Coral Reefs and Climate Change: Understanding Coral Bleaching Causes and Effects

Dr. David Wackenfeld explains coral bleaching, starting with an understanding of coral as a simple animal with symbiotic plants that provide energy and color. Coral bleaching occurs when this relationship breaks down under stress, causing corals to expel the plants and lose color. Stressors include temperature extremes, fresh water, and pollutants. Mass bleaching is primarily caused by temperature stress. Corals can recover if conditions improve, but climate change is increasing the frequency and severity of bleaching events, challenging coral recovery.

What is the primary role of the microscopic plants living within coral tissue?

• To protect coral from predators

• To help coral move

• To generate energy and sugars

• To provide structural support

What color are most healthy corals due to the presence of microscopic plants?

• Bright red

• Browny-green

• Deep blue

• Vibrant yellow

How does coral bleaching affect the appearance of coral?

• Coral grows larger

• Coral becomes paler or changes color

• Coral turns completely black

• Coral becomes more vibrant

What happens to the microscopic plants during coral bleaching?

• They become larger

• They change color

• They are expelled by the coral

• They multiply rapidly

Which of the following is NOT a cause of coral bleaching?

• Lack of sunlight

• Exposure to fresh water

• Temperature extremes

• Excessive nutrients

What is the main factor that leads to mass coral bleaching?

• Lack of nutrients

• Overfishing

• Temperature stress

• Pollution

What happens to coral if the temperature stress is relieved?

• Coral dies immediately

• Coral recovers and regains its color

• Coral changes species

• Coral becomes more stressed

How does climate change affect coral reef recovery?

• It has no effect on recovery

• It increases the recovery time

• It makes recovery easier

• It shortens the recovery time

What is a critical factor for coral reef recovery after bleaching?

• Higher temperatures

• Increased water pollution

• Sufficient recovery time

• Immediate human intervention

What is the consequence of increased frequency and severity of bleaching events?

• Reefs recover faster

• Reefs struggle to recover

• Reefs expand in size

• Reefs become more colorful