Sand Crabs and Shrimp at Stinson Beach, CA!

A few months ago, Manu introduced me to the foldscope in Stinson Beach, CA! Here are some movies of the organisms we collected.


  1. Sand crabs respond to waves by coming out of the sand to feed on plankton. After the wave has passed, they burrow back into the sand. Here, Manu is disturbing the water to simulate a wave, so we can collect some crabs in a frisbee for our foldscope.


2. We also found some shrimp, and looked at the embryos. The embryos had an interesting slit on one side.


3. This movie shows some different cell types in an adult shrimp. We found epithelial cell layers, circulating hemolymph, and a beating heart!


4. As Manu explains here, even in a very small volume of water, we found microplastic pollution.


5. Finally, we found some female sand crabs that were protecting clutches of eggs. The eggs were beautiful when viewed with the foldscope! We could see cellularized developing embryos, and we also saw that there was some kind of mesh holding the clutch of eggs together. We aren’t sure what the fibers are made of, but it was a cool (and unexpected) observation!



One Comment Add yours

  1. Manu Prakash says:

    Welcome to Foldscope community Lila. What a wonderful start. Absolutely love each of these videos. Thanks for sharing them with everyone in the Foldscope community. Sand crabs seem to appear and disappear like magic. I made some sketches based on observations we made at the beach; I will send them to you – so you can append them to this post.

    The way they get inside the sand is fascinating. It reminds me of how some organisms swim in “fluidized” sand.

    Also; @christina: Could you please write a little about these “puzzling” blue pigments. Its a big surprise to me.

    Laks: This is an incredible post. Please do take a look.


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