TY - JOUR
T1 - Decay of cacti and carbon cycling
AU - Garvie, Laurence
N1 - Funding Information:
Acknowledgements This work was supported by funding from the National Science Foundation (EAR-0418960). I am grateful to three anonymous reviewers for their insightful comments and suggestions.
PY - 2006/3
Y1 - 2006/3
N2 - Cacti contain large quantities of Ca oxalate biominerals, with C derived from atmospheric CO2. Their death releases these biominerals into the environment, which subsequently transform to calcite via a monohydrocalcite intermediate. Here, the fate of Ca oxalates released by plants in arid environments is investigated. This novel and widespread form of biomineralization has unexpected consequences on C cycling and calcite accumulation in areas with large numbers of cacti. The magnitude of this mineralization is revealed by studying the large columnar cactus Carnegiea gigantea (Engelm.) Britton and Rose in southwestern Arizona (locally called the saguaro). A large C. gigantea contains on the order of 1 × 105 g of the Ca oxalate weddellite - CaC2O4·2H 2O. In areas with high C. gigantea density, there is an estimated 40 g Catm m-2 sequestered in Ca oxalates. Following the death of the plant, the weddellite transforms to calcite on the order to 10-20 years. In areas with high saguaro density, there is an estimated release of up to 2.4 g calcite m-2 year-1 onto the desert soil. Similar transformation mechanisms occur with the Ca oxalates that are abundant in the majority of cacti. Thus, the total atmospheric C returned to the soil of areas with a high number density of cacti is large, suggesting that there may be a significant long-term accumulation of atmospheric C in these soils derived from Ca oxalate biominerals. These findings demonstrate that plant decay in arid environments may have locally significant impacts on the Ca and inorganic C cycles.
AB - Cacti contain large quantities of Ca oxalate biominerals, with C derived from atmospheric CO2. Their death releases these biominerals into the environment, which subsequently transform to calcite via a monohydrocalcite intermediate. Here, the fate of Ca oxalates released by plants in arid environments is investigated. This novel and widespread form of biomineralization has unexpected consequences on C cycling and calcite accumulation in areas with large numbers of cacti. The magnitude of this mineralization is revealed by studying the large columnar cactus Carnegiea gigantea (Engelm.) Britton and Rose in southwestern Arizona (locally called the saguaro). A large C. gigantea contains on the order of 1 × 105 g of the Ca oxalate weddellite - CaC2O4·2H 2O. In areas with high C. gigantea density, there is an estimated 40 g Catm m-2 sequestered in Ca oxalates. Following the death of the plant, the weddellite transforms to calcite on the order to 10-20 years. In areas with high saguaro density, there is an estimated release of up to 2.4 g calcite m-2 year-1 onto the desert soil. Similar transformation mechanisms occur with the Ca oxalates that are abundant in the majority of cacti. Thus, the total atmospheric C returned to the soil of areas with a high number density of cacti is large, suggesting that there may be a significant long-term accumulation of atmospheric C in these soils derived from Ca oxalate biominerals. These findings demonstrate that plant decay in arid environments may have locally significant impacts on the Ca and inorganic C cycles.
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U2 - 10.1007/s00114-005-0069-7
DO - 10.1007/s00114-005-0069-7
M3 - Article
C2 - 16453105
AN - SCOPUS:33644975408
SN - 0028-1042
VL - 93
SP - 114
EP - 118
JO - Naturwissenschaften
JF - Naturwissenschaften
IS - 3
ER -