If sea urchins were wiped from a kelp forest ecosystem, which of the following is the most likely immediate ecological consequence?

• A. Sea otter populations would increase due to more available food.
• B. Fish diversity would decrease because of increased predation by urchins.
• C. Kelp populations would increase due to reduced grazing pressure.
• D. Kelp forests would disappear due to lack of nutrients.

Answer: (C)

Verified step by step guidance

1. Step 1: Understand the role of sea urchins in the kelp forest ecosystem. Sea urchins are herbivores that feed on kelp, and their grazing activity can significantly impact kelp populations.
2. Step 2: Analyze the immediate ecological consequence of removing sea urchins. Without sea urchins, the grazing pressure on kelp would be reduced, allowing kelp populations to grow more freely.
3. Step 3: Evaluate the other options provided in the problem. For example, sea otter populations would not necessarily increase due to more available food, as sea otters primarily prey on sea urchins, not kelp. Similarly, fish diversity would not decrease because sea urchins are not predators of fish.
4. Step 4: Consider the nutrient dynamics in the ecosystem. Kelp forests would not disappear due to lack of nutrients because kelp primarily obtains nutrients from the water through its holdfasts, and the removal of sea urchins does not directly affect nutrient availability.
5. Step 5: Conclude that the most likely immediate ecological consequence of removing sea urchins is an increase in kelp populations due to reduced grazing pressure, as this aligns with the ecological interactions in the kelp forest ecosystem.