New discovery turns coral development theory upside down
27 Jul 2017 by qmtbqdmdjq.d qmtbqdmdjq.d
Coral growth theory needs revisiting, after large numbers of colonies were discovered in areas once thought inhabitable.
Coral growth theory needs a rethink after large numbers of colonies were discovered in areas once thought inhabitable.
This find suggests scientists are unaware about certain aspects of coral colony development and durability. The colonies were discovered in the waters of the Central and Northeast Pacific Ocean during an underwater vehicle survey of the Northwestern Hawaiian Islands.
Unexpected find
Dr Amy Baco-Taylor, from Florida State University and first author, said: “I've been exploring the deep sea around the Hawaiian Archipelago since 1998, and have seen enough to know that the presence of the reefs at these depths was definitely unexpected.”
Some ocean areas, such as the North Atlantic and South Pacific, are particularly fertile for deep-sea scleractinia – small, stony corals that settle on the seabed and grow bony skeletons. To the researchers’ surprise, they also discovered scleractinian reefs in the deep waters of the North Pacific.
The North Pacific has low levels of aragonite, an essential material in the formulation of scleractinian skeletal structures, making it hard for coral polyps to develop their exoskeletons. As well as this, carbonate dissolution rate, the speed at which carbonate substances such as coral skeletons dissolve, is double that in the North Atlantic. Essentially, these reefs should not exist.
Dr Baco-Taylor said: "Even if the corals could overcome low aragonite saturation and build up robust skeletons, there are areas on the reefs that are just exposed skeleton, and those should be dissolving. We shouldn't be finding an accumulation of reefs.” Higher chlorophyll concentrations in the areas of reef growth suggest an abundance of food may provide the excess energy needed for calcification in these waters – but that doesn't explain everything. For example, why the reefs are at unusual depths or why they get shallower in some areas. It’s still a mystery.
This discovery has also raised questions about ocean acidification and its effect on vulnerable coral colonies. If more of these reefs exist they could reveal important information about coral reef endurance at a time of increasing carbon dioxide levels and ocean acidification.
The research was published in Scientific Reports.
