Know Your New England Bioluminescants

posted by Sophia Tintori / on September 27th, 2010 / in Arthropods, Comb Jellies, Dinoflagellates

Towards the end of the summer the waters around southern Rhode Island get quite sparkly at night. I’ve wondered for a while what exactly the sparkling things might be, but it wasn’t until recently that I remembered to bring a bucket with me and look at its contents in the light of day.

When I went out to the ocean a couple of weeks ago, I noticed three distinct sizes of glowing creatures; the tiny specks that make a cloud when you kick the water, the medium ones that look like a pair of triangles, and the big circular ones, that stay glowing for a second or two.

Steve Haddock, one of our friends at the bioluminesence lab at the Monterey Bay Aquarium Research Insitute, helped characterize some of these organisms. Here’s what I found.

The larger circular ones are comb jellies.

We get a lot of comb jellies called Mnemiopsis around here. By the end of the summer there are sometimes so many that it feels like swimming in a giant bubble tea. This seems to be a very young Mnemiopsis, not quite mature yet. Comb jellies don’t have any stinging cells, and are not technically jellyfish– corals and anemones are more closely related to jellyfish than these creatures are, even though these look similar. For more about the psychedelic rainbow colors pulsing down the side of this animal, check out Brown undergrad Lee Stevens’ podcast on comb jellies.

According to Dr. Steve Haddock, bioluminesence correspondent, the smallest size of glowing thing is most probably a bunch of single celled organisms called dinoflagellates.

The last glowing group I found seems to be these copepods, a type of small crustacean.

The appendages at the very back of their bodies are long and thin, but move back and forth so fast that they look like little paddles. These thin appendages whipping around are probably what looked little triangles underwater.

These videos and photos were taken by Sophia Tintori, and released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license. Thanks to Steve Haddock for his help. If you see jellies in the water, you should let Steve know at Jellywatch.org. Thanks to Mickey Zacchilli for helping with the video. If you enjoy watching the pulsating comb rows of a comb jelly, here is another clip for you.

Jellyfish Capsule Hotel

posted by Sophia Tintori / on September 11th, 2010 / in Arthropods, Jellies, Parasites, Siphonophores

These little pinkish crustaceans have set up house inside the muscular pulsating swimming parts of the colonial jellyfish, Nanomia. Out in the deep sea, there are few solid structures to call home, so living things will often take shelter in or on other animals.

Fish or bugs often hang around the tentacles of jellyfish because the jellies catch food there and are likely to drop pieces that can be salvaged. But these crustaceans are taking a different approach. They are living inside of swimming bells that are nowhere near where food is caught and eaten. These powerful little pods contract to push the colony through the water. The amphipods are likely to be taking refuge in the sturdy tissue, and feeding off the jellies flesh from the inside of the swimming bell.

Stefan Siebert, a post-doc in the Dunn lab, took this photograph of a Nanomia that he caught on a collecting trip in California. The gas-filled gland that keeps the colony afloat is hanging off the left side of the page. Three swimming bells for jet propulsion (with one amphipod crustacean in each) are seen in the middle. The part of the colony that feeds, reproduces, protects, and more, starts in the bottom right corner of the photograph. These amphipod crustaceans happen to be very similar to the ones we just made an animation about, that live on the fried egg jelly.

Here is a video from Casey Dunn of some other colonial jellyfish, to get a sense of how this close up photograph fits into the context of the whole colony, and to see how the swimming bells pulsate.

This photograph, by Stefan Siebert, is released under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 license.