Biogeochemistry of Vaterite Formation in an Upland Afforested Environment. (5732)
Authors:
C.W. Zanner* - University of Nebraska R.A. Drijber - University of Nebraska
Abstract:
The Nebraska National Forest at Halsey is a 25,000-acre experimental forest
planted in the 1930s on prairie that stabilizes the largest sand sea in North America.
Ponderosa pine (Pinus ponderosa), eastern redcedar (Juniperus virginiana), and jack pine (Pinus banksiana) were planted. Today’s forest is made up of mainly
Ponderosas and redcedar. During a three-year study of the affects of afforestation on soil properties, we observed white crusts, eight- to twelve-cm in diameter, on soil surfaces under areas with the oldest redcedars. These crusts effervesced when dilute HCl was applied. X-ray diffractometry of these crusts showed the dominant mineral is vaterite, a calcite polymorph. Vaterite has not been reported to occur in these settings. Crusts are not under pines or in the prairie and are rare under
younger redcedars, but have been observed in the same redcedar areas for three years. Our data show that redcedars have been more efficient at cycling calcium to the surface. Thus, we propose that these vaterite-rich crusts are produced by an interaction between the fungal community associated with the redcedars,
opportunistic bacteria living off decaying fungi and actually produce the vaterite, and the higher calcium content of the surface soil/litter layer. It is unclear whether the persistent drought during the last three years is a significant factor.
Speaker Information: C. William Zanner, University of Nebraska, 133 Keim Hall University of Nebraska, Lincoln, NE 68583-0915; Phone: 402-472-0674; E-mail:
Session Information: Tuesday, November 2, 2004, 8:10 AM-3:45 PM Presentation Start: 8:10 AM
Keywords: Vaterite; Afforestation; Calcite; Fungi
