In photosynthesis, plants capture and store solar energy, using it to convert carbon dioxide in the air into sugar molecules which they use for food, producing oxygen as a byproduct.
“There is a net release of oxygen while the tree is growing and storing carbon in its wood, but when the tree dies the wood rots, removing the same amount of oxygen from the air to form carbon dioxide (CO2) from the carbon in the wood,” he said.
“A net release of oxygen occurs only if the carbon sequestered through photosynthesis is buried in a place where it cannot combine with oxygen to form CO2. On a global scale, the main location for this is at the bottom of the ocean, where some of the organisms sink to the bottom when they die and are buried in the sediments.”
Saleska notes that since 1990, the level of oxygen in the atmosphere has dropped by 0.005 percent—hardly at all.
