New News Biology #69

Cycles Explained: Carbon Cycle & Water Cycle

The earth is quite efficient at recycling everything, from water to carbon dioxide, and also individual atoms like nitrogen, carbon, and phosphorus as well.

Because of this, atoms can be used over and over again, and each of these atoms are part of a cycle.

Of the estimated 6 octillion atoms inside you, a lot of them came from other humans, volcanoes, and other organisms, etc.

The Water Cycle (we can start anywhere as its a cycle and its the same):

The sun shines down on a body of water (like a lake, river, ocean, or even water from the soil or a puddle), making the water molecules evaporate. We’ve taken water from the earth’s surface and turned it into water vapour.

Then this water vapour condenses into clouds, which can be blown by winds from one region to another.

These clouds will continue there floating until at some point, the water in these clouds falls back down to earth in the form of precipitation.

The Carbon Cycle

Most of the carbon is locked in five stores:

The air - as carbon dioxide

Plants - locked up in biological molecules

Soil - which contains a lot of bacteria and microorganisms

Fossil fuels - also in the ground

Animals - also locked up in biological molecules

How does the carbon move between these stores?

Photosynthesis - plants and algae take in carbon dioxide from the air and convert it into biological molecules

Respiration - the carbon trapped as biological molecules in the plants can be passed back out into the atmosphere.

Eaten - animals can eat the plants and the biological molecules with carbon trapped inside will be transferred to the animals.

Microbial respiration - after the animals and/or plants die, their remains would decay and be decomposed by microorganisms in the soil, and gradually, all the carbon dioxide trapped within these former biological molecules will again be released into the atmosphere.

Anaerobic decay - when the dead animal and/or plant somehow decays without oxygen, its remains will become fossil fuels.

Burning - humans could burn the fossil fuel stores, and release the carbon back into the atmosphere as carbon dioxide. You could also add an additional burning of plants (like burning bio-fuels in an engine) as a way of releasing carbon dioxide.