Alaska Sea Grant

Glossary

ABE - Autonomous Benthic Explorer - An Autonomous Underwater Vehicle designed at Woods Hole Oceanographic Institution in the 1990s. It is a true robot and can move on its own without being tethered to a ship or submersible. It can monitor underwater areas for long periods of time.

abiotic - Nonliving.

ablation - Reduction in volume of glacier ice by melting, calving, and evaporation.

abundance - A large amount.

abundant - Present in large numbers, plentiful.

abyssal currents - Currents deep in the ocean that cause cold, dense water, produced in high latitudes due to cooling by the atmosphere, to flow to the equator.

abyssal plains - Flat or very gently sloping areas of the deep ocean basin floor.

acoustic - Pertaining to hearing, sound, or the science of sound.

adapt - To adjust to different conditions, environment, etc.

adaptation - The gradual changing of structure, form or behavior of a plant or animal to increase its chances of survival and reproduction.

adult - A fully grown, mature organism.

advance - A glacier is said to advance when it grows or increases in volume.

albedo - The fraction of the total light striking a surface that gets reflected from that surface. An object that has a high albedo (near 1) is very bright; an object that has a low albedo (near 0) is dark. The Earth's albedo is about 0.37. The Moon's is about 0.12.

alevin - A salmon that has hatched and still has a yolk sack.

algae - Simple one-celled or many celled plant-like organisms, usually living in the water, that can make their own food through photosynthesis. They do not have true roots, stems, or leaves like plants and belong to the kingdom Protista. They can be microscopic, one-celled organisms or many-celled organisms up to 100 feet long.

amplitude - Height of a wave crest or depth of a wave trough. The amplitude of an ocean wave is the maximum height of the wave crest above the level of calm water, or the maximum depth of the wave trough below the level of calm water.

anadromous - A fish that lives in salt water, but spawns in fresh water.

aphelion - The point on the Earth's orbit that is farthest from the sun.

apogee - The point in the orbit of the moon that is farthest from the earth.

aquaculture - The farming of ocean and freshwater plants and animals for food.

aquatic - 1. Living or growing in water. 2. Taking place on or in water.

archaeology - The scientific study of past human life and culture by the examination of physical remains, such as graves, tools, and pottery.

arctic - The region lying north of the Arctic Circle or of the northernmost limit of tree growth.

array signal - A signal that comes from a group (or array) of hydrophones being towed by a ship.

aspect - The exposure, or direction that something faces, i.e. "southern aspect".

audio - Of or relating to the transmission, reception, or reproduction of sound.

autonomous - Independent.

AUV - Autonomous Underwater Vehicle - Autonomous Underwater Vehicles. Scientists can tell these machines where to go underwater. They will go to the sea floor, get information, and bring it back to the scientists.

balance - 1. A state of equilibrium; equal distribution of weight, amount, etc. 2. An instrument for determining weight, typically made up of a bar with a fulcrum at the center and with scales or pans at each end of the bar, one holding a known weight and the other holding the object to be weighed.

baleen - A flexible horny substance hanging in fringed plates from the upper jaw of some whales, called baleen whales. It is used to strain plankton from seawater when feeding.

ballast - Heavy material placed in the hold of a ship to make it more stable.

bathymetry - Measurements of the depths of the ocean floor. Data from the measurements gives information about the topography and features underwater.

bed - The rock surface underlying a glacier.

benthic - Relating to the bottom of the sea or other water body.

bidarki - Russian word for “boat".

biodegradable - Able to decompose naturally: made of substances that will decay relatively quickly as a result of the action of bacteria.

biodiversity - The number and variety of species within an area or region.

biological productivity - The rate at which organic matter is produced.

biopsy - The removal and examination of a sample of tissue from a living body for diagnostic purposes.

biotic - Living.

blog - Short for "weblog", a shared on-line journal where people post diary entries.

blubber - The fat layer between the skin and muscle of whales and some other marine mammals.

boundary - A border or limit.

bristles - Short, stiff hairs on certain animals.

cause - (noun) Something that produces an effect. A person or thing that acts, happens, or exists in such a way that something specific happens as a result. (verb) To be the cause of something.

change - To become different, or to cause something to become different.

