Carbon dioxide is a poisonous gas. Its molecular components are one part carbon to two parts oxygen. So it's written CO2. Carbon dioxide is found in our atmosphere and in lakes, ponds, steams and oceans. All living animals release carbon dioxide into the atmosphere. When you breathe in air, you exhale carbon dioxide. Insects, fish, plants and even bacteria release carbon dioxide into the air.
Plants and carbon dioxide
There is a continuous cycle involving carbon dioxide and plants. First, plants release oxygen into the atmosphere. Some of this released oxygen gets used up by bacteria to decompose dead animals and plants. Then carbon dioxide is given off by the decomposed animals and plants. The carbon dioxide is used by the plants and the plants release more oxygen.
Animals and carbon dioxide
Animals breathe oxygen and give off carbon dioxide too. Animals need oxygen to breathe. They exhale carbon dioxide, a breakdown of glucose during aerobic cell respiration. Decomposing animals still use up some oxygen and give off carbon dioxide during decay. If there is a higher level of carbon dioxide, it means that there is a lot of dead material that is being decomposed. Sometimes it's a natural cause, but often it indicates pollution. Because dead animals sink to the bottom of a lake, there is more carbon dioxide near the bottoms of lakes.
Oxygen is the most important gas of all breathing gases. People inhale air that is composed of
We exhale 4 to 5% by volume more carbon dioxide and 4% to 5% by volume less oxygen than what is inhaled. The air we exhale is composed of
Oxygen is used by your body for cellular respiration. Carbon dioxide is a product of this process. The exact amount of exhaled oxygen and carbon dioxide when breathing depends upon your diet, exercise and fitness level.
What is cellular respiration?
Cellular respiration is the process by which cells produce their own energy to survive. Cells use oxygen to break down glucose (sugar) and store the energy in molecules called adenosine triphosphate (ATP). Cellular respiration helps organisms stay alive because the energy cannot be used until it's stored in the ATP. Cells use ATP for all of their activities, such as growing, dividing and replacing dead cells. Cellular respiration occurs constantly inside cells, day and night.
Carbon dioxide levels: highs and lows
Carbon dioxide levels are higher at night because plants are using up oxygen and making carbon dioxide during this time. Also, spring and fall have higher carbon dioxide levels because there are more dead plants and animals. These plants and animals died during the winter and summer seasons and they decompose in the spring and fall.