Friday, November 14, 2008

How to make coral “popsicles”: a useful research tool!


Jessie Hallett, BREAM intern

The “popsicles” pictured here may resemble a cool summertime treat, but they are actually useful devices that we are using to design and implement various ecological experiments involving corals. They are also extremely easy to make!

They were created by first cutting ½” PVC pipe into one inch long tubes. Using marine silicone sealant, a small loop of fishing line was glued to the inside of each tube. Then, a branch of coral (in this case, we are using Madracis auretenra, or yellow-finger coral) is also glued into the pipe with the sealant. The sealant should be used above water, but once everything is set in place the corals can be returned to water. To hold the corals upright, we also made metal trays by cutting holes into ¼” mesh fencing, resulting in a semblance of a test tube rack.

With these trays and coral popsicles, it will be easy for us to set up an experiment in the lab or in the field. Since the number of corals and trays used are easy to change, we can easily fabricate and adjust manipulative experiments involving corals.

This design is also very useful for weighing corals. Using the fishing line loop, corals can be hung from a balance while they are immersed in water to weigh them using the buoyant weight method (see Jokiel, 1978). This is a simple way to measure coral growth!

Before you decide to begin designing a coral experiment though, remember to get a collection permit, and to collect only what you need!
Reference: Jokiel, P.L., J.E. Maragos, and L. Franzisket. 1978. Coral Growth: buoyant weight technique. In: Monographs on Oceanic Methodology Vol. 5: Coral reefs: research methods. Edited by D.R. Stoddart and R.E. Johannes. UNESCO, Paris, pp 529-541.