characteristic - A feature that helps to identify, tell apart, or describe; a distinguishing mark or trait.

chiton - Mollusk with a muscular foot on the underside of its body and a shell that consists of eight, white, overlapping butterfly-shaped plates.

claim - Statement that something is true or factual.

claw - A pincerlike structure on the end of a limb of a crustacean or other arthropod.

climate - The general or average weather conditions of a certain region, including temperature, rainfall, and wind.

clue - Anything that serves to guide or direct in the solution of a problem or mystery.

collaboration - Working together, especially in a joint effort.

colleagues - Fellow members of a profession.

communication - The imparting or interchange of thoughts, opinions, or information by speech, writing, or signs.

community - The plants and animals living and interacting within a specific area.

compare - To examine (two or more objects, ideas, people, etc.) in order to note similarities and differences.

compression wave - A shock wave that compresses the medium through which it is transmitted.

concentration - A measure of the amount of dissolved substance contained per unit of volume.

concentric topography - Landforms that are circular in shape, with a common center.

condensation - The opposite of evaporation. Condensation occurs when a gas is changed into a liquid.

condense - Water vapor that changes into a liquid.

conservation - The protection, preservation and careful management of the environment and of natural resources such as forests, soil, and water.

consumer - An organism, usually an animal, that feeds on plants or other animals.

continental shelf - The extended perimeter of each continent and associated coastal plain, covered by shallow seas and gulfs.

contour - The outline of a figure or body; the edge or line that defines or bounds a shape or object.

contour line - A line on a map that joins points of equal elevation.

contribution - Act of giving in common with others for a common purpose.

controversy - Strong disagreement between opposing points of view.

conference - (as in scientific conference) A formal meeting of members of a profession to discuss matters of common concern.

conveyor belt - The global system of currents that carries heat in the ocean and helps to moderate Earth's climate.

copepod - A tiny marine animal (crustacean) with a long body, a forked tail, and usually six pairs of limbs. They are an important food source for many water animals.

creek - A stream smaller than a river.

crest - The top or highest peak of a wave.

crevasse - A deep fissure, crack, or cleft in glacier ice.

crustacean - An aquatic invertebrate animal such as a lobster, crab, shrimp, or barnacle, characteristically having a segmented body, a hard shell, and paired, jointed limbs. A member of the class Crustacea and phylum Arthropoda.

current - A steady, smooth onward movement or flow.

cyst - Dormant brine shrimp eggs.

data - Individual facts, statistics, or items of information.

data collection - A process of gathering and preparing data.

decompose - To rot or decay.

decomposition - The process of rotting or decay. The process of breaking down organic material, such as dead plant or animal tissue, into smaller molecules that are available for use by the organisms of an ecosystem. Decomposition is carried on by bacteria, fungi, protists, worms, and certain other organisms.

dense - Crowded close together or compact.

density - The mass per unit of volume; compactness.

derelict - Deserted or abandoned.

details - Small, individual parts or items; particulars.

detective - A person who obtains evidence or information.

develop - To progress from an embryonic to an adult form.

diatom - Any of numerous microscopic, unicellular, marine or freshwater algae of the phylum Chrysophyta, having cell walls containing silica.

diffusion - The process in which there is movement of a substance from an area of high concentration of that substance to an area of lower concentration.

display - To show or exhibit.

diurnal tides - "daily" tides with one high and one low in a 24-hour period.

diversity - Variety; a variety of something such as plants and animals in an ecosystem.

ebb - To flow back or away.

ecological - Having to do with ecology, which is the science of the relationships between organisms and their environments.

ecosystem - A system formed by the interaction of a community of organisms with their environment.

eddy - A current moving in a direction that is different from the main current; usually currents involve circular motion.

edifice - A building, usually one that is large and imposing.

embryo - An animal in a developmental stage before birth or hatching.

endangered - A population of an organism which is at risk of becoming extinct because it is either few in number, or threatened by changing environmental or predation.

endemic - Native to or confined to a specific region.

enigmatic - Perplexing or mysterious.

equilibrium - A state of balance; a glacier is in equilbrium when it is neither advancing nor retreating because the accumulation of new ice balances the ice lost to melting, calving, and evaporation.

estimate - An approximate judgment or calculation, as of the value, amount, time, size, or weight of something.

