Recent studies indicate that nearly 60% of the world’s coral reefs could be lost within three decades and 85% of all natural oyster reefs have already been destroyed.
Ocean reefs provide shelter for many species of fish. They serve as spawning areas and barriers that protect coastal waters from strong currents and waves.
In particular, coral reefs play a role in regulating the amount of carbon dioxide in ocean water, turning the gas into a limestone shell.
However, reefs worldwide are being destroyed by rising water temperatures, sewage, pollutants, overfishing, negligence and disease.
Reef ecosystems that took centuries to develop can be obliterated in a single day by dredging or illegal fishing using dynamite or cyanide.
A recent report warns that all coral reefs could be gone by 2050 unless action is taken to protect them.
As reefs are lost, shorelines lose protection from storms and coastal communities lose their source of food security and tourism. Their disappearance could threaten the livelihoods of some 500 million people worldwide.
A major cause of dying reefs is climate change. Warming sea temperatures lead to “coral bleaching,” causing corals to expose their white skeletons.
As coral dies, concentrations of CO2 increase in a process called “acidification” that kills sea life and creates dead zones in the ocean.
Another study published in 2011 has shown that reefs formed by wild oysters have all but disappeared. Naturally occurring mollusk populations have been demolished by over-harvesting and disease, making the species “functionally extinct.”
That means they no longer play any significant role in their ecosystems and exist at less than one percent of their prior abundances. Only farming now allows oysters to survive at all.
According to the World Resources Institute, ocean reefs are harbingers of change. Their death could signal massive extinctions.
If policymakers fail to address the threats reefs face, precious ecosystems will unravel. On the other hand, coral reefs are by nature resilient. They can bounce back if humans begin to help, rather than continue to hinder, their growth.
Alfablue, October 2013