Glossary
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algae: a diverse group of photosynthetic marine organisms that includes seaweeds.
aerobic: used to describe 1) an organism that
can live only with free oxygen, or 2) an environment containing
free oxygen.
anaerobic: used to describe 1) an organism that can live without
free oxygen, or 2) an environment that contains no free oxygen.
anoxic: completely lacking free oxygen (O2)
archaea: micro-organisms that belong to a major division of
life, as different from bacteria as humans are.
asthenosphere: the layer in the Earth below the lithosphere
that is weak, probably due to the presence of some molten material.
It is this weak layer that allows the tectonic plates to move.
Austral: relating to or coming from the south, especially the southern hemisphere
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bacteria: a single-celled microorganism that
lacks a nucleus
bathymetric map: a map of the bottom of the
ocean, with water depths indicated by contours that join points
of equal water depth
benthos: organisms that live on or in the sediments of the seafloor
biofilm: a thin, slimy mat of bacteria and chemicals they produce.
biomass: the organic material that makes up the body of a plant, animal, or other organism.
black smoker: a chimney-like structure on the
seafloor made of metal sulfides, out of which hot (~350°C)
fluids that look like black smoke flow. The black color of the
fluid is due to mineral particles within it
brine: salty water
buoyancy: the tendency of a body or fluid to rise when it is
less dense than its surroundings.
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carbohydrates: compounds composed of carbon, hydrogen and oxygen,
including sugars and starches.
chemosynthesis: the process by which bacteria
use energy from chemicals, such as hydrogen sulfide, to combine
water and carbon dioxide to produce carbohydrates
climate: the accumulation of daily and seasonal
weather events over a long period of time. The sum of all statistical
weather information that helps describe a place or region.
cold seeps: A place on the seafloor where chemicals such as hydrocarbons and sulfides leak to the surface from below to support a variety of organisms.
consumer: organisms that get their energy from eating other
convection: the circulatory motion that occurs in fluids due
to differences in temperature, which cause variations in density.
converging plate boundary: boundary along which two lithospheric
plates are moving towards each other; e.g. the Himalayas are
forming as two plates collide.
coral: colonial animal that secretes a hard
outer calcareous (calcium carbonate) skeleton.
crust: the outermost shell of the Earth, made
of different materials depending on whether it is oceanic or
continental crust.
CTD (conductivity/temperature/depth): One of the most commonly
used electronic instruments in oceanography, which is lowered
on a conducting cable from a ship to measure the temperature,
pressure and electrical conductivity of ocean water and the height
above the seafloor. From these measurements, scientists can calculate
water depth, salinity, and density. By letting cable out or pulling
it in, scientists can measure water properties at different depths.
Some CTDs have batteries and computers that allow them to be
self-recording so they can be moored in one spot to make measurements
for days or months.
cyanobacteria: an abundant type of bacteria that use photosynthesis to live and grow, but are also capable of converting nitrogen gas from the atmosphere into other forms of nitrogen that they and other organisms need to live and grow.
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detritus: non-living organic material that typically includes the bodies or fragments of dead organisms as well as fecal material
DHAB: Deep Hypersaline Anoxic Basin
dispersant: a chemical used to break up large concentrations of oil
diverging plate boundary: a boundary between
two plates that are moving apart, where volcanic activity is
creating new oceanic crust - the mid-oceaen ridge is an example.
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East Pacific Rise: a part of the mid-ocean
ridge system running northeasterly from near New Zealand to just
off the coast of Mexico in the Gulf of California. There is a
lot of volcanic activity associated with this seafloor spreading
center, as well as many hydrothermal vents.
earthquake: movement (shaking or sudden motion)
of the Earth caused by the rapid release of strain.
ecology: the study of the relations between
organisms and their environment.
ecosystem: a unit in ecology consisting of
the community of organisms and the environment in which it lives.
enzymes: proteins that trigger or speed up specific biochemical reactions.
eukaryote: any organism whose cells contain a nucleus and membrane-bound organelles such as mitochondria; includes single-celled organisms such as protists and multicellular organisms such as plants and animals (including humans)
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food chain: a sequence of feeding relationships
by which energy is transferred from primary producers to consumers.
