You may not see coral reefs by 2070

  Researchers urge coral reef conservation groups to adopt a new and bolder approach to address the problems that lead to the degradation of coral reef ecosystems from a local and overall perspective. They suggested that Australian policymakers should replace coal and electricity with renewable energy in the 425,000 square kilometers of the Great Barrier Reef, develop land-based aquaculture, and restore or restore land vegetation and wetlands. These actions will “reduce global emissions, increase carbon capture, prevent agricultural runoff from flowing to coastal coral reefs, and improve human life and food security.”
Coral reef facing the crisis of the century

  Speaking of coral reefs, the most well-known is probably the Great Barrier Reef in Australia. The most famous coral reef in the world has been continuously affected by the warming of the sea. In 2016 and 2017, a large number of coral bleaching events occurred consecutively. In 2016, the warming of the sea caused more than 26% and 67% of coral deaths in the far north and north of the Great Barrier Reef. The mortality rate of corals in the central and southern parts of the Great Barrier Reef was relatively low in 2016, but they did not escape. The bleaching phenomenon worsened in 2017 and the impact on the central part was even greater.
  The documentary “Chasing Corals” also intuitively demonstrated the bleaching of corals on the Great Barrier Reef. A bird’s-eye view of a piece of white, pink or purple corals is announcing that death is approaching. At the end of the film, the records of the World Coral Reef Conference and reports on the status of coral reefs from all over the world reveal that coral reefs face seawater on a global scale. The threat of bleaching caused by warming.
  So why does the warming of sea water cause such a serious bleaching problem?
  This starts with the growth environment of corals.
  Coral reefs are mainly distributed in the isotherm of 20% of the average sea temperature in the northern and southern hemispheres. This is because the reef-building corals that form coral reefs have strict requirements on sea water temperature: the suitable water temperature for most reef-building corals is 18 to 29 ℃, which is too low and too low. High water temperature will cause bleaching and death of reef-building corals.
  As reef-building corals rely on the photosynthesis of the symbiotic zooxanthellae in their bodies to provide energy for them, most reef-building corals live in shallow waters below 50 meters, but some non-reef-building corals without zooxanthellae symbiosis live The depth can reach hundreds or even thousands of meters.
  It is precisely because of the symbiotic system of zooxanthellae and polyps that sustain the survival and growth of corals. However, this system is fragile. When the seawater temperature rises by 3 to 4°C above the normal temperature, the pair of corals and zooxanthellae will turn their faces, the zooxanthellae will leave the corals, and the corals lack energy provided by the zooxanthellae. And starved to death.
  In addition to temperature and depth, factors such as seawater salinity, nutrient content, and sediments will affect the distribution of reef-building corals. Therefore, to form a coral reef, many environmental conditions must be met. This is why in such a vast ocean, Coral reefs only occupy less than 0.2% of the area.
  But don’t underestimate this 0.2% area. The marine life here accounts for a quarter of the total species of marine life, and nearly one-third of marine fish live in it. Therefore, coral reefs are also called “tropical rainforests in the ocean.” “. In addition to bleaching, coral reefs are constantly exposed to various threats such as overfishing, pollution, coastal engineering damage, ocean acidification, sea level rise, coral diseases, and outbreaks of long-spine starfish.
The distressing state of coral reefs

  Take the situation in China again. As of 2010, coral reefs along the coasts of Guangdong, Guangxi, and Hainan of China have lost 80% of the number of reef-building corals due to destruction and pollution by human activities in the past 30 years; while coral islands in the South China Sea have not been affected by pollution, but Due to the overfishing of fisheries and the outbreak of long-thorn starfish, the average coral coverage has fallen from 60% to about 20% in the past 10-15 years.

Paracel Islands

  ”The beautiful and fertile Paracel Islands”, in the photos we see, are all thriving and vibrant coral reefs, but this is not the case. Pieces of dead coral skeletons remain on the coral reefs. The outbreak of clusters of long-thorn starfish on the coral reefs of Xisha Island has caused serious damage to the coral reefs like a locust plague.
What happens if the coral reef disappears?

  At present, more than half of coral reefs have been seriously degraded globally, but the more serious problem is that the rate of degradation of coral reefs will accelerate. If humans do not take rescue measures, then according to the current rate of degradation, coral reef ecosystems may disappear from the earth at the end of this century.
  ”The godfather of corals” Charlie Villon said: “A quarter to a third of all marine species spend part of their life cycle in coral reefs. When coral reefs die, these creatures Will subsequently perish, leading to the chaos and collapse of the ecosystem. ”
  What impact will the loss of coral reefs have on humans?
  Some people say that there is no impact, at most there are fewer tourist attractions, after all, not many people live near coral reefs.
  This view is really wrong.
  In fact, 500 million people around the world depend on coral reefs. They get food from coral reefs, feed their families with coral reef fisheries, engage in coral reef tourism, and rely on coral reefs to protect their homes. If there were no coral reefs, they would lose their jobs or even get enough food to survive.
  On a global scale, coral reefs provide humans with services worth US$2.7 trillion, including fisheries, tourism, coastal protection, maintenance of ecological diversity, drug development, and education industries. Coral reefs are even closely related to national territory and sovereignty. Many territorial waters are islands formed by coral reefs. For example, the territorial waters of China’s Paracel Islands are coral islands. If coral reefs degrade and lose their function of protecting islands, coral islands and reefs will shrink or even disappear under the destruction of seawater erosion, waves and typhoons, resulting in a reduction in the area of ​​the territorial sea.
  Take the Paracel Islands as an example. As coral reef fish use corals as their homes, spawning grounds or shelters, the degradation of the Paracel reef has caused a decline in the number of fish, which directly affects the lives of relevant fishermen and islanders.
  Under the unstoppable trend of global warming, we watched the colorful corals turn into piles of “bones”. Fortunately, the scientists are still working hard.