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Multiple Choice
Which of the following is the primary reason for the decline of coral populations since 1977?
A
Rising sea temperatures leading to coral bleaching
B
Increased volcanic activity in ocean regions
C
Greater abundance of plankton in coral reefs
D
A decrease in ocean salinity worldwide
Verified step by step guidance
1
Understand the problem: The question asks for the primary reason for the decline of coral populations since 1977. This requires knowledge of environmental factors affecting coral reefs.
Step 1: Recall the concept of coral bleaching. Coral bleaching occurs when corals expel their symbiotic algae (zooxanthellae) due to stress, often caused by rising sea temperatures. Without these algae, corals lose their color and their primary source of energy, leading to their decline.
Step 2: Evaluate the options provided. Rising sea temperatures leading to coral bleaching is a well-documented phenomenon and aligns with the primary cause of coral population decline. Increased volcanic activity, greater abundance of plankton, and decreased ocean salinity are not widely recognized as major contributors to coral decline.
Step 3: Connect the timeline. Since 1977, global climate change has led to rising sea temperatures, which directly impacts coral reefs. This aligns with the scientific understanding of coral bleaching as a result of thermal stress.
Step 4: Conclude that the correct answer is 'Rising sea temperatures leading to coral bleaching,' as it is the most scientifically supported explanation for the decline of coral populations.