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EarthSky // Earth, Science Wire Release Date: Jun 30, 2014

Amazing purple jelly in the deep sea

Many deep-sea creatures are red, but this one is a strange purple-blue. Oceanographers wonder what benefit there is to being purple under miles of ocean.

This creature, related to jellyfish, is a siphonophore. The most famous siphonophore is the portuguese man-of-war.  What's amazing about this deep-sea siphonophore is that it's purple!  Most deep-sea creatures are red.  Image via DeepSeaNews.com

Video still of the newly recognized purple siphonophore. via DeepSeaNews.com

R.R. Helm at DeepSeaNews.com is remarking this morning (June 30, 2014) on the remarkable discovery of a purple siphonophore, a relative of jellyfish. The most famous siphonophore is the portuguese man-of-war. Why is this one remarkable? R.R. Helm, who is a PhD candidate studying jellyfish development and evolution at Brown University, wrote:

I’ve seen red siphonophores like this, a couple orange, but never ever this strange purple-blue. It’s a shocking shade, and it makes me wonder what on earth a color like that is doing down so deep. Many deep-sea animals are red. Because there is no red light in the deep sea, very few animals can see red pigment (unless they make their own red light). In the deep sea, red looks like pitch black. But what about purple? Is there any benefit to being purple? Or is this just a side effect of something it eats or where it lives?

Answering these questions is difficult, because sightings of siphonophores like this one are pretty rare. These animals are only found in the very deep ocean, and though large, they’re still small compared to the miles of water a submersible had to travel in order to find one.

This creature made its appearance in a video collected as part of the Nautilus Live expedition. The expedition is being headed by Dr. Robert Ballard, who famously discovered the wreck of the Titanic. Watch the video here:

Bottom line: The Nautilus Live expedition created a video, and oceanographers have now commented on it, showing a stunning purple siphonophore, a relative of jellyfish.