The mosses crept out of the ocean, covering the bare rocks on our desolate planet over 400 million years ago. They sped up the chemical weathering of the rocks and decreased atmospheric carbon dioxide. These nefarious changes triggered glaciation events and a mass marine extinction! Muahahaha...... (yes mosses have an evil laugh) and that is how mosses conquered the land.
A couple of weeks ago, research was published examining the above scenario. The researchers carried out an experiment where they examined the ability of the moss Physcomitrella patens to weather rocks. One of the thoughts was that since mosses do not have true roots they might not alter substrates, such as rocks, in a similar manner. However, they found that the mosses secreted several different organic acids, just like vascular plants. Thus they have the ability to break down and weather rocks. This secretion of organic acids by mosses was not something I had heard about before. Their experiment only examined weathering with and without mosses. But when colonizing land the mosses were not alone. They would have been accompanied by fungi too. The researchers anticipate that the mosses in conjunction with fungal symbionts may even have greater weathering abilities!
Overall I think that it is a really interesting study connecting the colonization of land by mosses to historic patterns of climate change. It shows just how powerful and important plants are for life on our planet!
Timothy M. Lenton, Michael Crouch, Martin Johnson, Nuno Pires, and Liam Dolan. 2012. First plants cooled the Ordovician. Nature Geoscience 5:86–89.
This post was inspired by a friend who sent me a link to this sarcastic and funny article about this research. I take mild offense to the author calling the mosses names, but otherwise I enjoyed the piece. Thanks Emily!