Last spring, I gave a TED talk about plant-soil interactions and their importance in the global carbon cycle at a TEDx event organised by Amsterdam University College. You can watch the video below, but for those of you who rather read (actually, I am one of those people, as I never have the patience to watch a video from beginning to end!) you can also read the full text below.
Do you ever think about soils? Do you ever think about soils, other than, when your boots are muddy, or your vegetables dirty? Well, I’m going to talk about soils.
Soils! Without soils, we would not be here. Soils sustain all life on land. And that is because all energy flows through soils, via photosynthesis and respiration.
Have soils always been here?
Have you ever thought about how soils are formed? Where plants came from? And the tiny invisible microbes that live in the soil?
More than 4.5 billion years ago, there was no soil. There wasn’t even life. There were only oceans. But somewhere between 4.5 and 3.5 billion years ago, the first microorganisms appeared in the oceans. There wasn’t even free oxygen at that time! But then, photosynthesis evolved in bacteria, and cyanobacteria started producing oxygen around 2.7 billion years ago. About 1.5 billion years ago, the first fungi appeared, and much later, around 500 million years ago, the first land plants arose. Probably, photosynthesis in these plants was derived from photosynthetic bacteria inside plant cells (the endosymbiosis theory). Those first land plants – like this little liverwort – had no, or very rudimentary roots (remember, there was no soil that they could grow their root in, only rock!), and were likely helped on land by symbiotic fungi.
And this is where soil started to form.Continue reading