All sorts of chemicals necessary to life flow over time from the land to the sea. For life to go on, they have to find a way back. For many of these chemicals, the route back is through the air; dissolved compounds containing nitrogen, sulphur or iodine are turned into gases that escape into the atmosphere and blow back onto the land. The chemistry involved is mostly that of plankton and seaweed, and it is through their agency that life endlessly renews Earth’s habitability.
Science and technology