The Aquatic Environment Flashcards
7 cards from real PADI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 The Aquatic Environment flashcards as text
How does surge affect divers in shallow water near reef structures?
Answer: Surge pushes divers back and forth, increasing risk of contact with the reef
Surge in shallow water creates oscillating back-and-forth water movement that can push divers into reef structures, risking injury to both the diver and the reef.
Which marine animal's sting is best treated by immersing the affected area in hot water?
Answer: Stingray
Stingray venom is protein-based and heat-labile, so hot water (as hot as tolerable) denatures the venom and provides significant pain relief.
What does 'thermocline' describe in a diving context?
Answer: A layer of rapid temperature change between warmer and cooler water
A thermocline is a distinct horizontal layer in the water where temperature drops sharply over a short vertical distance, often visible as a shimmering distortion.
Why is it important for divers to understand prevailing current directions at a dive site?
Answer: Divers should plan to dive into the current first and return with it
Diving into the current first conserves energy for the outbound leg, allowing divers to drift back to the exit point when tired during the return.
What happens to natural light underwater as depth increases?
Answer: Red wavelengths are absorbed first, followed by orange, then yellow
Water selectively absorbs longer wavelengths first: red disappears around 5m, orange around 10m, and yellow around 20m, leaving only blue-green light at greater depths.
A rip current at a beach dive site is best identified by which visual cue?
Answer: A calm, discolored, or churning channel of water moving seaward
Rip currents often appear as a gap in the breaking waves with discolored, choppy, or murky water moving swiftly offshore, sometimes with foam or debris.
Which term describes the zone of the ocean that receives enough light to support photosynthesis?
Answer: Photic zone
The photic zone is the upper layer of the ocean (typically 0–200m) where sufficient sunlight penetrates to support photosynthesis by plants and algae.