| A | B |
|---|
| abyssal plain | the flattest part of the ocean floor, beginning at the base of the continental slope |
| adaptation | a physical structure or a behavior that enables an organism to survive in its environment |
| bivalve | a type of mollusk whose body is enclosed in a two-part, hinged shell. Examples include clams, oysters, and scallops |
| breaker | a wave that topples over as it approaches shallow water |
| buoyancy | the ability to float |
| cold-blooded | having an internal body temperature that changes with the temperature of the environment. Fish, amphibians, and reptiles are examples of cold-blooded animals |
| condensation | (1) the process of changing from a gaseous to a liquid sate. (2) the liquid that results from such a process |
| continental shelf | a gently sloping, submerged border of a continent that extends out from the coastline |
| continental slope | the steep incline at the edge of the continental shelf, where the ocean floor descends to the abyssal plain |
| Coriolis effect | the deflective force of Earth's rotation on its axis, causing wind and water currents moving across Earth's surface to turn from their original straight path |
| crest | the peak, or highest point, of a wave |
| density | the amount of matter in a given volume. The more matter per unit of volume, the denser the substance |
| density current | a type of ocean current caused by the flow of denser water to a region of less dense water. Salinity and temperature are the two main factors that affect the density of ocean water. Also known as a convection current |
| depth profile | a linear display of a series of depth measurements, showing the outline shape of land below sea level |
| dissolve | to thoroughly mix with and disappear into another substance |
| evaporation | the process of changing from a liquid to a gaseous state (vapor) |
| exoskeleton | a skeleton that is on the outside of the body; an external skeleton |
| gastropod | (literally "stomach-foot") a type of mollusk whose body serves as an organ of locomotion. In many, the body is protected by a single (univalve) spiral- or cone-shaped shell |
| gravitational pull | the attractive force that exists between all objects |
| high tide | the time at which the tide reaches its highest level. High tide occurs at approximately twelve-hour intervals at any given coastal location |
| hydrometer | an instrument used to measure the density of a liquid compared with that of water |
| insulation | any material that acts to prevent the passage of heat into or out of a substance |
| intertidal zone | the coastal area from the highest high-tide line to the lowest low-tide line. The intertidal zone may be rocky, sandy, or muddy, and is home to a variety of marine plants and animals |
| invertebrate | an animal lacking a backbone or spinal column |
| low tide | the time at which the tide reaches its lowest level. Low tide occurs approximately six hours after high tide |
| mid-ocean ridge | an underwater mountain chain that circles Earth, extending through the middle of most oceans. The Mid-Atlantic Ridge is the portion of the mid-ocean ridge that extends north-south through the Atlantic Ocean |
| mollusk | a member of the phylum Mollusca, characterized by a muscular foot, an outer mantle, and a rasping mouth-like radula. Includes gastropods and bivalves |
| neritic zone | the submerged ocean area that extends from the lowest low-tide line to the edge of the continental shelf. Ninety percent of all marine species live in the neritic zone |
| operculum | a lid or flap that covers the opening in a univalve shell to protect the animal inside from predators or from drying during low-tide exposure to air |
| precipitation | any form of water that falls from clouds in the sky. Rain, sleet, hail, and snow are all forms of precipitation |
| prevailing winds | the global wind systems caused by uneven heating of Earth's curved surface by the sun |
| runoff | water that does not seep into the ground or evaporate but instead flows over Earth's surface. This mineral-rich water often ends up in streams and rivers, which empty into the ocean |
| salinity | a measure of the amount of solids (salts) in ocean water. Ocean water has an average salinity of 3.5 percent |
| sea | a region of ocean water partly enclosed by land |
| seamount | a submerged mountain rising from the ocean floor |
| sonar | the use of acoustic (sound) waves to detect underwater objects and landforms |
| surface current | a type of ocean current caused by the friction of prevailing winds moving across the surface of the ocean. Surface currents are located in the upper 100 to 200 meters of ocean water |
| swim bladder | a balloon-like organ inside a fish that enables the fish to control its buoyancy |
| tides | the alternating rise and fall of the surface level of the ocean, caused primarily by the gravitational pull of the moon on Earth |
| trench | a deep canyon in the ocean floor. Trenches are the deepest crevices on Earth's surface |
| trough | the valley, or lowest point, between the crests of two successive waves |
| univalve | a mollusk having a shell consisting of a single piece, usually spiral- or cone-shaped |
| vertebrate | an animal with a backbone or spinal column |
| warm-blooded | having an internal body temperature that stays at a relatively constant level. Mammals and birds are examples of warm-blooded animals |
| water cycle | the continuous circulation of water - through evaporation, condensation, and precipitation - between Earth's surface and the atmosphere |
| wave height | the vertical distance between a wave crest and the subsequent trough |
| wavelength | the horizontal distance between two successive wave crests |
| world ocean | the continuous body of salt water that encircles the Earth. The four main oceans plus all the seas make up the world ocean |
