I consider myself both a marine organic geochemist and an environmental scientist. My research interests concern natural and anthropogenic coastal environmental phenomena, including 1) terrestrial carbon burial in the ocean, 2) microbial and vascular plant biomarkers in sediments as proxies of paleoecology and climate, 3) uptake and transformation of xenobiotic compounds by commercially and recreationally harvested fish and shellfish, 4) fate and transport of anthropogenic organic toxins in aquatic ecosystems, and 5) drivers of coastal hypoxia.
The amount of carbon stored in continental reservoirs and marine sediments dwarfs the quantity of carbon present as CO2 in the atmosphere, and therefore to understand past climates and predict future ones, it is absolutely necessary to accurately quantify the residence time of carbon in these reservoirs. My most recent work in this field has shown that fjords, an understudied type of glacially carved estuary, are responsible for burying more organic carbon than sediments underlying all high productivity regions of the ocean. This research, out for review in Nature Geoscience, re-quantifies the current rate of marine organic carbon burial and has major implications for climate models.
My current research interests broadly center around the interaction of anthropogenic contaminants with natural aquatic systems, with a focus on biological uptake and transformation in commercially and recreationally harvested fish and shellfish. my scientific background in the organic geochemistry of freshwater, estuarine and coastal marine environments, allows me to examine xenobiotic compounds in the context of aquatic carbon and nitrogen cycles, as well as their interaction with the complex organic and inorganic matrices in these systems
Currently at UCONN, I construct experimental mesocosms with local Long Island Sound sediments, seawater, and regionally important marine species including blue crabs, flounder, oysters, hard clams, and blue mussels. I meter in isotopically-labeled contaminants (15N) to these systems to reach steady-state, and examine their full distribution into organic and inorganic fractions by examining d15N enrichments in biological tissue, sediments, dissolved organic matter, and dissolved nutrients. This experimental approach allows for a complete mass balance and a holistic view of contaminate fate and transport. With my colleagues, I am developing sensitive compound-specific isotopic measurement techniques to scale up our experiments to impacted ecosystems, allowing us to differentiate between legacy contamination and experimentally introduced compounds. My analytical expertise includes bulk and compound-specific C and N isotopic analysis with isotope-ratio mass spectrometers (EA-IRMS, GC-IRMS), organic biomarker analysis with gas and liquid chromatographic mass spectrometers (GC-MS, LC-MS), and dissolved organic carbon analyses with total organic carbon (TOC) analyzers. These experimental tools uniquely allow me to examine pollutant exposure and deleterious effects to health at the molecular and ecosystem levels.
- Smith R.W., Bianchi T.S. and XinXin L. (2012) A Re-evaluation of the use of Branched GDGTs as Terrestrial Biomarkers: Implications for the BIT and TEX86 Geochimica et Cosmochimica Acta 80, 14-29.
- Shiller, A.M., Shim, M.J., Guo, L., Bianchi, T.S., Smith, R.W., and Duan, S. (2012) Hurricane Katrina impact on water quality in the East Pearl River, Mississippi. Journal of Hydrology 414-415, 388-392.
- Bianchi T.S., Cook R., Perdue M., Kolic P., Green N., Zhang Y., Smith R.W., Kolker A., Ameen A., King G., Ojwang L.M., Schneider C.L., Normand A.E., and Hetland R. (2011) Impacts of diverted freshwater on dissolved organic matter and microbial communities in Barataria Bay, Louisiana, U.S.A. Marine Environmental Research 72, 248-257.
- Smith R.W., Bianchi T.S. and Savage C. (2010) Comparison of Lignin Phenols and Branched/Isoprenoid Tetraethers (BIT Index) as Indices of Terrestrial Organic Matter in Doubtful Sound, Fiordland, New Zealand. Organic Geochemistry 41, 281-290.
- Bianchi T.S., Dimarco S.F., Smith R.W. and Schreiner K.M. (2009) A Gradient of Dissolved Organic Carbon and Lignin from Terrebonne-Timbalier Bay Estuary to the Louisiana Shelf (USA). Marine Chemistry 117, 32-41.
- Schouten S., Hopmans E.C., van der Meer J., Mets A., Bard E., Bianchi T.S., Diefendorf A., Escala M., Freeman K.H., Furukawa Y., Huguet C., Ingalls A., Menot-Combes G., Nederbragt A.J., Oba M., Pearson A., Rosell-Mele A., Schaeffer P., Shah S. R., Shanahan T.M., Smith R.W., Smittenberg R., Talbot H.M., Uchida M., Van Mooy B.A.S., Yamamoto M., Zhang Z. and Damste J.S.S. (2009) An Interlaboratory Study of TEX86 and BIT Analysis using High-performance Liquid Chromatography:Mass Spectrometry. Geochemistry, Geophysics, Geosystems 10, Q03012.
- Vaughan W.C., Briggs K.B., Kim J.W., Bianchi T.S. and Smith R.W. (2009) Storm-Generated Sediment Distribution Along the Northwest Florida Inner Continental Shelf. IEEE Journal of Oceanic Engineering 34, 495-515.
- Smith R.W., Bianchi T.S., Allison M., Galy V. and Savage C. The role of fjords in marine organic carbon burial: A case study in Fiordland, NZ. In Review at Nature Geoscience.
- Smith R.W., Tobias C., Vlahos P., Ballentine M., Ariyarathna T. Removal rates of TNT and RDX in seawater. Accepted in Chemosphere.
- Smith, R. W., Ballentine, M., Vlahos, P., Tobias, C., Ariyarathna, T. Biological uptake and transformation of 15N-[TNT] and 15N-[RDX] in Long Island Sound winter flounder, blue crabs, oysters, and hard clams. For Environmental Science and Technology
- Smith, R. W., Ballentine, M., Vlahos, P., Tobias, C. A comparison of GC-ECD and HPLC-UV analytical techniques for the quantification of explosives in marine biological tissue, waters, and sediments. For Marine Chemistry
- Smith, R. W., Cady, D., Tobias, C., Bohlke, J. K., Hatzinger, P., Sturchio, N. Compound Specific Nitrogen Isotope Analysis of TNT and RDX. For Analytical Chemistry
- Schmidt, M. W., Hertzberg, J. E., Bianchi, T., Smith, R. W., Shields, M. R. Holocene and Last Glacial Maximum TEX86 and Globigerinoides ruber Mg/Ca Sea Surface Temperatures from the Eastern Equatorial Pacific. For Paleoceanography
- Liu Y., Yvon-Lewis S.A., Hu L., Thornton D.C.O., Bianchi T.S., Campbell L., Smith, R.W.Spatial and temporal distributions of bromoform and dibromomethane in the Atlantic basin and their linkage with ocean primary production. For Global Biogeochemical Cycles