Carbon on the Move

In the picture

1. 1The cloud in the sky: the air carries carbon as carbon dioxide gas.
2. 2The oak leaf: photosynthesis takes carbon dioxide from the air and builds it into sugars and wood.
3. 3The cut soil face with roots and fallen leaves: dead plants rot and lock carbon into the soil, while microbes breathe some of it back out.
4. 4The ocean wave: seawater dissolves carbon dioxide, and plankton use it before sinking and carrying it into the deep.

Examples

• Breathing out on a cold morning releases carbon dioxide that a nearby tree can use the same day.
• A garden compost bin, where worms and microbes break down peelings, warms up and returns carbon to the soil and the air.

Quiz: Carbon on the Move (Age 15)

1. 1

   A young oak grows into a large tree with heavy wood. Where does most of the carbon in that wood come from?

   • Carbon dioxide gas that the leaves take from the air
   • Minerals that the roots pull out of the soil
   • Water that the roots draw up from the ground
2. 2

   Dead leaves and plants fall onto the forest floor and rot. What happens to the carbon they contain?

   • Much of it is locked into the soil, while microbes breathe some of it back into the air
   • It all stays locked in the soil for ever and never returns to the air
   • It all escapes into the air at once, so soil stores no carbon
3. 3

   How does the ocean take carbon out of the air and move it into deep water?

   • Seawater dissolves carbon dioxide, and plankton use it and carry it down when they sink
   • Only big animals such as whales absorb carbon, and it stays near the surface
   • The sea only holds carbon that rivers wash in from the land, none from the air

The answers, each with its explanation, are in the app. This lesson has left the free week, so its quiz is part of the subscription.