Laodong Guo

Laodong Guo

  • Professor, School of Freshwater Sciences



Dr. Guo’s major research focus is on aquatic biogeochemistry, with an emphasis on the role of natural organic matter and nano-sized colloids in governing the fate, transport and bioavailability of chemical species, including trace metals, radionuclides, engineered nanoparticles, and legacy and emerging contaminants.  He received his Ph.D. degree in Chemical Oceanography in 1995 from Texas A&M University (TAMU), College Station.  After working as a postdoc and assistant research scientist at TAMUG, Dr. Guo joined University of Alaska-Fairbanks (UAF) in 2000 as a research professor in the International Arctic Research Center (IARC) and then University of Southern Mississippi (USM) in 2005 as a faculty member (tenured in 2006) in the Department of Marine Science.  Dr. Guo has been a professor in the School of Freshwater Sciences at the University of Wisconsin-Milwaukee since 2012.

Dr. Guo has authored/coauthored over 200 peer-reviewed publications in the fields of earth and environmental sciences, with an H-index of 62 based on Google Scholar or 51 based on Web of Science (Researcher ID: F-6045-2010). He currently serves as an editor of Journal of Oceanography (Springer), an associate editor of Frontiers in Environmental Science - Biogeochemical Dynamics (Frontiers), and an editorial board member of Scientific Reports (Nature), Water (MDPI), and Journal of  Marine Science and Engineering (MDPI).


  • PhD, Chemical Oceanography, Texas A&M University, 1995

Research Interests

  • Biogeochemical cycling of carbon, nutrients, and trace elements
  • Role of natural organic matter and nano-sized colloids in regulating the fate, transport, and toxicity/bioavailability of trace metals, engineered nanoparticles, and legacy/emerging contaminants
  • Microplastics and nanoplastics in freshwater environments
  • Physicochemical processes at the particle-water, biota-water, river-lake, and land-ocean interfaces
  • Biogeochemical consequences of climate and environmental changes

Recent and Selected Publications (or see detailed publication list here)

