Algae-errific!

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.

Didymo!
Didymo!
some empty cells
some empty cells
more algae
more algae

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!

measuring transects for topography and substrate in South Yuba
measuring transects for topography and substrate in South Yuba
South Yuba River, look closely and see matted dry algae just above waterline on some rocks
South Yuba River, look closely and see matted dry algae just above waterline on some rocks
Underwater look at didymo coverage, like a thick carpet
Underwater look at didymo coverage, like a thick carpet
Rainbow trout in algae coated pool
Rainbow trout in algae coated pool

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Rana boylii tadpoles mired in algae, which they scrape diatoms off of for food. Some algae spp are really good, others are not
Rana boylii tadpoles mired in algae, which they scrape diatoms off of for food. Some algae spp are really good, others are not

5 Comments Add yours

  1. laksiyer says:

    What a wonderful Didymo shot. Hope you can capture different stages and dividing cells. Since they are a plenty when rivers are infected, you have access to plenty of material. BTW, you can actually get superior views with just a table lamp or ambient light. Check this post. https://microcosmos.foldscope.com/?p=16093

    1. riverpeek says:

      Fantastic…thanks for the heads up. I actually started playing around with dark field yesterday using a small lamp with a bendable neck, seems to work well. Appreciate the feedback!

  2. Manu Prakash says:

    Incredible work @RiverPeek. @Laks already mentioned some resources; if you read through foldscope posts; you will see a lot more pointers on maximizing your resolution.

    Could you also post a picture of what it looks like along the river. Getting an ecological context of the same will be very useful for others as well; so we can all spot this species from it’s macroscopic view on the river.

    cheers
    manu

    1. riverpeek says:

      Thank you Manu…and thank you for the encouragement and inspiration to make this what it is (and can be). I updated with some more photos. I definitely watched a bunch of videos and got some really great tips…looking forward to playing with dark phase and maybe playing with some fluorescence…the algae might be really cool if done right. More soon!

      @Laks, I watched those videos, much appreciated! I agree, I think the lighting and photos are better using alternate light sources.

  3. Cristina says:

    This is such a beautiful image! The striae can be seen so neatly! Did you use high magnification lens?

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