Earth Science 12th Edition Vocabulary Chapter 14

By Megan Andrews (GLY 1001 Student North Campus Fall 2006)


abyssal zone- a subdivision of the benthic zone characterized by extremely high pressures low temperatures, low oxygen, few nutrients, and no sun.


aphotic zone- that portion of the ocean where there is no sunlight.


benthic zone- the marine life zone that includes any sea bottom surface regardless of its distance from shore.


benthos- the forms of ocean marine life that live on or in the ocean floor.


biomass- total mass of a defined organism or group of organisms in a particular area or ecosystem.


density- mass per unit volume of a substance usually expressed as grams per cubic cm.


euphotic zone- portion of the photic zone near the surface where light is bright enough for photosynthesis.


food chain- a succession of organisms in a ecological community through which energy is transferred from producers through herbovores and on to one or more carnivores.


food web- a group of interrelated food chains.


intertidal zone- the area where land and sea meet and overlap; the zone between high and low tides.


nekton Pelagic organisms that can be move independently of ocean currents by swimming or other means of propulsion


neritic zone The marine life zone that extends from low tideline out to the shelf break


oceanic zone- marine life zone beyond the continental shelf.


pelagic zone - open ocean of any depth animals in this zone swim or float freely.


photic zone- the upper part of the ocean into which any sunlight penetrates


photosynthesis- the process in which plants an algae produce carbohydrates from carbon dioxide and water in the presence of chlorophyll, using light energy and releasing oxygen.


phytoplankton- algae plankton which are the most important community of primary producers in the ocean.


plankton- passively drifting or weakly swimming organisms that cannot move independently of ocean currents. Includes microscopic algae, protozoa, jellyfish, and larval forms of any kind.


primary productivity- amount of organic matter synthesized by organisms from inorganic substances through photosynthesis of chemosynthesis with in a given volume of water or habitat in a unit of time.


pycnocline- a layer of water in which there is a rapid change of density with depth.


salinity- the proportion of dissolved salts to pure water usually expressed in parts per thousandth.


thermocline A layer of water in which there is a rapid change in temperature in the vertical dimension.


trophic level A nourishment level in the food chain. Plant and algae producers constitute the lowest level, followed by herbivores, and a series of carnivores at progressively higher levels


zooplankton Animal Plankton