  • Abbott, B.W., Carey, J., Ernakovich, J., Frederick, J.M., Guo, L., and Others. We must stop fossil fuel emissions to protect permafrost ecosystems (mini review article). Frontiers in Environmental Science – Biogeochemical Dynamics, 10, 889428. doi: 10.3389/fenvs.2022.889428
  • Lin, H., Matsui, K., Newton, R.J. and Guo, L. Disproportionate changes in composition and molecular size spectra of dissolved organic matter between influent and effluent from a major metropolitan wasterwater treatment plant. ACS es&t Water, 2(1), 216–225.
  • Piyawardhana, P.N., Weerathunga, V.A., Chen, H.S., Guo, L., Ranatunga, K.P., and Hung, C.C. 2022. Occurrence of microplastics in commercial marine dried fish in Asian countries. Journal of Hazardous Materials, 423, 127093.
  • Liu, M.X., Han, X.K., Liu, C-Q, Guo, L., Ding, H. and Lang, Y.C. 2021. Differences in the spectroscopic characteristics of wetland dissolved organic matter binding with Fe3+, Cu2+, Cd2+, Cr3+ and Zn2+. Science of the Total Environment, 800, 149476.
  • Lin, H., Xu, H., Cai, Y. Belzile, C. Macdonald, R.W. and Guo, L. 2021. Dynamic changes in size-fractionated dissolved organic matter composition from the seasonally ice-covered Yukon River as characterized using fluorescence EEM-PARAFAC, FT-IR and data fusion. Limnology and Oceanography, 66, 3085-3099.
  • Wang, C.Y., Yang, Y., Yang, B., Lin, H., Miller, T.R., Newton, R.J., and Guo, L. 2021. Causal relationship between alkaline phosphatase activities and phosphorus dynamics in a eutrophic coastal lagoon in Lake Michigan. Science of the Total Environment, 787, 147681.
  • Yang, B., Lin, H., Bartlett, S.L., Houghton, E.M., Robertson, D.M. and Guo, L. 2021. Partitioning and transformation of organic and inorganic phosphorus among dissolved, colloidal and particulate phases in a hypereutrophic freshwater estuary. Water Research, 196, 117025.
  • O’Donnell, J.A., Douglas, T.A., Barker, A.J. and Guo, L. 2021. Changing Biogeochemical Cycles of Organic Carbon, Nitrogen, Phosphorus, and Trace Elements in Arctic Rivers. In “Arctic hydrology, permafrost and ecosystems” Chapter 11, 315-348, Springer.
  • O’Connor, J.A., Lu, K., Guo, L., Rosenheim, B.E., Liu, Z.F. 2020. Composition and lability of riverine dissolved organic matter: Insights from thermal slicing pyrolysis GC-MS , amino acid, and stable isotope analyses. Organic Geochemistry, 149, 104100.
  • Cai, Y.H., You, C.-F., Wu, S.-F., Cai, W.-J. and Guo, L. Seasonal variations in strontium and carbon isotope systematics in the Lower Mississippi River: Implications for chemical weathering. Chemical Geology, 553, 119810.
  • Lin, H and Guo, L. 2020. Variations in colloidal DOM composition with molecular weight within individual water samples as characterized by flow field-flow fractionation and EEM-PARAFAC analysis. Environ. Sci. Technol., 54(3), 1657-1667.
  • Lei, X.T., Zhang, H., Chen, M. Guo, L.D., Zhang, X.G., Jiang, Z.H., Blake, R. and Chen, Z.G. 2020. The effectivity of sequential extraction of phosphorus in soil and sediment: insights from the oxygen isotope of phosphate. Journal of Soils and Sediments, 20, 1332–1343.
  • Li, D., Xie, L., Carvan, M. and Guo, L. 2019. Mitigative effects of natural and model dissolved organic matter on the toxicity of methylmercury in embryonic Zebrafish. Environmental Pollution, 252, 616-626.
  • , X.T., Chen, M., Guo, L., Zhang, X.G., Jiang, Z.H., Chen, Z.G. 2019. Diurnal variations in the content and oxygen isotope composition of phosphate pools in a subtropical agriculture soil. Geoderma, 337, 863-870.
  • Xu, H., Lin, H. Jiang, H. and Guo, L. 2018. Dynamic molecular size transformation of aquatic colloidal organic matter as a function of pH and cations. Water Research, 144, 543-552.
  • Xu, H., Yan, M., Li, W., Jiang H. and Guo, L. 2018. Dissolved organic matter binding with Pb(II) as characterized by differential spectra and 2-D UV–FTIR heterospectral correlation analysis. Water Research, 144: 435-443.
  • Lin, P., Klump, J.V. and Guo, L. 2018. Variations in chemical speciation and reactivity of phosphorus between suspended-particles and surface-sediments in seasonal hypoxia-influenced Green Bay. Journal of Great Lakes Research, 44, 864-874.
  • Kteeba, S.M., El-Adawi , H.I., El-Rayis, O.A., El-Ghobashy, A.E., Sreevidya, V.S., Guo, L. and Svoboda, K.R. 2018. Exposure to ZnO nanoparticles alters neuronal and vascular development in zebrafish: Acute and transgenerational effects mitigated with dissolved organic matter. Environmental Pollution, 242: 433-448,
  • Xu, H., Xu, M., Li, Y., Liu, X., Guo, L. and Jiang, H. 2018. Characterization, origin and aggregation behavior of colloids in eutrophic shallow lake. Water Research, 142, 176–186.
  • Gao, L., Zhou, Z., Reyes, A. and Guo, L. 2018. Yields and characterization of dissolved organic matter from different-aged soils from northern Alaska. JGR-Biogeosciences, 123(7), 2035-2052.
  • Xu, H., Guan, D., Lin, H. and Guo, L. 2018. Contrasting effects of photochemical and microbial degradation on Cu(II) binding with fluorescent DOM from different origins. Environmental Pollution, 239, 205-214.
  • Baalousha, M., Afshinnia, K, and Guo, L. 2018. Natural organic matter composition determines the molecular nature of nanomaterial NOM-corona. Environmental Science: Nano, 5, 868-881.
  • Xu, H, and Guo, L. Intriguing changes in molecular size and composition of dissolved organic matter induced by microbial degradation and self-assembly. Water Research, 135, 187-194.
  • Yang, W. and Guo L. 2018. Sources and burial fluxes of soot black carbon in sediments on the Mackenzie, Chukchi, and Bering Shelves. Continental Shelf Research, 155, 1-10.
  • Xu, H., Houghton, E.M., Houghton, C.J., Guo, L. 2018. Variations in size and composition of colloidal organic matter in a negative freshwater estuary (Green Bay). Science of the Total Environment, 615, 931–941.
  • Dou, F. Ping, C.L., Li, X., Jorgenson, M.T., Guo, L., Chen, K., Michaelson, G. 2017. Soil organic carbon reactivity along the eroding coastline of Northern Alaska. Soil Science, 182(6), 227-232.
  • Kteeba, S.M., El-Adawi, H.I., El-Rayis, O.A., El-Ghobashy, A.E., Schuld, J.L., Svoboda, K.R., Guo, L. Zinc oxide nanoparticle toxicity in embryonic zebrafish: Mitigation with different natural organic matter. Environmental Pollution, 230, 1125–1140.
  • Welti, N., Striebel, M., Ulseth, A.J., Cross, W. F., DeVilbiss, S.E., Glibert, P.M., Guo, L., Hirst, A.G., Hood, J., Kominoski, J. S., MacNeill, K.L., Mehring, A.S., Welter, J. R., and Hillebrand, H. 2017. Bridging food webs, ecosystem metabolism, and biogeochemistry using ecological stoichiometry theory. Frontiers in Microbiology, 8, 01298.
  • Wang, W.H., Chen, M., Guo, L., Wang, W.X. 2017. Size partitioning and mixing behavior of trace metals and dissolved organic matter in a South China estuary. Science of the Total Environment, 603–604, 434–444.
  • Xu, H.C. and Guo, L. 2017. Molecular size-dependent abundance and chemical composition of dissolved organic matter in river, lake and sea waters. Water Research, 117, 115-126.
  • DeVilbiss, S.E. and Guo, L. 2017. Excretion of organic matter and nutrients from invasive quagga mussels and potential impact on carbon dynamics in Lake Michigan. Journal of Great Lakes Research, 43(3), 79-89.
  • Duan, S.W., He, Y., Kaushal, S., Bianchi, T.S., Ward, N., Guo, L. 2017. Impact of wetland decline on decreasing dissolved organic carbon concentration along the Mississippi River continuum. Frontiers in Marine Science, 3, doi: 10.3389/fmars.2016.0028

More publications can be found here.