New DOE Award | Sticky Roots and the Fate of Soil Carbon in Natural Ecosystems

MBL Ecosystems Center Senior Scientist Zoe Cardon has received a collaborative grant from the U.S. Department of Energy (DOE) to study "sticky roots" and the fate of soil carbon in natural ecosystems. This grant was one of nine funded under the DOE Environmental Systems Science Program aimed at improving the understanding of watersheds, wetlands, and other terrestrial environments.  The official press release may be found on the Office of Science website.

Human activities are driving increasing concentrations of CO₂ in the atmosphere, and the resulting climate change is becoming more and more obvious. But there are natural mechanisms operating in ecosystems that can transform atmospheric CO₂ into organic forms and store it in soil long-term. In particular, that organic matter can become bound to soil minerals, where it can remain protected for millennia. Such long-term protection has great value to humans as climate change looms. However, the growth of living plants and soil microbes may depend on accessing nutrients trapped in the mineral-associated organic matter. In this DOE-funded work, Cardon (MBL), Keiluweit (UMass Amherst), Malmstrom (MSU), and Riley (LBNL) are using experiments and modeling to examine mechanisms by which plant roots and their associated microbes can dislodge organic matter from soil minerals, making nutrients available for recycling supporting new growth, but also making carbon vulnerable to re-release to the atmosphere as CO₂.

A novel twist of the planned work lies in the aboveground treatment through which the researchers will test belowground ecosystem function: controlled viral infection of plants. Viral infection strongly affects the types and amounts of compounds released by plant roots, and Cardon and colleagues hypothesize that some of those compounds can dislodge stored organic matter from minerals. Since viral infection of plants is widespread in terrestrial ecosystems (with 25-70% of plants commonly infected), this new work promises to build knowledge about a prevalent, natural phenomenon with large potential to affect the productivity of ecosystems and the fate of large reserves of carbon stored in soil.