BBC: Will we ever... lose all of our coral reefs?

---

Will we ever... lose all of our coral reefs? - from BBC Future

---

　A third of reef-buikding corals are in danger of extinction across the world, and the reefs are in serious decline. In Caribbean sea, the proportion of the reef covered by live coral has been plummeting from 50% in the 1970s to just 8% nowadays.

　Coral reefs have been besieged with multiple anthoropogenic factors. For example, rampant overfishing declines the number of herbivorous fish that consume competitors of corals, such as seaweed and algae. Some diseases are exacerbated by bacteria carried in human sewage, and agricultural run-offs load seas with excess of nutrient, results in algae blooms.

　Climate change, especially the vast input of carbon dioxide, is considered as the most responsible one for the plunge of coral reefs. The majority of corals seem to be sensitive to the increase of temperature, In warmer water, corals expel the algae that live inside their tissues and produce nutrients by harnessing sunlight, which causes corals bleached. Meanwhile, the decline of ocean pH induced by the rise in carbon dioxide, so-called ocean acidification, inhibits corals from building their limestone fortresses.

　An ecologist remarks that there is no hope to save the global coral reef ecosystems, although many other coral scientists see less doom and gloom, and call for help from local communities.

　Corals could survive ancient dramatic climate fluctuation for several times, therefore they proved to be remarkably resilient. However, the recent upheaval of temperature is so rapid that some corals species end up with extinction.

---