Earth Science 12^th 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