So, I’ve recently started following the publications of a few scientific journals in my field. It’s impossible to stay informed of everything, but I’m trying to at least keep abreast of Coral Reefs, Marine Ecology Progress Series, and, of course, Science. I’ll be honest with you, I’m not really reading many of the papers these journals publish, just scanning the tables of contents for the titles. Still, I’ve found a few gems that merited further inspection.
One is titled “Bubble curtains attenuate noise from offshore wind farm construction and reduce temporary habitat loss for harbour porpoises” by Dähne et al. (2017). I have just one question -how can you not be intrigued by a bubble curtain?? I’m imagining something fantastic, like the home décor of Willy Wonka. Or maybe it’s the perfect complement to a bounce castle? I honestly don’t know. Plus, if you manage to contain your excitement for a few seconds and read past the bubble curtains, you’ll see that this paper is also about porpoises (Phocena phocena). You and I both know that marine mammals are just the cutest ever. Yes, it seems the authors have a real winner here and we’re only 17 words in!
Does this paper live up to the hype? Well, in my opinion, not really. Bubble curtains do turn out to be just what they sound like: streaming walls of bubbles emitted from perforated air hoses (see below). The idea is that the bubble curtains interfere with sound waves traveling through the water, reducing overall decibel levels and the area of ocean impacted by the noise. In this case, they’re being used to mitigate the sound of pile-driving during the construction of a German off-shore wind farm. Pile-driving is a loud activity. You’re ramming a big-ass piece of concrete with a hydraulic hammer of similar-ass proportions – it makes sense. The problem is that this noise can be harmful to marine mammals, causing them to flee the area (habitat loss) and temporary, or even permanent, hearing damage. You may recall that porpoises make extensive use of echolocation, something which relies heavily on being able to hear. People will say “it’s so loud I can’t hear myself think”, well what if it was so loud you couldn’t hear yourself see. That’s these porpoises.
Anyway, what the study found was that impacts on porpoises, and potentially other marine mammals, seem to be reduced with bubble curtains in place around pilings. Data was collected using underwater hydrophones to record porpoise clicks, the frequency and timing of which were then analyzed. The scientists looked for things like how quickly after pile-driving stopped that they started hearing clicks again, AKA porpoises returning to the area. The porpoises returned quicker with the bubble curtains mitigating the noise than they did when there was pile-driving without bubble curtains.
So is this important, relevant science? Sure –especially as offshore wind farms become much more commonplace with improving wind energy technology. Is it as cool as the title makes it sound? Not really, but that’s ok. Not everything needs to blow your mind or change the planet or bring a major world religion to its knees. Sometimes you just get lured in by the promise of bubble curtains and walk out knowing way more about the statistical methods used to analyze the frequency of porpoise clicks than you ever needed. What else is Saturday for?
Johnny Venger also has a laser on his head.
Dähne M, Tougaard J, Carstensen J, Rose A, Nabe-Nielsen J (2017) Bubble curtains attenuate noise from offshore wind farm construction and reduce temporary habitat loss for harbour porpoises. Mar Ecol Prog Ser 580:221–237