selected publications academic article Kamalanathan, M., Schwehr, K. A., Labonté, J. M., Taylor, C., Bergen, C., Patterson, N., ... Quigg, A. (2021). The Interplay of Phototrophic and Heterotrophic Microbes Under Oil Exposure: A Microcosm Study. FRONTIERS IN MICROBIOLOGY. 12, 675328. Bacosa, H. P., Kamalanathan, M., Cullen, J., Shi, D., Xu, C., Schwehr, K. A., ... Quigg, A. (2020). Marine Snow Aggregates are Enriched in Polycyclic Aromatic Hydrocarbons (PAHs) in Oil Contaminated Waters: Insights from a Mesocosm Study. Journal of Marine Science and Engineering. 8(10), 781-781. Santschi, P. H., Xu, C., Schwehr, K. A., Lin, P., Sun, L., Chin, W., ... Quigg, A. (2020). Can the protein/carbohydrate (P/C) ratio of exopolymeric substances (EPS) be used as a proxy for their ‘stickiness’ and aggregation propensity?. Marine Chemistry. 218, 103734-103734. Lin, P., Xu, C., Xing, W., Sun, L., Schwehr, K. A., Quigg, A., & Santschi, P. H. (2020). Partitioning of iron and plutonium to exopolymeric substances and intracellular biopolymers: A comparison study between the coccolithophore Emiliania huxleyi and the diatom Skeletonema costatum. Marine Chemistry. 218, 103735-103735. Li, D., Xu, C., Yeager, C. M., Lin, P., Xing, W., Schwehr, K. A., ... Santschi, P. H. (2019). Molecular Interaction of Aqueous Iodine Species with Humic Acid Studied by I and C K-Edge X-ray Absorption Spectroscopy. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 53(21), 12416-12424. Xu, C., Lin, P., Zhang, S., Sun, L., Xing, W., Schwehr, K. A., ... Santschi, P. H. (2019). The interplay of extracellular polymeric substances and oil/Corexit to affect the petroleum incorporation into sinking marine oil snow in four mesocosms. Science of the Total Environment. 693, 133626-133626. Xu, C., Chin, W., Lin, P., Chen, H., Chiu, M., Waggoner, D. C., ... Santschi, P. H. (2019). Comparison of microgels, extracellular polymeric substances (EPS) and transparent exopolymeric particles (TEP) determined in seawater with and without oil. Marine Chemistry. 215, 103667-103667. Lin, P., Xu, C., Kaplan, D. I., Chen, H., Yeager, C. M., Xing, W., ... Santschi, P. H. (2019). Nagasaki sediments reveal that long-term fate of plutonium is controlled by select organic matter moieties. Science of the Total Environment. 678, 409-418. Kaplan, D. I., Price, K. A., Xu, C., Li, D., Lin, P., Xing, W., ... Santschi, P. H. (2019). Iodine speciation in a silver-amended cementitious system. Environ Int. 126, 576-584. Kaplan, D. I., Xu, C., Li, D., Lin, P., Xing, W., Nichols, R., Schwehr, K., & Santschi, P. H. (2019). Iodine speciation in cementitious environments. APPLIED GEOCHEMISTRY. 103, 15-22. Wozniak, A. S., Prem, P. M., Obeid, W., Waggoner, D. C., Quigg, A., Xu, C., ... Hatcher, P. G. (2019). Rapid Degradation of Oil in Mesocosm Simulations of Marine Oil Snow Events. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 53(7), 3441-3450. Sun, L., Chin, W., Chiu, M., Xu, C., Lin, P., Schwehr, K. A., Quigg, A., & Santschi, P. H. (2019). Sunlight induced aggregation of dissolved organic matter: Role of proteins in linking organic carbon and nitrogen cycling in seawater. Science of the Total Environment. 654, 872-877. Bacosa, H. P., Kamalanathan, M., Chiu, M., Tsai, S., Sun, L., Labonté, J. M., ... Quigg, A. (2018). Extracellular polymeric substances (EPS) producing and oil degrading bacteria isolated from the northern Gulf of Mexico. PLoS One. 13(12), e0208406-e0208406. Xu, C., Zhang, S., Beaver, M., Wozniak, A., Obeid, W., Lin, Y., ... Santschi, P. H. (2018). Decreased sedimentation efficiency of petro- and non-petro-carbon caused by a dispersant for Macondo surrogate oil in a mesocosm simulating a coastal microbial community. Marine Chemistry. 