
Importance of corals
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16 July 2020Corals, essential to our ocean’s health, are in danger.
Corals represent an exceptional biodiversity, and are present in both tropical and cold waters. Scientists estimate that coral reefs are home to more than 25% of marine species and yet they cover less than 0.2% of the ocean. Corals are also at the core of the formation of other ecosystems.
Reefs only cover 0.2% of the oceans. Yet they protect more than 150,000 kilometres of coastline in more than 100 countries and territories. They can form a barrier that absorbs wave energy and thus help reduce coastal erosion.
Approximately 1 billion people live within 100 kilometres of coral reefs and are likely to benefit from their ecosystem services. 500 million people directly depend on them, i.e. almost 8% of the world’s population, in terms of coastal protection, fisheries resources and tourism.
Reefs are often an essential part in the economy of the tropical regions where they are located. Indeed, they attract divers, snorkelers, recreational fishermen and beach and white sand enthusiasts.
Millions of people around the world depend on reefs for employment. According to an estimate, the total annual net benefit of the world’s coral reefs is $29.8 billion.
Corals also contribute to research advancements, in particular by providing interesting possibilities for the treatment of various diseases.
Corals are very sensitive to temperature changes. 1 to 2°C increase in surface water temperature above the usual maxima is enough to cause massive bleaching, affecting reef growth, feeding, and other ecological processes. The IPCC’s forecasts anticipate a global temperature increase of 1.5°C by 2050. This means that ocean surface water will continue to warm.
Global climate regulation is achieved through the absorption by the oceans of 33% of the CO2 emitted. However, human activities are generating an exponential increase in these emissions, raising the dissolution of CO2 and causing ocean acidification. This has a huge impact on the proper development of organisms with calcareous skeletons.
Wastes such as oil, fertilizers, sewage and toxic chemicals can be released directly at sea or indirectly (via rivers). This causes an enrichment of nutrients that promote the formation of algae. The supports used by coral larvae are smothered by a proliferation of algae thus affecting their development.
In certain countries, the use of homemade bombs for fishing is disastrous. It leads to the destruction of reefs leaving only unstable rubble remains in their wake, making recolonisation by coral larvae impossible. It is also a social problem: fishermen have to go further afield (at a higher cost to them) and take more risks in order to find fish. Potassium cyanide also destroys all life on reefs and is used to harvest species for the aquarium and food markets in Asian countries.
The increase in the demand for fish has resulted in the overfishing of reef fish which in turn affects the balance of the coral ecosystem. For example, overfishing of herbivorous fish can lead to levels of growth in algae, which asphyxiates the coral by depleting it of oxygen.
More than 100 countries benefit from reef-related tourism and it contributes to more than 30% of export earnings in more than 20 countries. Moreover, reef tourism is on the rise. Indeed, reefs attract divers, snorkelers, recreational fishermen and white sandy beach-lovers. Thus, they are an essential part of the economy for the regions where they are located. In many small islands, more than 90% of new economic development depends on this coastal tourism.
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16 July 2020Around the world, coral reefs are facing a degradation driven by global and local human-derived pressures including climate change, coastal development, pollution, amongst others. In…
16 July 2020Written by Jeanne Kault, Florina Jacob and Olivier Detournay. Acknowledgments to Eric Rƶttinger. Coral reefs cover an area of 284,300 km2 (Spalding et al.,…
16 July 2020Your Name (required) Your Email (required) Subject Your Message
16 July 2020Your Name (required) Your Email (required) Subject Your Message
16 July 2020Your Name (required) Your Email (required) Subject Your Message
16 July 2020