Hydroid-a-rama
A few months ago, I put racks of settlement plates out on docks around Woods Hole. My intention was to monitor any organisms that recruited over the winter and practice identifying them. Well, I can tell you that not much at all recruits to shallow dock communities in Woods Hole, Massachusetts in the winter. I found a few hydroid colonies at one site, but really not much else. (Seriously, I've seen higher winter recruitment in the Arctic!)
Here's the thing about hydroids, though: they live in colonies. They clone themselves. And when there's nothing to eat them or compete with them, those colonies can grow pretty darn fast.
The photo at right shows what my monitoring plates on the WHOI dock looked like this week. It was hydroid-a-rama! The clusters with the pink buds are an athecate hydroid called Tubularia. They started showing up on my plates in early January, and they've proliferated since. But look in the middle of the picture. You'll see a brown-orange fuzz that almost looks like hair. (I marked it with a small arrow.) Any idea what that is?
It's another species of hydroid, this one thecate (with a cup around its tentacles). It's called Obelia geniculata. There were two strands of Obelia on the plate a few weeks ago, but the one colony has just exploded.
Hydroids are suspension feeders, so they eat small particles in the water around them. To survive, they need good flow. The WHOI dock, where the hydroids are growing, is the most exposed of my four dock sites. The other three sites have had essentially no recruitment in four months, so I'm starting to think the flow of the water has a lot to do with what grows where.
In case you missed it, my monitoring plates made it onto the WHOI website. I was the Image of the Day on Wednesday. I'll keep checking the plates over the next few months, in the hopes of witnessing the spring recruitment pulse. Once I see a wide diversity organisms starting to settle, I'll start the experiments I have planned for this summer. I'm excited to learn as much as I can about the invertebrate communities around me!
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| My monitoring plates at the WHOI dock, 15 Feb 2017 |
The photo at right shows what my monitoring plates on the WHOI dock looked like this week. It was hydroid-a-rama! The clusters with the pink buds are an athecate hydroid called Tubularia. They started showing up on my plates in early January, and they've proliferated since. But look in the middle of the picture. You'll see a brown-orange fuzz that almost looks like hair. (I marked it with a small arrow.) Any idea what that is?
It's another species of hydroid, this one thecate (with a cup around its tentacles). It's called Obelia geniculata. There were two strands of Obelia on the plate a few weeks ago, but the one colony has just exploded.
Hydroids are suspension feeders, so they eat small particles in the water around them. To survive, they need good flow. The WHOI dock, where the hydroids are growing, is the most exposed of my four dock sites. The other three sites have had essentially no recruitment in four months, so I'm starting to think the flow of the water has a lot to do with what grows where.
In case you missed it, my monitoring plates made it onto the WHOI website. I was the Image of the Day on Wednesday. I'll keep checking the plates over the next few months, in the hopes of witnessing the spring recruitment pulse. Once I see a wide diversity organisms starting to settle, I'll start the experiments I have planned for this summer. I'm excited to learn as much as I can about the invertebrate communities around me!
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