In a new study published in PNAS, corals have been shown to actively manipulate their environment by stirring up currents to supply nutrients to reef ecosystems. The scientists studied six different species of growing reef corals in a laboratory tank and observed their movements with microscopes and video cameras. They found that through small epidermal appendages called cilia, polyps are able to create vortical currents that greatly enhance their exchange of dissolved oxygen and nutrients such as nitrogen and phosphorus with the surrounding water. Coral reefs were previously assumed to be dependent entirely on ambient flow and turbulence for their nourishment, but these results show that they have the ability to actively affect mass transport. This mechanism may be critical to the survival of corals and is likely part of their evolutionary succes.
Click here to watch the accompanying video for a fascinating look at how corals stir up water currents and control nutrient transport.
Journal reference: Shapiro, O. H., Fernandez, V. I., Garren, M., Guasto, J. S., Debaillon-Vesque, F. P., Kramarsky-Winter, E., … & Stocker, R. (2014). Vortical ciliary flows actively enhance mass transport in reef corals. Proceedings of the National Academy of Sciences, 111(37), 13391-13396.
Image: Corals in the Red Sea, Egypt. Source: Mahmoud Habeeb, Wikimedia Commons.