206, 34-43. Schwehr, K. A., Xu, C., Chiu, M., Zhang, S., Sun, L., Lin, P., ... Santschi, P. H. (2018). Protein: Polysaccharide ratio in exopolymeric substances controlling the surface tension of seawater in the presence or absence of surrogate Macondo oil with and without Corexit. Marine Chemistry. 206, 84-92. Xu, C., Zhang, S., Beaver, M., Lin, P., Sun, L., Doyle, S. M., ... Santschi, P. H. (2018). The role of microbially-mediated exopolymeric substances (EPS) in regulating Macondo oil transport in a mesocosm experiment. Marine Chemistry. 206, 52-61. Yeager, K. M., Schwehr, K. A., Schindler, K. J., & Santschi, P. H. (2018). Sediment accumulation and mixing in the Penobscot River and estuary, Maine. Science of the Total Environment. 635, 228-239. Sun, L., Chiu, M., Xu, C., Lin, P., Schwehr, K. A., Bacosa, H., ... Santschi, P. H. (2018). The effects of sunlight on the composition of exopolymeric substances and subsequent aggregate formation during oil spills. Marine Chemistry. 203, 49-54. Kamalanathan, M., Schwehr, K. A., Bretherton, L., Genzer, J., Hillhouse, J., Xu, C., ... Quigg, A. (2018). Diagnostic tool to ascertain marine phytoplankton exposure to chemically enhanced water accommodated fraction of oil using Fourier Transform Infrared spectroscopy. MARINE POLLUTION BULLETIN. 130, 170-178. Yeager, K. M., Schwehr, K. A., Louchouarn, P., Feagin, R. A., Schindler, K. J., & Santschi, P. H. (2018). Mercury inputs and redistribution in the Penobscot River and estuary, Maine. Science of the Total Environment. 622-623, 172-183. Lin, P., Xu, C., Xing, W., Sun, L., Kaplan, D. I., Fujitake, N., ... Santschi, P. H. (2018). Radionuclide uptake by colloidal and particulate humic acids obtained from 14 soils collected worldwide. Scientific Reports. 8(1), 4795. Santschi, P. H., Yeager, K. M., Schwehr, K. A., & Schindler, K. J. (2017). Estimates of recovery of the Penobscot River and estuarine system from mercury contamination in the 1960's. Science of the Total Environment. 596-597, 351-359. Santschi, P. H., Xu, C., Zhang, S., Schwehr, K. A., Grandbois, R., Kaplan, D. I., & Yeager, C. M. (2017). Iodine and plutonium association with natural organic matter: A review of recent advances. APPLIED GEOCHEMISTRY. 85, 121-127. Lin, P., Xu, C., Zhang, S., Fujitake, N., Kaplan, D. I., Yeager, C. M., ... Santschi, P. H. (2017). Plutonium Partitioning Behavior to Humic Acids from Widely Varying Soils Is Related to Carboxyl-Containing Organic Compounds. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 51(20), 11742-11751. Yeager, C. M., Amachi, S., Grandbois, R., Kaplan, D. I., Xu, C., Schwehr, K. A., & Santschi, P. H. (2017). Microbial Transformation of Iodine: From Radioisotopes to Iodine Deficiency. Adv Appl Microbiol. 101, 83-136. Lin, P., Xu, C., Zhang, S., Sun, L., Schwehr, K. A., Bretherton, L., Quigg, A., & Santschi, P. H. (2017). Importance of coccolithophoreassociated organic biopolymers for fractionating particlereactive radionuclides ( 234 Th, 233 Pa, 210 Pb, 210 Po, and 7 Be) in the ocean. JOURNAL OF GEOPHYSICAL RESEARCH-BIOGEOSCIENCES. 122(8), 2033-2045. Sun, L., Xu, C., Zhang, S., Lin, P., Schwehr, K. A., Quigg, A., ... Santschi, P. H. (2017). Light-induced aggregation of microbial exopolymeric substances. Chemosphere. 181, 675-681. Santschi, P. H., Xu, C., Zhang, S., Schwehr, K. A., Lin, P., Yeager, C. M., & Kaplan, D. I. (2017). Recent advances in the detection of specific natural organic compounds as carriers for radionuclides in soil and water environments, with examples of radioiodine and plutonium. J Environ Radioact. 171, 226-233. Xu, C., Zhang, S., Sugiyama, Y., Ohte, N., Ho, Y., Fujitake, N., ... Santschi, P. H. (2016). Role of natural organic matter on iodine and (239)(,240)Pu distribution and mobility in environmental samples from the northwestern Fukushima Prefecture, Japan. J Environ Radioact. 