## How to measure dry mass?

Discussion of the distribution and abundance of living organisms and how these properties are affected by interactions between the organisms and their environment

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canalon
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Well I am just suggesting a method that could work. There are no reference because I made it on the spot. I am basing that on the fact that absorption is, within certain limit, linearly correlated with growth in bacteria, and that the size of bacteria will be roughly constant during the exponential growth phase. So I guess, but that is an educated guess, that the absorbance would be similarly correlated with dry mass.
And I suggested that you verify and calibrate that. But I made the assumption that your microalgae would behave similarly as bacteria, and that there is a known optimal wave length that would give a similarly linear relation with growth. So try and see if that works, if so you can either publish that as a stand alone quick letter to the editor/method paper or just put it as an additional result in your paper and claim the technique for yourself.

Good luck
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

hsoroosh
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### Re: How to measure dry mass?

haha! nice point of view. Your theory should logically work. I'll try but my time is so tight .

Thank you anyway for your kind support and efforts

hsoroosh
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Joined: Thu Aug 04, 2011 2:53 pm

### Re:

canalon wrote:No equation. One simple experimental procedure:
take sample put in the oven/desiccator until totally dehydrated and weigh. That simple.

Thank you very much. I got a very nice linear relation between dry mass and absorbance in 680nm.it's y = 0.2372x + 0.019 (R² = 0.9928) which Y is dry mass and x is absorbance for Scenedesmus sp.
This method is very easy, quick and precise.

Cheers

canalon
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Joined: Thu Feb 03, 2005 2:46 pm
I am happy to have been of help. Good luck for your future experiments.
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

oaktree
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Location: Augusta, Kansas

### Re: How to measure dry mass?

If you need to measure by acre, you need a 1.94 m2 frame. Clip everything inside that frame, dry it, then weight. From the measurement (most in grams) you multiply it by 50.

Example: dry weight is 23.3 g. X 50 = 1165 lbs per acre of forage.

canalon
Inland Taipan
Posts: 3909
Joined: Thu Feb 03, 2005 2:46 pm

### Re: How to measure dry mass?

oaktree wrote:If you need to measure by acre, you need a 1.94 m2 frame. Clip everything inside that frame, dry it, then weight. From the measurement (most in grams) you multiply it by 50.

Example: dry weight is 23.3 g. X 50 = 1165 lbs per acre of forage.

Your number are probably correct, but have you considered reading the thread before posting?
Patrick

Science has proof without any certainty. Creationists have certainty without
any proof. (Ashley Montague)

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