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The Phosphorus Cycle

Start from the beginning

Make it Rain!

The Producers

The Consumers

The Decomposers

The Quiz

The Human Factor

Why is Phosphorus Important?

DNA molecules are made from three smaller molecules:

(1) Sugar

(2) Nitrogen base

(3) ???

What is the 3rd molecule of DNA?

Fatty acidPhosphate

groupMono-

saccharide

No. Fatty acids are in lipids.

No. Monosaccharaides are in carbohydrates.correct

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Why is Phosphorus Important?

ATP is a molecule needed by cells for _______.

ATP stands for Adenosine Tri________?

Energy FoodReleasing

CO2

prokaryotePoly-

saccharidephosphate

Hint: What does the mitochondria create?

Hint: What does the mitochondria create?

correct

Which choice looks like “phosphorus?”

Which choice looks like “phosphorus?”

correct

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Why is Phosphorus Important?

Which part of a cell is semi-permeable and allows some materials to enter/exit the cell?

The cell membrane is made from a double layer of lipids called “phospholipids.” Which element is implied by the prefix “phospho?”

Mito-chondria

Cell membrane

Rough ER

Phosphorus Potassium Plutoniumglucose

glucose

glucose

wastewaste

waste

correct

correct

Hint: What does the mitochondria create?

Hint: What does the mitochondria create?

Phospho…cmon! Phospho…cmon!

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Why is Phosphorus Important?

Our cells need phospholipids, DNA, and ATP. They each have phosphorus in them.

So where does the phosphorus come from? Phosphorus come from rocks. Rocks are solid lumps of minerals, and some of those minerals are phosphorus. So when rocks crumble and erode, phosphorus is released from the rocks. The weather causes rocks to crumble. Wind, cold, and rain cause dust sized fragments of rocks to chip off, thus releasing phosphorus into the ground

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Make it Rain!

The weather causes phosphorus to be released from rocks. Click the cloud to make it rain.

Small bits of phosphorus are released into the ecosystem due to the weather.

Click the cloud to make it stop raining.

Now that there is phosphorus in the soil, click on the land organism that can absorb it through their roots.

P PP PPP

Snails don’t have roots.

Roots… think roots

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The Producers

Of course! Plants simply absorb the phosphorus through their roots. Click on the roots to proceed.

Now that plants have phosphorus they can use it to make their DNA, ATP, and phospholipids.

Click on the herbivore (primary consumer) in the diagram.P P

P

PP

P

Decomposers feed on the dead. This

plant is alive.

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The Consumers

Of course! The snail is an herbivore so it eats the plant. This is how animals get the phosphorus to make their DNA, ATP, and phospholipids.

Phosphorus simply moves up the food chain. Which organism would likely eat snails?

PP

P

P

P

P

PPP

Maybe accidentally, but

cows are herbivores too.

Wolves are hunters. I don’t

think they would hunt snails.

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Up the Food Chain

The snail eats the plant…

The frog eats the snail…

Which would likely eat the frog?

You got it. Phosphorus moves up the food chain.

P

P

I’m an herbivore.

I’m an herbivore.

P

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The Decomposers

This whole thing started with crumbling rocks…remember?

Decomposers are organisms such as mushrooms and bacteria. They have DNA, ATP, and phospholipids also, so that means they need phosphorus too.

Will decomposers feed on dead plants?

You got it. Will they feed on dead snails?

We’re almost done.

PP

P

PP

P

P

P

P

yes no

P

yes no

Like any organism, decomposers make waste. They release their waste into the ecosystem. Some of their waste even contains phosphorus.

P

Examine the picture… if decomposers release phosphorus into the soil, which organism can reuse the phosphorus?

The plants

The rocks

The snails

I hope you see why it’s called the phosphorus

cycle.

Rocks aren’t organisms

What do snails eat?

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1. Which molecule does not contain phosphorus?

2. How does phosphorus get into the soil in the first place?

3. Where do herbivores get phosphorus from?

4. Where do carnivores get phosphorus from?

5. Where do decomposers get phosphorus from?

The Quiz

DNA ATP Carbohydrate Phospholipid

From rocksFrom

decomposersFrom

consumersFrom

producers

From rocksFrom

decomposersFrom

consumersFrom

producers

From rocksFrom

decomposersFrom

consumersFrom

producers

From any dead

organism

From decomposers

only

From consumers

only

From producers

only

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The Human FactorSadly, human actions are disrupting the phosphorus cycle. Humans, like this farmer, routinely add extra phosphorus to soil because phosphorus is a fertilizer. What do you think the extra phosphorus does for the farmer’s crops?

P

P

P

P

P

PPPPPP

Kill weeds Kill bugs Stimulates growthNo. Weed killer kills weeds.

No. Pesticides kill bugs.

Yes, exactly!

So if phosphorus helps crops grow, why is this bad?

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Why is this Bad?The extra phosphorus is intended to help crops grow better, but often the phosphorus is washed away into rivers, lakes, and ponds when it rains.

P

P

PP

PPPThe extra phosphorus got washed

away and is collecting in this pond. Since the phosphorus is a fertilizer, it causes algae in the pond to grow at an extreme rate. These extreme algae growths are called “algal blooms.” As the algae eventually die, the decaying process uses up the oxygen in the pond, thus all the fish die. Once the fish die, so does the rest of the ecosystem.

Make it rainRain Rain Go Away

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Wanna go for a swim?Back Home

Wanna go for a swim?Back Home

Wanna go for a swim?Back Home

You can help stop this problem.

Purchasing organic food supports farmers who do NOT use extra fertilizers.

Is There Any Hope?Back Home

You can help stop this problem.

Purchasing organic food supports farmers who do NOT use extra fertilizers.

Not using fertilizers in your home garden prevents the spread of excess phosphorus.

Is There Any Hope?Back Home

The image above illustrates the two cycles of phosphorus

Short-term cycle: cycles phosphorus from soil to producers to consumers to decomposers back to soil.

Long-term cycle: weathering or erosion of rocks slowly adds phosphorus to soil.

Short Term vs. Long TermBack Home

Plants absorb phosphates from

water or soil

Consumers obtain phosphorus by eating plants or eating other

consumers

Decomposers break down animal waster and decaying

organisms and return phosphates to soil

Phosphorus is carried by rivers or lakes to the

ocean bottom

Phosphorus is stored for long periods of time in

sediment and sedimentary

rock

Stored phosphorus is eventually returned to soil

through erosion, weathering, or human

construction

The EndBack Home