As we approach the final day before the AP exam, have you reviewed the nutrient cycles? Knowledge of these cycles is critical-they tie everything together. In the fall we learned primary reservoirs, key chemical reactions, and anthropogenic impacts. I also had each of you write a creative short-story of a cycle. Here is a good one by MiriamA:
To be consistent is Carl’s game. His friends even go as far as to call him a connoisseur of consistency. But even the existence of a consistent Carbon molecule can be quite stressful. Sometimes, the mundane routine of Carl’s daily reality was overpowering: wake up, realize he’s stuck in a rock, think about eating breakfast, but realize he’s in a rock, take a nap, consider breaking out of his rock prison, and then realizing he is stuck. In a rock. Repeat for millennia.
Carl’s predicament made him pretty bored. His life seemed doomed to be forever consistent, when all of a sudden, Carl realized his rock was on top. Way on top: Consistent Carl was king of the lithosphere. Through weathering, Carl’s little piece of sedimentary rock was exposed and divided. Centuries went by; he was trod on by wooly mammoths, rained on incessantly, rolled by the wind down hills, and pushed back up them by construction trucks as gravel. And just when our friend Carl could no longer take the inconsistency of his new life, the greatest change yet struck him: Lichen was Carl’s new immediate neighbor. Carl’s rock was broken down by lichen into the soil. Carl was excited to be returned to the soil once more, but to his surprise…he was RESPIRATED.
As Carl considered changing his vacation response on his email back to his classic signature of “-You’re Favorite Boring Molecule”, Carl had yet another wake up call. His neighbor Lichen (fondly known as DJ Breakdown) had used energy to break him down, and had respired in the process, releasing Carl airborne as CO2 into the atmosphere.
Feeling like a new molecule, Carl was in ‘CO2 Tattoo Parlor’, inking in his newfound freedom, when he felt himself being pulled eastward over a body of water. He was newly surrounded by other, unfamiliar, yet similarly liberated CO2 molecules (some with ‘Stairway to Heaven’) inked across their covalent bonds), bumping about in the atmosphere. Back in his consistent days, Carl had attended school with perfect attendance, and thus new that the amount of CO2 in the air pocket he was in was greater than that in water, and that he would soon be diffused below the water’s surface. As he mentally prepared for the big plunge, Carl was yet again surprised when he was intercepted by a surface-dwelling aquatic organism and used for photosynthesis.
When the surface-dweller decayed, Carl was yet again released by the help of decomposers. He floated down, down, down, past his previously airborne friends who had arrived at the same place he had through diffusion. He bumped in H20, and formed Carbonic Acid. Carl, who had never been part of such a demanding relationship before, could barely recognize himself. The change kept going when he was transformed into bicarbonate, and then met Calcium. Before Carl knew it, he was part of Calcium Carbonate; planted on the bottom of the ocean floor as part of a coral reef. Carl had come a long way since his rock days, and was here to stay. He bought a new desk, got a haircut, and moved in for a while.
But what happened to some of Carl’s tattooed friends? Some of them were diffused, some of them decayed, but some were used in photosynthesis in photosynthetic organisms on the surface of the water. When that producer was eaten, the consumer respired to use glucose, and released the CO2 back into the atmosphere. They were airborne once more (‘Free Bird’ was added to the covalent bonds), but that did not last long. The CO2 was used once again for photosynthesis on the shore, helping a tree to grow. Years and years passed, and Carl’s friends went with the decaying tree to the soil, where they were broken into smaller and smaller pieces. And like Carl’s favorite book, Life Swap, Carl’s friends settled down over the millennia for a nice consistent life as sedimentary rock.
A little summary of pathways also by MiriamA:
Rock
Decay
Detritus respire
Released to atmosphere
Used by plants for photosynthesis
Plants eaten by consumers
Higher level consumers eat those consumers and respire, returning to atmosphere
Co2 travels on over to a large body of water
Diffuses into the ocean (high to low)
Used by surface dwelling creatures, respire, returned to atmosphere
Where it is used by plants for photosynthesis
Decay
Turn into sedimentary rock again………
OR
Diffused Co2 meets up with H20, makes carbonic acid, which turns into bicarbonate
Bicarbonate meets with calcium to make calcium bicarbonate
Precipitates, becomes coral!!
Degraded coral is impacted together, turns into sedimentary rock
So, do you remember the steps of the carbon cycle? Do you remember the formulas for these forms of carbon? Do you recall all the ways humans alter this cycle?