Mention the common of the features atolls-reaf?

Some common features of atolls include:

1. Circular or oval shape with a central lagoon
2. Coral reefs surrounding the lagoon
3. Low-lying islands or islets made of coral or sand
4. Barrier reef protecting the lagoon from open ocean waves
5. Rich marine biodiversity and coral ecosystems
6. Vulnerability to sea level rise and climate change impacts
7. Popular for tourism and recreational activities such as diving and snorkeling.

Common Features of Atolls and Reefs:

- Raised coral formations: Both atolls and reefs are formed by the accumulation of calcium carbonate deposited by coral polyps over time.
- Marine ecosystem: They support a diverse range of marine life, including fish, corals, sponges, and other invertebrates.
- Clear water: The surrounding waters are often crystal clear due to the filtering effect of corals, making them popular for snorkeling and diving.
- Location: Found in tropical and subtropical oceans, primarily in the Pacific and Indian Oceans.
- Structure:

- Atolls: Ring-shaped or horseshoe-shaped coral reefs that enclose a lagoon. They are typically found in the deep ocean, far from land.
- Reefs: Submerged or partially submerged coral formations that attach to the seabed. They can be fringing (attached to land), barrier (separated from land by a lagoon), or patch reefs.

- Environmental importance:

- Provide shelter and food for marine life.
- Protect coastlines from erosion and storm surges.
- Support tourism and recreational activities.
- Threats:

- Rising sea levels and ocean acidification due to climate change.
- Overfishing and habitat destruction.
- Pollution and nutrient runoff.