The Research Rollercoaster

My research project has seen many twists and turns this semester, but things are finally starting to look up.

I initially wanted to explore the incidence of cloning in brittle star larvae, specifically in the daisy brittlestar, Ophiopholis aculeata. Larval cloning is a phenomenon found in many echinoderm species, but is least studied in brittle stars. My goal was to learn more about what induces cloning in brittle stars, to help better understand why they clone. In order for any experiments to happen, I needed to get the adult brittle stars to spawn. This proved to be more challenging than expected, and none of the adults ended up spawning.

From here I decided to switch my attention to a different species, a type of brood star called Leptasterias tenera. Female brood stars hold their young instead of releasing them into the water, which is what gives them their name. I decided to use the larvae from two female brood stars to test the effects of chemical stains on their development.

Stains can be useful tools in tracking growth or distinguishing treatment groups in experiments. However, it is important to make sure these stains don’t act as confounding variables that impact larval developement. In order to determine if staining has any effect on brood star development, I was going to soak the larvae in four different stains, then monitor their development over time.

Soon this plan too had to be altered, as the majority of the larvae died before I was able to start staining. This high mortality rate was most likely caused by the females releasing their broods earlier than normal, due to the high stress conditions of being shipped to our lab.

When the remaining larvae eventually developed into juveniles, only 10 tiny sea stars remained. It was no longer feasible to use four stains with such a small sample size, so I soaked 5 in calcein, which creates a neon yellow/green florescent stain under UV light, and 5 in calcein blue, which creates a blue color under UV light.

Since staining my 10 surviving juveniles I’ve had more success. The stains were absorbed and the juveniles are continuing to grow. Last week I started feeding them frozen brine shrimp, which they have taken well to. Since the brood stars are eating now,, I can start taking pictures of them undertake microscope weekly to measuring their growth.