Measuring algae and cyanobacteria

Measurements, Protocols & Macros

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Tsai Lab

Nov 2018

Hello! I was wondering how you would recommend taking measurements of cyanobacteria and algae. I suspect that you could use a cuvette but it is unclear the effectiveness and where to attach it. I saw in the tutorials and in prior forums that there is a way to do so, but I can't seem to find a protocol on how to do this. Thanks, Trevor

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David M. Kramer

Nov 2018

Hi Tsai Lab,

If you remove the little rubber rings (that squeeze the leaf) you will see that the leaf clamp can, indeed, hold a standard cuvette. In fact, we designed it to do so. You can get data that way.

You can also set up the device ,pre favorably for fluorescence measurements by removing the lower housing of the leaf clamp and re-positioning it so that the excitation and fluorescence detectors are at 90o to each other. HOWEVER, please consider this option to be a hack and that if you screw of the instrument, its on you ;-)

We have built a prototype version of MultispeQ that is specifically designed for cuvettes. and it works quite well, has cyano-specific wavelengths etc. It'd be interesting to see if there is sufficient interest in this to consider actually producing it.

Have fun!

Dave

Hi David. If I don't do it "re-positioning it so that the excitation and fluorescence detectors are at 90o to each other". Can I get correct parameters fluorescence from algae?

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David M. Kramer

Nov 2018

In principle, yes. We have done a few tests, but have not explored it rigorously. One thing that can interfere with results are direct back-scatter of the measuring pulse, which can give you an offset in the fluorescence. I'd recommend testing it out with a series of chlorophyll concentrations to optimize. I'd love to hear about the results, and maybe we can figure out the best way to make it work!

Our result. Influense Se, Se+Zn, Se+Cr combination on fluorescence parameters. enter link description here

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David M. Kramer

24 days ago

Wow, that data looks great. Can you share some details, e.g. chlorophyll content? Also, I would strongly recommend using the new RIDES protocols, as they give much better ECS and P700 data. Anyway, thanks for sharing this. I hope it will inspire others to give it a try.

Best

Chlorophyll "a" content (mg/m3) on the 7 day of incubation. Blank - 142; Se - 193; Se+Zn -280; Se+Cr -176