11. Biogeochemical Cycles

Chapter 11 of our Biology e-book course for the ENEM exam will address an extremely important topic, Biogeochemical Cycles. This is a topic that involves an in-depth understanding of natural processes and the interaction between living beings and the environment in which they live. Let's dive into this fascinating world of cycles and processes that sustain life on Earth.

Biogeochemical Cycles are natural processes that recycle essential nutrients in the biosphere. These cycles involve the transformation and circulation of chemical elements in the atmosphere, hydrosphere and lithosphere, and are essential for maintaining life on Earth. There are several biogeochemical cycles, including the carbon cycle, nitrogen cycle, oxygen cycle, water cycle, phosphorus cycle, and others.

The Carbon Cycle

The carbon cycle is a process by which carbon circulates on Earth. Carbon is an essential component of all forms of life and plays a crucial role in regulating the global climate. The carbon cycle involves the process of photosynthesis, where plants and algae absorb carbon dioxide from the atmosphere and transform it into glucose and oxygen. This carbon is then transferred through the food chain as animals consume plants and are consumed by other animals. When animals and plants die, the carbon is returned to the soil, where it can be taken up again by plants or released back into the atmosphere through decomposition.

The Nitrogen Cycle

The nitrogen cycle is another important biogeochemical cycle. Nitrogen is an essential component of amino acids and nucleic acids, which are the building blocks of proteins and DNA, respectively. The nitrogen cycle involves nitrogen fixation, where bacteria in the soil convert gaseous nitrogen into nitrogen compounds that can be used by plants. Animals obtain nitrogen by consuming plants or other animals. When animals and plants die, nitrogen is returned to the soil, where it can be taken up again by plants or released back into the atmosphere through decomposition or denitrification.

The Water Cycle

The water cycle, also known as the hydrologic cycle, involves the circulation of water on Earth. Water evaporates from oceans, lakes and rivers and turns into water vapour, which condenses to form clouds. The water is then returned to the earth in the form of precipitation (rain, snow, etc.). Water that falls to land can be absorbed by plants, evaporated back into the atmosphere, or run off into rivers and oceans.

The Phosphorus Cycle

The phosphorus cycle is a process by which phosphorus circulates on Earth. Phosphorus is an essential component of nucleic acids and ATP, a molecule that stores and supplies energy in cells. Phosphorus is released in nature through erosion of rocks and is taken up by plants from the soil. Animals obtain phosphorus by consuming plants or other animals. When animals and plants die, phosphorus is returned to the soil, where it can be taken up again by plants.

In conclusion, biogeochemical cycles are fundamental processes that recycle essential nutrients in the biosphere. They play a crucial role in maintaining life on Earth and are an important topic for understanding biology and ecology. By studying these cycles, we can appreciate the complexity and interconnectedness of life on Earth and better understand how to protect and preserve our planet.

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