[Answered] How important are coral reefs to the marine ecosystem? Can the process of coral bleaching be reversed and the reefs rejuvenated?

Corals are marine invertebrates. They are the largest living structures on the planet and are also called the “rainforests of the seas”. Australia’s Great Barrier Reef is the world’s largest reef system stretching across 2,300 km and generates $4.6 billion annually through tourism. Coral bleaching happens when corals experience stress in their environment due to changes in temperature and pollution of the ocean.

Importance of coral reefs to marine ecosystem:

• Coral reefs support over 25% of marine biodiversity, including fish, turtles and lobsters.
• Marine life supported by reefs further fuels global fishing industries. Even giant clams and whales depend on the reefs to live.
• Aside from adding economic value, coral reefs also provide protection from storm waves.
• They help protect areas such as mangrove forests and seagrass beds that act as nurseries for marine animals, as well as human coastal populations.
• They are the source of nitrogen and other essential nutrients for marine food chains and also assist in carbon and nitrogen fixing.
• It helps with nutrient recycling.

Due to the stressful conditions created by changes in temperature, pollution, or high levels of ocean acidity, the zooxanthellae or food-producing algae living inside coral polyps is expelled, which exposes their pale white exoskeleton, giving the corals a bleached appearance.

Bleached corals can survive depending on the levels of bleaching and the recovery of sea temperatures to normal levels. Dead reefs can revive over time if there are enough fish species that can graze off the weeds that settle on dead corals. There are the following ways to rejuvenate corals-

1. Biological restoration: It uses methods for coral growth and transplanting to assist the restoration of a coral reef. It includes Asexual propagation and Coral Gardening. First one involves the transplanting of coral fragments or larger colonies from a donor reef site to a reef of choice. Coral gardening is the process of collecting, growing and reattaching coral fragments at a degraded reef site.
2. Structural restoration: It involves the construction of artificial reefs, or relocation of rocks/dead coral heads. The goal is to increase the amount of reef structure and habitat available for the corals and other reef organisms to grow on.eg. Bio rock technology
3. Physical restoration: It addresses the conditions in which the corals are growing to improve their health, growth rates, or reproductive ability.

Coral reefs are an important part of the ecosystem. It is an important indicator of environmental health and provides various economic opportunities. Recent rise in coral bleaching has raised various concerns and efforts have been made to restore the same.