Yesterday I ran my first trial run of the experiment. I started shortly after 7 a.m. and finished cleaning up the test tubes and beakers around 9:30 p.m. There was a lot of prep work. We had to determine the sex of all the COT we had collected by cutting into them as I showed you in previous posts. We then placed the males and females in separate blue tanks to minimize the chance that sensing the presence of the opposite sex would stimulate spawning. We also had to make up various solutions, label tubes, gather pipettes, etc. So the actual experiment didn't start until the afternoon. Here's what my lab space looks like, pretty crowded but that is typical here:
The blue rack of tubes to the right of the dissecting microscope is holding the COT eggs and sperm. The experimental design involves putting about the same number of eggs in each tube (400-500) but making a serial dilution of sperm. If things go as planned, some tubes will have too many sperm causing more than one sperm to fertilize an egg ("polyspermy") resulting in abnormal development, and some tubes having too few sperm resulting in some eggs not getting fertilized. After the eggs and sperm were mixed, the tubes were floated in one of Emily's coral buckets (the subject of a future blog) that had flowing sea water at ambient temperature (28.1 degrees C or 82.6 degrees F). I collected the tubes after about 3 hours and counted how many of the eggs were developing normally, how many were abnormal, how many were not fertilized, etc. This is what some of them looked like:
The eggs and embryos are put on a raster slide that has a grid on it to facilitate counting. The brown spheres are unfertilized eggs and the groups of cells contained within a fertilization membrane are developing embryos. The cells look pretty disorganized and not as neatly arranged as they are in the early embryos of most other organisms, but this is typical of star fish.
Yesterday's experiment clearly showed that this experimental protocol can work with the COT. However, progress has slowed today because of one of the challenges of working with Acanthaster, whose name literally means "spiny star." I've been stabbed several times collecting these guys. The initial stick feels like a needle prick, with more pain from the toxins increasing over the next several days. The wounds from January 18 are just about healed, with what feels like a lump of scar tissue under the skin.
Two days ago we went back to the spot on the NW corner of the island and collected 7 more COT, some of them huge (~2 feet across). With the surge from the waves coming over the reef, we were getting knocked around and it was hard maneuvering the stars into our catch bag. Even though I was trying to be careful and wearing gloves, I got stabbed a couple more times. Neither stab seemed that bad at the time, but as luck would have it, the one in my left index finger has become increasingly inflamed. Here is a picture I just took of it:
(There's a COT in the background in its tub for context.) The skin is taut and the last two digits are so swollen that I can't bend the joint. Redness is progressing towards the base of the finger. (I'm typing this without the use of that finger, which is really slowing things down!) I don't see clear evidence of infection, I just think the redness and swelling are due to the toxins. However, if things aren't better in the morning I'll see if I can find a doctor, assuming doctors here have experience with COT wounds!
So even though my finger throbs, a good anesthetic is just looking around at the scenery:
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