Enhancing soil carbon storage for carbon remediation: potential contributions and constraints by microbes

Terrestrial carbon sequestration represents an important option for partially mitigating anthropogenic CO2 emissions. Evidence suggests that terrestrial ecosystems can be managed for carbon sequestration, but it is not certain to what extent the microbes within them can be manipulated. Challenges include identifying which specific microbes and mechanisms contribute to sequestered carbon; understanding how microbial communities respond over large spatial and long temporal scales to crucial environmental variables; and developing management strategies suitable for large spatial and long temporal scales. The growing recognition that microbes produce proteins that limit organic matter degradation suggests targets for basic research. Directly manipulating microbes to sequester CO2 through other processes such as mineral formation offers intriguing alternatives that merit further attention, but at present the prospects for practical implementation appear remote. Terrestrial carbon sequestration represents an important option for partially mitigating anthropogenic CO2 emissions. Evidence suggests that terrestrial ecosystems can be managed for carbon sequestration, but it is not certain to what extent the microbes within them can be manipulated. Challenges include identifying which specific microbes and mechanisms contribute to sequestered carbon; understanding how microbial communities respond over large spatial and long temporal scales to crucial environmental variables; and developing management strategies suitable for large spatial and long temporal scales. The growing recognition that microbes produce proteins that limit organic matter degradation suggests targets for basic research. Directly manipulating microbes to sequester CO2 through other processes such as mineral formation offers intriguing alternatives that merit further attention, but at present the prospects for practical implementation appear remote. the process of reducing CO2 emissions to the atmosphere through the use of abiological or biological methods. Abiological approaches capture CO2 from production sites (e.g. flue gases of fossil–fuel burning power plants) and inject it into deep reservoirs associated with oil fields or other geological formations. small cell-surface proteins with hydrophobic properties that form amyloid structures involved with the formation of aerial hyphae by Streptomyces. The functions of chaplins might be similar to those of hydrophobins. a glycoprotein produced solely by mycorrhizal fungi of the order Glomales. Glomalin appears similar to a class of heat shock proteins (Hsp60) and functions in cellular metabolism; in soil matrices, glomalin contributes to aggregation and sequestration of organic matter. small (100 residue) cysteine-rich proteins with hydrophobic properties produced by a wide range of filamentous fungi. Hydrophobins promote extensions of filaments across air–water boundaries and contribute to the ramification of fungi through soil. organo–mineral complexes operationally defined as 53–212 μm in size that contain pore spaces for air and water and harbor a range of microbes, but in which organic matter turnover occurs more slowly than in macroaggregates (>212 μm). Microaggregates can be stabilized by several fungal and bacterial proteins. the process of deposition external to a root surface of organic matter in any of several low and high molecular weight forms that affect organic concentrations in the soil matrix and microbial activity. Rhizodeposition can promote or destabilize sequestration. ‘black earth’, a name given to certain soils found in the Amazon, which contain high concentrations of charcoal derived from the cultivation practices of native people who burned various crop and plant residues. Terra preta soils are known to be more productive than neighboring unmanaged soils and could serve as models for managed carbon sequestration in diverse agroecosystems.