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Title: LONG-TERM CO2 ELEVATION AFFECTS SOIL STRUCTURE OF NATURAL ECOSYSTEMS

Author
item RILLIG, MATTHIAS - CARNEIGE INST STANFORD CA
item Wright, Sara
item ALLEN, MICHAEL - UNIV CA RIVERSIDE, CA
item FIELD, CHRISTOPHER - CARNEIGE INST STANFORD CA

Submitted to: Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2000
Publication Date: N/A
Citation: N/A

Interpretive Summary: Consideration of soil as a sink for atmospheric CO2 requires quantification of inputs and understanding of the processes involved in trapping CO2. A recent discovery showed that a ubiquitous group of soil fungi is involved in soil stabilization through production of a highly stable glue-like glycoprotein (protein with attached carbohydrates). The current report shows that under elevated CO2 in three natural ecosystems soil stability and the glycoprotein concentration increase. These results indicate that atmospheric CO2 can be sequestered in glomalin (the carbohydrates attached to the protein), but also as a consequence of the process of soils stabilization. Soil is stabilized when glue-like compounds (i.e., glomalin) coat soil minerals and organic matter resulting in formation of aggregates. Stable soil aggregates promote plant health by allowing water and air to be maintained at optimal levels. Also, aggregated soil is less susceptible to erosion by wind and water.

Technical Abstract: Elevated atmospheric CO2 could increase carbon allocation to soils globally, but the effects on soil physiochemical properties are almost unknown. Multi-year exposure of three natural ecosystems to elevated CO2 increased water-stability of soil aggregates, altered aggregate size distribution (and hence soil structure), and increased concentrations of the aggregate-stability related arbuscular mycorrhizal fungal protein glomalin. Altered soil structure resulting from atmospheric change could lead to a wide range of indirect effects on the structure and function (e.g., carbon storage) of natural and managed ecosystems. One consequence could be decreased sensitivity of ecosystems to soil erosion by water, wind and land-use changes.