Hello again Foldscope Community! Erika here with some more exciting discoveries from Foldscoping out in the rocky intertidal zone. This time, our Marine Ecology class consisting of CSU Monterey Bay graduate students went out to explore the rocky intertidal zone at Point Pinos in Pacific Grove, California. We saw many amazing critters in the rocky intertidal, including chitons, anemones, octopus, squid, and much more! I had the opportunity to put a few specimens under my Foldscope, and I’m excited to share with you what I found!
CSUMB graduate students exploring the intertidal out at Point Pinos
Amanda Wasserman putting fish eggs on a slide to view under her Foldscope
Carrie Boyle looking at the fish eggs under her Foldscope
One of the exciting critters we saw while out on the intertidal was a brittle star! Brittle stars are closely related to starfish, and they use their flexible arms for locomotion. Unfortunately, when they become stressed, brittle stars lose part of their arm(s). They utilize this tactic to escape predators. While I was holding this brittle star, it lost a tip on one of its arms. Of course I felt bad that I stressed the little guy out, so I quickly placed it back in the water. However, I held onto the arm piece so that I could look at it under my Foldscope later. Even though I got a scientific benefit out of this encounter, it is still important to remember to help protect and conserve the sensitive species living out in rocky intertidal habitats.
Brittle star we found out at Point Pinos
I used a wet mount to place the brittle star arm piece on a slide, and then I viewed it under my Foldscope. After moving the slide around a bit, I was able to see the definition of the arm! In the Foldscope image below, you can see the serrations on the arm, which probably helps the brittle star to cling onto hard substrates. These serrations may also assist in locomotion, providing friction so that the brittle star can pull itself along the rocky intertidal.
Piece of a brittle star arm under a wet mount on a slide
Image of the brittle star arm piece under my Foldscope
A second cool critter we saw while out at the intertidal was a Valella valella ! These are a carnivorous species of Cnidarian. The jellies were unfortunately washed up on the beach and had died. We saw hundreds, maybe even thousands, of them and they gave the beach a very purple color when viewed from a distance. Larissa Lemon, another graduate student, and I brought a deceased V. vallela specimen back to our classroom to look at under our Foldscopes.
Vallela vallela we found washed up on the beach at Point Pinos
I placed the V. vallela under a wet mount on a slide and viewed it under my Foldscope. I was able to see in better detail the awesome patterning on the body of the specimen. You can really get a good sense of the textures by looking through the Foldscope!
Vallela vallela placed under a wet mount on a slide
Image of Vallela vallela under my Foldscope
The last specimen I viewed under my Foldscope was an unidentified species of green algae. I’m still not sure what it might be- any thoughts? In this image, if you look closely it appears that you can see the green cells (with cell walls) making up the algae specimen.

In this post, I wanted to spend some time reflecting on my overall Foldscope experiences so far. I am extremely impressed with the functionality, effectiveness, and yet simplicity of this tool. The assembly was straightforward and was not time consuming, and the Foldscope was ready to use immediately following its assembly. I was impressed by how easy it was to use the Foldscope in the field when you have natural daylight to illuminate the specimens on your slide. Indoors, using the Foldscope also worked by either holding it up to a lamp or by using a flashlight, phone light, or other backlight source to illuminate the slides.
Having a partner while Foldscoping is not only more fun, but is extremely helpful. I often worked with a couple other graduate students. We combined efforts by using two phones: one to provide a backlight (flashlight on the phone) and the other to snap a picture of the specimen on the slide. We also tag-teamed this by having one person hold the phone steady and move the slide around, while the other person pressed the button on the phone to take the picture.
A few things that gave me some difficulty while using the Foldscope were focusing in on the specimen properly, having just the right amount of light to illuminate the slide, and trying to do all of this on my own. I often had more problems while using my phone to capture images on my Foldscope versus just looking through my Foldscope in the field. All of these issues could potentially be solved by having some more experience and practice with the tool.
For future Foldscope users, I have the following suggestions:

1. When starting out, have a buddy to practice with!
2. Don’t try to put too large of specimens on a slide and use a wet mount to view live organisms
3. If you are having problems focusing, sometimes it isn’t your resolution, but it is the amount of light hitting your slide. Play around with both of these aspects.
4. Look at a large variety of organisms to get a better feel of how to set up your slides and view them through the Foldscope
5. If you aren’t seeing anything through your Foldscope, it might be because there is a bit too much black plastic on the lens. VERY carefully, use a small razor blade to try shaving some of the plastic off. I did this and it worked immediately.
6. Before you start using your phone to take pictures of your slides, first get comfortable using the Foldscope organically out in the field with sunlight!
7. Don’t give up! It may not work perfectly at first, but with a bit of troubleshooting you will be on your way in no time!

Thank you again to everyone who helped provide our class with these Foldscopes! What a unique and fulfilling experience we’ve had so far. It was refreshing to be able to engage with the organisms we were seeing in our surroundings and look at the marine environment on a microscopic level. Please keep encouraging kids (and adults) to explore their natural environment. I’m definitely going to bring my Foldscope with me on my next adventure!
Just keep swimming,
Erika Senyk