CHAPTER 2 SECTION 1CYCLES OF

MATTER

Cycles of Matter

Also called biogeochemical cycles These cycles are nature’s way of

recycling because…Matter is always conserved

The three main cycles are water, carbon, and nitrogen

The Water Cycle

Water is constantly moving between biotic and abiotic things.

Water can move through the environment in four main ways

1. Precipitation—movement of water from the atmosphere to the land

Includes rain, snow, sleet, hail Approx. 91% falls on the ocean; the other

9% falls on land to replenish the fresh water supply.

The Water Cycle

2. Evaporation—Water moving from the land to the atmosphere

Transpiration—a form of evaporation from the surface of living things

Condensation—When water vapor cools to form a liquid (falls as precipitation)

The Water Cycle

3. Ground Water—when water seeps into the ground, where it is stored in places like underground caverns. Provides water to the soil, streams, rivers,

and oceans

4. Runoff—Water that does not seep into the ground, but rather flows on top of it

The Carbon Cycle

Every living thing contains carbon. Carbon also moves through the

environment in four main ways.

The Carbon Cycle Photosynthesis—producers use carbon

dioxide (CO2) from the air to make food for themselves

Respiration—when carbon is returned to the atmosphere as animals exhale

Decomposition—when bacteria and fungi break down dead materials to release carbon

Combustion—when fossil fuels are burned, carbon is released

The Nitrogen Cycle Approx. 78% of Earth’s atmosphere is nitrogen

gas. However, most organisms cannot use this form

directly from the atmosphere Nitrogen Fixation—bacteria in the soil are able

to convert atmospheric nitrogen into a usable form for plants and animalsLightning can also “fix” nitrogen

Denitrification—other bacteria do the opposite: convert usable nitrogen back into atmospheric nitrogen