Archive for October 2nd, 2009

Barnacle Update

Friday, October 2nd, 2009

For readers who aren't very familiar with RU27's flight: during the summer, Scarlet began spinning uncontrollably during her eight hour missions. Biology growth seemed to be the most likely source for the uncharacteristic, erratic dive patterns, and after sending a team out to the Azores to check on her, the culprit could be clearly identified. What mischievious parasite has been growing on our poor Scarlet? Drum-roll, please: barnacles! She looked very much like a bearded lady.

The task of our student research group - Brian, Gina, Montana, and myself (Amanda) - is to figure out exactly who these little squatters are: what species are they? how fast have they grown? when and where did they first attach? how can we prevent gliders from becoming a desirable home for these drifters in the future?

On arriving at the Library of Science and Medicine, Brian, Gina, Montana, and I went on a search for barnacle literature. Surprisingly (or not), there wasn't much (two books). After a long conversation with the woman at the reference desk (the books we were looking for did not exist in the library system), we made our way to the QL section of the second floor. And low and behold, books on barnacles!

What we discovered among the stacks:

Utilizing a most helpful text,Barnacles: Structure, Function, Development and Evolution, we compared the illustrations and descriptions of the text with JPEGs of the actual barnacle 'colonies' that had been growing on RU27 at sea. The genus Lepas seems to be the most fitting aesthetically, and we think that of that genus, there were about four or five different species making their home on Scarlet. Very exciting!

Here they are:

a)

l. anatifera

l. anatifera


b) l. anserifera

c) l. australis

d) l. hillii

e)

l. pectinata

l. pectinata

Each of these species share general characteristics, but vary slightly phenotypically. And, they are all known to attach to free floating objects such as logs, or man-made structures (288), like ships (...and now, autonomous underwater vehicles too, i suppose...). in general, the growth rate from attachment to adulthood (cyprid) averages about two weeks. That would, we think, fit nicely with the irregularities in flight dynamics (spinning, ect.) that occurred suddenly in July! Maybe not, but it can't hurt to dream.

Our next task is to find specific sample growths of each species on the glider and to find a way to measure each sample to determine actual growth rate. Do our barnacles fit the average growth rate of Lepas?

- Amanda, Brian, Montana, and Gina

999 Kilometers To Go

Friday, October 2nd, 2009

When Scarlet surfaced this morning at 4 am, she had flown a total path length of 6369 kilometers, continuing to increase the world record.  But that's not today's news.

091002_ru27_sst_big

At 4 am this morning, Scarlet's distance to our target point in the middle of the Galcia CODAR field dropped to 999 km. 

091002_ru27_alt

The present path will take us out of the slightly warmer water where we have been flying into a head current, and into to cooler water where we hope to find a more favorable environment.

091002_ru27_sst_alt

We have traveled over 81% of the way across, and based on our theoretical calculations, we still have over half a tank of gas.    We need to beat the high waves of the approaching winter, and fly faster than the growth rate of any biological activity.  We know something is out there, likely barnacles again, that is decreasing our speed. We are flying full speed to compensate. The race is now against time.  And its time to burn some energy.