Oxygen

Danakil Desert   https://en.wikipedia.org/wiki/Danakil_Desert

The Danakil Desert is a desert in northeast Ethiopia, southern Eritrea, and northwestern Djibouti. Situated in the Afar Triangle, it stretches across 136,956 square kilometres (52,879 sq miles) of arid terrain. The area is known for its volcanoes and extreme heat, with daytime temperatures surpassing 50 °C (122 °F). Less than an inch of rainfall occurs each year. The Danakil Desert is one of the lowest and hottest places on Earth. It is inhabited by a few Afar, who engage in salt mining.

Winds take dust from this and other deserts from North Africa across the Atlantic to the Amazon basin in South America (Brazil) and annually dump 27 million tons of African desert dust into the Amazonian rain forest. This is the perfect fertilizer. Plants and trees grow and consume carbon dioxide and produce oxygen. One tree produces enough oxygen for two people to consume in a year. The Amazon basin in 10 times the size of Texas and produces 20 times the amount of oxygen that all humans on our planet need to consume in one year. But not one breath escapes the Amazon. Everything is consumed by the animals, reptiles, insects, mammals, birds that live in the Amazon. The trees however suck up the water from the ground and it travels up the tree and is eventually released as vapor. This in the presence of sunlight and wind creates a massive river in the sky which is bigger than the Amazon and covers everything beneath when viewed from the ISS. This river of water vapor travels north until it hits a wall – the 5500 miles long and 4 miles high Andes. It cools and rains. The rain erodes rock and converts it into sediment and dumps it into the ocean. This sediment is full of nutrients. There something is waiting for it.
Diatoms. https://diatoms.org/what-are-diatoms

Diatoms are single-celled algae 4 – times thinner than hair. Diatoms are algae that live in houses made of glass. They are the only organism on the planet with cell walls composed of transparent, opaline silica. Diatom cell walls are ornamented by intricate and striking patterns of silica. Diatoms produce 50% of the air we breathe. Without diatoms, we would be dead.

Through carbon fixation, diatoms remove carbon dioxide (CO2) from the atmosphere. The CO2 is converted to organic carbon in the form of sugar, and oxygen (O2) is released. We breathe the oxygen that diatoms release. Diatoms multiply daily and double their number. Sometimes this is slowed down in the absence of nutrients. Diatoms are also found in the Arctic and use the nutrients from powdered rock that glacier movement produces. Estimates of the number of diatom species range from 20,000 – 2 million. Scientists are discovering new species every year.

When nutrients are scarce, diatoms die and sink to the ocean floor. Their shells don’t degrade and are preserved for tens of millions of years. In some places, the sediment of dead diatoms is half a mile thick. Times change, ocean level falls, ocean floor rises and we have a salt desert and dust storms. The cycle is complete.

Oxygen forms 20.95 % of our atmosphere. Exactly. If there is too little oxygen as happens at high altitudes, we choke and have breathing problems. If there is too much oxygen, it causes spontaneous fires and we burn. We need an exact balance of oxygen which is exactly 20.95%. We don’t know how the earth does it, but that is exactly how much oxygen there is in our atmosphere and has been for millions of years.

Book suggestion: Chris Hadfield: https://www.amazon.com/Astronauts-Guide-Life-Earth-Determination/dp/0316253030