NAUI Marine Environment & Ecology 2

Question 1

What is the primary cause of coral bleaching?

Accepted Answer

Elevated water temperatures causing coral to expel zooxanthellae algae

Answer

Coral bleaching occurs when thermal stress causes corals to expel their symbiotic algae (zooxanthellae), which provide color and nutrients, leaving the coral white and weakened.

Question 2

Which species is considered a keystone predator in kelp forest ecosystems on the US Pacific Coast?

Accepted Answer

Sea otter

Answer

Sea otters are keystone species because they prey on sea urchins; without sea otters, urchin populations explode and overgraze kelp, destroying the entire ecosystem.

Question 3

What characterizes a benthic marine organism?

Accepted Answer

It lives on or near the ocean floor

Answer

Benthic organisms live on or within the seafloor substrate, including animals like sea stars, lobsters, flatfish, and worms.

Question 4

What is the primary function of a fish's lateral line system?

Accepted Answer

Detects pressure changes and vibrations in surrounding water

Answer

The lateral line is a mechanosensory system that detects subtle changes in water pressure and vibrations, helping fish navigate, detect predators, and coordinate schooling behavior.

Question 5

Coral reefs cover less than 1% of the ocean floor but support what approximate percentage of all marine species?

Accepted Answer

25%

Answer

Coral reefs support approximately 25% of all marine species despite covering less than 1% of the ocean, earning them the title 'rainforest of the sea.'

(NAUI) National Association of Underwater Instructors Certification Practice Test

(NAUI) National Association of Underwater Instructors Certification Practice Test

NAUI Marine Environment & Ecology 2