Explain how carbon is cycled between the atmosphere and hydrosphere. Use specific examples.

Geosphere Carbon dioxide is a gas but carbon can also be found in solid form (coal) and liquid form (oil). Carbon based fuels are fossils extracted from the Earth's interior. The minerals, rocks and land formations below and on the Earth's surface are called the geosphere. These fossilized deposits were created millions of years ago when plants and animals died and were compacted and preserved by geologic processes. Coal, oil and natural gas are the product of these geological processes and when we burn these fuels to create electricity or heat we release the chemicals like carbon dioxide and methane into the atmosphere, both of which are greenhouse gases. Hydrosphere Water plants, like algae and phytoplankton absorb carbon dioxide. The carbon dioxide is originally absorbed into the water column and aquatic plants draw the carbon dioxide from the water. In fact, 70% of the Earth's surface is covered with water and is called the hydrosphere. The oceans, seas, lakes, ponds, rivers and streams are huge carbon sinks, meaning carbon sinks into them and is stored for a long period of time. Ocean acidification occurs when too much carbon is absorbed into the water column making oceans acidic which decreases ecosystem sustainability. Coral reefs are being destroyed because the acidic water inhibits the production of calcium necessary for coral development.

Carbon is cycled through the hydrosphere and geosphere through biological, chemical, geological, and human activity.

Let's take a forest, for example. These autotrophs take in carbon dioxide (CO2) during photosynthesis. They then release oxygen to the environment and give organisms that perform cellular respiration enough oxygen. Then, the organisms that perform cellular respiration breathe out CO2 that can be used by autotrophs. The consumers can also eat the autotrophs and release CO2 as they breathe out.

When rainwater falls from clouds in the atmosphere, CO2 is dissolved into the drops of rain. The rain (some of it) then goes into oceans and is dissolved into the ocean with the CO2. Then, it comes back from the water and floats up into the atmosphere again.

Rocks at the bottom of the ocean are naturally turned into carbonated rocks, and it releases CO2 through volcanoes. Also, it can convert organic matter into fossil fuels.

Humans take fossil fuels from the Earth and use them as a source of fuel. This naturally releases the carbon dioxide in them, as they are converted into carbon over a very long period of time. Also, humans sometimes burn forests. The fire releases carbon dioxide into the atmosphere.

The same processes that occur geologically and biologically occur in the ocean. Green algae take in CO2 and use it the same way.