153, 156-166. Xu, C., Zhang, S., Kaplan, D. I., Ho, Y., Schwehr, K. A., Roberts, K. A., ... Santschi, P. H. (2015). Evidence for Hydroxamate Siderophores and Other N-Containing Organic Compounds Controlling (239,240)Pu Immobilization and Remobilization in a Wetland Sediment. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 49(19), 11458-11467. Chuang, C., Santschi, P. H., Wen, L., Guo, L., Xu, C., Zhang, S., ... Schumann, D. (2015). Binding of Th, Pa, Pb, Po and Be radionuclides to marine colloidal macromolecular organic matter. Marine Chemistry. 173, 320-329. Xu, C., Kaplan, D. I., Zhang, S., Athon, M., Ho, Y., Li, H., ... Santschi, P. H. (2015). Radioiodine sorption/desorption and speciation transformation by subsurface sediments from the Hanford Site. J Environ Radioact. 139, 43-55. Schwehr, K. A., Otosaka, S., Merchel, S., Kaplan, D. I., Zhang, S., Xu, C., ... ASTER Team. (2014). Speciation of iodine isotopes inside and outside of a contaminant plume at the Savannah River Site. Science of the Total Environment. 497-498, 671-678. Kaplan, D. I., Denham, M. E., Zhang, S., Yeager, C., Xu, C., Schwehr, K. A., ... Santschi, P. H. (2014). Radioiodine Biogeochemistry and Prevalence in Groundwater. CRITICAL REVIEWS IN ENVIRONMENTAL SCIENCE AND TECHNOLOGY. 44(20), 2287-2335. Zhang, S., Ho, Y., Creeley, D., Roberts, K. A., Xu, C., Li, H., ... Santschi, P. H. (2014). Temporal variation of iodine concentration and speciation (127I and 129I) in wetland groundwater from the Savannah River Site, USA. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 48(19), 11218-11226. Emerson, H. P., Xu, C., Ho, Y., Zhang, S., Schwehr, K. A., Lilley, M., ... Powell, B. A. (2014). Geochemical controls of iodine uptake and transport in Savannah River Site subsurface sediments. APPLIED GEOCHEMISTRY. 45, 105-113. Li, H., Daniel, B., Creeley, D., Grandbois, R., Zhang, S., Xu, C., ... Yeager, C. M. (2014). Superoxide production by a manganese-oxidizing bacterium facilitates iodide oxidation. Appl Environ Microbiol. 80(9), 2693-2699. Xu, C., Athon, M., Ho, Y., Chang, H., Zhang, S., Kaplan, D. I., ... Santschi, P. H. (2014). Plutonium immobilization and remobilization by soil mineral and organic matter in the far-field of the Savannah River Site, U.S. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 48(6), 3186-3195. Zhang, S., Xu, C., Creeley, D., Ho, Y., Li, H., Grandbois, R., ... Santschi, P. H. (2013). Response to comment on "Iodine-129 and iodine-127 speciation in groundwater at Hanford Site, U.S.: iodate incorporation into calcite". ENVIRONMENTAL SCIENCE & TECHNOLOGY. 47(22), 13205-13206. Zhang, S., Xu, C., Creeley, D., Ho, Y., Li, H., Grandbois, R., ... Santschi, P. H. (2013). Iodine-129 and iodine-127 speciation in groundwater at the Hanford site, US: iodate incorporation into calcite. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 47(17), 9635-9642. Quigg, A., Chin, W., Chen, C., Zhang, S., Jiang, Y., Miao, A., ... Santschi, P. H. (2013). Direct and Indirect Toxic Effects of Engineered Nanoparticles on Algae: Role of Natural Organic Matter. ACS SUSTAINABLE CHEMISTRY & ENGINEERING. 1(7), 686-702. Xu, C., Chen, H., Sugiyama, Y., Zhang, S., Li, H., Ho, Y., ... Santschi, P. H. (2013). Novel molecular-level evidence of iodine binding to natural organic matter from Fourier transform ion cyclotron resonance mass spectrometry. Science of the Total Environment. 449, 244-252. Zhang, S., Jiang, Y., Chen, C., Creeley, D., Schwehr, K. A., Quigg, A., Chin, W., & Santschi, P. H. (2013). Ameliorating effects of extracellular polymeric substances excreted by Thalassiosira pseudonana on algal toxicity of CdSe quantum dots. Aquatic Toxicology. 