Back to: Environmental Biology 100 Level
Welcome to class!
Hello brilliant learner! I’m excited to have you here today because we are about to learn something very fascinating that explains how nature recycles essential materials to keep life going. Our topic is Biogeochemical Cycles, and by the end of this lesson, you will understand how elements like water, carbon, nitrogen, and others move through living and non-living parts of the environment. Let’s begin!
Biogeochemical Cycles
Have you ever wondered what happens to the water after it rains, or how plants always seem to have the nutrients they need? Nature has a system that recycles these materials so that they do not run out. This system is called a biogeochemical cycle. It is one of the most important ways the Earth maintains balance.
What are Biogeochemical Cycles?
Biogeochemical cycles are natural processes that recycle essential elements like water, carbon, oxygen, and nitrogen through living things (plants, animals, microorganisms) and non-living things (air, soil, water). The term comes from three words:
Bio – life
Geo – earth
Chemical – elements and compounds
These cycles ensure that nutrients keep moving in ecosystems without getting exhausted.
Major Types of Biogeochemical Cycles
Water Cycle
This is the continuous movement of water on, above, and below the surface of the Earth. It includes:
Evaporation: Water from rivers, lakes, and oceans changes into vapour.
Condensation: Water vapour cools and forms clouds.
Precipitation: Water falls back to the Earth as rain.
Runoff and Infiltration: Water flows into rivers and seeps into the soil.
Example: In Nigeria, during the rainy season, water evaporates from the Atlantic Ocean, forms clouds, and falls as rain in Lagos.
Carbon Cycle
Carbon moves between the atmosphere, plants, animals, and the soil. Plants take in carbon dioxide during photosynthesis, and animals return it to the air when they breathe out. Decomposers also release carbon when breaking down dead organisms.
Example: When you eat yam (from a plant) and breathe out carbon dioxide, you are part of the carbon cycle!
Nitrogen Cycle
Nitrogen is important for making proteins in plants and animals. In the nitrogen cycle:
Nitrogen in the air is converted into usable forms by bacteria (nitrogen fixation).
Plants absorb nitrogen from the soil.
Animals eat plants and use nitrogen for growth.
Decomposers return nitrogen to the soil when plants and animals die.
Example: In farmlands in Kano, legumes like beans help add nitrogen to the soil through nitrogen-fixing bacteria in their roots.
Oxygen Cycle
Oxygen moves between the atmosphere and living organisms. Plants release oxygen during photosynthesis, and animals use it for breathing (respiration).
Importance of Biogeochemical Cycles
They recycle essential nutrients for living things.
They maintain balance in ecosystems.
They prevent waste and shortage of resources.
Summary
Biogeochemical cycles are natural processes that recycle water, carbon, nitrogen, oxygen, and other elements through living and non-living components of the Earth. They help maintain life and keep ecosystems balanced.
Evaluation
- What are biogeochemical cycles?
- List and explain two major cycles.
- Why are these cycles important in nature?
Fantastic work today! The more you understand how nature works, the better you can help protect it. Keep learning with Afrilearn because you’re building knowledge that can change the world. See you in the next class!