Christopher G. Smith, Ph.D.
As a coastal geologist, my research focuses on the transport, transformation, and deposition of particulate and dissolved constituents within the coastal realm and how system processes will respond to large-scale environmental forcings (e.g., climate change).
Coastal systems provide a dynamic interface between terrestrial and marine realms; anthropogenic activity and natural processes occurring within terrestrial ecosystems can have a significant impact to the coastal zone and adjacent marine system. Augmentation of coastal systems is inevitable from a human perspective as nearly half of the population of the United States reside within coastal counties. Understanding modern processes (sedimentologic, hydrologic, and geochemical) occurring along this terrestrial-marine continuum is critical in predicting the response associated with natural and anthropogenic perturbations.
My research interests generally fall into two categories: 1) fluid exchange (e.g., surface water – groundwater exchange, submarine and coastal groundwater discharge) and 2) fine-grained sediment dynamics, specifically in marsh and estuarine environments. Linking these two seemingly disparate research topics are naturally-occurring (e.g., U-Th series) and anthropogenically-introduced/spiked (e.g., 137Cs) radionuclides. Particle reactive radionuclides (e.g., 7Be, 234Th, 210Pb, 210Po, and 137Cs) provide excellent tracers to quantify sediment deposition and re-mobilization over time-scales of months to decades. Examining the final sedimentary product in the context of the temporal framework and associated transient changes also provide a breadth of knowledge to environmental conditions that persisted in recent past and the outcome that may be expected if similar conditions persist in the present or future. Alternatively, the more conservative behavior of radon and radium isotopes have proven these as excellent tracers to quantify groundwater discharge in both fresh and marine environments.
Over the last three decades, groundwater discharge to the coastal zone has received increasing recognition as a substantial material vector, influencing water quality and nutrient fluxes. Quantification of fresh and marine groundwater end-members and the processes that drive the exchange (e.g., seasonal recharge cycles, hurricanes and tropical cyclones) are critical to assess the overall importance of coastal groundwater and has been at the forefront of my research.
Professional Experience
2010-Present: Research Geologist, USGS, St. Petersburg Coastal and Marine Science Center
2008 - 2010: USGS Mendenhall Fellow, St. Petersburg Coastal and Marine Science Center
Education and Certifications
PhD - Oceanography & Coastal Science (Geological conc) (2008) from Louisiana State University (Geaux Tigers!)
MS - Geology (2004) from East Carolina University
BS - Geology (2001) from East Carolina University (NC)
Science and Products
Sedimentological and radiochemical characteristics of marsh deposits from Assateague Island and the adjacent vicinity, Maryland and Virginia, following Hurricane Sandy
Biological and geochemical data along Indian Point, Vermilion Bay, Louisiana
Ground-truthing electrical resistivity methods in support of submarine groundwater discharge studies: Examples from Hawaii, Washington, and California
A Geochemical and Geophysical Assessment of Coastal Groundwater Discharge at Select Sites in Maui and O’ahu, Hawai’i
Assessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges
Temporal changes in lithology and radiochemistry from the back-barrier environments along the Chandeleur Islands, Louisiana: March 2012-July 2013
Archive of single-beam bathymetry data collected from select areas in Weeks Bay and Weeks Bayou, southwest Louisiana, January 2013
Predictions of barrier island berm evolution in a time-varying storm climatology
An evaluation of temporal changes in sediment accumulation and impacts on carbon burial in Mobile Bay, Alabama, USA
Biological and geochemical data of gravity cores from Mobile Bay, Alabama
Variations of iron flux and organic carbon remineralization in a subterranean estuary caused by interannual variations in recharge
An examination of historic inorganic sedimentation and organic matter accumulation in several marsh types within the Mobile Bay and and Mobile-Tensaw River Delta region
Non-USGS Publications**
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
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Sedimentological and radiochemical characteristics of marsh deposits from Assateague Island and the adjacent vicinity, Maryland and Virginia, following Hurricane Sandy
