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  Department of Marine Science | Dr. Steven Lohrenz
Dr. Steven Lohrenz
Dr. Steven Lohrenz

Chair and Professor of Marine Science
Department of Marine Science
1020 Balch Blvd.
Stennis Space Center, MS 39529-9904
phone: 228-688-3177
fax: 228-688-1121
steven.lohrenz@usm.edu

Additional information about courses and research can be found at my personal home page.

EDUCATION

  • Ph.D., Biological Oceanography, Massachusetts Institute of Technology--Woods Hole Oceanographic Institution, 1985
  • B.A., Biology and Chemistry, University of Oregon (Eugene), 1978

RESEARCH INTERESTS

  • Application of remote sensing, in situ optical measurements and models for description of primary production and phytoplankton distributions
  • Optical assessment of air-sea carbon fluxes in river-dominated margins
  • Optical detection and assessment of harmful algal blooms
  • Characterization of biogeochemical constituents and their effects on optical properties in aquatic environments
  • Fine-scale distributions of photosynthetic pigments and associated microbial biomass and activity
  • Production, transformation and transport of organic matter in coastal ecosystems
  • Microbial cycling of nutrients and dissolved organic matter
  • Interrelationships among biological and physical dynamics at oceanic frontal regions
  • Single-cell techniques for characterization of growth and photosynthetic processes in phytoplankton
  • Radioisotopic tracing of algal physiological state and biochemical composition
  • Protein and nucleic acid metabolism in unicellular algae

COURSES

        This course is intended as a comprehensive overview of estuarine processes including physics, chemistry, biology and the impact of human activities. The importance of individual processes in regulating estuarine properties will be illustrated through comparison of different ecosystems.

Special Topics - Microbial Dynamics (MAR 682)
Special Topics - Environmental Biochemistry (MAR 682)

        This is an upper level introduction to marine bio-optics. The course initially covers definitions and basic principles of optics, a toolbox if you will, that is required to discuss more advanced concepts. The first half of the course deals primarily with optics, and the second half covers the application of optics for the study of biological problems, i.e., bio-optics.

        This course will explore current concepts in biological oceanography through a combination of lectures and discussions, relying on past and current scientific literature as source of information. Interactions between biological processes and physical, chemical and geochemical oceanography will be examined.

SELECTED PUBLICATIONS

Lohrenz, S.E., Redalje, D.G., Cai, W.-J., Acker, J., Dagg, M.J., 2007. A Retrospective Analysis of Nutrients and Phytoplankton Productivity in the Mississippi River Plume. Continental Shelf Research, in press.

Cai, W.-J., Guo, X., Chen, C.-T.A., Dai, M., Zhang, L., Zhai, W., Lohrenz, S.E., Yin, K., Harrison, P.J., Wang, Y., 2007. A comparative overview of weathering intensity and HCO3- flux in the world’s major rivers with emphasis on the Changjiang, Huanghe, Zhujiang (Pearl) and Mississippi Rivers. Continental Shelf Research, in press.

Green, R.E., Breed, G.A., Dagg, M.J., Lohrenz, S.E., 2007. Modeling planktonic response to variable nitrate loading in the Mississippi River plume Continental Shelf Research, in press.

Lohrenz, S. E., and W. J. Cai (2006), Satellite ocean color assessment of air-sea fluxes of CO2 in a river-dominated coastal margin, Geophys. Res. Lett., 33, doi:10.1029/2005GL023942.

Craig, S.E., Lohrenz, S.E., Lee, Z.P., Kirkpatrick, G.J., Schofield, O.M., Steward, R.G. (2006). Use of hyperspectral remote sensing reflectance for detection and assessment of Karenia brevis blooms. Applied Optics, 45(21), 5414-5425.

Schofield, O., J. Kerfoot, K. Mahoney, M. Moline, M. Oliver, S. Lohrenz, G. Kirkpatrick (2006), Vertical migration of the toxic dinoflagellate Karenia brevis and the impact on ocean optical properties. Journal of Geophysical Research, Vol. 111, C06009, doi:10.1029/2005JC003115.

Cai, W. J., and S. E. Lohrenz (2005), Carbon, Nitrogen, and Phosphorus Fluxes from the Mississippi River and the Transformation and Fate of Biological Elements in the River Plume and the Adjacent Margin, in Carbon and nutrient fluxes in continental margins: a global synthesis , edited by K. K. Liu, et al., Springer-Verlag, NY.

Bergmann, T., G. Fahnenstiel, S. Lohrenz, D. Millie, and O. Schofield (2004), Impacts of a recurrent resuspension event and variable phytoplankton community composition on remote sensing reflectance, J. Geophys. Res.-Oceans, 109, doi:10.1029/2002JC001575.

Campbell, J., D. Antoine, R. Armstrong, K. Arrigo, W. Balch, R. Barber, M. Behrenfeld, R. Bidigare, J. Bishop, M. E. Carr, W. Esaias, P. Falkowski, N. Hoepffner, R. Iverson, D. Kiefer, S. Lohrenz, J. Marra, A. Morel, J. Ryan, V. Vedernikov, K. Waters, C. Yentsch, and J. Yoder (2002), Comparison of algorithms for estimating ocean primary production from surface chlorophyll, temperature, and irradiance, Glob. Biogeochem. Cycle , 16 , art. no.-1035.

