The Aquatic Environment Flashcards

What causes tidal patterns in the ocean?

Answer: The gravitational pull of the moon and sun

Tides are primarily caused by the gravitational forces exerted by the moon and, to a lesser extent, the sun on Earth's oceans.

Which type of current is created when dense, cold water sinks and displaces warmer water upward?

Answer: Convection current

Convection currents form when temperature differences cause denser cold water to sink, displacing lighter warm water upward in a circulatory pattern.

What is the primary hazard of diving in areas with kelp forests?

Answer: Kelp can entangle divers and restrict movement

Kelp fronds can entangle equipment or limbs, so divers should move slowly and deliberately, and know how to escape entanglement by rolling or backing out.

A halocline is a layer in the water column characterized by a rapid change in:

Answer: Salinity

A halocline is a distinct layer where salinity changes sharply with depth, often creating a visual blurring effect that divers can observe at the boundary.

Which wave characteristic describes the horizontal distance between two successive wave crests?

Answer: Wave wavelength

Wavelength is the horizontal distance measured from one wave crest to the next successive crest.

When diving in areas with boat traffic, which practice is most important for diver safety?

Answer: Towing a surface marker buoy (SMB) when ascending

Deploying a surface marker buoy (SMB) during ascent alerts boat operators to a diver below and marks the surfacing location, significantly reducing collision risk.

What is a 'spring tide' and when does it occur?

Answer: An exceptionally high or low tide occurring at new and full moon

Spring tides occur during new and full moon phases when the sun, moon, and Earth align, combining gravitational forces to produce the highest high tides and lowest low tides.