Week six and I’m still learning new tricks —like how to make seawater fizz. This past week made me feel more like a chemist than a marine biologist, dissolving chiton shells and trying to take calcium out of real seawater. I started off the week by dissolving juvenile chiton shells in my boneless chicken water to see if the mysterious crystals persist the formation of the chitons’ shells. They do! We now know that chiton still have these crystals 15 days after settlement (22 days after hatching) and have a method to continue to observe the disco balls in the juveniles I have (Figure 1). I also redid my calcium experiment on a smaller scale, and this time my controls survived! However, they also did not form the spicules, which suggest the artificial seawater I am using has some unintended effect on chiton development. Additionally, my lowest concentration of calcium delayed the formation of the mysterious crystals by a day (relative to the other treatments), contrary to my previous iteration of the experiment where there was no delay. Therefore, I will be doing this experiment again to test the repeatability of this new result. Additionally, I will be modifying my methods to create calcium-depleted seawater from real seawater that will (hopefully) not interfere with the calcification of the spicules.
Unfortunately, I have been unable to find methods for removing calcium from seawater but many methods for making artificial seawater without calcium. However, I have been able to find some usable techniques, the most promising is making calcium oxalate from oxalic acid. In seawater, calcium and oxalate react to form a solid (calcium oxalate), allowing me to remove it from seawater. The unfortunate side effect is by putting oxalic acid in seawater, I acidify the water far beyond what could be considered normal for seawater. I have been experimenting with different ways to neutralize the acid before or after adding it to seawater. Playing chemist has been fun and led to some funny moments, a particularly memorable one is surmised by the quote, “Alondra, why is my seawater fizzing?” When I haven’t been dissolving shells and making seawater fizz, I’ve been out looking for chitons or relaxing with the other REUs at a bonfire. This week I started noticing a particular species of sea cucumber (Cucumaria miniata, Figure 2) at one of the sites I frequent in search of chitons. Richard had pointed them out to me last week at a different site so it has been fun to notice them on my own in a place I’m familiar with!
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AuthorI'm a rising fourth year at Villanova University in Pennsylvania from San Diego, California. I enjoy going tidepooling and making music. I'm looking forward to a great summer at OIMB! Archives
August 2021
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