Question

which of the following is the most likely impact of plastic and marine debris on coral ecosystems?
○ microplastics can be ingested by the corals and can smother the reefs.
○ debris can cause the temperature of the water near corals to increase.
○ microplastics can increase the numbers of phytoplankton near the reef.
○ it can prevent marine mammals from finding appropriate mates near the reefs.

Explanation:

• For the first option: Corals can ingest microplastics, and debris (including plastic) can physically cover (smother) coral reefs, disrupting their function and health.
• Second option: Marine debris like plastic doesn't directly cause water temperature increase (temperature change in coral habitats is more related to climate change, ocean currents, etc.).
• Third option: Microplastics generally harm ecosystems and don't promote phytoplankton growth in a beneficial way for reefs; they can actually contaminate the environment and disrupt food chains.
• Fourth option: The question is about coral ecosystems, and preventing marine mammals from mating is not a direct impact on corals themselves.

Answer:

A. Microplastics can be ingested by the corals and can smother the reefs.