The Bacteria Family’s The Bacteria Family’s Big Bash!Big Bash!

By Jessica Davis, Molly By Jessica Davis, Molly Sober, and Anne ThurberSober, and Anne Thurber

Once upon a time there was a small plot of land Once upon a time there was a small plot of land where many plants and animals lived. where many plants and animals lived.

Also on the plot of land, or rather, inside of Also on the plot of land, or rather, inside of it, lived the bouncy Bacteria family.it, lived the bouncy Bacteria family.

Bertha BertBaby

Blair Bobby

The family lived in The family lived in a home around the a home around the many grass roots. many grass roots.

Not only did the Not only did the bacteria help to bacteria help to

protect the grass protect the grass roots, they also roots, they also

fixed the nitrogen fixed the nitrogen in the soil so that in the soil so that

the plants could the plants could use it. In return for use it. In return for

their protection their protection and food, the roots and food, the roots

gave the Bacteria gave the Bacteria family a place to family a place to

live safely.live safely.

At least, this is what they had always At least, this is what they had always thought.thought.

One day, the youngest of the One day, the youngest of the Bacteria family, Baby Bacteria, Bacteria family, Baby Bacteria, began wailing for no reason at began wailing for no reason at all.all.

It wasn’t evident why Baby Bacteria (who was really It wasn’t evident why Baby Bacteria (who was really psychic) was crying until Blair Bacteria ventured up to psychic) was crying until Blair Bacteria ventured up to

the surface of the soil.the surface of the soil.

““I saw horrible things!” She wailed to the rest of I saw horrible things!” She wailed to the rest of her family. “There were huge yellow monsters her family. “There were huge yellow monsters everywhere, and these strange animals were everywhere, and these strange animals were

carrying heavy stones, and digging up our homes!”carrying heavy stones, and digging up our homes!”“That’s awful!” Bertha Bacteria cried. “I hope “That’s awful!” Bertha Bacteria cried. “I hope

everyone is okay.”everyone is okay.”

Sure enough, the next couple of months, Sure enough, the next couple of months, many bacteria and fungi disappeared many bacteria and fungi disappeared

under the stones the animals were under the stones the animals were placing everywhere.placing everywhere.

Even more microbes had managed to Even more microbes had managed to escape because of the mass amounts escape because of the mass amounts

of water the beasts were pouring of water the beasts were pouring over the now bare soil. Now all the over the now bare soil. Now all the microbes were crowded around the microbes were crowded around the Bacteria family’s home, trying to Bacteria family’s home, trying to

share the few roots the evil creatures share the few roots the evil creatures had spared from their destruction. had spared from their destruction. Many of the bacteria felt a lot safer Many of the bacteria felt a lot safer

after the giant beasts were gone, and after the giant beasts were gone, and they could finally live without the they could finally live without the

fear of the yellow monsters.fear of the yellow monsters.

But it did not take long for But it did not take long for the bacteria to realize they the bacteria to realize they could not escape danger so could not escape danger so

easily. easily. In their disruption of the In their disruption of the

land, the animals had built a land, the animals had built a very strange structure very very strange structure very

closely to the Bacteria closely to the Bacteria family’s home.family’s home. . . . .

Bert Bacteria so eloquently named the object Bert Bacteria so eloquently named the object the “black hole”, as the inside of it seemed to the “black hole”, as the inside of it seemed to

disappear into infinity.disappear into infinity.

The strange thing about the hole was it The strange thing about the hole was it had the peculiar habit of spitting out had the peculiar habit of spitting out large amounts of water, especially large amounts of water, especially

when it was raining. when it was raining. Often bacteria, minerals, fungi, and Often bacteria, minerals, fungi, and nutrients were swept away. Without nutrients were swept away. Without

the many beneficial microbes the grass the many beneficial microbes the grass wasn’t growing as well, and there were wasn’t growing as well, and there were less and less roots for the bacteria to less and less roots for the bacteria to

live on.live on.

““We can’t keep living like this.” We can’t keep living like this.” Bobby bacteria commented while Bobby bacteria commented while

clinging to the root during a clinging to the root during a thunderstorm. “We need to do thunderstorm. “We need to do

something about this!” But what something about this!” But what could the bacteria do?could the bacteria do?

During a very bad surge of water, During a very bad surge of water, Baby Bacteria was swept away with Baby Bacteria was swept away with

many other bacteria, fungi, and even many other bacteria, fungi, and even Bobby’s three best friends Michael Bobby’s three best friends Michael Mineral, Phoebe Phosphorous, and Mineral, Phoebe Phosphorous, and

Peter Potassium.Peter Potassium.

““We have to go save her!” We have to go save her!” Blair Bacteria cried. Blair Bacteria cried.

But Bert Bacteria’s only But Bert Bacteria’s only respond was “How?”respond was “How?”

One day, some of the animals came by the Bacteria One day, some of the animals came by the Bacteria family’s home and said they could help.family’s home and said they could help.

“We can’t save Baby Bacteria.” Juanita, added.“We can’t save Baby Bacteria.” Juanita, added.“She’s most likely floating somewhere inside the “She’s most likely floating somewhere inside the

stream by now.” Said Magdalena.stream by now.” Said Magdalena.

