Broccoli Coral

by B. N. Sullivan

Broccoli Coral (Dendronephthya sp.)This is the second in a series of posts intended to showcase the many colors and shapes of soft corals in the taxonomic family Nephtheidae.

In the first post I mentioned that these corals appear in a countless array of colors. Most grow as tree-like structures having a stem, or stalk, with many branches. Near the ends of the branches are clusters of polyps which open like tiny flowers when they are feeding. When the polyps are closed, they look like little beads.

In fact, when the polyps are retracted, these corals -- especially the greenish colored ones -- resemble broccoli plants, and "Broccoli Coral" is one of the common nicknames given to this type of coral. One look at the photo here, and you'll understand why. (Click on the photo to enlarge.)

Although this kind of coral can resemble broccoli in appearance, it definitely is not a plant. It is a colony of animals -- the coral polyps. The polyps arrange themselves in bundles at the ends of the rubbery stalks. Each polyp has exactly eight short, feathery tentacles. In order to feed, the polyps open and close their little tentacles, grabbing tiny nutrient particles that are suspended in the water.

Many Nephtheid coral colonies contract during daylight hours, making them look a bit shrunken and withered. They expand to feed at night, plumping themselves out and extending all of their little tentacles like bouquets of flowers at the tips of their stalks. For this reason, many of the best photos of these corals are taken during night dives.

I took the photo on this page in the Red Sea, during daylight hours. You can see that the polyps are tightly shut. In tomorrow's "Wordless Wednesday" post, you'll see some macro photos of this same variety of soft coral.

7 comments:

  1. I've been lurking over your blog for several months and absolutely love what I've seen here. The pictures are one of a kind and your commentary shows off your knowledge and passion. I love this picture of the broccoli coral. Keep it up!

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  2. Thank you, Kevin. That's a very nice compliment, coming from a marine biologist. I hope you'll continue to join the conversations here instead of returning to lurk mode. (And congratulations on joining the team at Deep Sea News.)

    Bobbie

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  3. Great shot and info Bobbie, it does look amazingly like broccoli, the sea is such an awesome place !!

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  4. Yes, Bernie, the sea is an awesome place indeed. I'm only sorry that so few people get to see what's under the surface of the water.

    Bobbie

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  5. Hi Bobbie - Such beautiful corals! Do they continue to grow polyps over their lifespan? They must be so beautiful when they are in "bloom" during feeding time.

    Kathy

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  6. Hi Kathy - I have to admit, I don't know the answer to your question about the polyps. In fact, I'm not sure how long the lifespan of these corals is. Some of the colonies can grow rather tall -- two or three feet -- but most of the ones we've seen are not quite that big. I will be posting some photos of Nephtheid corals with their polyps, so you'll be able to see that they are indeed very beautiful

    Bobbie

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  7. Hello,
    I'd like to know what species this coral is. Can you help? great work...

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We welcome your comments and invite your questions. Dialogue is a good thing!

Bobbie & Jerry