Chapter 14 Vocabulary

benthic zone

- any sea-bottom surface regardless of its distance from shore - mostly inhabited by benthos organisms

oceanic zone

- beyond the continental shelf - reaches great depths

density

- mass per unit volume - determines the water's vertical position in the ocean

pelagic zone

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

neritic zone

- seaward from the low-tide line - covers the gently sloping continental shelf out to the shelf break

food chain

- sequence of organisms through which energy is transferred - starts with a primary producer, then a herbivore, then carnivores, then culminating with the "top carnivore"

abyssal zone

- subdivision of the benthic zone - includes the deep-ocean floor - characterized by extremely high water pressure, consistently low temperature, no sunlight, and sparse life

intertidal zone

- the area where the land and ocean meet and overlap - alternately covered and uncovered by seawater with each tidal change

salinity

Total amount of solid material dissolved in water; ratio of the mass of dissolved substances to the mass of the water sample

food web

a diagram where top carnivores in a food chain feed on a number of different animals, each of which has its own simple or complex feeding relationships

plankton

all organisms that drift with ocean currents

aphotic zone

deep in the ocean where there is no sunlight

trophic level

each feeding stage from algae to carnivores

nekton

include all animals capable of moving independently of ocean currents

benthos

organisms living on or in the ocean bottom

euphotic zone

portion of the photic zone near the surface where light is strong enough for photosynthesis to occur

phytoplankton

the algae among plankton

primary productivity

the amount of carbon fixed by organisms through the synthesis of organic matter using energy derived from solar radiation or chemical reactions

zooplankton

the animals among plankton

thermocline

the layer of ocean water between 300 and 1,000 meters where there is a rapid change in temperature with depth

pycnocline

the layer of ocean water between 300 and 1,000 meters where there is a rapid change of density with depth

biomass

the mass of all living organisms

photosynthesis

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

photic zone

the upper part of the ocean into which sunlight penetrates