BIOGEOCHEMICAL CYCLES

🌱CARBON CYCLE.

What is the carbon cycle?

The carbon cycle is nature's way of recycling carbon atoms. Carbon is the foundation for all life on Earth.

The carbon cycle describes the process in which carbon atoms continually travel from the atmosphere to the Earth and then back into the atmosphere. Human activities have a tremendous impact on this cycle. Burning fossil fuels, changing land use, and using limestone to make concrete all transfer massive quantities of carbon into the atmosphere. As a result, the amount of carbon dioxide in the atmosphere is rapidly rising — it is now greater than at any time in the last 3.6 million years.

🌌NITROGEN CYCLE.

• Process which transforms the inert nitrogen present in the atmosphere to a more usable form for living organisms.
• Process through which nitrogen is converted into many forms, consecutively passing from the atmosphere to the soil to organism and back into the atmosphere.

🔥PHOSPHORUS CYCLE.

1. Over time, rain and weathering cause rocks to release phosphate ions and other minerals. This inorganic phosphate is then distributed in soils and water.
2. Plants take up inorganic phosphate from the soil. The plants may then be consumed by animals. Once in the plant or animal, the phosphate is incorporated into organic molecules such as DNA. When the plant or animal dies, it decays, and the organic phosphate is returned to the soil.
3. Within the soil, organic forms of phosphate can be made available to plants by bacteria that break down organic matter to inorganic forms of phosphorus. This process is known as mineralisation.
4. Phosphorus in soil can end up in waterways and eventually oceans. Once there, it can be incorporated into sediments over time.

Click here - Experiment by pairs

🌟SULFUR CYCLE.

Sulfur-containing proteins are degraded into their constituent amino acids by the action of a variety of soil organisms. The sulfur of the amino acids is converted to hydrogen sulfide (H₂S) by another series of soil microbes. In the presence of oxygen, H₂S is converted to sulfur and then to sulfate by sulfur bacteria. Eventually the sulfate becomes H₂S.

Hydrogen sulfide rapidly oxidizes to gases that dissolve in water to form sulfurous and sulfuric acids. These compounds contribute in large part to the “acid rain” that can kill sensitive aquatic organisms and damage marble monuments and stone buildings.