Stuffing Carbon Away: Mechanisms of Carbon Sequestration in Soils

Reimer, P J ; Masiello, C A ; Southon, J R ; Trumbore, S E ; Harden, J W ; White, A F ; Chadwick, O A ; Torn, M S

Lawrence Livermore National Laboratory

关键词: Aluminium;    Management;    Storage;    Mineralogy;    54;   

DOI  :  10.2172/15004040
RP-ID  :  UCRL-ID-151702
RP-ID  :  W-7405-ENG-48
RP-ID  :  15004040

美国|英语

来源: UNT Digital Library

【 摘 要 】

Soils offer the potential to sequester large quantities of carbon from the atmosphere for decades to millennia and so may ameliorate the anthropogenic influence of fossil fuel release. However changes in climate can drastically affect the soil's ability to store carbon through changes mineralogy on time scales of human interest. It is essential to understand the major controls on soil carbon dynamics before we attempt to manage sequestration to control atmospheric CO{sub 2} buildup. Models of the terrestrial carbon cycle often use clay content to parameterize soil carbon turnover. Evidence from volcanic soils suggests that soil mineralogy is a major control on a soil's ability to store carbon, because different types of minerals have widely varying abilities to physically and chemically isolate soil organic matter from decomposition, however volcanic soils represent only a small percentage of the earth's soils. The relationship between precipitation and soil carbon storage is also complex and poorly constrained. Significantly, precipitation changes predicted as a result of atmospheric CO{sub 2} doubling include increased rainfall throughout California. We utilized {sup 14}C, {delta}{sup 13}C, and the total organic carbon, iron, and aluminum contents to address the question of the importance of mineralogy and climate on carbon storage in soils formed on a globally representative parent material. The California coastal terraces, formed over the last 500 thousand years as a result of tectonic uplift and sea level change, provide a natural laboratory to examine the effect of mineralogy and climate on carbon storage. We have focused on two terraces sequences, one near Eureka and one near Santa Cruz. Within each set of terraces only soil mineral development varies; all other variables are constant (rainfall, plant systems, and soil parent material, and land management). Annual precipitation at Eureka is twice that at Santa Cruz, allowing us to examine its role in the transport of organic carbon to deeper horizons. The objective of the study is to improve the understanding of soil carbon storage and derive a set of proxies for organic carbon turnover for terrestrial carbon cycle models.