Dagg, M., R. Benner, S. Lohrenz, and D. Lawrence (2004), Transformation of dissolved and particulate materials on continental shelves influenced by large rivers: plume processes, Cont. Shelf Res. , 24 , 833-858.

Fahnenstiel, G. L., S. E. Lohrenz, and R. Stone (2002), Standard Niskin and Van Dorn bottles inhibit phytoplankton photosynthesis in Lake Michigan, Verh. Internat. Verein. Limnol. , 28 , 376-380.

Kerfoot, J., G. Kirkpatrick, S. Lohrenz, K. Mahoney, M. Moline, and O. Schofield (2003), Vertical migration of a Karenia brevis bloom: implications for remote sensing of harmful algal blooms, Journal of Phycology , in review .

Lohrenz, S. E. (2003), Biological Oceanography, in Water: Science and Issues , edited by E. J. Dasch, pp. 157-159, Macmillan Reference USA, New York.

Lohrenz, S. E., C. L. Carroll, A. D. Weidemann, and M. Tuel (2003), Variations in phytoplankton pigments, size structure and community composition related to wind forcing and water mass properties on the North Carolina inner shelf, Cont. Shelf Res. , 23 , 1447-1464.

Lohrenz, S. E., G. L. Fahnenstiel, D. F. Millie, O. M. E. Schofield, T. Johengen, and T. Bergmann (2004), Spring phytoplankton photosynthesis, growth, and primary production and relationships to a recurrent coastal sediment plume and river inputs in southeastern Lake Michigan, J. Geophys. Res.-Oceans , 109 (C10S15), doi:10.1029/2002JC001575.

Lohrenz, S. E., D. G. Redalje, P. G. Verity, C. N. Flagg, and K. V. Matulewski (2002), Primary production on the continental shelf off Cape Hatteras, North Carolina, Deep-Sea Res. Part II-Top. Stud. Oceanogr. , 49 , 4479-4509.

Lohrenz, S. E., and P. G. Verity (2004), Chapter 6, Regional Oceanography: Southeastern United States and Gulf of Mexico (2,W), in The Sea, Vol. 14, The Global Coastal Ocean: Interdisciplinary Regional Studies And Syntheses , edited by A. R. Robinson and K. H. Brink, p. in press, Harvard Press, Cambridge.

Lohrenz, S. E., A. D. Weidemann, and M. Tuel (2003), Phytoplankton spectral absorption as influenced by community size structure and pigment composition, Journal of Plankton Research , 25 , 35-61.

Mahoney, K. L. (2003), Backscattering of light by Karenia brevis and implications for optical detection and monitoring, Ph.D. thesis, 135 pp, The University of Southern Mississippi, Hattiesburg, MS.

Mahoney, K. L., S. E. Lohrenz, and G. J. Kirkpatrick (2002), Backscattering properties of Karenia brevis , paper presented at Ocean Optics XVI, Santa Fe, New Mexico, November 18-22, 2002.

Millie, D. F., G. L. Fahnenstiel, H. J. Carrick, S. E. Lohrenz, and O. M. E. Schofield (2002), Spatial variation in Lake Michigan phytoplankton composition during sediment resuspension events, Internationale Vereinigung für Theoretische und Angewandte Limnologie: Verhandlungen , 28 , 1216-1220.

Millie, D. F., G. L. Fahnenstiel, S. E. Lohrenz, H. J. Carrick, T. H. Johengen, and O. M. E. Schofield (2003), Physical-biological coupling in southern Lake Michigan: Influence of episodic sediment resuspension on phytoplankton, Aquatic Ecology , 37 , 393-408.

Millie, D. F., G. L. Fahnenstiel, S. E. Lohrenz, H. J. Carrick, and O. M. E. Schofield (2002), Phytoplankton pigments in coastal Lake Michigan: Distributions during the spring isothermal period and relation with episodic sediment resuspension, Journal of Phycology , 38 , 1-11.

Redalje, D. G., S. E. Lohrenz, P. G. Verity, and C. N. Flagg (2002), Phytoplankton dynamics within a discrete water mass off Cape Hatteras, North Carolina: the Lagrangian experiment, Deep-Sea Res. Part II-Top. Stud. Oceanogr. , 49 , 4511-4531.

Verity, P. G., D. G. Redalje, S. R. Lohrenz, C. Flagg, and R. Hristov (2002), Coupling between primary production and pelagic consumption in temperate ocean margin pelagic ecosystems, Deep-Sea Res. Part II-Top. Stud. Oceanogr. , 49 , 4553-4569.

Lohrenz, S. E., A. D. Weidemann, and M. Tuel (2000), A novel theoretical approach to correct for pathlength amplification and variable sampling loading in measurements of particulate spectral absorption by the quantitative filter technique, Journal of Plankton Research , 22 , 639-657.