M

J

A

““But we can learn how to save bacteria.” Anita said But we can learn how to save bacteria.” Anita said happily.happily.

“We would just like to take a bit of your soil.” “We would just like to take a bit of your soil.” Said Juanita. The Bacteria family agreed and the Said Juanita. The Bacteria family agreed and the microbes were transported by the animals into microbes were transported by the animals into

plastic bags.plastic bags.

““First we need to choose a few First we need to choose a few bacteria.” Anita said while filling bacteria.” Anita said while filling

some beakers with distilled water.some beakers with distilled water.The bacteria allowed Magdalena The bacteria allowed Magdalena

to place one cubic centimeter of their to place one cubic centimeter of their soil into the water.soil into the water.

“Each time I pick up some of the “Each time I pick up some of the muddy water, I get less and less muddy water, I get less and less

bacteria.” Anita explained.bacteria.” Anita explained.“This way, we can estimate how “This way, we can estimate how

many bacteria were in the soil.” many bacteria were in the soil.” Juanita smiled as she diluted the Juanita smiled as she diluted the

muddy water four times.muddy water four times.

““This is called serial dilution.”This is called serial dilution.”

““This is called serial dilution.”This is called serial dilution.”

““This is called serial dilution.”This is called serial dilution.”

““This is called serial dilution.”This is called serial dilution.”

““This is called serial dilution.”This is called serial dilution.”

““And with a drop of the diluted soil on this Petri And with a drop of the diluted soil on this Petri film®, we can count the colonies of bacteria.” film®, we can count the colonies of bacteria.” Magdalena placed a drop on the Petri film® and put Magdalena placed a drop on the Petri film® and put it aside.it aside.

“Now we wait…”“Now we wait…”

Petri Film ®

Two days later the girls returned.Two days later the girls returned.“Are you ready?” Juanita asked the bacteria. “Are you ready?” Juanita asked the bacteria.

There were now little red dots of bacteria colonies There were now little red dots of bacteria colonies all over the films.all over the films.

“By using a special equation, we can now “By using a special equation, we can now figure out how much bacteria was in the original soil figure out how much bacteria was in the original soil sample!” Anita said happily.sample!” Anita said happily.

Petri Film ®

After the girls had calculated After the girls had calculated their results, they turned to the their results, they turned to the

bacteria and beamed at their bacteria and beamed at their conclusion.conclusion.

“Just take a look at these “Just take a look at these beautiful graphs.”beautiful graphs.”

GraphsGraphs

Bacteria Density

300,000

500,000

1,000,000

500,000 500,000

1,100,000

500,000

200,000

1,900,000

0

100,000

0

400,000

100,000

200,000

100,000 100,000

500,000

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

1,600,000

1,800,000

2,000,000

0 50 100 0 50 100 0 50 100

Trial A Trial B Trial C

Distance Away from Drainpipe (in cm)

Bact

eria

Den

sity

(in

mill

ions

)

Density of Bacteria percubic centimeter at 15cm deep

Density of bacteria percubic centimeter at 30cm deep

Density of Bacteria at Different Distances Away from the Drainpipe for Different Depths

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

1,400,000

0 10 20 30 40 50 60 70 80 90 100 110

Distance Away from Drainpipe (in cm)

Num

ber o

f Bac

teria

in S

oil S

ampl

e (in

mill

ions

)

Density of Bacteria per cubic centimeter at 15 cmdeep

Density of bacteria per cubic centimeter at 30 cmdeep

Average Density of Bacteria at Different Distances Away from the Drainpipe

0

100,000

200,000

300,000

400,000

500,000

600,000

700,000

800,000

0 10 20 30 40 50 60 70 80 90 100 110

Distances (in cm) Away from the Drainpipe

Aver

age

Dens

ity o

f Bac

teria

(in

mill

ions

)

Average Denisty of Bacteria at different Depths

0

200,000

400,000

600,000

800,000

1,000,000

1,200,000

Average Density of Bacteria per cubic centimeter at 15 cm deep Average Density of bacteria per cubic centimeter at 30 cm deep

Depth Below Surface (either 15 cm or 30 cm)

Aver

age

Deni

sty

of B

acte

ria (i

n m

illio

ns)

ConclusionConclusion

Hypothesis: Closer to the runoff location and closer to the soil surface, bacterial density will be lower than the bacterial density of soil samples taken at greater depths and distances from the point of origin of runoff location.

Runoff has a negative affect on bacteria. Our results proved our hypothesis wrong. According to our data, there were less bacteria 100 cm (our greatest distance away) from the drainpipe 30 cm deep into the soil. There were two sources of error in our experiment. First, the surface we tested was on a slope, therefore the runoff process was most likely accelerated or altered. Second, we did not know the depth the drainpipe released the water.

Future Research Questions

• Research Fungi reaction to runoff– Can withstand more acidic soil and harsher

conditions

• Research different runoff chemicals effect on bacteria

• Research alternative runoff techniques that would be less detrimental to bacteria and other microbes

““Thank you so much!” The Bacteria family shouted in Thank you so much!” The Bacteria family shouted in unison. “You have made Baby Bacteria proud.” And so unison. “You have made Baby Bacteria proud.” And so

they had.they had.

The EndThe End