Wow, week three has come and gone faster than you can say Cyanoplax dentiens! This week I set up an experiment testing how larval chitons respond to different salinities of seawater. Manipulating the salinity of seawater changes the concentration of different ions (such as calcium or magnesium) available for animals to build shells or other crystalline structures. So I hypothesized decreasing salinity (and therefore the concentration of ions needed to build different crystals) would delay the formation of the mysterious crystals. To do this I had to place the chiton in different salinities before these crystals formed. And, as it turns out, I did manage to delay the formation of crystals –but that’s not the full story. Unfortunately (but also interestingly), chitons at different salinity levels (low and normal) ended up on different developmental timelines. As chiton larvae grow, they add new structures, which allow us to mark where they are in their development. Right before chitons develop the mysterious crystals, they grow gridle spicules (calcium structures that form around the periphery of the animal). In my experiment, chiton in normal salinity formed spicules before chiton growing in lower salinity seawater, despite being the same age (figure 1). The formation of spicules occurs right before the mysterious crystals so while I was able to delay their formation it was likely an indirect consequence of delayed development rather than a direct effect on the crystals. Therefore, my future experiments will manipulate ions (e.g. calcium) without changing salinity and will focus on trying to target chitons in the brief time when they have spicules and no crystals. Outside of running experiments, this week we went camping at Sunset Bay and trekked to an island at low tide. The tide was low enough where we could wade to the island and poke around in the tide pools. We saw plenty of awesome stuff but my highlights were: finding a red urchin test (shell) about the size of a grapefruit, seeing a neat color morph of a gooseneck barnacle (figure 2), and coming across dislodged sea palm (figure 3). Sea palms are pretty intense algae because they usually exist only in areas exposed to the full force of crashing waves. figure 3. The picture on the right is the dislodged sea palm I found. The left? Home sweet, sea palm home! Within the green circle is a cluster of sea palms, these algae are known for inhabiting areas in the intertidal where the rocks experience the full force of crashing waves –and they seem to like it!
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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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