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Explore intermediate-level trivia on ocean ecosystems and sea creatures.
1. What is coral made of?
💡 Coral reefs are formed by colonies of tiny living organisms called coral polyps, which secrete calcium carbonate skeletons.
2. What is the name for animals that live on the ocean floor?
💡 Benthic organisms live on, in, or near the ocean floor or seabed.
3. What percentage of Earth's oxygen is estimated to be produced by ocean phytoplankton?
💡 Ocean phytoplankton are estimated to produce at least 50% of the Earth's oxygen through photosynthesis.
4. What is the primary cause of coral bleaching?
💡 Coral bleaching occurs primarily when rising ocean temperatures cause coral to expel the algae living in their tissues.
5. What is the largest species of shark?
💡 The whale shark is the largest fish species in the world, but it's a filter feeder and not dangerous to humans.
6. Which marine animal is known to change its gender during its lifetime?
💡 Clownfish are sequential hermaphrodites; all are born male, and the dominant one in a group changes to female.
7. Which marine mammal is known for using rocks as tools to crack open shellfish?
💡 Sea otters are known to use rocks as tools to break open hard-shelled prey like clams and mussels.
8. What is a group of jellyfish called?
💡 A large group of jellyfish is called a 'bloom' or 'smack'.
9. Which layer of the ocean receives no sunlight at all?
💡 The midnight zone, below about 1,000 meters, receives no sunlight and is home to unique bioluminescent creatures.
10. Which sea creature has three hearts?
💡 Octopuses have three hearts — two pump blood to the gills, and one pumps blood to the rest of the body.
11. What is the largest species of shark?
💡 The whale shark is the largest fish species in the world, but it's a filter feeder and not dangerous to humans.
12. Which whale is known for producing the loudest sound of any animal?
💡 The blue whale can produce sounds reaching up to 188 decibels, louder than a jet engine, used for long-distance communication.
13. What is the primary cause of coral bleaching?
💡 Coral bleaching occurs primarily when rising ocean temperatures cause coral to expel the algae living in their tissues.
14. What is coral made of?
💡 Coral reefs are formed by colonies of tiny living organisms called coral polyps, which secrete calcium carbonate skeletons.
15. Which layer of the ocean receives no sunlight at all?
💡 The midnight zone, below about 1,000 meters, receives no sunlight and is home to unique bioluminescent creatures.