126, 214-223. Xu, C., Zhong, J., Hatcher, P. G., Zhang, S., Li, H., Ho, Y., ... Santschi, P. H. (2012). Molecular environment of stable iodine and radioiodine (129I) in natural organic matter: Evidence inferred from NMR and binding experiments at environmentally relevant concentrations. GEOCHIMICA ET COSMOCHIMICA ACTA. 97, 166-182. Zhang, S., Jiang, Y., Chen, C., Spurgin, J., Schwehr, K. A., Quigg, A., Chin, W., & Santschi, P. H. (2012). Aggregation, dissolution, and stability of quantum dots in marine environments: importance of extracellular polymeric substances. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 46(16), 8764-8772. Li, H., Yeager, C. M., Brinkmeyer, R., Zhang, S., Ho, Y., Xu, C., ... Santschi, P. H. (2012). Bacterial production of organic acids enhances H2O2-dependent iodide oxidation. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 46(9), 4837-4844. Xu, C., Miller, E. J., Zhang, S., Li, H., Ho, Y., Schwehr, K. A., ... Santschi, P. H. (2011). Sequestration and remobilization of radioiodine (129I) by soil organic matter and possible consequences of the remedial action at Savannah River Site. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 45(23), 9975-9983. Xu, C., Zhang, S., Ho, Y., Miller, E. J., Roberts, K. A., Li, H., ... Santschi, P. H. (2011). Is soil natural organic matter a sink or source for mobile radioiodine (129I) at the Savannah River Site?. GEOCHIMICA ET COSMOCHIMICA ACTA. 75(19), 5716-5735. Xu, C., Zhang, S., Chuang, C., Miller, E. J., Schwehr, K. A., & Santschi, P. H. (2011). Chemical composition and relative hydrophobicity of microbial exopolymeric substances (EPS) isolated by anion exchange chromatography and their actinide-binding affinities. Marine Chemistry. 126(1-4), 27-36. Otosaka, S., Schwehr, K. A., Kaplan, D. I., Roberts, K. A., Zhang, S., Xu, C., ... Santschi, P. H. (2011). Factors controlling mobility of 127I and 129I species in an acidic groundwater plume at the Savannah River Site. Science of the Total Environment. 409(19), 3857-3865. Zhang, S., Du, J., Xu, C., Schwehr, K. A., Ho, Y., Li, H., ... Santschi, P. H. (2011). Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 45(13), 5543-5549. Chen, C., Anaya, J. M., Zhang, S., Spurgin, J., Chuang, C., Xu, C., ... Chin, W. (2011). Effects of engineered nanoparticles on the assembly of exopolymeric substances from phytoplankton. PLoS One. 6(7), e21865-e21865. Li, H., Brinkmeyer, R., Jones, W. L., Zhang, S., Xu, C., Schwehr, K. A., ... Yeager, C. M. (2011). Iodide accumulation by aerobic bacteria isolated from subsurface sediments of a 129I-contaminated aquifer at the Savannah River site, South Carolina. Appl Environ Microbiol. 77(6), 2153-2160. Xu, C., Santschi, P. H., Hung, C., Zhang, S., Schwehr, K. A., Roberts, K. A., ... Wei, C. (2011). Controls of 234Th removal from the oligotrophic ocean by polyuronic acids and modification by microbial activity. Marine Chemistry. 123(1-4), 111-126. Kaplan, D. I., Roberts, K. A., Schwehr, K. A., Lilley, M. S., Brinkmeyer, R., Denham, M. E., ... Santschi, P. H. (2011). Evaluation of a radioiodine plume increasing in concentration at the Savannah River Site. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 45(2), 489-495. Zhang, S., Schwehr, K. A., Ho, Y., Xu, C., Roberts, K. A., Kaplan, D. I., ... Santschi, P. H. (2010). A novel approach for the simultaneous determination of iodide, iodate and organo-iodide for 127I and 129I in environmental samples using gas chromatography-mass spectrometry. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 44(23), 9042-9048. Hung, C., Xu, C., Santschi, P. H., Zhang, S., Schwehr, K. A., Quigg, A., ... Wei, C. (2010). Comparative evaluation of sediment trap and 234Th-derived POC fluxes from the upper oligotrophic waters of the Gulf of Mexico and the subtropical northwestern Pacific Ocean. Marine Chemistry. 