While the effects of climate change can currently be seen all over the world, they are hitting the oceans hardest. Greenhouse gases in the atmosphere dissolve in the water and make it more acidic, which is disastrous to marine life like crabs, clams, and coral. A new study has found that these increasing global temperatures also interrupts the ability of coral reefs to protect themselves from the bleaching effects of ocean acidification.
Coral reefs are important ecosystems as they help support an incredible amount of tropical marine life. The most famous coral reef is the Great Barrier Reef off the coast of Queensland, Australia, which is home to more than 1,500 fish species, hundreds of coral species, and hundreds of species of sea turtles, sharks, and sea mammals.
Acidic ocean water makes it inhospitable to symbiotic microorganisms that are essential for the survival of the coral. These microorganisms also give the coral most of its color so they appear "bleached" when they are gone.
The study looked back at 27 years of data and found that before a harmful bleaching event, the coral can be exposed to a minor period of stress because of temperature fluctuations. After this smaller stress is over, the coral has a chance to prepare itself for a bigger stress in the future and stands a better chance of survival.
"When corals are exposed to a pre-stress period in the weeks before bleaching, as temperatures start to climb, this acts like a practice run and prepares the coral," explained Tracy Ainsworth, lead author of the paper published in Science. "Corals that are exposed to this pattern are then less stressed and more tolerant when bleaching does occur."
After one of these "practice runs," the coral has time to relax and prepare for the next event. However, increased temperatures are putting the coral through an extended period of stress, which makes it harder for coral to resist the effects of bleaching.
These results may seem grim, but having a better understanding of how coral bleaching occurs allows scientists to develop a better plan to prevent it from happening. First and foremost, they say, global temperatures cannot be allowed to continue rising at their current rate.
If the global community can take a stronger stance against greenhouse gases and slow down the rate of climate change, coral reefs around the globe — including the legendary Great Barrier Reef — could be saved.
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