Limpet Land

Summer is quickly ramping up at WHOI, and that means experiments are starting! I set up an experiment on Friday to look at the effects of slipper shell limpets, Crepidula fornicata, on subtidal fouling communities. This work builds on the experiments I did last summer.

My experimental panels with live limpets or shells

Last year, I noticed that tiny slipper limpets settled on my panels along with the other sessile organisms. The limpets crawled around on the panels, each in the small area near where it had settled, and bulldozed recruits of other species as they went. The end result was that no sessile species could grow on the panel in a limpet-affected area, so there were halos around each of the limpets.

The halos were cleared by bulldozing limpets, but they didn't stay clear for long. One species of ascidian, Diplosoma listerianum, colonized all new space on the panels, including the halos, and it even grew over the limpet shells. It was a strange sight to see a limpet crawling around on the panel with an ascidian on its back.

Part of me thinks that the reason Diplosoma was so good at colonizing the limpet halos is because the limpet shells disrupted the flow of water over the panel and created turbulence that delivered their larvae to the substratum. I started to wonder about the net effect of limpets on the fouling community, and I wanted to try disentangling the halo effect and the turbulence effect.

I suspect that the physical structure created by limpet shells
may create turbulence that affects the community.

Hence my present experiment. I'm using large (adult female) and small (juvenile) limpets. On some panels, I kept them live (limpets tend to stay in place once on a panel), and on other panels, I glued down empty shells. I also left some panels blank as a control. Live limpets have the turbulence effect and can bulldoze halos, while shells alone will just create turbulence. I can compare the recruitment on panels in these treatments and the control to tell how bulldozing and turbulence affect recruitment. I can also contrast results from the two different sizes (large adults or small juveniles) to tell if the size of the limpet has any effect.

I got everything set up and hung my panels beneath a floating dock in Eel Pond. I'll revisit them in a couple of weeks to see what I get!