HR: 0830h
AN: B21C-0720    [PDF]
TI: Mechanisms of Biogeochemical Influence on Phosphorus Bioavailablity in Cold Terrestrial Ecosystems
AU: * Kearns, J P
EM: jkearns@eps.berkeley.edu
AF: Department of Earth and Planetary Science, 307 McCone Hall University of California-Berkeley, Berkeley, CA 94720 United States
AU: Cervini-Silva, J
EM: jcervinisilva@yahoo.com
AF: Department of Earth and Planetary Science, 307 McCone Hall University of California-Berkeley, Berkeley, CA 94720 United States
AU: Fournelle, J
EM: johnf@geology.wisc.edu
AF: Department of Geology, Weeks Hall University of Wisconsin-Madison, Madion, WI 53706 United States
AU: Schloss, P
EM: pds@plantpath.wisc.edu
AF: Department of Plant Pathology, 1630 Linden Drive University of Wiscoinsin-Madison, Madison, WI 53706
AU: Williamson, L
EM: llw@plantpath.wisc.edu
AF: Department of Plant Pathology, 1630 Linden Drive University of Wiscoinsin-Madison, Madison, WI 53706
AU: Reuss, R
EM: ffrwr@uaf.edu
AF: Institute of Arctic Biology, Department of Biology and Wildlife University of Alaska-Fairbanks, Fairbanks, AK 99775 United States
AU: Handlesman, J
EM: joh@plantpath.wisc.edu
AF: Department of Plant Pathology, 1630 Linden Drive University of Wiscoinsin-Madison, Madison, WI 53706
AU: Banfield, J F
EM: jill@eps.berkeley.edu
AF: Department of Earth and Planetary Science, 307 McCone Hall University of California-Berkeley, Berkeley, CA 94720 United States
AB: The Bonanza Creek LTER site along the Tanana River near Fairbanks, Alaska is a phosphorus-limited ecosystem. Our research combines microbiological and geochemical approaches to understand factors controlling phosphorus bioavailability at this site. Our first objective was to identify the phosphate minerals within the sediment and soils of vegetated islands in the river. Detailed electron microprobe studies revealed that the predominant inorganic phosphate source is fluorapatite. Thus, we are conducting microbial and abiotic experiments to evaluate the role of organic ligands in fluorapatite dissolution. Kinetic data are obtained in flow through reaction vessels as a function of apatite variety and ligand type. Batch experiments are used to investigate organic adsorption to apatite surfaces to test a hypothesized relationship between the propensity of a ligand to adsorb and its influence on dissolution rates. These data will contribute to understanding of biological impact on mineral weathering and nutrient cycling in terrestrial environments. At Bonanza Creek, and in many other soils, phosphorus released by apatite weathering is sequestered into secondary lanthanide, aluminum, and iron phosphate minerals. These represent important, highly insoluble phosphate reservoirs in some phosphorus-limited ecosystems. We have studied the selectivity of biogenic organic ligands in promoting mineral dissolution through strong metal ion complexation. Of particular interest are siderophores, which modeling results indicate have the potential to influence both iron and phosphorus bioavailability.
DE: 1045 Low-temperature geochemistry
DE: 1055 Organic geochemistry
DE: 1615 Biogeochemical processes (4805)
DE: 1625 Geomorphology and weathering (1824, 1886)
DE: 1886 Weathering (1625)
SC: Biogeosciences [B]
MN: 2003 Fall Meeting