Unit 12- Oceans Study Guide

Sea

A large, commonly saline body of water that is smaller than an ocean and that may be partially or completely surrounded by land

Oceanography

The scientific study of the properties and movements of ocean water, the characteristics of the ocean floor, and the organisms that live in the ocean

Sonar

Sound navigation and ranging, a system that uses acoustic signals and returned echoes to determine the location of objects or to communicate

submersible

Underwater research vessels

Continetal Margin

The shallow sea floor that is located between the shoreline and the deep-ocean bottom

Deep-Ocean Basin

The part of the ocean floor that is under deep water beyond the continent margin and that is composed of oceanic crust and a thin layer of sediment

Continental Shelf

The part of the continent that is covered by water

Continental Slope

The seaweed edge of a continental shelf is a steeper slope

Turbidity Current

Canyons formed over time as a very dense current

Submarine Canyon

A deep V-shaped valley cut by the continental shelf and continental slope

Trench

A long, narrow, and steep depression that forms on the ocean floor as a result of subduction of a tectonic plate, that runs parallel to the trend of a chain of volcanic islands or the coastline of a continent, and that may be as deep as 11 km below sea level; also called an ocean trench or a deep-ocean trench

Abyssal Plain

A large, flat, almost level area of the deep-ocean basin

Mid-Ocean Ridges

Form underwater mountain ranges that run along the floors of all oceans

Abyssal Hills

Fault-bounded blocks of crust that form parallel to the ridges as the lithosphere cools and contracts

Seamounts

Submerged volcanic mountains that are taller than 1 km

Guyots/Tablemounts

When an island is taken away from its hotspot, the island sinks and erodes by waves to form flat-topped, submerged seamounts

Atoll

During the intermediate stage of a guyot being created

Nodule

A lump of minerals that is made of oxides of manganese, iron, copper, or nickel and that is found in scattered groups on the ocean floor

Inorganic Sediments

Tiny pieces of rock or minerals that come from non-living things

Biogenic Sediments

Bits of dead plants or animals, like shells or skeletons, that collect on the ground or seafloor

Muds

Soft, wet soil made of very fine particles like clay and silt

Ooze

Soft, deep-sea mud made mostly from tiny dead sea creatures

Salinity

How salty the water is

Thermocline

A layer in water where the temperature changes quickly with depth

Density

How heavy something is for its size

Upwelling

Movement of deep, cold, and nutrient-rich water to the surface

Plankton

Free-floating, microscopic plants and animals are base of complex food web

Nekton

All organisms that swim actively in open water

Banthos

Organisms that live on the ocean floor

Benthic Zone

Bottom region of oceans and bodies of fresh water

Pelagic Zone

Regions of an ocean or body of fresh water above the benthic zone

Desalination

The process of removing salt and other impurities from seawater to produce fresh water

Aquaculture

The raising of aquatic plants and animals for human use or consumption

Current

A horizontal movement of water in a well-defined pattern, such as a river or stream

Surface Current

A horizontal movement of ocean water that is caused by wind and that occurs at or near the oceans surface

Trade Winds

Winds that blow from east to west near the equator

Westerlies

Winds that blow from west to east in the middle parts of the Earth

Coriolis Effect

The curving of the path of a moving object from an otherwise straight path due to Earth’s rotation

Grye

A huge circle of moving ocean water found above and below the equator

Gulf Stream

The swift, deep, and warm Atlantic current that flows along the eastern coast of the United States toward the northeast

Deep current

A stream like movement of ocean water far below the surface

Wave

A periodic distribution in a solid, liquid, or gas as energy is transmitted through a medium

Wave Period

The time required for identical points on consecutive waves to pass a given point

Wind

Moving air caused by differences in temperature and pressure

Fetch

The distance that wind blows across an area of the sea to generate waves

Refraction

The process by which ocean waves bend directly toward the coastline as they approach shallow water

Tide

The periodic rise and fall of the water level in the oceans and other large bodies of water

Tidal Range

The difference in levels of ocean water at high tide and low tide

Tidal Oscillation

The slow, rocking motion of ocean water that occurs as the tidal bulges move around the ocean basins

Tidal Current

The movement of water toward and away from the coast as a result of the rise and fall of the tides