A novel source of atmospheric H₂: Abiotic degradation of organic material

Here, we show laboratory observations of H₂ production and its temperature dependence during abiotic degradation of four plant litter types as well as pure cellulose and high lignin content woody material. A greater amount of H₂ was produced in the absence of solar radiation than from photodegradation alone, verifying that low temperature thermal degradation of plant litter is a source of H₂. In addition, we measured a significant release of H₂ both in the presence and absence of O₂.

Our results suggest that abiotic release of H₂ during organic matter degradation is ubiquitous in arid ecosystems and may also occur in other terrestrial ecosystems. We propose that because these processes occur at the soil-atmosphere interface, they provide a previously unrecognized proximal source of H₂ for microbial uptake and confound interpretation of direct measurements of atmospheric uptake that are important for constraining the global H₂ budget.