Coral Reef Islands Return Thanks To Rising Sea Levels

Research has found evidence to suggest that rising sea levels may actually help build coral reefs, instead of destroying them like scientists originally believed. Low-lying coral reef islands are usually less than three meters above sea level which means that they can be impacted by climate change and the rising sea levels that come with it. This rise in sea level may be a danger to those of us on land but it could be a huge help in the growth of coral reefs as long as these reefs remain healthy.

How Were Coral Reefs Formed?

At the time the five islands in the southern Maldives formed, sea levels were 0.5 meters higher than they are today. Having more water gave the waves a lot more energy when they hit land. The islands in question were formed by large waves from distant storms off the coast over three to four thousand years ago.

Known as high-energy wave events, these large waves were able to break coral rubble off the reef and move it to the reef platforms which in turn created the foundations for reef islands. This could mean only one thing – the higher sea levels and large wave events were essential to the creation of these islands.

Coral Bleaching Won’t Help

Coral Bleaching is a huge problem when it comes to the growth of coral reefs. A few ecological causes for bleaching include temperature, subaerial exposure, freshwater dilution, and a few others.

Subaerial exposure is the one that will be solved by rising sea levels because it involves the sudden exposure of reef flat corals to the atmosphere which usually occurs during low tide and a drop-in sea level.

When corals are stressed by changes in conditions such as the ones stated above, they expel the symbiotic algae living in their tissues causing them to turn white and become “bleached”. This bleaching will kill the coral if it is not resolved quickly which is why growth is not possible when bleaching is present.

Ideal Conditions For Growth

The ideal conditions for coral growth are stable climate conditions so bleaching can’t occur, perpetually warm waters, shallow water, clear salt water, abundant plankton, and little or no pollution. The only condition that would be impacted by the sudden change in sea level is having to be in shallow water.

Coral needs sunlight to survive and if they are any further than 45m to 55m below sea level, they will not get enough light and will eventually die. However, it would keep them from being exposed to the elements reducing the change of any bleaching.

Adapt To Survive

According to Dr. Holly East, the lead researcher from the Department of Geography and Environmental Sciences at Northumbria University, coral reefs face a range of threats from climate change. The reefs need to be able to adapt to the conditions around them to survive.

By using the large wave events, researchers are hoping that the coral reefs will be able to rebuild themselves over time. However, this will only be possible if the reefs are not bleached already. We may have the perfect building conditions, but it is up to the reefs themselves to provide the bricks.