Lagoons are among the most beautiful types of reef zones in existence. Commonly found both in continental coastal areas and surrounding volcanic or barrier islands, these bodies of water are essential for maintaining the balance associated with a coral reef’s biosphere.
Also known as sounds, bays or estuaries, lagoons are often sheltered by small islands or islets, as well as small or large coral reef formations that sometimes stretch out for miles offshore, allowing the lagoon to grow to a significant size.
A lagoon is essentially a body of water protected by islands or reefs that are more common on coasts, and commonly surrounded either by barrier or atoll corals.
Due to this fact, the water is relatively shallow and calm, having access to the open sea through smaller channel that filter out larger waves and make it possible for water circulation to continue at a slow but consistent rate, while maintaining water temperatures quite stable (around 75-80 degrees in most cases).
The dimensions of a lagoon can range from very small ones found near fringing or atoll reef that are located quite close to the shoreline of a small island, to elongated or irregularly shaped, larger bodies of water that can be found between the shoreline of a larger island or continent and a barrier reef formation situated parallel to the land mass and stretching out in both directions.
These types of lagoon formations can be seen, for example, on the East Coast of the United States, where they extend intermittently for about 1,500 km.
The coastal lagoon is the most common type found in nature, widely distributed throughout the world, and forming about 13% of all continental coastlines. It is generally found near coasts protected from the open sea by barrier islands.
Water movement here is facilitated through discharging rivers and tidal forces, the latter playing a less significant role than in the case of a coral lagoon.
A coral lagoon can be found in the tropics and is restricted to tropical open seas that allow for the specific conditions required for coral growth. The presence of the lagoon is often essential for the thriving of all coral reef zones, particularly due to the calm, stable water and rich biosphere that it can support.
Most of these reef zones are found in the Caribbean and around volcanic islands located in the Pacific Ocean. Surrounded by either atoll or barrier reefs and, in some cases, also associated with the formation of larger fringing reefs that are located farther away from the shore and allow for the formation of a lagoon, they often feature a largely uniform depth, and are considered to be essential for the evolution and sustenance of a wide array of marine life species.
All these types of lagoons are extremely rich in marine flora and fauna, and sheltered by coral formations or islands, they can in most cases maintain a well-balanced ecosystem, away from the strong waves of the ocean.