Under the sea: Mystery shrimp and footy mollusks

I went on a mini-vacation to Carmel this week (we’re on break), and insisted to my parents that we go to the beaches so I could finally have an excuse to get my feet wet…for science!

A selfie I took while scouring for samples in the water. The water was freezing cold and stones were poking my feet, but this is the face of excitement.
A selfie I took while scouring for samples in the water. The water was freezing cold and stones were poking my feet, but this is the face of excitement.

Here’s some of the scenery from Pebble Beach. I saw a bounty of marine life in the water; sea snail, hermit crabs, fish, sea anemones. It was all very colorful and very lively:















I scooped some sea water in a small water bottle and used my Foldscope kit (tweezers, tape, hole punch, paper slides, coverslips, imaging station) to take some shots on site. Here’s me sitting on a ledge trying to make a wet mount on my knee. I used the slide design I thought of last time, with the coverslips sandwiching a paper slide taped with double-stick tape on both sides (it creates a tiny well that won’t squish the organisms).

My dad took this while I was preparing slides.
My dad took this while I was preparing slides.

I found a krill/shrimp, but unfortunately killed it in death-by-squish while transferring it onto my slide:

Taken in the field. I had a harder time getting a good image because I didn't have as many tools as I would have had back at school or home.
Taken in the field. I had a harder time getting a good image because I didn’t have as many tools as I would have had back at school or home.

I have to say, it’s really hard making slides in the field (especially since I forgot to bring scissors and a pipette). I decided to take my sample 80 miles back home and spent the next day at my table imaging.

My sample from the beach is in the cut-up water bottle on the top-left of the picture. There’s a broken glass on the right with another bag of sea-water and marine plant samples (I was desperate because there was a hole in the bag, so I cracked a sake bottle on the sidewalk…) All of my traveling Foldscope materials go in the revamped iPad box on the right (it’s surprisingly a perfect size). The imaging station is on the bottom left, and finally, I found some scissors. I didn’t have a pipette at home, so I improvised and used a coffee straw for suction (it’s sitting on the water bottle).

These are what my slides looked like:


I found some amazing organisms that I can’t specifically identify. In laymen’s terms, here’s some moss growth with a developing shrimp/krill/prawn zooming about.

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Here’s a video of this organism swimming around the slide. Any advice on how to suspend samples in order to slow down movements? Scroll to 1:45 to see a good image of the organism.

After, I looked into my magical water bottle of microorganisms.IMG_0037

I found another shrimp/krill/prawn that looked slightly different. It had a longer and more pink/coral body. I didn’t see the forked tail that I saw on the first shrimp/krill prawn and its swimming form was different (more lateral/sideways).


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Scroll to 1:45 in the next video to see a good shot of this organism:

Lastly, I found a snail and filmed its contractions! I saw a shell in one of the marine plants and decided to image it for fun. Only when I looked at the shell under the FoldscopeĀ did I realize that there was a living sea snail inside the shell. It was awesome getting to see the foot move, and there may be a parasite-like organism attached to the foot (I’m not sure. What do you think?).

Needless to say, I found a lot of amazing organisms on my trip. Any thoughts?


7 Comments Add yours

  1. Manu Prakash says:

    Dear @Alice,

    This is the most incredible post – for so many reasons. The fact that you were out in the field collecting and stumbled upon all these magical “almost alien” looking creatures – that are in every drop of sea water. What a fascinating world.

    So the shrimp guy is most definitely a copepod. They are an incredibly abundant crustaceans found in almost all sea water. The “shrimp guys” are also crustaceans (Decapoda) and the best way to identify things is by counting the number of legs and body segments. Copepods are incredible organisms, you already see that they are so so so fast. It’s fascinating that you were actually able to catch them swimming and for some short time freeze under the microscope. They are known to have an incredible capacity to “jump” which is fascinating.

    Hackel (the famous biologists) had drawn many copepods; they are fascinating.
    Sometimes they have eggs attached next to the forked tail; so you see many tiny copeod developing inside a bag of eggs attached to the adult. It’s beautiful.

    The second “shrimp guys cousin” is tricky for me to identify. I was initially thinking it;s a polychete worm. It’s probably another crustaceans; I will do the leg count and report back. I wonder if the “pink” color is from some kind of hemoglobin protein – similar reason why our blood is red.

    Finally, the snail is marvelous. Clearly you are getting very very good at sample mounting.

    The joy of science is when you are out and about and you stumble upon something that is so inspirational. Your posts have a fascinating tone of discovery; which is so incredible and inspirational. It’s an unimaginably vast world of life forms right at our finger tips; only if we care to look.

    I will follow up this note with an identification key, which will help all os us to identify new creatures we see.

    Brilliant post.


  2. Manu Prakash says:

    Here is the identification key I mentioned. Roll through the options to keep matching an organism closest to what you saw; and see if you can actually identify the species.



  3. Manu Prakash says:

    Also; the really branched green algae looks like a “Cladophora genus” – it’s a really beautiful branching algae but it will be hard to identify the species. Algae provides an incredible “forest – an environmental niche” for other animals to call home. No wonder you found so many things in this water sample; they are a great sign for a healthy eco system.


    Don’t throw your sample – keep it “open” for a day or two; it’s sea water so you can not add fresh water to it but you can keep it open for a few days. Bacteria will grow in it; and it will increase the density of other things that will thrive on the bacteria. At some point, it will start smelling (since the bacteria will overwhelm the system – and they produce compounds that make the smell); but until that time – you might actually find many more interesting “gems” hidden in this magical wonderland.

    Keep exploring.


  4. laksiyer says:

    Alice.. These are incredible videos, incredible. Keep the water sample for a few weeks and keep imaging. You can close it to reduce evapration. The alga will maintain the dissolved oxygen and the ecosystem will survive, Only when the animals die, will a stiinky anaerobic growth take over (which is nice to image too). Wow, these crustaceans are amazing and the snail out of the world.

  5. Alice Dai says:

    Hi Manu, according to the ID guide, because the copepod has a hooked antenna and short antennae, it’s part of the Ergasilus family. Thanks for the resource. Laks, I threw away my water sample! I’m going to ask my biology teacher to get me some next week because he goes paddle boarding in Santa Cruz a lot. I’m still trying to identify “shrimp guy’s cousin” and will get back with some ideas.

  6. Matthew Rossi says:


    Love this post! I think it’s remarkable you caught a shot of the copepod and its underbelly so clearly. They’re such fast moving, difficult to catch creatures, even once you have one under the scope it’s difficult to see them. Great video (and solid narration).

    I’ll tell you from experience it’s terribly easy to accidentally crush a critter in the slide. A bit sad and gruesome when it happens, but it’s totally par for the course.

    Definitely keep your sample next time! It’s amazing what new things pop up you haven’t noticed when you image and reimage the same sample of water. I like to go plankton hunting by shining a side light on the jar or tank of water I’m using. The side light illuminates the many otherwise invisible dots floating in the water (think dust in a sunbeam) and helps me find things I would miss otherwise.

  7. Alice Dai says:

    HI @Matt I’m glad us Foldscopers can bond over our slide-mounting misadventures. I should be getting a new sample soon, so watch out for a post! Thanks for the advice, and yes, the video narration has been a hit so far.

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