Tuesday, April 12, 2016

Barnacle tales

Earlier this week, I got an e-mail from a dear friend in Brazil. She told me tales of her tropical field work, of communicating with the boat driver in broken Portuguese, of battling sun- and windburn, of warding off insects, and of the countless scrapes on her hands from mussels and barnacles. I had to smile as I read her message, because this particular friend is both highly intelligent and fearless. I understand a little of what she's going through, having been a field-working foreigner myself. Granted, I've never had to communicate my wishes to a boat driver in Portuguese, but I know exactly what she means about the barnacles.

Hesperibalanus hesperius and Onchidoris bilamellata on a
settlement plate. Can you tell which is which?
I've seen my share of barnacles both in the Arctic and on the temperate Oregon coast. As my fearless friend battles barnacles a hemisphere away, I'm analyzing my own barnacle data. I've actually set the Svalbard data aside for a bit and started playing around with my Cape Arago recruitment data. If you remember, I outplanted cement blocks off the Oregon coast the past two summers in the hopes of observing recruitment of hard-bottom species at different distances away from a rocky reef. Despite the best of intentions, my hypotheses turned out to be all wrong, and I ended up finding something completely different than I expected.

I found barnacles. Hesperibalanus hesperius, to be exact, which is a poorly-understood and little-known species. And I found lots of them. What I thought would be an exploration of the biodiversity of recruits on isolated hard substrata turned out to be a story about barnacles. They colonized my settlement plates in high numbers, and they brought predators with them. For example, I found plenty of Onchidoris bilamellata, a nudibranch (sea slug) that is a barnacle predator. It actually looks like them, too - it's white and kind of nubby and can make itself into a mound shape. Check out the photo above to see what I mean.  

My challenge now is to turn my barnacle data into a meaningful scientific analysis. We'll see how this goes!

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