The effect of tropical and extratropical cyclones on coastal wetlands and marshes is highly variable and depends on a number of climatic, geologic, and physical variables. The impacts of storms can be either positive or negative with respect to the wetland and marsh ecosystems. Small to moderate amounts of inorganic sediment added to the marsh surface during storms or other events help to abate prAuthorsChristopher G. Smith, Marci E. Marot, Alisha M. Ellis, Cathryn J. Wheaton, Julie Bernier, C. Scott AdamsBiological and geochemical data along Indian Point, Vermilion Bay, Louisiana
Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center collected shallow sediment cores and surface samples from a coastal salt marsh environment next to Vermilion Bay in southwest Louisiana in January 2013. The sampling was part of a larger USGS study to gather data for assessing environmental changes over the past 150 years. The objective of the study was toAuthorsKathryn A. Richwine, Marci E. Marot, Christopher G. Smith, Lisa E. Osterman, C. Scott AdamsGround-truthing electrical resistivity methods in support of submarine groundwater discharge studies: Examples from Hawaii, Washington, and California
Submarine groundwater discharge (SGD) is an important conduit that links terrestrial and marine environments. SGD conveys both water and water-borne constituents into coastal waters, where these inflows may impact near-shore ecosystem health and sustainability. Multichannel electrical resistivity techniques have proven to be a powerful tool to examine scales and dynamics of SGD and SGD forcings. HAuthorsCordell Johnson, Peter W. Swarzenski, Christina M. Richardson, Christopher G. Smith, Kevin D. Kroeger, Priya M. GanguliA Geochemical and Geophysical Assessment of Coastal Groundwater Discharge at Select Sites in Maui and O’ahu, Hawai’i
This chapter summarizes fieldwork conducted to derive new estimates of coastal groundwater discharge and associated nutrient loadings at select coastal sites in Hawai’i, USA. Locations for this work were typically identified based on pronounced, recent ecosystem degradation that may at least partially be attributable to sustained coastal groundwater discharge. Our suite of tools used to evaluate gAuthorsPeter W. Swarzenski, Curt D. Storlazzi, M.L. Dalier, C.R. Glenn, C.G. SmithAssessing inundation hazards to nuclear powerplant sites using geologically extended histories of riverine floods, tsunamis, and storm surges
Most nuclear powerplants in the United States are near rivers, large lakes, or oceans. As evident from the Fukushima Daiichi, Japan, disaster of 2011, these water bodies pose inundation threats. Geologic records can extend knowledge of rare hazards from flooding, storm surges, and tsunamis. This knowledge can aid in assessing the safety of critical structures such as dams and energy plants, for whAuthorsJim O'Connor, Brian F. Atwater, Timothy A. Cohn, Thomas M. Cronin, Mackenzie K. Keith, Christopher G. Smith, Robert R. Mason,Temporal changes in lithology and radiochemistry from the back-barrier environments along the Chandeleur Islands, Louisiana: March 2012-July 2013
Scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center conducted a time-series collection of shallow sediment cores from the back-barrier environments along the Chandeleur Islands, Louisiana from March 2012 through July 2013. The sampling efforts were part of a larger USGS study to evaluate effects on the geomorphology of the Chandeleur Islands following the cAuthorsMarci E. Marot, C. Scott Adams, Kathryn A. Richwine, Christopher G. Smith, Lisa E. Osterman, Julie BernierArchive of single-beam bathymetry data collected from select areas in Weeks Bay and Weeks Bayou, southwest Louisiana, January 2013
A team of scientists from the U.S. Geological Survey, St. Petersburg Coastal and Marine Science Center, collected 92 line-kilometers of dual-frequency single-beam bathymetry data in the tidal creeks, bayous, and coastal areas near Weeks Bay, southwest Louisiana. Limited bathymetry data exist for these tidally and meteorologically influenced shallow-water estuarine environments. In order to reduceAuthorsNancy T. DeWitt, Christopher D. Reich, Christopher G. Smith, Billy J. ReynoldsPredictions of barrier island berm evolution in a time-varying storm climatology
Low-lying barrier islands are ubiquitous features of the world's coastlines, and the processes responsible for their formation, maintenance, and destruction are related to the evolution of smaller, superimposed features including sand dunes, beach berms, and sandbars. The barrier island and its superimposed features interact with oceanographic forces (e.g., overwash) and exchange sediment with eacAuthorsNathaniel G. Plant, James Flocks, Hilary F. Stockdon, Joseph W. Long, Kristy K. Guy, David M. Thompson, Jamie M. Cormier, Christopher G. Smith, Jennifer L. Miselis, P. Soupy DalyanderAn evaluation of temporal changes in sediment accumulation and impacts on carbon burial in Mobile Bay, Alabama, USA
