet.

Until recently, electricity produced from fuel cells was

more expensive than that obtained from other sources, and

they have been used in only specialized applications. One

of these is in spacecrafts, where their light weight represents

an important advantage. For example, the fuel cell used on

an 11-day Apollo moon flight, weighed 500 lb (227 kg),

while a conventional generator would have weighed several

tons. In addition, the water produced in the cell was purified

and then used for drinking.

A great many variations on the simple hydrogen/oxy-

gen fuel cell have been investigated. In theory, any fuel

that contains hydrogen can be used at the anode, while any

oxidizing agent

can be used at the cathode. Elemental

hydrogen and oxygen are only the simplest, most fundamen-

tal examples of each.

Among the hydrogen-containing compounds explored

as possible fuels are hydrazine,

methanol

, ammonia, and a

variety of

hydrocarbons

. The order in which these fuels

are listed here corresponds to the efficiency with which they

react in a fuel cell, with hydrazine being most reactive (after

hydrogen itself) and the hydrocarbons being least reactive.

Each of these potential alternatives has serious disadvan-

tages. Hydrazine, for example, is expensive to manufacture

and dangerous to work with.

In addition to oxygen, liquid oxidants such as hydrogen

peroxide and nitric

acid

have also been investigated as possi-

ble cathode reactants. Again, neither compound works as

efficiently as oxygen itself, and each presents problems of

its own as a working fluid in a fuel cell.

The details of fuel cell construction often differ de-

pending on the specific use of the cell. Cells used in space-

craft, for example, use cathodes made of

nickel

oxide or

gold and anodes made of a platinum alloy. The hydrogen

and oxygen used in such cells are supplied in liquid form

that must be maintained at high pressure and very low tem-

perature.

Fuel cells can also operate with an acidic electrolyte

such as phosphoric or a fluorinated sulfuric acid. The chemi-

cal reactions that occur in such a cell are different from

those described for the alkaline (potassium hydroxide) cell

described above. Fuel cells of the acidic type are more com-

monly used in industrial applications. They operate at a

higher temperature than alkaline cells, with slightly less effi-

ciency.

Another type of fuel cell makes use of a molten salt

instead of a water solution as the electrolyte. In a typical

cell of this kind, hydrogen is supplied at the anode of the

cell,

carbon dioxide

is supplied at the cathode, and molten

604

potassium carbonate is used as the electrolyte. In such a

cell, the fundamental process is the same as in an aqueous

electrolyte cell. Electrons are released at the anode. The

electrons then travel through the external circuit where they

can do work. They return to the cell through the cathode

where they make the cathodic reaction possible.

Yet a third type of fuel cell is now being explored, one

that makes use of state-of-the-art and sometimes exotic

solid-state technology. This is the high- temperature solid

ionic cell. In one design of this cell, the anode is made

of nickel metal combined with zirconium oxide while the

cathode is composed of a lanthanum-manganese alloy doped

with strontium. The electrolyte in the cell is a mixed oxide

of yttrium and zirconium. The fuel provided to the cell is

carbon monoxide

or hydrogen, either of which is oxidized

by the oxygen in ordinary air. A series of these cells are

connected to each other by connections made of lanthanum

chromite doped with magnesium metal.

The solid ionic cell is particularly attractive to

electric

utilities

and other industries because it contains no liquid,

as the other fuel cell designs do. The presence of such liquids

creates problems in the handling and maintenance of con-

ventional fuel cells that are eliminated with the all-solid cell.

The Proton Exchange Membrane (PEM) fuel cell and

Direct Methanol Fuel cells (DMFC) are similar in that

they both use a polymer membrane as the electrolyte, but a

DMFC has an anode catalyst that utilizes hydrogen from

liquid methanol, rather than from hydrogen gas. This im-

provement avoids the storage problems that are inherent

with the use of hydrogen gas. Other possibilities are made

up of stacks of fuel cells that use PEM-type technology. In

2001, the

U.S. Department of Energy

started a new pro-

gram designed to implement the development of efficient

and low-cost versions of these “planar solid-oxide fuel cells",

or SOFCs.

Some experts are enthusiastic about the future role of

fuel cells in the world’s energy equation. If costs for all these

emerging technologies can be reduced, their high efficiency

should make them attractive alternatives to fossil fuel- and

nuclear-generated electricity. The major concerns about fuel

cell technologies include the inability of fuel cells to store

power and the associated requirement that energy be gener-

ated on an “as needed” basis. Proposals have been made to

use pumped water, compressed air, and batteries to store

energy that is generated when times of demand are low.

