Dr. Gregg Davidson

Areas of Expertise

Hydrogeology, geochemistry, isotope geochemistry, wetland hydrology/ecology, levee hydrology, atmospheric CO2 sinks

Recent Projects


Adsorption of atmospheric CO2 by soils and volcanic substrates

A portion of the CO2 added to the atmosphere each year is removed by several processes. A portion is simply adsorbed to mineral surfaces.








Wetland Hydro-ecology

Some studies report that cypress trees growing in water grow more when it rains. Long term studies at Sky Lake are tracking water levels, sap flow, radial growth, and soil redox conditions to understand the influence of water depth and timing of flooding.



Geochemistry and flow path of water under levees during flood events

When water transports sediment from under a levee, sand boils are formed at the surface, and the levee is at risk of failure. Geochemical tools are being applied, including tritium, isotopes of oxygen, hydrogen, iron, and strontium, to understand the chemical evolution of water beneath the levees, to identify deep vs shallow flow pathways, and to identify rapid means of identifying regions of greater risk of failure.


Publications

Books

Hill, C., G. Davidson, W. Ranney, T. Helble, Eds., (2016) The Grand Canyon, Monument to an Ancient Earth: Can Noah's Flood Explain the Grand Canyon?, Kregel Publications, Grand Rapids, MI, 240 p.

Journals

Davidson, G. and K. Wolgemuth (2018) Testing and verifying old age evidence: Lake Suigetsu varves, tree rings, and carbon-14. PSCF, 70(2):75-89.

Davidson, G.R., C.A. Hill, and K. Wolgemuth (2017) The need for a paradigm shift in science advocacy. GSA Today, 27:58-59. doi:10.1130/GSATG280GW.1

Wren, D., J.R. Rigby, G.R. Davidson, and M.A. Locke (2016) Determination of lake sediment accumulation rates in an agricultural watershed using lead-210 and cesium-137. Journal of Soil and Water Conservation, 71:137-147. doi:10.2489/jswc.71.2.137

Chen, J., P. Chakravarty, G.R. Davidson, D.G. Wren, M.A. Locke, Y. Zhou, G. Brown, Jr., and J.V. Cizdziel (2015) Simultaneous determination of mercury and organic carbon in sediment an soils using a direct mercury analyzer based on thermal decomposition by Atomic Absorption Spectrophotometry, Analytica Chimica Acta, 871:9-17. doi:10.1016/j.aca.2015.03.011

Davidson, G. (2015) Genetics, the Nephilim, and the Historicity of Adam, Perspectives on Science and Christian Faith, 67(1):24-34.

Davidson, G.R., J.R. Rigby, D. Pennington, and J.V. Cizdziel (2013) Elemental chemistry of sand-boil discharge used to trace variable pathways of seepage beneath levees during the 2011 Mississippi River flood. Applied Geochemistry, 28:62-68. doi:10.1016/j.apgeochem.2012.10.018

Davidson, G.R., A. Phillips-Housley, and M.T. Stevens (2013) Soil-zone adsorption of atmospheric CO2 as a terrestrial carbon sink. Geochimica et Cosmochimica Acta, 106:44-50. doi:10.1016/j.gca.2012.12.015

Bennett, S.J., J.A. Dunbar, F.E. Rhoton, P.M. Allen, J.M. Bigham, G.R. Davidson, and D.G. Wren (2013) Assessing sedimentation issues within aging flood control reservoirs, in: The Challenges of Dam Removal and River Restoration, J.V. De Graff and J.E. Evans, eds., Reviews in Engineering Geology, 21:25-44. doi:10.1130/2013.4021(03).

Wren, D.G. and G.R. Davidson (2011) Using lake sedimentation rates to quantify the effectiveness of erosion control in watersheds. Journal of Soil and Water Conservationem>, 66:313-322. doi: 10.2489/jswc.66.5.313

White, K., G.R. Davidson and P. Paquin (2009) Hydrologic evolution of the Edwards Aquifer (Balcones Fault Zone) recharge zone as recorded in the DNA of endemic cave spiders, south-central Texas, Geology, 37:339-342. doi: 10.1130/G25373A.1

Galicki, S.J., G.R. Davidson and S.T. Threlkeld (2008) Element mobility in bald cypress xylem. Tree Ring Research, 64:39-46.

