摘要

Various methods that rely on new or undeveloped technologies, or that require large amounts of capital and energy, have been proposed for removal of CO(2) from the atmosphere. Of the methods that take advantage of the Earth's natural cycles, the approach of sequestering terrigenous agricultural byproducts in deep sea sediments has received little attention. To evaluate the potential of crop residue sequestration in deep sea sediments, a controlled 700 day incubation experiment was conducted where crop residues (soy stalk, maize stover, and alder wood chips) were added to deep sea hemipelagic sediments. An initial pulse of remineralization lasting 1 week oxidized less than 1% of the added material. Thereafter, remineralization rate constants for terrestrial materials (avg k = 0.004 y(-1)) were more than two orders of magnitude slower than for marine planktonic material incubated separately (k = 3.0 y(-1)). Over the 2-year incubation, soy residue was least remineralized (3%) with stover (6%) and wood (8%) also showing little remineralization compared to marine plankton (19%). Lignin losses were impacted by sediment redox condition, with the greatest degradation of lignin occurring under oxic conditions, but degradation of lignin continued under suboxic conditions for the maize treatment. Model fits to the data are consistent with the hypothesis that sequestration of terrestrial crop residues in the deep sea could effectively remove this material from the active carbon cycle. Implementation of crop residue ocean permanent sequestration (CROPS) could potentially remove as much as 15% of the current annual anthropogenic burden of CO(2) to the atmosphere. This idea, while unsavory, might represent a viable tool in the fight against the rise of atmospheric CO(2).

  • 出版日期2010-10