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geophysics: a field of geology using the principles
of physics to explore the structure and physical characteristics
of the Earth
geyser: a type of hot spring seen on land that episodically
erupts jets of hot water and steam. It results from ground water
being heated by coming in contact with hot rock deep in the Earth's
crust, and then rising to the surface.
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halocline: zone where the concentration of salt changes from high to low
halophile: organism that thrives in a high-salt environment
hydrogen sulfide: a colorless, poisonous gas
with an odor of rotten eggs.
hydrothermal: pertaining to hot water.
hydrothermal deposit: a mineral deposit formed from precipitation
of minerals from fluids.
hydrothermal plume: A cloud of hot, mineral-rich water that
flows out of a hydrothermal vent and disperses into the ocean,
usually several hundred meters above the seafloor vent site.
Rock particles and minerals in the plume water often make the
plume look smoky, like a cloud of ash over an erupting volcano.
hydrothermal system: a system of circulation of fluid caused
by a heat source (often a magma chamber or hot rock) in which
water flows into the crust in one area (the recharge zone) and
out of the crust in another area (the discharge zone).
hypersaline: environment that has a very high concentration of salt
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igneous rock: a rock that solidified from molten
or partly molten material, i.e. magma.
in situ: Latin phrase for “in place.” A procedure done in situ is done where the sample was collected, rather than back in the lab or on a ship.
island arc: series of volcanic islands that are built above
a subduction zone.
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krill: shrimp-like planktonic crustaceans; an abundant and major food source for Antarctic animals such as whales, fish, and penguins.
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latitude: The angular distance north or south from the Earth’s
equator, measured in degrees, minutes, and seconds. One degree
equals 60 nautical miles. A combination of latitude and longitude
can be used to locate any spot on the earth’s surface.
lava: Melted, or molten, rock is called magma
if it is below the earth's surface, and lava if it reaches the
earth's surface.
lithosphere: a strong layer of the Earth, about 100 km in thickness,
consisting of the Earth's crust and a portion of the underlying
upper mantle. This layer lies on top of the weaker asthenosphere.
longitude: The angular distance east or west from a meridian
drawn between the North Pole to the South Pole and passing through
Greenwich, England, measured in degrees, minutes, and seconds.
A combination of latitude and longitude can be used to locate
any spot on the Earth’s surface.
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mantle: the 2900 km thick zone of the Earth
below the crust and above the mantle made up of minerals that
contain iron, silica, magnesium and oxygen.
metabolic rate: a measure of how quickly an organism uses energy.
metal: an element, such as iron or copper, that are good conductors
of heat and electricity, and have a characteristic luster.
metal sulfide: a mineral in which the element sulfur is linked
with a metal, such as iron sulfide in the mineral pyrite, commonly
known as fool's gold.
metamorphic rock: a rock derived from a pre-existing rock that
has been changed in its minerals, chemistry and structure in
response to changes in temperature, pressure and stress.
metazoan: any multicellular organism.
microbe: a microscopically visible organism
in the size range of 1/100 to 1/1000 millimeter, mostly consisting
of only a single cell. Individual Bacteria and Archaea are microbes.
mid-ocean ridge system: The volcanic mountain
chain that is formed by volcanic activity at the boundary between
two tectonic plates that are drifting apart. Molten rock from
the mantle below rises to the surface and solidifies to form
new oceanic crust.
mineral deposit: Accumulation of naturally occurring minerals.
mutualism: the form of symbiosis in which both participants benefit
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organelle: structure, located inside a cell, that has a specific function and is surrounded by a membrane. Examples are mitochondria and Golgi apparatus.
