Marjorie A.M. Friedrichs

Research Associate Professor of Marine Science

Email: [[marjy]]
Phone: (804) 684-7695
Office: Andrews Hall 337
Department: Biological Sciences

Education

• B.A., Middlebury College
• M.S., Massachusetts Institute of Technology/Woods Hole Oceanographic Institution
• Ph.D., Old Dominion University

Research Interests

My research program centers on the use of coupled biological-physical models and analyses of satellite and in-situ data to better understand how and why carbon and nitrogen cycling vary among diverse marine environments, in the past, present and future. Much of my current research is aimed at improving how key carbon-related processes are represented in coupled biological-physical models and examining how projected climate-related environmental changes will affect biogeochemical and ecosystem dynamics on continental shelves. By using climate projections to force our model scenarios, we can address a key source of uncertainty in future CO2 concentrations: carbon cycling on continental shelves. Ultimately our future scenario simulations will help us better understand how predicted environmental changes, such as increased levels of CO2, increased temperatures and changes in river runoff, will affect the interactions between coastal ocean carbon cycling, biogeochemical dynamics, and marine food webs.

Another focus of my research involves assessment of the relative skill of the many different biological/physical models currently being used in the oceanographic community. Do more complex models have more skill than the simplest models? Which ecosystem model structures are most geographically portable and able to perform well in diverse regions and physical settings? If such structures can be identified, and the reasons for their success understood, we will have taken a significant step toward ocean biogeochemical prediction. Another focus of my research program involves optimally combining data and models using data assimilation methods. Such methods have been applied to physical circulation models for decades, but have only relatively recently been applied to marine ecosystem models. Such methods are becoming increasingly important with the increased emphasis within the community of long-term ocean observing systems.

Current Projects

• Regional Ecosystem Modeling Testbed Project website (RTB)
• Primary Productivity Algorithm Round Robin (PPARR)
• U.S. Eastern Continental Shelf Carbon Cycling: Modeling, Data Assimilation and Analysis (USECoS)
• Glider Observations of Variability in the Ross Sea (GoVARS)

Selected Publications

• Friedrichs, M.A.M., Carr, M.-E., Barber, R., Scardi, M., Antoine, D., Armstrong, R.A., Asanuma,I., Behrenfeld, M.J., Buitenhuis, E.T., Chai, F., Christian, J.R., Ciotti, A.M., Doney, S.C., Dowell, M., Dunne, J., Gentili, B., Gregg, W., Hoepffner, N., Ishizaka, J., Kameda, T., Lima, I., Marra, J., Mélin, F., Moore, J.K., Morel, A., O'Malley, R.T., O'Reilly, J., Saba, V.S., Schmeltz, M., Smyth, T.J., Tjiputra, J., Waters, K., Westberry, T.K., Winguth, A., 2009. Assessing the uncertainties of model estimates of primary productivity in the tropical Pacific Ocean. Journal of Marine Systems, 76, doi:10.1016/j.marsys.2008.05.010. Download or Request Reprint.
• Gregg, W., M.A.M. Friedrichs, A. R. Robinson, K. Rose, R. Schlitzer, and K.R. Thompson, 2009. Skill assessment in ocean biological data assimilation. Journal of Marine Systems, 76, doi:10.1016/j.marsys.2008.05.010. Download or Request Reprint.
• Jolliff, J., J.C. Kindle, I. Shulman, B. Penta, M.A.M.Friedrichs, R.Helber, R.A. Arnone, 2009. Summary diagrams for coupled hydrodynamic-ecosystem model skill assessment. Journal of Marine Systems, 76, doi:10.1016/j.marsys.2008.05.014. Download or Request Reprint.
• Stow, C.A., J.K. Jolliff, D.J. McGillicuddy, Jr., S.C. Doney, M.A.M. Friedrichs, J.I. Allen, K.A Rose, and P. Wallhead, 2009. Skill Assessment for Coupled Biological/Physical Models of Marine Systems. Journal of Marine Systems, 76, doi:10.1016/j.marsys.2008.03.011. Download or Request Reprint.
• Hofmann, E. E., J.-N. Druon, K. Fennel, M.A.M. Friedrichs, D. Haidvogel, C. Lee, A. Mannino, C. McClain, R. Najjar, J. Siewert, J. OReilly, D. Pollard, M. Previdi, S. Seitzinger, S. Signorini, J. Wilkin, 2008. Eastern U.S. Continental Shelf Carbon Budget: Integrating Models, Data Assimilation, and Analysis, Oceanography, 21 (1): 86-104. Download or Request Reprint.
• Friedrichs, M.A.M., J. Dusenberry, L. Anderson, R. Armstrong, F. Chai, J. Christian, S.C. Doney, J. Dunne, M. Fujii, R. Hood, D. McGillicuddy, K. Moore, M. Schartau, Y. H. Sptiz, J. Wiggert, 2007. Assessment of skill and portability in regional marine biogeochemical models: role of multiple phytoplankton groups. Journal of Geophysical Research, 112, CO8001, doi:10.1029/2006JC003852. Download or Request Reprint.
• Carr, M.-E., M.A.M. Friedrichs and the PPARR3 team, 2006. A comparison of global estimates of marine primary production from ocean color. Deep-Sea Research II, 53: 741-770. Download or Request Reprint.
• Friedrichs, M.A.M., R. Hood, and J. Wiggert, 2006. Ecosystem model complexity versus physical forcing: Quantification of their relative impact with assimilated Arabian Sea data. Deep-Sea Research II, 53: 576-600. Download or Request Reprint.
• Hood, R., E. Laws, K. Moore, R. Armstrong, N. Bates, C. Carlson, F. Chai, S. Doney, P. Falkowski, D. Feely, M. Friedrichs, M. Landry, R. Letelier, D. Nelson, T. Richardson, B. Salihoglu, J. Wiggert, and M. Schartau, 2006. Functional group modeling: progress, challenges and prospects. Deep-Sea Research II, 53: 459-512. Download or Request Reprint.
• Friedrichs, M.A.M., 2002. Assimilation of SeaWiFS and JGOFS EqPac data into a marine ecosystem model of the central equatorial Pacific. Deep-Sea Research II, 49: 289-319. Download or Request Reprint.
• Hofmann E.E., and Friedrichs M.A.M., 2002. Predictive modeling for marine ecosystems. In: Robinson, A.R.; McCarthy, J.J.; Rothschild B.J. (eds.), The Sea, Volume 12: Biological-Physical Interactions in the Ocean, John Wiley and Sons, Inc., NY, pp. 537-565. Request Reprint.
• Doney, S.C., I. Lima, K. Lindsay, J.K. Moore, S. Dutkiewicz, M.A.M. Friedrichs, and R. Matear, 2001. Marine biogeochemical modeling. Oceanography, 14 (4): 93-107. Download or Request Reprint.
• Friedrichs, M.A.M., 2001. A data-assimilative marine ecosystem model of the central equatorial Pacific: numerical twin experiments. Journal of Marine Research, 59: 859-894. Download or Request Reprint.
• Friedrichs, M.A.M., and E.E. Hofmann, 2001. Physical control of biological processes in the central equatorial Pacific. Deep-Sea Research I, 48: 1023-1069. Download or Request Reprint.
• Hofmann, E.E., and M.A.M. Friedrichs, 2001. Biogeochemical data assimilation. In: J.H. Steele, S.A. Thorpe, and K.K. Turekian (eds.) Encyclopedia of Ocean Sciences Vol. 1, pp. 302-308. London, UK: Academic Press. Request Reprint.

Professional Memberships

• American Society of Limnology and Oceanography (ASLO)
• American Geophysical Union (AGU)