Coral reefs(珊瑚礁) are a unique ocean ecosystem consisting of rocky structures mainly formed by coral animals and some other ocean life. Despite only covering 0.2 percent of the ocean floor, coral reefs support at least 25 percent of marine species, as well as providing food and economic security for hundreds of millions of people.
However, coral reefs across the world are under threat. Warmer oceans can cause the coral bleaching(漂白). It happens when the corals lose colored algae(海藻) living in their bodies and turn completely white. Without the algae, the corals lose their main food source and can die. In addition, as oceans become more acidic(酸性的) from absorbing CO2, corals in acidic conditions become weak in forming reefs.
In 2021, the United Nations reported a 14 percent loss of corals across the world largely from rising sea temperatures in the previous 13 years. Australia declared mass bleaching events in 2022 across large parts of the Great Barrier Reef, four times since 2016. Data from the Philippines showed higher than usual ocean temperatures between 2015 and 2017 had caused a serious three-year bleaching events in reefs across the planet.
Scientists have been cooperating to see how coral reefs can be protected. Thankfully, they find those coral reefs in the hot parts of the globe are the worst affected. They contain corals with better heat resistance. So their research focus on finding genes(基因) for heat tolerance so that they can be passed on to future generations. Biologists also mix corals that are more resilient to higher temperatures with those that are not and the resulting generation has a better chance of survival.
Ultimately, scientists add that without a serious reduction in greenhouse gas, 99 percent of the world’s coral reefs will be gone by the end of the century. There is a limit to how quickly corals can adapt warm climate, but if temperatures rise rapidly, then extinction is certain.
【小题1】Which is the main threat to coral reefs?| A．Declining ocean acidification. | B．Loss of colored algae. |
| C．Increasing sea temperatures. | D．Lack of food source. |
| A．No actions are taken to protect coral reefs. | B．Coral bleaching is the worst in Australia. |
| C．Coral reefs have grown rapidly for years. | D．Coral reefs receive impacts globally. |
| A．Lowering emission. | B．Transplanting them to the hot parts. |
| C．Relying on genes science. | D．Limiting their spread. |
| A．Where Are Coral Reefs Spread? | B．How Can Coral Reefs Survive? |
| C．Coral Reefs, A New Threat To Ocean Life | D．Coral Reefs, A Busy Underwater Community |
