I recently went to my brothers graduation in Chico and on the way home took a little detour to visit Clear Lake, California, hypothesized to be one of the oldest lakes in North America at 480,000 years old according to USGS. The lake is teaming with life and in the summer gets deep green with all of the microorganisms. I didn’t have time to hangout with my Foldscope at the shoreline, so I took a scoop home to play with at a later date:


A few nights later I finally got to the sample and here is a selection of the organisms I saw with my Foldscope:


How to find diatoms: I’ve had the best luck in freshwater. I find them in salt water, but for whatever reason I’ve had better luck with big sized diatoms in freshwater. My normal hunting ground for them is the shoreline or the edge of some obstacle in the water. I like to take a container and scrape the edge of a dock, a rock or anything else solid I can find or take a little sampling of the first layer of mud as they get stuck in it. Diatoms seem to survive pretty well in an air tight container for up to a week if not longer from what I can tell.
How these images were taken: I placed a drop of water on a glass slide and gently placed a glass coverslip over that and slid it into the Foldscope with the low magnification lens and my iphone5 cell phone attached using the magnet system of the Foldscope. I then held the Foldscope at an angle to a desk lamp and moved around until I got a really sharp contrast and took images. I found that a smaller drop of water was easier to work with as I had less of a problem of water getting out from underneath the coverslip and onto the lens. When the lens got wet I would remove the slide, wipe the lens with lens paper and start all over.
I like to cross post into iNaturalist as that community can help me identify the organisms and you can find the above observations in this day’s organism list:
http://www.inaturalist.org/calendar/damontighe/2016/5/22