Despite the old saying “dead as dirt,” Earth’s soil is an incredibly rich and dynamic environment. Invertebrates, microbes, and plants all interact beneath the surface in a complex dance that determines the health of ecosystems and plays a part in larger biogeochemical cycles. Plants, in particular, play a major role in mediating mass transfers among different compartments of the biosphere. Their root systems create twisting underground superhighways of gases and liquids, moving the molecules essential for life up into the plant to be broken apart or added together as needed and generating waste products to be exhaled and excreted into the air. The gas transporting capacity of wetland plants is due to porous, gas-filled root tissues called aerenchyma that transport oxygen to the anoxic root zone and also facilitate gas transfer in the opposite direction, from soils to atmosphere.
February 5, 2016