Water Sampling at Arroyo Seco, Los Padres National Forest

This past weekend, we (Erika and myself) escaped grad student work at Berkeley to go camping in the Los Padres National Forest in the hills east of Big Sur. We stayed in the Arroyo Seco area, which you reach by driving south of Monterey through wine country, and then cutting west into the forest.

On Saturday, we sampled at the Arroyo Seco creek and found some astonishing life forms, as always. Here is an image of our sampling location:

We used some of the new tools in the Foldscope deluxe kit, especially the PVC depression slides for trapping swimming aquatic organisms. Here is a “macro” picture of such an organism in the PVC cut-out before adding the coverslip on top:

Using the zoom on my phone you can make out very rough detail of the bugger inside the drop:

I then sealed the PVC coverslip over the top to trap him inside. Unfortunately, the PVC cut-out is only 0.15 millimeters thick, and the organism must have been thicker than that, as it was squished and killed when the coverslip was put on. You can still make out pretty good anatomical, even if the physiology is a bit, well, dead. There are three hairy structures coming out of the tail end of the creature. At first I thought this might be a mosquito larvae, but online searching doesn’t seem to corroborate this. As always, any ideas are much appreciated.

Here is another video with more detail:

But perhaps even more interestingly than the squished bugger above, I found a pair of very alive creatures that I also am unable to identify. Their overall morphology appeared the same, but one was totally static and appeared to be carrying two green eggs, while the slightly smaller one was quite motile and egg-less.


Any help identifying these creatures would be tremendously appreciated! If it helps, here is another short clip of the motile one flexing its tail/leg!

As always, thanks for watching and exploring with me!

3 Comments Add yours

  1. Manu Prakash says:

    Dear @Max,
    What wonderful observations. Love the outdoors picture.

    1) The first observation looks like an insect larvae – and I have narrowed it down to being a “MayFly Larva”. The giveaway for me was the little breathing organs that hang on the edge after the legs. From a. patterning perspective that is quiet bizarre. Also; Mayfly’s have a strange existence.- where the adult metamorphosed state is only alive for days/hours. How strange.

    It would be awesome to identify the species; and you could even see what time they come out. I don’t know how this works – but mayfly’s coordinate the time of metamorphosis. Imagine synchronizing metamorphosis of billions of mayflies simultaneously.

    Lots of possible aquatic larvae are around – here is one – which is a beetle larvae: https://microcosmos.foldscope.com/?p=23503

    2) The second one; I think is a Daphnia. Now, I know they are usually not so round; but Daphnia have a fascinating “plasticity in development” and can actually change shape based on temperature/environment. I only learnt this when sampling in Asaam, India (https://microcosmos.foldscope.com/?p=12198). The other reason I believe it is Daphnia is the “blue” pigment in the cells. I have seen a very similar eggs in Daphnia as well. I find it remarkable – what possible “blue” pigments can be present. I know certain oxygen carrying metallic compounds can be blue (now I forget; but this is why horse show crab blood is blue). Since Daphnia are also crustaceans, maybe they are related to Horse shoe crabs.

    What a wonderful set of observations. Here is a link on morphological plasticity of Daphnia (they have been used to measure lake toxicity because of this reason): This induced morphological change stuff is fascinating – https://www.ncbi.nlm.nih.gov/pubmed/26994174
    Imagine growing a third arm since you like to solder circuit boards 😉

    Let’s go together folds coping sometimes. Maybe with Nicole’s lab.



  2. dhsamt says:

    Amazing video , thanks to foldscope .

  3. MaxCoyle says:

    As always, thanks for the super thoughtful comments Manu!

    you are absolutely right about the mayfly larva: those gills are incredible! perhaps i will return to arroyo seco in the spring to see if i can observe the emergence of the adults. i read that it can be so dense that it causes traffic accidents.

    as for the daphnia morphological adaptations that is awesome. i would love to try to add some of those “kairomones” to a daphnia culture and see if i can induce necktooth development….

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