The Epipelagic zone near the surface is also called this.
Sunlight zone
The Chesapeake Bay is the largest one of these ecosystems in North America.
Estuary
Dolphins and porpoises are member of this group of whales.
Toothed whales
Dead zones can occur because warming ocean water can't hold as much of this gas.
Oxygen
Phytoplankton live in this ocean zone.
Epipelagic
The mesopelagic, or middle zone is also known as this.
Twilight zone
This biome plays home to about 25% of all marine creatures.
Coral reefs
Crabs are called this because they have 10 legs.
Decapods
Farming fish is called this.
Aquaculture
Surface ocean currents are primarily caused by this.
Wind
What's called the midnight zone is more formally known as this.
Bathypelagic zone
The strength of magnetic fields are measured in these units.
teslas
Unlike seals and sealions, walruses don't have this to keep them warm.
Fur
This scale is used to measure the acidity of ocean water.
pH scale
This is the largest species of shark.
Whale shark
This famous trench can be found in the deep ocean Hadal zone.
Marianas trench
The direction of a magnetic field induced by an electrical current can be found using this rule.
The right hand rule
The scientific name for this group of animals literally means "head foot".
Cephalopods
Warming oceans can kill off the symbiotic algae that coral rely on, causing this condition.
Coral bleaching
The highest tide of the month is called this.
Spring tide
This zone extends from about 4000 m to the ocean floor.
Abyssopelagic zone
This process allows bacteria living around undersea vents to produce energy.
Chemosynthesis
Unlike most fish, sharks have this type of skeleton.
Cartilaginous
When CO2 combines with water it reacts to form this chemical.
Carbonic acid
Kelp have these to help them float.
Gas bladders