Wren, D.G. and G.R. Davidson (2008) Practical implications of quantifying ancient sedimentation rates in lakes. Journal of Soil and Water Conservation, 63:89. (Invited paper) doi: 10.2489/jswc.63.3.89A

Wren, D.G., G.R. Davidson, W.G. Walker and S.J. Galicki (2008) The evolution of an oxbow lake in the Mississippi alluvial floodplain. Journal of Soil and Water Conservation, 63:129-135. doi: 10.2489/jswc.63.3.129

Galicki, S.J., G.R. Davidson and S.T., Threlkeld (2008) Transport of agricultural Pb, As, and P through a riparian wetland. American Midland Naturalist, 159:457-467.

Walker, W.G., G.R. Davidson, T. Lange and D. Wren (2007) Accurate lacustrine and wetland sediment accumulation rates determined from 14C activity of bulk sediment fractions. Radiocarbon. 49:983-992.

Tan, Y., G.R. Davidson, C.H. See, S. Rice, D.C. Dunbar, J.H. O'Haver, D.W. Harrelson and M. Zahikhani (2006) Picric acid degradation in sediments from the Louisiana Army Ammunition Plant. Water, Air, and Soil Pollution. 177:169-181. doi: 10.1007/s11270-006-9133-y

Davidson, G.R., B.C. Laine, S.J. Galicki and S.T. Threlkeld (2006) Root-zone hydrology: why bald cypress in flooded wetlands grow more when it rains. Tree Ring Research, 62:3-12.

Davidson, G.R., S.J. Bennett, W.C. Beard, III and P. Waldo (2005) Trace elements in sediments of an aging reservoir in rural Mississippi: potential for mobilization following dredging. Water, Air, and Soil Pollution. 163:281-292. doi: 10.1007/s11270-005-0731-x

Davidson, G.R., M. Carnley, T. Lange, S.J. Galicki and A. Douglas (2004) Changes in sediment accumulation rate in an oxbow lake following late 19th century clearing of land for agricultural use: a 210Pb, 137Cs and 14C study in Mississippi, USA. Radiocarbon, 46:755-764.

Davidson, G.R. (2002) Use of SF6 to label drilling air in unsaturated, fractured rock studies: risk of over-purging. Applied Geochemistry, 17:1361-1370. doi:10.1016/S0883-2927(02)00044-6

Yang, I.C., G.R. Davidson and K.M. Scofield (2000) Carbon-14 activity of pore water obtained by vacuum-distillation and one-dimensional compression methods on Yucca Mountain cores: Proceedings of the 3rd International Conference on Isotopes, Vancouver, Canada, Sept. 6-10, 1999, Nigel R. Stevenson, editor, World Scientific Publishing Company, River Edge, New Jersey, p.246-250.

Davidson, G.R. and I.C. Yang (1999) Changes in 14C activity over time during vacuum distillation of carbon from rock pore-water. Radiocarbon, 41:141-148.

Davidson, G.R., R.L. Bassett, E.L. Hardin and D.L. Thompson (1998) Geochemical and isotopic evidence of aquifer recharge through fractures in unsaturated fractured tuff. Applied Geochemistry, 13:185-195.

Davidson, G.R., R.L. Hardin and R.L. Bassett (1995) Extraction of 14C from unsaturated zone pore-water using vacuum distillation. Radiocarbon, 37:861-874.

Davidson, G.R. (1995) The stable isotopic composition and measurement of carbon in soil CO2. Geochimica et Cosmochimica Acta, 59:2485-2489. doi: 10.1016/0016-7037(95)00143-3

Bassett, R.L., P. Buszka, G.R. Davidson and D. Diaz-Chong (1995) The identification of groundwater sources using boron isotopic composition. Environmental Science and Technology, 29:2915-2922. doi: 10.1021/es00012a005

Davidson, G.R. and R.L. Bassett (1993) Application of boron isotopes for identifying contaminants such as fly ash leachate in groundwater. Environmental Science and Technology, 27:172-176. doi: 10.1021/es00038a020