|Two new papers this week in Nature – Geoscience highlight the powerful role of plants in shaping the world around us – in one case, literally!
First, in “Paleozoic landscapes shaped by plant evolution, Martin Gibling and Neil Davies argue that the evolution of vascular plants with root systems, beginning around 450 million years ago, changed the way that rivers form channels and meander. It wasn’t until about 250 million years ago that the landscapes we know and love today were firmly established. I can’t help but wonder if further study of the surprisingly Earth-like but plant-free ice landscapes of Titan will provide more insights into “biogeomorphology”.
The second paper extends an old idea: that the spread of vascular plants was also important because it pulled down atmospheric CO2 , irreversibly cooling the climate. The link between plants and climate is not that plants consume CO2 by photosynthesis (although they do), but that plants break down rocks to obtain nutrients, like the elements phosphorous and iron.That break-down process enhances the rate at which
|CO2 reacts with rocks, ultimately moving carbon from the atmosphere to sediments in the deep sea. Root systems help plants do this very effectively! In the second paper, “First land plants cooled the Ordovician“, Tim Lenton and colleagues in the UK propose that this mechanism began to affect climate tens of millions of years earlier than generally supposed – as early as about 490 million years ago – when “non-vascular” plants first appeared on land.|
Maybe it’s not easy being green, but once a planet goes green there’s no going back!