Measuring Microorganisms Survival Rate Through Pumps

Measuring Microorganisms Survival Rate Through Pumps can be simply measured. It is very important for the survival of a biosphere or an application of compost tea.  When microorganisms are sent through a pump, a certain percentage is damaged.  If too much is damaged, the ecosystem they are create cannot be sustained.  

When using pumps for applying compost teas on branches and leafs of trees, an improper pump can render the tea worthless because the pump physically blends or crushes the microorganism(s).  

Throwing compost tea or ecosystem water can also reduce life.  This includes water hitting the leaves or trunk of the tree at a high rate where it damages the microorganisms.


The sample is measured by taking your "pump under test" and cycling water through it a few times.  If your sample water is passed through the pump one time, it's hard to tell if anything died.  If you are using a pump that takes microorganism into consideration, you will not see much of a difference between the starting sample and finishing sample.  It's best to run the water through the "pump under test" a few times and then count the number of bacteria alive under the microscope.

Below is a bucket of compost tea.  The beginning sample has been sampled under the microscope at 400X.  The number of live and already dead bacteria is noted.  

Two gallons of sample is placed in the bucket and run through the pump.

Tea Bucket With Battery

In this example a diaphragm pump is the "pump under test".  This is a 12 volt pump used for spraying compost tea on leafs for disease suppression.  It pumps about 2 gallons per minute and can keep a head pressure of 10 psi.   

Another Pump View

Let the pump circulate water several times.  For instance, if the pump can move 2 gallons per minute and there are 2 gallons of water in the bucket, let it run for 10 minutes to move the water 10 times.  Them take another sample and check it under the microscope to see how many microorganisms are still alive and dead.

Calculating Mortality Rate

The microorganism mortality rate is determined by allowing the microorganisms to be pumped several times through the pump and counting the number of bacteria alive in the microscope field of view.  The rate is expressed as a percentage (%).  Each time the water is pumped through the pump, this is the probability of microorganism making it through.  Multiplying the probability percentage of each time will give you the number you will receive at the end of your test.

An example:

If the pump can move 2 gallons of water per minute, then leave the pump on for 10 minutes to cycle all of the water through the pump 10 times.

Before conducting the test, it is counted that 1400 bacteria microorganisms are alive and 300 are already dead.  This is your starting number.

Run the pump for 10 minutes cycling the water through 10 times.

Take another sample is takend and it is counted that 420 microorganisms are alive and the rest are dead. Remember to take out the number of already dead bacteria (namely 300).  Determine the percent of alive bacteria.  Take 420/1400 = .30  or 30%.  Since the water went through the pump 10 times, take the 10th root of 0.3 and this equals 88.6%.

Each time water goes through the pump, there is an 88.6% probability rate of survival.  The rest are dead.  This means you will lose roughly 12% of your microbiology using this pump.


0.886 X 0.886 X 0.886 X 0.886 X 0.886 X 0.886 X 0.886 X 0.886 X 0.886 X 0.886 X  =  0.30

Confocal Microscope Images

This microscope is used to measure the amount of alive and dead microorganisms in your sample.  A confocal microscope uses lasers, light filters and stains/dyes to see objects in the microscope view. Below is pictured a confocal microscope where the lasers and microscope stage is off to the left.  The right has the computer and DSP for filtering the light spectrum.   

Confocal Microscope

When sampling compost teas (in this exercise), we are interested in the number of alive and dead microorganisms in the sample.  The sample is stained with a florescent stain that indicates bacteria what is alive and not alive.  Below are two pictures showing alive bacteria in the tea sample (green) and dead bacteria (red).  The sample is hit with a blue laser absorbed by the stain.  Depending on the condition of the bacteria, it returns green or red color.

Below is alive bacteria in green.

Compost Tea Confocal 1

Below is dead bacteria in red

Compost Tea After

The unpleasant task of counting the spots gives you the number of alive or dead bacterium.

It's also possible to use an optical microscope.  It's a bit harder because it's hard to see if the bacteria is alive or dead.  A live bacteria vibrate in the field of view.  Cold, dormant or dead bacteria does not vibrate.


Created by Pholowko. Last Modification: Monday 12 of October, 2015 22:50:31 CDT by admin.