estuary - The mouth of a river where fresh water meets and mixes with salt water.

etiquette - Rules and requirements for proper conduct and behavior.

euphotic - Pertaining to the layer or zone of water that receives enough sunlight for photosynthesis to occur.

evaporate - To convert or change into a vapor.

evaporation - Process in which the heat energy of the sun causes the water on the Earth’s surface to change into a vapor.

evidence - Information or other thing(s) helpful in forming a conclusion or in providing a basis for believing that something is true.

exoskeleton - A hard protective structure on the outside of the body.

expert - A person who has special skill or knowledge in some particular field; specialist; authority.

explanation - A statement or thought that makes something understandable.

extinction - Coming to an end or dying out so that the species no longer exists. A species becomes extinct when the last existing member of that species dies.

features - A part or detail that stands out; a prominent or conspicuous part or characteristic.

firn - Granular, partially consolidated snow that has passed through one summer melt season but is not yet glacial ice.

flood - The rise or flowing in of the tide.

flotsam and jetsam - Material or refuse floating on the water.

fluctuate - To change continually or shift back and forth.

food - Interconnected feeding relationship of who eats whom in an ecosystem, starting with algae and plants and ending with the carnivores.

forum - A means (as a newspaper or online service) of open discussion or expression of ideas.

frequency - The number of crests of a wave that move past a given point in a given unit of time.

fry - A young salmon that is free-swimming and feeding.

geophysicist - A geologist who studies the physics of earth and its atmosphere.

glacier - A huge mass of ice, formed on land by the compaction and recrystallization of snow, that moves very slowly downslope or outward due to its own weight.

Global Positioning System (GPS) - A system of satellites, computers, and receivers that is able to determine the latitude and longitude of a receiver on Earth by calculating the time difference for signals from different satellites to reach the receiver.

gravity - The natural force of attraction exerted by the Earth (or another celestial body) upon objects at or near its surface, tending to draw them toward the center of the body.

groundwater - Water stored underground in rock crevices and in the pores of geologic materials that make up the earth's crust.

gyre - A spiral oceanic surface current driven primarily by the global wind system and constrained by the continents surrounding the three ocean basins (Atlantic, Pacific, and Indian). Each ocean basin has a large gyre in the subtropical region, centered around 30° north and south latitude. Smaller gyres occur at 50° north latitude in the North Atlantic and Pacific Oceans. The direction of a gyre's rotation is determined by the prevailing winds in the region, with the large subtropical gyres rotating clockwise in the Northern Hemisphere and counterclockwise in the Southern Hemisphere.

habitat - The natural place where an organism lives and grows.

harvest - To gather, catch, take or remove for use.

hazardous - Risky; dangerous.

HMI lights - Hydrargyrum medium-arc iodide. These lights are two to four times brighter than ordinary lights, are less sensitive to shock and vibration, and produce a steady, natural light. They are used commonly with ROVs.

holdfast - A structure anchoring seaweeds to rocks and other hard surfaces.

HOV - Human Occupied Vehicle - A submersible vehicle that can take people into the depths of the ocean.

hydrographic survey - The process of gathering information to describe the seafloor.

hydrological - Having to do with the scientific study of water on the earth's surface, in the soil and underlying rocks, and in the atmosphere.

hydrophone - A device used to detect or monitor sound under water.

hydrothermal - Relating to or produced by hot water, especially water heated underground by the Earth's internal heat.

hypothesis - A tentative explanation for an observation, phenomenon, or scientific problem that can be tested by further investigation.

inextricably - Unavoidably, inescapably.

infiltration - An important process where rain water soaks into the ground, through the soil and underlying rock layers.

interconnect - To connect reciprocally, to operate as a unit, to be interwoven.

interconnectedness - The state of being connected to each other.

intertidal - The area between the high tide mark and the low tide mark on a seashore.

invertebrate - A creature without a backbone.

investigate - Examine, study, or inquire in detail.

investigation - Searching for facts; detailed or careful examination.

isostatic rebound - The rise of land masses that were depressed by the huge weight of ice sheets during the last glacial period.

justification - The section of a proposal that explains the need for a project and the reasons that a project should be supported.

kelp - Large, brown seaweeds with strong holdfasts.

kelp forest - A place where large numbers of kelp grow near each other, forming a “forest".

keystone - A species that is expecially important in an ecosystem because it has an unusually strong effect on other organisms within the system. It might be an important predator or an organism like a coral or a beaver that alters the habitat around it.

kinetic energy - The mechanical energy that a body has as a result of its motion.

lagoon - A shallow channel or pond near or connected to a larger body of water.

larvae - An early form of any animal that is very different from its parents at birth or hatching.

leather chiton - A small chiton, with a tough, black, leathery covering on its back. Its scientific name is Katherina tunicata, with the first name, or genus, in honor of a woman scientist, Lady Katherine Douglas.

