Thursday, August 10, 2017

The end

"Save yourself, serve yourself
World serves its own needs, listen to your heart bleed
Tell me with the rapture and the reverent in the right
You vitriolic, patriotic, slam, fight, bright light
Feeling pretty psyched...
It's the end of the world as we know it
It's time I had some time alone"
- "It's the end of the world as we know it (and I feel fine)" by R.E.M.

Well, friends, my succession experiment is done. This week, my intern and I collected our last round of data from Eel Pond and finished the experiment. It is over! Finished! No more!

As you know, the fouling panels at the WHOI pier surprised me in their last week by having barnacles. Well, Eel Pond had a surprise in store for me too. Do you remember the random plates that were covered in Ascidiella, the large squishy ascidian? Well, surprise! All of the Ascidiella disappeared. My plates that were covered in large, gelatinous mounds of the species were instead covered with small, new recruits of bryozoans and spirorbids. Another species of ascidian, Botryllus schlosseri, was also conspicuously absent from the plates. Botryllus used to cover large areas on my fouling panels, but it too has vanished.

I have two hypotheses for why the ascidians disappeared. The first is that Ascidiella mounds were heavy. In fact, the experimental panels got hard to lift out of the water when Ascidiella was so abundant. Maybe they sloughed off the panels, dragged off by their own weight. This explanation doesn't apply for Botryllus, though, since Botryllus was light and lay flat to the panel surface. Another possible explanation is that the ascidian disappearance was temperature-related. Similar to hydroids at the WHOI pier, they may have died in the ever-warming water. I have yet to download and analyze the temperature data from my loggers, but once I do, I will let you know what I find!
"Hey Kirstin, you match the plates!" - my intern, Nicole

With Ascidiella and Botryllus out of the way, the ascidian Botrylloides and all the bryozoans were able to flourish! Botrylloides is red-orange, and most of the bryozoans are tan-yellow, so the panels had a very bright color scheme this week. You can probably guess that orange is my favorite color just by looking at this blog, and as you might imagine, I was quite pleased to end the experiment with orange fouling panels!

Here's to the end of a great experiment!

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