Depth of Field #2: The Sea Hare Emerges

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Photo Credit: Carrie Schuman

The sun is starting to set on expanses of mirror-reflective tide pools speckling the beach of the Tawharanui Marine Reserve in New Zealand. I’ve been walking along staring into them at random in my search for anything novel when I chance across what is at best guess an example of Aplysia dactylomelathe variable sea or spotted hare.

In a surprising contrast to the small chitins, tunicates, and other finds, the sea hare was relatively large, measuring somewhere in the range of 5 to 6 inches in length. As seen in this additional photo, a smattering of spots can be seen along its body:

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Photo Credit: Carrie Schuman

According to this source, sea hares are hermaphroditic though they do not practice self-fertilization. They may often form reproductive “chains”.

As suggested by one of their common names, they may be highly variable in appearance with their coloration primarily determined by the type of algae they feed on.

They release a purple dye as a mechanism to surprise and confuse predators. This particular characteristic was one I had once experienced first hand when handling my first sea hare in the mangroves of Key West. It certainly has a startling quality to it.

Variable sea hares tend to be more solitary, and nocturnal in nature. So perhaps no small amount of dumb luck governed this thrilling little chance encounter.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Aplysia dactylomela

Speck of Science – 1/7/2016: Aye Calypso

Sometimes I come across some interesting news item that I don’t have time to write about in depth but still want to share. I’ve decided to start a new Speck of Science feature on my blog as a way to share brief blips and recaps of internet curiosities and dispatches.

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Today’s item is an article from the Guardian reporting that Jacques Cousteau’s ship, the Calypso, will soon be ready to begin life anew. The ship was downed by an accident and since 2007 had been languishing in a sort of boatyard purgatory due to disagreements over payment and the purpose of its restoration. This is truly exciting news for the continuing legacy of marine exploration, and our care for the world’s oceans.

 

 

 

 

 

The Weird and Wonderful World of the Water Bear

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Photo Credit: Steve Gschmeissner/Science Photo Library/Corbis

I have long been fascinated by water bears (also known as tardigrades, and more amusingly and infrequently as moss piglets), though I have yet been lucky enough to see them for myself, wandering about their microscopic worlds.

However, they have been items of interest as of late due to some of their more bizarre qualities. (I like to think of them as literal inclusions in the news, wandering about among inky words on printed pages). If the distinction of being able to survive in the vacuum of space along with other extreme environments wasn’t enough, it was recently revealed that they have an inordinately high amount of foreign DNA in their genome – almost 18% relative to many organism’s 1% – earning them the playful moniker of “DNA thief” in articles on the subject.

Water Bear

Much of this extra DNA may be incorporated into the tardigrade’s potential tool kit during periods of desiccation. Water bear DNA is suspected to actually sheer and fragment when dried out, and to reassemble once re-hydrated. This period of genome construction probably provides ample opportunity for stray genetic material to sneak in.

Researchers have also recently discovered more about how water bears may cope with this extreme drying out and jumbling of their genetic material. Apparently these bitty creatures produce a sort of “bioglass” that coats and protects their cellular contents.

So along with discoveries of new members of the water bear extended family, there’s no doubt there are many strange revelations to come concerning these curious creatures.

Updated note: Thanks to Robie and her comment below. Turns out there is some conversation occurring right now with regards to whether the figure of ~ 17% foreign DNA is, in fact, accurate. So while it may take a little time for researchers to suss out the truth of the matter, this is an interesting insight into the tug and pull of the scientific process.