For that reason, still more variations in the fuel cell

are being explored. One of the most intriguing of these

future possibilities is a cell no more than 0.04–0.07 in (1–

2 mm) in diameter. These cells have the advantage of a

greater electrode surface area on which oxidation and reduc-

tion occur than do conventional cells. The distance that

electrons have to travel in such cells is also much shorter,

Environmental Encyclopedia 3

Fund for Animals

resulting in their having a greater power output per unit

volume than that of conventional cells. The technology for

constructing and maintaining such small cells is not, how-

ever, fully developed. Because of more stringent clean air

standards, the

transportation

industry is especially inter-

ested in increasing

energy efficiency

of the

automobile

industry. The utility of

hybrid vehicles

that use conven-

tional fuels when accelerating and fuel cells for highway

driving is being investigated. These cars would use

gasoline

or methanol as a fuel source for both the conventional engine

and as a source of hydrogen for the fuel cells. Fuel cells are

also being researched for the aviation industry. An innovative

approach is to couple photovoltaic or solar cell technology

with fuel cell technology to provide a source of energy for

the plane that could be used day or night.

[David E Newton and Marie H. Bundy]

ESOURCES

OOKS

Hoffmann, Peter, and Tom Harkin. Tomorrow’s Energy: Hydrogen, Fuel

Cells, and the Prospects for a Cleaner Planet. Cambridge, MA: MIT

Press, 2001.

Hoogers, G., ed. Fuel Cell Technology Handbook. Boca Raton: CRC

Press, 2002.

Joesten, M. D., et al. World of Chemistry. Philadelphia: Saunders College

Publishing, 1991.

Larminie, James, and Andrew Dicks. Fuel Cell Systems Explained. New

York: John Wiley & Sons, 2000.

RGANIZATIONS

Argonne National Laboratory, 9700 S. Cass Avenue, Argonne, IL USA

60439 (630) 252-2000, <http://www.anl.gov>

DOE Office of Energy Efficiency and Renewable Energy (EERE),

Department of Energy, Mail Stop EE-1, Washington, DC USA 20585

(202) 586-9220, <http://www.eren.doe.gov>

The Online Fuel Cell Information Center, <http://www.fuelcells.org>

Fuel switching

Fuel switching is the substitution of one energy source for

another in order to meet requirements for heat, power, and/

or electrical generation. Generally, this term refers to the

practices of some industries that can substitute among

natu-

ral gas

, electricity,

coal

, and LPG within 30 days without

modifying their fuel-consuming equipment and that can

resume the same level of production following the change.

The

U.S. Department of Energy

estimates that among

manufacturers in 1991, 2.8 quadrillion Btus of energy con-

sumption could be switched from a total consumption of

about 20.3 quadrillion Btus, representing about 14%. Price

is the primary reason for fuel switching; however, additional

factors may include environmental regulations, agreements

with energy or fuel suppliers, and equipment capabilities.

605

Fugitive emissions

Contaminants that enter the air without going through a

smokestack and, thus, are often not subject to control by

conventional

emission

control equipment or techniques.

Most fugitive emissions are caused by activities involving the

production of dust, such as

soil erosion

and

strip mining

,or

building demolition, or the use of volatile compounds. In a

steel-making complex, for example, there are several identifi-

able smokestacks from which emissions come, but there are

also numerous sources of fugitive emissions, which escape

into the air as a result of processes such as producing coke,

for which there is no identifiable smokestack. The control

of fugitive emissions is generally much more complicated

and costly than the control of smokestack emissions for

which known add-on technologies to the smokestack have

been developed. Baghouses and other costly mechanisms

typically are needed to control fugitive emissions.

Fumigation

Most commonly, fumigation refers to the process of disin-

fecting a material or an area by using some type of toxic

material in gaseous form. The term has a more specialized

meaning in

environmental science

, where it refers to the

process by which pollutants are mixed in the

atmosphere

Under certain conditions, emitted pollutants rise above a

stable layer of air near the ground. These pollutants remain

aloft until convective currents develop, often in the morning,

at which time the cooler pollutants “trade places” with air

at ground level as it is warmed by the sun and rises. The

resulting damage to ecosystems from the pollutants is most

obvious around metal smelters.

Fund for Animals

Founded in 1967 by author and humorist

Cleveland

Amory

, the Fund is one of the most activist of the national

animal protection groups. Formed “to speak for those who

can’t,” it has led sometimes militant campaigns against sport

hunting

trapping

, and wearing furs, as well as the killing

whales

seals

, bears, and other creatures. Amory, in

particular, has campaigned tirelessly against these activities

on television and radio, and in lectures, articles, and books.

In the early 1970s, the Fund worked effectively to rally

public opinion in favor of passage of the Marine Mammal

Protection Act, which was signed into law in October 1972.

