My favorite topic: coral growth

The future of Acropora corals on some Caribbean coral reefs may depend on active restoration efforts, especially for reefs that have been heavily affected by human use and coral disease, such as those in the Florida Keys. Ken Nedimyer of the Coral Restoration Foundation is growing thousands of staghorn coral (Acropora cervicornis) colonies in offshore nurseries by suspending colony fragments on tree-like racks that are able to withstand stormy conditions. I had heard about this, but I’d never seen what it looks like, until now. Named a CNN hero for his work on coral restoration, Nedimyer gives a tour of his staghorn coral nursery in this CNN piece.

A great thing about staghorn corals is that they grow quickly, up to about 10 cm/year. Like plants, they actually grow towards the light, and even though they have an orientation (as you can see in the video below, they grow up by extension at the growing tip of the branch) they can initiate growth from the bottom as well. You can check out a time-lapse video of the growth of A. cervicornis in an aquarium over two years (posted by Dave Lackland). First you can see how the branches extend out and up towards the light – and then at about one year of growth, the branches run into the glass wall of the aquarium and start to sheet until most of the field of view is covered.

The growing tip of an A. cervicornis branch under the dissecting scope. Photo: Liz Hemond

As you may have guessed, Acropora cervicornis is my favorite coral… I didn’t know that it would be before I started working with it. If you get a chance to see it in person, take a close look at it. Up close it even has stripes; you can see where the high concentration of endosymbionts (the photosynthetic algal cells inside the coral tissues) reside and give the coral their brown color from the photosynthetic pigments. Unfortunately, the photo to the right does not do the coral justice, since you can’t see their charming tentacles, which have been retracted. Despite that, hopefully you agree that they (and other corals too!) are worth preserving 🙂


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s