Useful Vocabulary Terms

Marine Biology

detritus

Dead organic material that fuels detrital food webs.

chemosynthetic

Producing organic matter using chemical energy instead of sunlight.

photophores

Light-producing organs used for communication or camouflage.

epipelagic

Sunlit surface ocean zone (0–200 m).

zooxanthellae

Photosynthetic symbiotic algae living in coral tissue.

larvacean

Planktonic tunicate that retains larval form.

copepods

Small crustaceans; major consumers of phytoplankton.

deposit feeders

Animals that ingest sediment to extract organic matter.

epifauna

Animals living on sediment surfaces.

infauna

Animals living within sediments.

salt wedge

Dense seawater layer beneath freshwater in estuaries.

euryhaline

Able to tolerate wide salinity ranges.

osmoconformers

Organisms whose internal salinity matches the environment.

littoral

Nearshore intertidal zone.

sessile

Permanently attached organisms.

motile

Capable of movement.

oozes

Deep-sea sediments made of plankton shells (siliceous, calcareous).

nekton

Actively swimming organisms.

neuston

Organisms living at the air–water interface.

pluston

Floating surface organisms.

meiofauna

Microscopic sediment-dwelling animals.

hermatypic

Reef-building corals.

planula

Free-swimming cnidarian larva.

dissolved organic matter

Organic molecules dissolved in seawater.

notochord

Flexible support rod in chordates.

demersal

Living near or on the seafloor.

spiracles

Openings allowing water into shark gills.

counter-current system

Opposing flow that maximizes gas exchange.

lateral line

Sensory system detecting water movement.

anadromous

Fish migrating from sea to freshwater to spawn.

catadromous

Fish migrating from freshwater to sea to spawn.

claspers

Male shark reproductive organs.

ovoviviparous

Eggs hatch inside parent.

oviparous

Egg-laying.

viviparous

Live birth with maternal nourishment.

lophophore

Ciliated feeding structure.

salp

Free-floating tunicate.

pedicellaria

Small pincer structures on echinoderms.

chitin

Structural polysaccharide forming arthropod exoskeletons.