Unit A

Module 1 ~ Lesson 4

The Carbon Cycle

Photosynthesis and cellular respiration are important processes in the carbon cycle

The movement of carbon through the carbon cycle is highly affected by carbon being stored in a variety of reservoirs, including fossil fuels and the vast reserves of calcium carbonate in the oceans.

Reservoirs of carbon are called carbon sinks. Boreal forest ecosystems are now recognized as significant carbon sinks, not only due to the trees that live there but also because of the accumulation of peat in these wetland ecosystems. Peat in bogs in Alberta are also called muskeg. Studies of peat bogs in Siberia have revealed that some of these bogs have been around since the last ice age, which makes them 10,000 years old. These studies have also determined that peat bogs are among the world's top carbon sinks. Unfortunately, if peat bogs are drained and decomposition is allowed to occur, the carbon stored there is released as carbon dioxide. These ecosystems then become a source of carbon instead of a sink. Human activities can disrupt the carbon cycle, releasing carbon from carbon sinks into the atmosphere as carbon dioxide.
Peter Reid/Scottish Centre for Carbon Storage. CC-BY

Web Activity

  1. Print the lab activity sheet. If you do not have a printer, use the Word or Google document.
  2. Visit the Carbon Cycle interactive.
  3. Follow the instructions on the activity sheet.
  4. Identify where human activities disrupt the carbon cycle.