Archive for October 11th, 2009

Pesky barnacles evade our attempt to scale them!

Sunday, October 11th, 2009

Friday, the biology student research group got together in the COOL Room for a meeting. The prospective outcome of the meeting was to have been the successful scaling of the JPEG provided to us by Tina, showing both the growth on the tail and around the sealing rings of RU27. We were excited. Finally, something tangible to say about these disasterous parasites: their size. Knowing the approximate size of the Lepas species would allow us to go ahead and narrow down our species list, speculate growth rate, and send sample measurements to barnacle experts. 

Unfortunately, the images we were provided with show Scarlet on an angle! The team sat around the long table in the lab pondering this unexpected conundrum. What on earth were we to do? The tail on the image is larger than the tail on the gliders itself, and the depth of perspective of the glider in the image is not proportional! The ring closest to the tail is a different size from the ring closest to the nose in the image, making scaling of the glider very difficult. Very quickly, the group realized that understanding barnacle size was a trickier business than first anticipated. We are, uh, 'biologists,' not mathematicians, and so, accounting for this angle would be a difficult task indeed. The consensus that we came to (after seeking advice from Chip in the glider lab) was that it would be much easier to try to procure another image from the original footage; one that illustrates the glider from a direct profile (where the rings are all proportional to one another), rather than attempting a complicated equation.

A glitch in our plans, certainly. But the meeting was not entirely a failure. After doing a bit of light reading in the books we checked out from the library last week, we stumbled upon a key factor in barnacle physiology, the specific characteristic that promotes adhesion to surfaces like Scarlet: the cement gland. This gland secretes a protein compound that bonds with the substrate, in our case the surface of RU27 in particular, forming disulfide bonds.

disulfide bond

Once formed, these stable bonds are not easily broken and are insoluble in water. Very convenient for a barnacle catching a ride on a whale, or a turtle, or an AUV, but a dangerous reality for Scarlet. As Scott has been posting in recent days, Scarlet's vertical velocity is declining rapidly, steadily, however graceful.

More on Cement Gland

Our current task, aside from accurately scaling a more suitable JPEG, is to find surface materials that inhibit disulfide bonding. But scaling is the priority. The quicker we can size these crustaceans, the quicker we can compare growth rate to vertical velocity. I guess we better get moving...


Side note: We are also trying to checkout the bibliography you've provided for us this weekend, Antonios. Thank you.


Cheers, everyone.


Amanda [...Brian, Gina, and Montana]