LIDAR - Light Detection and Ranging. LIDAR sends laser light from the bottom of an airplane to the sea floor.

life cycle - The series of stages of form and activity through which a living thing passes from a beginning stage (as an egg) in one individual to the same stage in its offspring.

living - To be alive.

magma - Molten material beneath or within the earth's crust, from which igneous rock is formed.

magnify - 1. To increase in importance. 2. To enlarge in fact or in appearance.

mariculture - Cultivation of marine organisms in their natural habitats, usually for commercial purposes. Also called ocean farming.

marigram - A graph that depicts the rise and fall of the tide.

marine biologist - A person who studies the living organisms in the ocean or other marine or brackish bodies of water.

marine - Usually applies to floating waste such as bottles, cans, styrofoam, cruise ship waste, offshore oil and gas exploration and production facilities pollution, and fishing gear from professional and recreational boaters. Marine debris is also called litter.

mercator projection - a map projection of the earth onto a cylinder, on which the meridians and parallels of latitude appear as lines crossing at right angles, and areas appear greater the farther they are from the equator.

meteorological - Pertaining to the atmosphere or weather.

methane - A colorless, odorless, flammable gas that is the major constituent of natural gas and is released during the decomposition of plant or other organic compounds, as in marshes and coal mines.

microbe - A very small organism (usually called a microorganism).

microscopic - Something so small that it is able to be seen only through a microscope.

mid-atlantic ridge (MAR) - a long narrow north-south mountain range on the floor of the Atlantic Ocean that runs from Iceland to Antarctica.

mid-ocean ridge - A long mountain range on the ocean floor, extending almost continuously through the North and South Atlantic Oceans, the Indian Ocean, and the South Pacific Ocean. A deep rift valley is located at its center, from which magma flows and forms new oceanic crust. As the magma cools and hardens it becomes part of the mountain range.

mixed semi-diurnal tides - Tides that have two highs and two lows in each 24-hour period, with the two highs being quite different in height.

mollusk - Marine invertebrate having a soft unsegmented body. They usually have a shell of one, two, or more pieces that protect the body. Snails, bivalves, chitons, squid and octopuses are mollusks. .

multibeam sonar - Measures the depth of the sea floor. It measures the length of time it takes for the sound to travel from the boat to the sea floor and back as an echo.

mystery - Something that is secret, unexplained, or unknown.

nautical chart - A special kind of map that shows the coastline and tells boaters about things under the water.

navigation - Finding our way from one place to another.

neap tides - A lower than average tide that occurs twice each month when the sun and moon are at right angles to the earth.

non-living - Not alive; not endowed with life.

observation - Noticing; watching carefully.

ocean - A vast body of water occupying a major part of the earth's surface.

oceanic basin - A large depression covered by sea water. Geologists do not consider continental shelves, deep ocean trenches, underwater mountain ranges and other features to be part of the oceanic basin, but hydrologists consider ocean basins to include the shelves and shallow seas.

oceanic trenches - Very long but narrow topographic depressions of the sea floor. They are also the deepest parts of the ocean floor. They occur where two lithospheric plates come together.

organism - A living thing with the ability to act or function independently.

parr - The vertical stripes and bars found on the sides of juvenile salmon that help to camouflage them.

pelt - The skin of an animal.

perigee - The point in the orbit of the moon or a satellite that is nearest the earth's center .

perihelion - The point in the orbit of a planet or comet at which it is nearest to the sun.

photosynthesis - The process in green plants and certain other organisms by which carbohydrates are made from carbon dioxide and water using sunlight as an energy source.

