It’s been awhile since I posted, and I am sorry I haven’t sooner. The LED light died shortly after I received the foldscope and I was working on a few work-arounds.
However, so impressed with this thing! I’ve been able to take some decent pictures though the LED would make them nicer and much easier to do. Truly amazing the magnification possible. Able to ID some diatoms that can be quite small and seeing details is helpful, though the pictures aren’t all that great here.
There is an invasive algae called Didymosphenia geminata, or “Rocksnot” for short, which can grow in very high densities and coat entire stream/river beds. It can cause a number of problems, but primarily it simply dominates the ecosystem as the primary aquatic algae, growing in a monoculture. So, we try to keep tabs on where it occurs and monitor a number of rivers/streams to see how they change through time, in places with and without rocksnot.
And here’s the environment where some of these samples are from…both underwater and above. These photos are from a monitoring site on the South Yuba River, in the Sierra Nevada of California, USA. We have been tracking local aquatic insect communities and a native frog, the foothill yellow-legged frog (Rana boylii), as well as how the river shape and morphology shift through time. This river is regulated, meaning it has a dam upstream and thus an altered flow regime, which has many impacts on the ecosystem and hydrology of the system. The site has reduced flows (to what it would have had historically pre-dam). We’ve observed didymo increase in distribution and density throughout the river, particularly since 2011 (during California’s extreme drought). Largely we observe a lower diversity of species at the regulated sites with didymo, though often much higher densities of benthic aquatic macroinvertebrates (bugs!). So a few very tolerant species seem to run rampant because they have such abundant food, which also translates to lots of food for fish, and the rainbow trout population is quite dense as well.
Ultimately, this research can be compared with similar data we collect from rivers without dams (unregulated), and we can quantify and assess the impacts river regulation has on the biota and hydrology of river systems.
I’ll try to get some pictures and another post up on some of the native algae from another river, and I’d like to try and get some pictures of the aquatic insect parts, but it’s a bit harder since they are larger (makes slides a bit tougher to prepare). More practice!