This act provides strong protection to whales,

seals and

sea lions

dolphins

, sea otters, polar bears, and other ocean

mammals. In 1978, the Fund bought a British trawler and

renamed it Sea Shepherd. Under the direction of its captain,

Environmental Encyclopedia 3

Fungi

Paul Watson, they used the ship to interfere with the baby

seal kill on the ice floes off Canada. Activists sprayed some

1,000 baby harp seals with a harmless dye that destroyed

the commercial value of their white coats as fur, and the

ensuing publicity helped generate worldwide to the seal kill

and a ban on imports into Europe. In 1979, Sea Shepherd

hunted down and rammed Sierra, an outlaw

whaling

vessel

that was illegally killing protected and

endangered species

of whales. After Sea Shepherd was seized by Portuguese au-

thorities, Watson and his crew scuttled the ship to prevent

it from being given to the owners of Sierra for use as a

whaler.

Also in 1979, the Fund used helicopters to airlift from

the Grand Canyon almost 600 wild burros that were sched-

uled to be shot by the

National Park Service

. The airlift

was so successful, and generated so much favorable publicity,

that it led to similar rescues of feral animals on public lands

that the government wanted removed to prevent damage to

vegetation. Burros were also airlifted by the Fund from

Death Valley National Monument, as were some 3,000 wild

goats on San Clemente Island, off the coast of California,

scheduled to be shot by the United States Navy.

Many of the wild horses, burros, goats, and other

animals rescued by the Fund end up, at least temporarily

before adoption, at Black Beauty Ranch, a 1430-acre (578-

ha) sanctuary near Arlington, Texas. The ranch has provided

a home for abused race and show horses, a non-performing

elephant, and Nim, the famous signing chimpanzee who

was saved from a medical laboratory.

Legal action initiated by the Fund has resulted in the

addition of almost 200

species

to the U.S. Department

of the Interior’s list of threatened and endangered species,

including the

grizzly bear

, the Mexican wolf, the Asian

elephant, and several species of kangaroos. The Fund is also

active on the grassroots level, working on measures to restrict

hunting and trapping

. A recent example is the passage of

an initiative in Colorado in November 1992 banning the

use of dogs and bait to hunt bears, and halting the spring

bear hunt, when mothers are still nursing their cubs.

[Lewis G. Regenstein]

ESOURCES

RGANIZATIONS

The Fund for Animals, 200 West 57th Street, New York, NY USA 10019

(212) 246-2096, Fax: (212) 246-2633, Email: hdquarters@fund.org,

<http://fund.org>

Fungi

Fungi are one of the five Phyla of organisms. Fungi are

broadly characterized by cells that possess nuclei and rigid

606

cell walls but lack chlorophyll. Fungal spores germinate and

grow slender tube-like structures called hyphae, separated by

cell walls called septae. The vegetative

biomass

of most

fungi in

nature

consists of masses of hyphae, or mycelia.

Most

species

of fungi inhabit

soil

, where they are active in

the

decomposition

of organic matter. The biologically most

complex fungi periodically form spore-producing fruiting

structures, known as mushrooms. Some fungi occur in close

associations, known as mycorrhizae, with the roots of many

species of vascular plants. The plant benefits mostly through

an enhancement of

nutrient

uptake, while the fungus bene-

fits through access to metabolites. Certain fungi are also

partners in the symbioses with algae known as

lichens

. See

also Fungicide

Fungicide

A fungus is a tiny plant-like organism that obtains its nour-

ishment from dead or living organic matter. Some examples

fungi

include mushrooms, toadstools, smuts, molds, rusts,

and mildew.

Fungi have long been recognized as a serious threat

to natural plants and human crops. They attack food both

while it is growing and also after it has been harvested and

placed into storage. One of the great agricultural disasters

of the second half of the twentieth century was caused by a

fungus. In 1970, the fungus that causes southern corn-leaf

blight swept through the southern and midwestern United

States and destroyed about 15% of the nation’s corn crop.

Potato blight, wheat rust, wheat smut, and grape mildew

are other important disasters caused by fungi.

Chestnut blight is another example of the devastation

that can be caused by fungi. Until 1900, chestnut trees were

common in many parts of the United States. In 1904, how-

ever, chestnut trees from Asia were imported and planted

in parts of New York. The imported trees carried with them

a fungus that attacked and killed the native chestnut trees.

Over a period of five decades, the native trees were all but

totally eliminated from the eastern part of the country.

It is hardly surprising that humans began looking for

fungicides—substances that will kill or control the growth

of fungi—early on in history. The first of these fungicides

was a naturally occurring substance, sulfur. One of the most

effective of all fungicides, Bordeaux mixture was invented

in 1885. Bordeaux mixture is a combination of two inorganic

compounds,

copper

sulfate and lime.

With the growth of the chemical industry during the

twentieth century, a number of synthetic fungicides have

been invented; these include ferbam, ziram, captan, naban,

dithiocarbonate, quinone, and 8-hydroxyquinoline.