phytoplankton - Tiny free-floating aquatic plants and plant-like organisms. Phytoplankton are photosynthetic and form the beginning of the food chain for aquatic animals.

pincers - 1. A claw (as of a lobster) resembling a pair of pincers. 2. An instrument having two handles and two jaws that is used to grip things.

plankton - The tiny, floating plants and animals drifting in the ocean currents; the food of filter-feeders.

plot - A small area of ground.

pollutant - Something that pollutes, especially a waste material that harms the air, soil, or water.

pond - A body of water usually smaller than a lake.

precipitation - Forms of condensed water vapor that are heavy enough to fall to Earth; rain, sleet, snow.

predation - The capturing of prey in order to survive.

predator - An animal that lives by capturing and eating other animals.

preservation - To keep safe from harm or injury; protect or spare.

pressure - The force per unit area that one region of a gas, liquid, or solid exerts on another. Pressure is usually measured in Pascal units, atmospheres, or pounds per square inch.

prey - An animal hunted or caught for food.

producer - An organism, such as a plant, that is able to produce its own food from nonliving substances.

protocol - Detailed plan or rules for collecting data or carrying out an experiment or scientific study.

prove - To show to be true or correct.

quadrat - A square or rectangular plot of land marked off for the study of plants and animals.

radula - A hard, file-like rasping band with many tiny teeth, that extends out of the mouth on the underside of the animal to scrape algae and other small organisms off rocks in the intertidal zone.

random sampling - The selection of a random sample in such a way that each element of the population has an equal chance of been selected.

recede - To retreat or withdraw.

recolonize - To migrate to, settle in, and occupy again.

redd - A gravel area in a stream bed where a female salmon digs a hole and lays her eggs.

relief - The differences in elevation and slope between the higher and lower parts of the land surface of a given area.

retreat - To move back. A glacier retreats when it is losing more ice due to melting, calving, and evaporation than it is gaining from the addition of new snow.

rift valley - Deep undersea valley located along the center of the mid-ocean ridge. It is associated with the crustal thinning spreading that causes magma to upwell onto the ocean floor.

river - Water flowing in a channel towards the sea or a large lake.

rookery - A breeding ground or colony of birds or other animals.

ROV - Remotely Operated Vehicle - a tethered underwater robot. ROVs are unoccupied, highly maneuverable and operated by a person aboard a vessel. They are linked to the ship by a cable.

runoff - Much of the water that returns to Earth as precipitation runs off the surface of the land, and flows down hill into streams, rivers, ponds and lakes.

rupture - To break open or burst.

salinity - The relative proportion of salt in a solution.

sample - (verb) To test or examine a portion, piece, or section that is representative of a whole. (noun) Items selected at random from a population and used to test hypotheses about the population.

scatterplot - A graph with points plotted to show the relationship between two variables.

scavenger - An animal or other organism that feeds on dead organic matter.

sea - A great body of salty water that covers much of the earth; ocean.

seamount - An underwater mountain rising from the ocean floor and having a peaked or flat-topped summit below the surface of the sea.

sea urchin - A shallow-water animal (echinoderm) that has a soft body enclosed in a thin,spiny, globe-shaped shell.

segments - Any of the parts into which a thing is divided or naturally separates.

semi-durnal tides - Tides that have two high tides and two low tides of about the same height.

semipermanent - Extending over a relatively long time; not quite permanent.

serial - Occurs when a predator or predators reduce their prey populations in sequence,first greatly reducing numbers of one prey species, then switching to an alternative prey speciesuntilseveral prey species become scarce.

shelter - Something that covers or protects.

side scan sonar - Creates a picture or an image of the sea floor. It measures the strength of how "loud" the return echo is, and paints a picture.

sinewave - An s-shaped, smooth, regular wave that oscillates above and below zero.

slough - A marshy or reedy pool, pond, inlet, or backwater.

smolt - A young salmon preparing to enter salt water.

sonar - SOund NAvigation and Ranging) is a technique that uses sound propagation (usually underwater) to navigate, communicate or to detect other vessels. The study of underwater sound is known as underwater acoustics or sometimes hydroacoustics.

sonar screen - A screen on which sonar measurements are observed.

sonobouy - A buoy equipped with an acoustic receiver and a radio transmitter that emits radio signals when it detects underwater sounds.

