التفاصيل البيبلوغرافية
| العنوان: |
Evidence of old soil carbon in grass biosilica particles. |
| المؤلفون: |
Reyerson, P. E., Alexandre, A., Harutyunyan, A., Corbineau, R., De La Torre, H. A. Martinez, Badeck, F., Cattivelli, L., Santos, G. M. |
| المصدر: |
Biogeosciences Discussions; 2015, Vol. 12 Issue 18, p15369-15410, 42p, 1 Diagram, 2 Charts, 6 Graphs |
| مصطلحات موضوعية: |
CARBON in soils, SILICA content in soils, PHYTOLITHS, PHOTOSYNTHESIS, SEQUESTRATION (Chemistry) |
| مستخلص: |
Plant biosilica particles (phytoliths) contain small amounts of carbon called phytC. Based on the assumptions that phytC is of photosynthetic origin and a closed system, claims were recently made that phytoliths from grasslands play a significant role in atmospheric CO2 sequestration. However, anomalous phytC radiocarbon (14C) dates suggested contributions from a non-photosynthetic source to phytC. Here we address this non-photosynthetic source hypothesis using comparative isotopic measurements (14C and δ13C) of phytC, plant tissues, atmospheric CO2, and soil organic matter. State-of-the-art methods assured phytolith purity, while sequential stepwise-combustion revealed complex chemical-thermal decomposability properties of phytC. Although photosynthesis is the main source of carbon in plant tissue, it is found that phytC is partially derived from soil carbon that can be several thousand years old. The accumulation of old soil organic matter derived carbon in plant biosilica suggests that Si absorption and phytolith production promote old soil organic carbon mobilization. Although the magnitude of this mechanism still needs to be properly assessed at plant and ecosystem scales, its confirmation alone argues against attempts to use phytC as a proxy of plant carbon and call for the reexamination of phytolith atmospheric CO2 biosequestration estimates. [ABSTRACT FROM AUTHOR] |
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| قاعدة البيانات: |
Complementary Index |
