Biogeochemical Cycles

3.4 Cycles of Matter

​I understand why the cycling of matter is important to life on Earth

I can describe how matter cycles among the living and nonlivng parts of an ecosystem​

I can explain why nutrients are important to living systems​

Recycling in the Biosphere

Matter, unlike energy, is recycled within and between ecosystems. Elements pass from one organism to another and from one part of the biosphere to another through biogeochemical cycles, which are closed loops powered by the flow of energy.

Water Cycle

Water moves between the ocean, the atmosphere, and land--sometimes outside living organisms and sometime inside them.

• Evaporation is the process in which water changes from a liquid to a gas.

• Transpiration is the process in which water evaporates from the leaves of plants.

Open Ended

What is the difference between evaporation and transpiration?

​Nutrient Cycles

The chemical substances that an organism needs to survive are called nutrients. Like water, nutrients pass through organisms and the environment.

Carbon Cycle: Carbon is a key ingredient of all organic compounds. Processes involved in the carbon cycle include photosynthesis and human activities such as burning.

Nitrogen Cycle: Nitrogen is needed by all organisms to build proteins. Processes involved in the nitrogen cycle include nitrogen fixation and denitrification.

·    In nitrogen fixation, certain bacteria convert nitrogen gas into ammonia.

·   In denitrification, other soil bacteria convert nitrogen compounds called nitrates back into nitrogen gas.

​Phosphorus Cycle: Phosphorus is needed for molecules such as DNA and RNA. Most of the phosphorus in the biosphere is stored in rocks and ocean sediments. Stored phosphorus is gradually released into water and soil, where it is used by organisms.

Open Ended

Describe what nutrients are.

Nutrient Limitation

A nutrient that, in short supply, can limit the productivity of an ecosystem is called a limiting nutrient.

Open Ended

When is a substance a limiting nutrient?

Open Ended

How does the way that matter flows through an ecosystem differ from the way that energy flows?

Open Ended

Why do living organisms need nutrients?