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photosynthesis: The process by which green plants use energy
from the sun to combine water and carbon dioxide to produce carbohydrates
and oxygen.
phytoplankton: small or microscopic photosynthetic organisms that float or drift in great numbers in fresh or salt water near the surface and are the base of the ocean food chain
pillow lava: lava that erupts under water and forms rocks that
display a typical rounded, pillow shape.
plate: a rigid piece of the Earth's lithosphere
that moves horizontally and interacts with other plates along
its boundaries.
plate boundary: zones of seismic and tectonic
activity along the edges of lithospheric plates.
plate tectonics: the idea that the Earth's lithosphere can be
divided into a number of plates that move and interact with each
other along their boundaries.
primary producers: living things that produce their own food
(e.g., bacteria and plants).
prokaryote: single-celled organism that lacks a nucleus and membrane-bound organelles. Includes bacteria and archaea.
protist: mostly single-celled eukaryotic organism. It has a nucleus and organelles. Examples include Amoeba, Paramecium, and Trypanosoma.
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radiocarbon dating: a method of dating material
that contains the element carbon. The method uses isotopes of
carbon, and can determine the age of materials as old as 70,000
years.
redox reaction: short for “reduction-oxidation.” A chemical reaction involving the exchange of electrons between two atoms or molecules, releasing energy in the process.
remote sensing: way of getting information about an object without
having the measuring device in direct contact with it. Examples
include radar’s use of radio waves and sonar’s use of sound waves
to detect objects.
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salinity: A measure of dissolved salts in sea water. It is calculated as the amount of salt (in grams) dissolved in 1,000 grams (1 kilogram) of seawater.
salps: transparent, barrel-shaped planktonic marine animals found singly or in chains that sometimes reach 20 feet in length
seafloor speading: area where two tectonic
plates are moving apart (diverging), opening the seafloor and
allowing magma to rise and form new oceanic crust.
seamount: an extinct, underwater volcano that
rises more than 1 km above the seafloor but whose peak is below
the sea surface.
sediment trap: an oceanographic instrument used to collect material floating down to the seafloor from above
sedimentary rock: a rock formed from the consolidation
seep: A small area where water – that may be of a different
temperature and density flows from below the seafloor and rises
slowly into the ocean.
seismic wave: waves generated either by an earthquake or artificially.
sonar: acronym for sound navigation and
ranging. A device that is used primarily for the detection
and location of underwater objects by reflecting acoustic (sound)
waves from them.
subduction zone: the region where one lithospheric plate descends
beneath another as the two plates are moving towards each other.
It is characterized by a line of earthquakes that demarcate the
upper edge of the descending plate.
symbiosis: close physiological relationship between two different organisms for the majority of their life cycles. If the relationship benefits both organisms, it is called mutualism. If one organism benefits at the expense of the other, it is called parasitism. If one organism benefits and the other is neither helped nor harmed, it is called commensalism.
symbiotic algae: algae (a simple type of plant
that can photosynthesize) that live together with another organism
in a mutually beneficial relationship.
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tectonics: a field of geology dealing with processes that shape
the Earth's surface.
transform fault: a type of plate boundary where
two plates slide past each other.
transponder: An acoustic device that scientists place above
the seafloor, usually in groups of two or more, to help them
navigate deep submergence vehicles. To locate a transponder,
a ping is broadcast from a ship to the seafloor. If the transponder
hears the ping, it sends a reply ping, letting researchers know
they’re in the right place. The transponder and its batteries
are protected inside a plastic case the size of a beach ball,
and can operate from the seafloor for up to five years.
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uranium-series dating: a method of dating material
that contains elements that have been formed by radioactive decay
of uranium.
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volcanic eruption: ejection of hot steam, molten
rock, and/or rock fragments through openings in the earth's surface.
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water mass: a body of seawater that shares
the same origin. Each water mass has characteristic temperatures
and salinities.
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zooplankton: small or microscopic animals that float or drift in great numbers in fresh or salt water near the surface and are the base of the ocean food chain.
Credit: Tasa Graphic Arts, Inc.
Tasa Graphic Arts, Inc. has been illustrating college textbooks
since 1978, specializing in the area of geology and geography.
In 1993 they began producing earth science educational computer
software on CD-ROM.
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