But you're right 'guest Larry' we do have a very serious issue in the Phytoplankton population shrinking. " "A measure of productivity is the net amount of carbon dioxide taken up by phytoplankton," said Jorge Sarmiento, a professor of atmospheric and ocean sciences at Princeton University in New Jersey. The one-celled plants use energy from the sun to convert carbon dioxide and nutrients into complex organic compounds, which form new plant material. This process, known as photosynthesis, is how phytoplankton grow.
Herbivorous marine creatures eat the phytoplankton. Carnivores, in turn, eat the herbivores, and so on up the food chain to the top predators like killer whales and sharks... Phytoplankton need two things for photosynthesis and thus their survival: energy from the sun and nutrients from the water. Phytoplankton absorb both across their cell walls.
In the process of photosynthesis, phytoplankton release oxygen into the water. Half of the world's oxygen is produced via phytoplankton photosynthesis. The other half is produced via photosynthesis on land by trees, shrubs, grasses, and other plants."
As for it producing 70%? of the oxygen. as above I trust in fifty percent myself. Another thing we can't really say we know though, but 50% seems a comfortably conservative number :) Here's a article about 'PLANKTON LEVELS IN THE OCEAN' from 2002. (http://www.fisherycrisis.com/plankton.html). So, that was then, how about now? A simple way of checking that statement, although not proving that it is only the Phytoplankton, is to look at the atmosphere, do you agree?
So is the oxygen concentration in our atmosphere shrinking? Well, yes, unfortunately it is. A Scientist, His Work and a Climate Reckoning. (http://www.nytimes.com/2010/12/22/science/earth/22carbon.html?pagewanted=all) The overshadowing problem being if it is the CO2 raising, or if it is a combination of both the oxygen-levels shrinking as well as our man-made CO2 raising. I would put my guess on a combination myself.
(https://www.thenakedscientists.com/forum/proxy.php?request=http%3A%2F%2Fscrippsco2.ucsd.edu%2Fimages%2Fstories%2Fhome%2Fmlo_front_plot.png&hash=981c7f6a03297c5b8a41e10b33eba736)
If the oxygen lever really shrunk 50% it should mean your babies born into a world, constantly of short breath, and, just guessing here, it should also mean that species not needing that much oxygen should flourish, taking a larger part of the world than those needing oxygen. It would become a harsh world for us humans to adapt too, as you can forget most of what your wilderness programs shows you on the telly. Jelly fish seems to flourish under such conditions though, as well as some species of octopuses, cockroaches too I presume, but as for the rest of the animal kingdom? I don't really expect them to survive.. Some idiots envision a depleted Earth with us as the sole inhabitants, and that, that is more than stupidity. It's Egos screaming 'MEEE !!' and believing in it too. Don't become one of those please.
And if someone have read this far you should try to read this link too :)
What Goes Around Comes Around. (http://www.visionlearning.com/library/module_viewer.php?mid=95) It's actually good for you :)
Believe it or not.