rhythmic back-and-forth motions of water that transfer energy

the period when the ocean's levels are at their highest

a sandy, gently sloping underwater plain near a continent

a shallow pool of salty water at the center of an atoll

a device that emits a "ping" of sound waves underwater that is reflected by any submerged object

the measure of the quantity of dissolved salt in seawater

the period when the ocean's levels are at their lowest

where the sea floor drops away from the continent abruptly

a sharp drop-off at the outer edge of the continental shelf

"self-contained underwater breathing apparatus" used by divers to reach deeper depths; originally called an aqualung

the deepest known point in the sea

one high tide and one low tide in a day

an underwater mountain range

a thick layer of sediments that slopes gently toward deep ocean basins

a device with an open tube that is dropped to the sea floor, allowing its weight to puncture the sediment

the region where cold, deep water meets the sun-warmed surface water

two high and two low tides of approximate equal size each day

a huge valley where the crust appears to be separating

large underwater fissures in the continental shelf

a framework that many Niskin bottles are attached for conveniently collecting multiple water samples at various depths

any area of the sea that exceeds 6000 meters found in the trenches

a tide that is higher than normal at high tide and lower than normal at low tide; occurs twice a month at the new moon and full moon

a huge level region of the deep oceanic floor

circular, coral reef islands that grow around seamounts

oceanographers collect water samples from the ocean depths using this type of bottle