Читать книгу Oceans For Dummies - Joseph Kraynak - Страница 31

You’ve probably heard the Amazon described as “the lungs of our planet.” However, while this incredible ecosystem is very important, rainforests supply only about 28 percent of the oxygen on our planet. That’s nothing to sneeze at, unless, of course, you’re allergic to rainforests. So where does the other roughly 70 percent come from? Well, over half of all oxygen produced on Earth comes from the sea (by some estimates it is as high as 80 percent!). While most of it is consumed by marine organisms, a small fraction of it escapes and over geologic time has given rise to an atmosphere that is about 20 percent oxygen, which has made life as we know it possible. Thank you, ocean. And this is mostly thanks to microscopic plantlike organisms floating in the sea, the tiny but mighty phytoplankton. (See Chapters 7 and 8 for more about phytoplankton and other ocean plants.)

Powered by the sun, these microscopic wonders turn carbon dioxide and water into sugar and oxygen through the process of photosynthesis, as do plants that grow on land (and in your flower pots), but it performs this magic on a much larger scale. According to some estimates, phytoplankton account for only one percent of all the biomass on our planet. Now, that may be a tiny slice of the pie, but they are able to conduct nearly as much photosynthesis as all the land plants that account for a much larger fraction of that pie. Without phytoplankton creating oxygen in the ocean, life on Earth, in its current form, could not exist.