spawn - The act of fish depositing eggs or sperm directly into the water.

spectrogram - A photograph, map, or diagram of a spectrum.

spring tides - The exceptionally high and low tides that occur at the time of the new moon or the full moon when the sun, moon, and earth are approximately aligned.

stewardship - The responsibility to take care of our natural resources to ensure that they are sustainably managed for current and future generations. Stewardship of the environment can include recycling, conservation, and restoration.

submersible - A vessel capable of operating or remaining under water.

subsistence - A system of farming or fishing or gathering that provides all or almost all the goods required by a family.

subtidal - Describes the area below the intertidal zone, which is always under water.

sustainability - To be able to keep in existence; maintain at a certain level.

sustainable - Use of an ecosystem’s resources (such as water or trees) so that is has time to replenish what is used and continues to meet the needs of the organisms that depend on it.

systematic sampling - A statistical or field sampling method involving the selection of samples at set intervals. For example, every fifth number might be selected, or a sample might be taken every 3 meters.

tally - A number or group of items recorded.

tectonic - The forces or conditions within the earth that cause movements of the crust.

telepresence - A set of technologies which allow a person to feel as if they were present at a location other than their true location.

temporary - Lasting for a short period of time; not permanent.

terminus - The end or extremity of anything; the end of a glacier at any given point in time.

thermal expansion - The tendency of matter to change in volume in response to a change in temperature.

thermocline - A distinct layer in a large body of water, such as an ocean or lake, in which temperature changes more rapidly with depth than it does in the layers above or below.

thermohaline - Derives from thermo- referring to temperature and -haline referring to salt content, factors which together determine the density of sea water and thus create currents and circulation within the ocean.

tidal current - A current caused by the motion of tides.

tidal range - The difference in height between high and low tides.

tide - The periodic rise and fall of the waters of the ocean and its inlets, produced by the attraction of the moon and sun, and occurring about every 12 hours.

timed - Counting something or several things for a certain period of time.

topographic map - A map showing the relief features of the earth's surface, usually by means of contour lines to show changes in elevation.

topography - The relief features or surface configuration of an area.

transient - Staying in a place only a short time.

transparency - The property or quality of transmitting rays of light through its substance so that bodies situated beyond or behind can be distinctly seen.

transpiration - As plants absorb water from the soil, the water moves from the roots through the stems to the leaves. Once the water reaches the leaves, some of it evaporates from the leaves, adding to the amount of water vapor in the air. This process of evaporation through plant leaves is called transpiration.

trehalose - A substance that protects brine shrimp from drying out, or getting too hot or cold.

trough - The part of a wave with the least magnitude; the lowest part of a wave.

tsunami - A very large ocean wave caused by an underwater earthquake or volcanic eruption.

turbidity - Muddiness created by stirring up sediment or having foreign particles suspended.

underfur - The fine, soft, thick, hairy coat under the longer and coarser outer hair in certain animals, as seals, otters, and beavers.

uniform - The same always or everywhere; not changing or varying.

urchin - (See sea urchin).

vernal - Temporary pools of water that usually form in the spring, dries out in the summer and reforms in the fall.

vertical circle - A great circle on the celestial sphere passing through the zenith (the point that is directly above the observer) and perpendicular to the horizon.

vocalization - The act of making sounds with the voice.

volcanic arc - A usually arc-shaped chain of volcanoes located on the margin of the overriding plate at a boundary where two crustal plates come together.

water cycle - Continuous movement of water from the oceans and fresh water sources to the air and land and then back to the oceans.

watershed - An area of land from which rainwater and snowmelt drain into a particular river, stream, or lake, which is the lowest point in the surrounding landscape. All watersheds are connected, directly or indirectly, to the ocean.

wave - One of a series of ridges that moves across the surface of a liquid (especially across a large body of water).

wave height - The vertical distance between trough and crest, usually expressed in feet.

wave length - The distance between corresponding parts of any two successive waves, i.e. the distance from crest to crest .

wave period - The duration of one cycle of a wave; the time that it takes for the whole wave to pass a stationary point.

weight - Most of the available evidence; the best evidence.

zooplankton - Tiny, free-floating animals and animal-like organisms, including mainly small crustaceans and fish larvae.

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