Mangroves protect coral from climate change

Coral reefs make up some of the most biologically diverse habitats on Earth and face many threats such as coastal pollution, dredging and disease. However, some of their most widespread threats involve warming ocean temperatures, solar radiation and increased ocean acidification. It is from these threats that corals are finding refuge under the red mangroves.

Red mangroves, subtropical or tropical trees that colonize coastlines and brackish water habitats, have networks of prop roots that extend down toward the seafloor, and corals are growing on and under these roots. Mangroves and their associated habitats and biological processes protect corals in a variety of ways.

• The shade provided by mangroves protects the corals from high levels of solar radiation. This, in turn, may reduce some of the stress caused by warming ocean waters.

• A combination of chemical, biological and physical conditions around the mangrove habitats helps protect the corals by keeping acidity in the water below harmful levels. With oceans becoming more acidic due to the increased amount of carbon dioxide absorbed from the atmosphere, ocean animals like corals are threatened by rising acidity levels, which can slow coral growth and impact reef structure.

• The shade provided by the mangroves helps deter coral bleaching, a condition that essentially starves coral and can, in prolonged cases, result in their death. With climate change, coral bleaching episodes are becoming more frequent around the world.