121(1-4), 132-144. Xu, C., Santschi, P. H., Schwehr, K. A., & Hung, C. (2009). Optimized isolation procedure for obtaining strongly actinide binding exopolymeric substances (EPS) from two bacteria (Sagittula stellata and Pseudomonas fluorescens Biovar II). Bioresour Technol. 100(23), 6010-6021. Miao, A., Schwehr, K. A., Xu, C., Zhang, S., Luo, Z., Quigg, A., & Santschi, P. H. (2009). The algal toxicity of silver engineered nanoparticles and detoxification by exopolymeric substances. Environmental Pollution. 157(11), 3034-3041. Schwehr, K. A., Santschi, P. H., Kaplan, D. J., Yeager, C. M., & Brinkmeyer, R. (2009). Organo-iodine formation in soils and aquifer sediments at ambient concentrations. ENVIRONMENTAL SCIENCE & TECHNOLOGY. 43(19), 7258-7264. Schwehr, K. A., Santschi, P. H., Moran, J. E., & Elmore, D. (2005). Near-conservative behavior of 129I in the orange county aquifer system, California. APPLIED GEOCHEMISTRY. 20(8), 1461-1472. Schwehr, K. A., Santschi, P. H., & Elmore, D. (2005). The dissolved organic iodine species of the isotopic ratio of129I/127I: A novel tool for tracing terrestrial organic carbon in the estuarine surface waters of Galveston Bay, Texas. Limnology and Oceanography Methods. 3(8), 326-337. Santschi, P. H., & Schwehr, K. A. (2004). 129I/(127)I as a new environmental tracer or geochronometer for biogeochemical or hydrodynamic processes in the hydrosphere and geosphere: the central role of organo-iodine. Science of the Total Environment. 321(1-3), 257-271. Schwehr, K. A., & Santschi, P. H. (2003). Sensitive determination of iodine species, including organo-iodine, for freshwater and seawater samples using high performance liquid chromatography and spectrophotometric detection. Analytica Chimica Acta. 482(1), 59-71. conference paper Kaplan, D., Xu, C., Lin, P., Schwehr, K., Fujitake, N., Yeager, C., & Santschi, P. (2018). Soil organic matter and plutonium interactions. ACS National Meeting Book of Abstracts. Jiang, Y., Zhang, S., Chen, C., Creeley, D., Schwehr, K. A., Chin, W., Santschi, P. H., & Quigg, A. (2012). Effects of extracellular polymeric substances of Thalassiosira pseudonana and nitrogen-depletion on the fate of Cd/Se quantum dots. ACS National Meeting Book of Abstracts. Xu, C., Sugiyama, Y., Hatcher, P. G., Zhang, S., Li, H., Ho, Y., ... Santschi, P. H. (2012). Investigation of the radioiodine binding environment in terrestrial aquatic natural organic matter by FT-ICR-MS. ACS National Meeting Book of Abstracts. Kaplan, D. I., Brinkmeyer, R., Denham, M. E., Noonkester, J. V., Roberts, K. A., Schwehr, K. A., ... Santschi, P. H. (2010). Groundwater Iodine-129 speciation and its causes for release from a subsurface burial basin. GEOCHIMICA ET COSMOCHIMICA ACTA. A495-A495. Zhang, S., Du, J., Xu, C., Schwehr, K. A., Ho, Y., Santschi, P. H., & Kaplan, D. I. (2010). Mobility of iodine (I-129 and I-127) species in sediment columns from the Savannah River Site. GEOCHIMICA ET COSMOCHIMICA ACTA. A1211-A1211. Schwehr, K. A., Santschi, P. H., & Kaplan, D. I. (2009). Organo-iodine formation in aquifer sediments at ambient concentrations. GEOCHIMICA ET COSMOCHIMICA ACTA. A1187-A1187. Schwehr, K. A., Santschi, P. H., Moran, J. E., & Elmore, D. (2005). Near-conservative behavior of (129)Iodine in the Orange County Aquifer System, California. GEOCHIMICA ET COSMOCHIMICA ACTA. A721-A721.
education and training Ph.D. in Oceanography, Texas A&M University - (College Station, Texas, United States) 2004 M.S. in Geosciences, University of Houston - (Houston, Texas, United States) 1998 B.S. in Geophysical Engineering, Montana Tech of the University of Montana - (Butte, Montana, United States) 1982