Biogeochemical Cycles

There are four main biochemical cycles: nitrogen, phosphorus, water, and carbon. These cycles are integral to maintaining the woodland ecosystem.

The first cycle listed, the nitrogen cycle, is a very important part of the woodland ecosystem because plants and animals need nitrogen to live; also, plants need nitrogen to make chlorophyll, which plants use in photosynthesis. There are five steps to the nitrogen cycle.

Fixation - Fixation is the first step in the process of making nitrogen usable by plants. Here bacteria change nitrogen into ammonium.

Nitrification - This is the process by which ammonium gets changed into nitrates by bacteria. Nitrates are what the plants can then absorb.

Assimilation - This is how plants get nitrogen. They absorb nitrates from the soil into their roots. Then the nitrogen gets used in amino acids, nucleic acids, and chlorophyll.

Ammonification - This is part of the decaying process. When a plant or animal dies, decomposers like fungi and bacteria turn the nitrogen back into ammonium so it can reenter the nitrogen cycle.

Denitrification - Extra nitrogen in the soil gets put back out into the air. There are special bacteria that perform this task as well.

Below is a diagram of the nitrogen cycle.

The second cycle named, the phosphorus cycle, is also really important to not only a woodland ecosystem, but to all ecosystems, as phosphorus is in DNA. The phosphorus cycle has four main stages.

Rain and weathering cause rocks to release phosphate, which is distributed into the ground and water.

Plants get phosphate from soil, and animals get phosphate from plants.

Phosphorus soil can also end up in water and then be incorporated into sediments.

Once an animal or plant dies, the phosphate that helped make up their body returns to the dirt.

An example of the phosphorus cycle is below.

The Water Cycle

The water cycle is a biogeochemical cycle. Water is needed by plants, animals and humans to survive. The largest reservoir of water is in the Earth’s oceans and seas.

The Carbon Cycle

The carbon cycle is a biogeochemical cycle in which carbon is moved throughout the Earth’s atmosphere. It is crucial for life on Earth because living things need carbon. Human activities have impacted the carbon cycle, especially in the atmosphere.