The estuarine environment can serve as either a source or sink of carbon relative to the coastal ocean carbon budget. A variety of time-dependent processes such as sedimentation, carbon supply, and productivity dictate how estuarine systems operate, and Mobile Bay is a system that has experienced both natural and anthropogenic perturbations that influenced depositional processes and carbon cyclingAuthorsChristopher G. Smith, Lisa E. OstermanBiological and geochemical data of gravity cores from Mobile Bay, Alabama
A study was conducted to understand the marine-influenced environments of Mobile Bay, Alabama, by collecting a series of box cores and gravity cores. One gravity core in particular demonstrates a long reference for changing paleoenvironmental parameters in Mobile Bay. Due to lack of abundance of foraminifers and (or) lack of diversity, the benthic foraminiferal data for two of the three gravity coAuthorsKathryn A. Richwine, Marci Marot, Christopher G. Smith, Lisa E. Osterman, C. Scott AdamsVariations of iron flux and organic carbon remineralization in a subterranean estuary caused by interannual variations in recharge
We determine the inter-annual variations in diagenetic reaction rates of sedimentary iron (Fe ) in an east Florida subterranean estuary and evaluate the connection between metal fluxes and recharge to the coastal aquifer. Over the three-year study period (from 2004 to 2007), the amount of Fe-oxides reduced at the study site decreased from 192 g/yr to 153 g/yr and associated organic carbon (OC) reAuthorsMoutusi Roy, Jonathan B. Martin, Jaye E. Cable, Christopher G. SmithAn examination of historic inorganic sedimentation and organic matter accumulation in several marsh types within the Mobile Bay and and Mobile-Tensaw River Delta region
Mass accumulation rates (MAR; g cm-2 y-1), linear sedimentation rates (LSR; cm y-1), and core geochronology derived from excess lead-210 (210Pb) profiles and inventories measured in six sediment cores collected from marsh sites from the MobileTensaw River Delta and Mobile Bay region record the importance of both continuous and event-driven inorganic sedimentation over the last 120 years. MAR in frAuthorsChristopher G. Smith, Lisa E. Osterman, Richard Z. PooreNon-USGS Publications**
Cable, J.E., Smith, C.G., Blanford, W.J. 2009. Dispersivity and distribution coefficients in marine sediments using Tritium and Radium-226. Radioprotection, 44:185-190.Smith, C.G., Cable, J.E., Martin, J.B., and Roy, M. 2008. Evaluating the source and seasonality of submarine groundwater discharge using a Radon-222 pore water transport model, Earth and Planetary Science Letters 273:312-322.Culver, S.J., Grand Pre, C., Mallinson, D., Riggs, S., Corbett, D.R., Foley, J., Hale, M., Ricardo, J., Rosenberger, J., Smith, C.G., Smith, C.W., Snyder, S., Twamley, D., Farrell, K., Horton, B. 2007. Late Holocene barrier island collapse: Outer Banks, North Carolina, U.S.A. The Sedimentary Record 5:4-8.Smith, C.G., Cable, J.E., Martin, J.B. 2008. Episodic high intensity mixing events in a subterranean estuary: Effects of tropical cyclones, Limnology and Oceanography 53:666-674.Smith, C.G., Culver, S.J., Riggs, S.R., Ames, D., Corbett, D.R., Mallinson, D.J. 2008. Geospatial analysis of barrier island width of two segments of the Outer Banks, North Carolina, USA: anthropogenic curtailment of natural self-sustaining processes. Journal of Coastal Research 24:70-83.Martin, J.B., Cable, J., Smith, C.G., Roy, M. and Cherrier, J. 2007. Magnitudes of submarine groundwater discharge from marine and terrestrial sources: Indian River Lagoon, Florida. Water Resources Research 43: doi:10.1029/2006WR005266.Smith, C.G., Cable, J.E., Martin, J.B., Cherrier, J., and Roy, M. 2006. Mixing in the subterranean estuary: a comparison of Radon-222 pore water models. p. 355-368, In V. P. Singh and Y. J. Xu [eds.], Annual American Institute of Hydrology Meeting & International Conference: Challenges in Coastal Hydrology and Water Quality. Water Resources Publications, LLC, 534 pp.Martin, J.B., Cable, J.E., Jaeger, J., Hartl, K.M., and Smith, C.G. 2006. Thermal and chemical evidence for rapid water exchange across the sediment-water interface by bioirrigation in the Indian River Lagoon, Florida. Limnology and Oceanography 51:1332-1341.Culver, S.J., Ames, D.V., Corbett, D.R., Malllinson, D., Riggs, S.R., Smith, C.G., and Vance, D. 2005. Foraminiferal and sedimentary record of late Holocene barrier island evolution, Pea Island, North Carolina. Journal of Coastal Research 21:406-416.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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