Protozoan Protozoan and the and the Three Three

Aeration Aeration MethodsMethods

Once upon Once upon a time…a time…

There was a protozoan.There was a protozoan.He was a normal protozoan. He was a normal protozoan. Like the rest of his family and Like the rest of his family and friends, he spent his days friends, he spent his days consuming bacteriaconsuming bacteria, , producing nitrogenproducing nitrogen, and trying , and trying to escape his predators, to escape his predators, especially the big bad especially the big bad earthwormearthworm..

The big bad earthworms were The big bad earthworms were eaten by larger organisms eaten by larger organisms which the little protozoan which the little protozoan had only heard of. So had only heard of. So although the little although the little protozoan and his relatives protozoan and his relatives were unaware of this, they were unaware of this, they played a very important role played a very important role in the environment by being in the environment by being the the basis of the food chainbasis of the food chain..

Besides bacteria, little protozoan’s Besides bacteria, little protozoan’s favorite food was favorite food was oxygenoxygen. .

His favorite activity was His favorite activity was swimmingswimming, , which was convenient because which was convenient because that was also his that was also his mode of mode of transportationtransportation through the soil. through the soil.

O2O2

O2O2

O2

O2

One day, when swimming through One day, when swimming through the soil, little protozoan the soil, little protozoan overheard an interesting overheard an interesting conversation from above ground.conversation from above ground.

Aeration is punching holes in the ground…

To let in oxygen and

water!

I wonder if different I wonder if different aeration methods will aeration methods will increase or decrease increase or decrease

the number of the number of protozoa?protozoa?

This really caught Proty’s attention…so This really caught Proty’s attention…so he kept listening. He found out some he kept listening. He found out some interesting factsinteresting facts

This Hollow Tine method involves taking chunks

out of the ground with a soil sampler, so it will

probably dry out the plot a lot.

You’re right! The holes in the Forking plot are

smaller because they are made with a screwdriver at an angle so it won’t cause

as much desiccation

Say what?It means

drying of the soil

Yea…or bigger holes would allow for more

oxygen, so there would be an increase in

bacteria, and therefore also in protozoa

Oh! So maybe the Hollow Tine plot will cause the number of protozoa to

decrease because they swim in water, and the chunks

would make the soil dry out

Well now that you say that, I I think that the protozoa in the think that the protozoa in the hollow tine will decrease the hollow tine will decrease the

most, then the forking, and the no most, then the forking, and the no aeration plot will have the highest aeration plot will have the highest

population density of protozoapopulation density of protozoa

Little Proty soon forgot about Little Proty soon forgot about the conversation…until…the conversation…until…

One day, little protozoan was One day, little protozoan was just going about his business just going about his business when he heard his mother when he heard his mother scream, “Get out of the way!”scream, “Get out of the way!”

Little protozoan was scared, so Little protozoan was scared, so he swam through the soil as he swam through the soil as fast as his little fast as his little flagellaflagella would would carry him.carry him.

He looked above him, and what He looked above him, and what he saw sparked his memory…he saw sparked his memory…

Soil

Sampler

Soil

Sampler

Soil

Sampler

!!!!

That area of soil had too That area of soil had too much much desiccationdesiccation and he and he could feel himself getting could feel himself getting dried up.dried up.

He swam away as fast as he He swam away as fast as he could… but he soon found could… but he soon found himself in just as scary of a himself in just as scary of a situation.situation.

Screw

driver

!!!!

Screw

driver

Little Proty swam as fast as he could Little Proty swam as fast as he could and finally found peace in an area of and finally found peace in an area of No AerationNo Aeration..

This area was just right…This area was just right…

The mayor soon came and gathered The mayor soon came and gathered together the protozoa. He thought together the protozoa. He thought it would be best if the protozoa it would be best if the protozoa stay there while he figured out what stay there while he figured out what was going on…was going on…

As it turned out…the holes As it turned out…the holes came back three times about came back three times about every three days.every three days.

After the seventh day, the After the seventh day, the holes ceased to come…holes ceased to come…

The mayor cut a slice of The mayor cut a slice of bacteria pie and they all bacteria pie and they all celebrated !celebrated !

So everyone So everyone lived happily lived happily ever after…ever after…

……right?right?

What really happened to What really happened to little Proty…little Proty…

The mayor called a final town The mayor called a final town meeting…and this time he meeting…and this time he called in the P.P.I (private called in the P.P.I (private protozoa investigators)protozoa investigators)

They had just come back from They had just come back from their investigations abroad…their investigations abroad…in Mr. Brock’s classroomin Mr. Brock’s classroom

Yes! We can! When it is clear out, not aerating the soil is better for the protozoa levels than any method of aeration- humans are actually harming us by aerating!

When it is rainy, aeration on the soil actually helps our levels of protozoa, or otherwise doesn’t harm them.

Son, can you tell us what has been happening as a

cause of this “aeration”?

Forking method is better for when it is clear because there is less surface desiccation and more water stays in the ground

The Hollow Tine method is better for when it is raining because more water can get into the soil

Other than on Day 5 (when it was rainy)- There was

not really enough difference between the two

aeration methods to conclude that one was better than the other

Look! We have made up this graph to try and explain what has been

going on!

Number of Protozoa Per Gram of Soil Per Day

0100000020000003000000400000050000006000000700000080000009000000

10000000

0 1 2 3 4 5 6 7 8

Day of Experiment

Num

ber o

f Pro

tozo

a

Pre-Experimental Data No Aeration Forking Hollow Tine

Pre-Experimental Data No Aeration Forking Hollow Tine

The truth behind the story The truth behind the story of little Protozoan… of little Protozoan… (sources (sources

of error)of error)

• Rain!- led to interesting observations– Filled in our aeration holes- defeated the

purpose of aerating in the first place

• Repetition of Plots– How do we know that our data was not just

because our plots were in a specific location?

• We lost some of our data due to misplaced Uhlig extractors…unless the big bad earthworm took it– No Aeration, Day 5, Sample 3– Forking, Day 5, Sample 1– Forking, Day 7, Sample 1

Little Proty wants to Little Proty wants to know…know…

• Would repetition of plots have changed our data in any way?

• If our experiment had gone on longer, would that have changed our data in any way?

• Testing for…– Nitrogen levels– Bacteria levels

• How do different levels of moisture increase and decrease the protozoa levels?

• What other weather conditions would have affected the protozoa levels?

??