Page 727 - Environment: The Science Behind the Stories

to islands of habitat (patches of one type of landrace A locally adapted domesticated vari- old lead pipes or ingesting dust or chips of old
habitat isolated within “seas” of others). As- ety of an agricultural crop native to a particular lead-based paint.
pects of the theory include immigration and area. legislation Statutory law.
extinction rates, the effect of island size (area landscape ecology The study of how landscape
effect), and the effect of distance from the structure affects the abundance, distribution, Leopold, Aldo (1887–1949) American scien-
mainland (distance effect). Full name is the and interaction of organisms. This approach tist, scholar, philosopher, and author. His book
equilibrium theory of island biogeography. The Land Ethic argued that humans should
to the study of organisms and their environ- view themselves and the land itself as mem-
isotope One of several forms of an element ments at the landscape scale focuses on broad bers of the same community and that humans
having differing numbers of neutrons in the geographical areas that include multiple eco- are obligated to treat the land ethically.
nucleus of its atoms. Chemically, isotopes of systems.
an element behave almost identically, but they landslide The collapse and downhill flow of levee See dike.
have different physical properties because they large amounts of rock or soil. A severe and life-cycle analysis A quantitative analysis of
differ in mass. inputs and outputs across the entire life cycle
sudden form of mass wasting.
of a product—from its origins, through its pro-
land trust A local or regional organization duction, transport, sale, and use, and finally its
jet stream A high-altitude air current that that preserves lands valued by its members. disposal—in an attempt to judge the sustain-
blows west to east, meandering north and In most cases, land trusts purchase land out- ability of the process and make it more ecologi-
south, and which influences weather across right with the aim of preserving it in its natural cally efficient.
much of North America and Eurasia. condition.
life expectancy The average number of years
La Niña An exceptionally strong cooling of sur- that individuals in particular age groups are
kelp Large brown algae or seaweed that can face water in the equatorial Pacific Ocean that likely to continue to live.
form underwater “forests,” providing habitat occurs every 2 to 7 years and has widespread
for marine organisms. climatic consequences. Compare El Niño. lifestyle hazard See cultural hazard.
kerogen A substance derived from deeply bur- latitudinal gradient The increase in species light pollution Pollution from urban or subur-
ied organic matter that acts as a source material richness as one approaches the equator. This ban lights that obscures the night sky, impair-
for both natural gas and crude oil. pattern of variation with latitude has been one ing people’s visibility of stars.
of the most obvious patterns in ecology, but light rail A mass transit rail system of trains
keystone species A species that has an espe- one of the most difficult ones for scientists to
cially far-reaching effect on a community. powered by electricity, often at a moderate
explain. scale.
kinetic energy Energy of motion. Compare lava Magma that is released from the litho-
potential energy. limiting factor A physical, chemical, or bio-
sphere and flows or spatters across Earth’s logical characteristic of the environment that
K–selected Term denoting a species with surface. restrains population growth.
low biotic potential whose members produce law of conservation of matter The physical
a small number of offspring and take a long law stating that matter may be transformed limnetic zone In a water body, the layer of
time to gestate and raise each of their young, from one type of substance into others, but that open water through which sunlight penetrates.
but invest heavily in promoting the survival it cannot be created or destroyed. Compare littoral zone; benthic zone; profundal
and growth of these few offspring. Popula- zone.
tions of K–selected species are generally regu- LD (lethal dose–50%) The amount of a toxi- lipids A class of chemical compounds that do
50
lated by density-dependent factors. Compare cant it takes to kill 50% of a population of test not dissolve in water and are used in organisms
r–selected. animals. Compare ED ; threshold dose. for energy storage, for structural support, and
50
kwashiorkor A form of malnutrition that re- leachate Liquids that seep through liners of a as key components of cellular membranes.
sults from a high-starch diet with inadequate sanitary landfill and leach into the soil under- liquefied natural gas (LNG) Natural gas that
protein or amino acids. In children, causes neath. has been converted to a liquid at low tempera-
bloating of the abdomen, deterioration and dis- leaching The process by which solid materials tures and that can be shipped long distances in
coloration of hair, mental disability, immune such as minerals are dissolved in a liquid (usu- refrigerated tankers.
suppression, developmental delays, anemia, ally water) and transported to another location. lithosols Soils with high mineral content and
and reduced growth.
lead A heavy metal that may be ingested low organic matter content. Common in de-
Kyoto Protocol An international agreement through water or paint, or that may enter the serts.
drafted in 1997 that called for reducing, by atmosphere as a particulate pollutant through lithosphere The outer layer of Earth, consist-
2012, emissions of six greenhouse gases to lev- combustion of leaded gasoline or other pro- ing of crust and uppermost mantle and located
els lower than their levels in 1990. It has been cesses. Atmospheric lead deposited on land just above the asthenosphere. More generally,
extended to 2020 until a replacement treaty and water can enter the food chain, accumulate the solid part of Earth, including the rocks,
can be reached. An outgrowth of the United within body tissues, and cause lead poison- sediment, and soil at the surface and extend-
Nations Framework Convention on Climate ing in animals and people. An EPA criteria ing down many miles underground. Compare
Change.
pollutant. atmosphere, biosphere, and hydrosphere.
Leadership in Energy and Environmental De- littoral Near the shore of a water body. See in-
land degradation A general deterioration of sign (LEED) The leading set of standards for tertidal.
land that diminishes its productivity and bio- sustainable building. Compare green building.
diversity, impairs the functioning of its ecosys- lead poisoning Poisoning by ingestion or inha- littoral zone The region ringing the edge of a
tems, and reduces the ecosystem services the lation of the heavy metal lead, causing an array water body. Compare benthic zone; limnetic
land can offer us. Compare desertification; soil of maladies including damage to the brain, zone; profundal zone.
degradation. loam Soil with a relatively even mixture of
liver, kidney, and stomach; learning problems
landfill gas A mix of gases that consists of and behavioral abnormalities; anemia; hear- clay-, silt-, and sand-sized particles.
roughly half methane produced by anaerobic ing loss; and even death. Lead poisoning can lobbying The expenditure of time or money in
G-12 decomposition deep inside landfills. result from drinking water that passes through an attempt to influence an elected official.

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