GFDL - Geophysical Fluid Dynamics Laboratory

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Ryan R. Rykaczewski

Ryan Rykaczewski, Nippon Foundation

Assistant Professor

Marine Science Program
Department of Biological Sciences
University of South Carolina
715 Sumter St.
Columbia, SC  29208    USA

Phone: +1-803-777-8159
E-mail: ryk (at) 
In collaboration with the Nereus Program and Princeton University/GFDL Climate and Ecosystems: John Dunne, Charlie Stock, and Jorge Sarmiento

CV:  pdf

Research Interests

I am interested in exploring the responses of ecosystem and fisheries production to past and future climate variability and climate change. This research involves consideration of theory, observations, and models.  Currently, I investigate the biogeochemical implications of changes in physical climate that are particularly robust in the projections of atmosphere-ocean general circulation models (e.g., meridional shifts in zonal winds, increases in ocean stratification, and changes in phenology). In the past, changes in primary production, carbon export, the structure of food webs, and fisheries have often correlated with simple physical climate measures such as SST. However, these relationships rarely reflect an understanding of the actual mechanisms relating the environment to the physics. My recent research questions whether reliance on past correlations is appropriate for prediction of future conditions; the empirical relationships between biological and physical processes may differ as the earth system is perturbed in a manner not observed over the past century.

Key areas of interest:

  • mechanisms of fisheries-climate interactions
  • atmospheric forcing of marine biogeochemistry (e.g., oxygen, pH, nutrient cycling) and ecosystems
  • size spectra of phytoplankton and zooplankton communties; size-structured interactions
  • large-scale and long-term changes to marine environments
  • nonlinear relationships between physics and ecosystems
  • dynamics of upwelling systems, eastern boundary currents, and small pelagic fish populations
  • ecology of marine zooplankton; mediation of trophic transfers (physics-chemistry-phytoplankton-zooplankton-fish)


Ph.D. Oceanography Scripps Institution of Oceanography, University of California, San Diego. La Jolla, CA. Advisor: Dr. David M. Checkley, Jr.
Marine Science and Biology          (with Chemistry minor) University of Miami. Coral Gables, FL. Advisor: Dr. Donald B. Olson.

Graduate Research Program at USC

My group at the University of South Carolina is actively recruiting prospective graduate students an postdoctoral researchers who are interested in the responses of marine ecosystems to climate variability and change.  Please contact me by email at ryk (at) to discuss opportunities.  Graduate appointments are available in both the School of the Earth, Ocean, and Environment and the Department of Biological Sciences.

Upcoming Meetings

2014 - Ocean Sciences Meeting
Honolulu, HI
Mesoscale ocean processes and their representation in earth system models

Mehmet Ilicak, Ryan R. Rykaczewski, Nikolai Maximenko, Ali Belmadani, and Detlef Stammer


García-Reyes, M, WJ Sydeman, BB Black, RR Rykaczewski, DS Schoeman, SA Thompson, and SJ Bograd. 2013. Relative influence of oceanic and terrestrial pressure systems in driving upwelling-favorable winds. Geophys. Res. Lett. doi:10.1002/2013GL057729. Link.

Osterblom, H, A Merrie, M Metian, W Boonstra, T Blenckner, K Watson, RR Rykaczewski, Y Ota, J Sarmiento, V Christensen, M Schlueter, S Birnbaum, B Gustavsson, C Humborg, C-M Morth, B Muller-Karulis, M Tomczak, M Troel, C Folke. Modeling social-ecological scenarios in marine systems. BioScience 63:735-744. doi:10.1525/bio.2013.63.9.9. Link.

García-Reyes, M, WJ Sydeman, SA Thompson, BA Black, RR Rykaczewski, JA Thayer, and SJ Bograd. 2013. Integrated assessment of wind effects on Central California’s pelagic ecosystem. Ecosystems, doi:10.1007/s10021-013-9643-6. Link.

Beaulieu, C, SA Henson, JL Sarmiento, JP Dunne, SC Doney, RR Rykaczewski, and L Bopp. 2013. Factors challenging our ability to detect long-term trends in ocean chlorophyll. Biogeosciences 10:2711-2724, doi:10.5194/bg-10-2711-2013. Link.

Hazen, EL, E Jorgensen, RR Rykaczewski, SJ Bograd, DG Foley, ID Jonsen, SA Shaffer, JP Dunne, DP Costa, LB Crowder, and BA Block. 2012. Predicted habitat shifts of Pacific top predators in a changing climate. Nat. Clim. Change 3:234-238. doi:10.1038/nclimate1686. Link.

Sydeman, WJ, SA Thompson, JA Santora, JC Field, WT Peterson, RA Tanasichuk, HJ Freeland, SJ Bograd, and RR Rykaczewski. 2011. Does positioning of the North Pacific Current affect downstream ecosystem productivity? Geophys. Res. Lett. 38:L12606, doi:10.1029/2011GL047212. Link. Copy.

Rykaczewski, RR and JP Dunne. 2011. A measured look at ocean chlorophyll trends. Nature 472:E5-E6 doi:10.1038/nature09952 [A comment arising from DG Boyce et al. Nature 466:591-296 (2010)]. Link. Copy. Discussion.

Decima, M, MR Landry, and RR Rykaczewski. 2011. Broad-scale patterns in mesozooplankton biomass and grazing in the eastern equatorial Pacific. Deep-Sea Res. II. 58:387-399, doi:10.1016/j.dsr2.2010.08.006. Link.

Stock, CA, MA Alexander, NA Bond, K Brander, WWL Cheung, EN Curchitser, TL Delworth, JP Dunne, SM Griffies, MA Haltuch, JA Hare, AB Hollowed, P Lehodey, SA Levin, JS Link, KA Rose, RR Rykaczewski, JL Sarmiento, RJ Stouffer, FB Schwing, GA Vecchi, FE Werner. 2011. On the use of IPCC-class models to assess the impact of climate on living marine resources. Prog. Oceanogr. 88:1-27, doi:10.1016/j.pocean.2010.09.00. Link. Copy.

Rykaczewski, RR and JP Dunne. 2010. Enhanced nutrient supply to the California Current Ecosystem with global warming and increased stratification in an earth system model. Geophys. Res. Lett. 37:L21606, doi:10.1029/2010GL045019. Link. Copy.

Rykaczewski, RR and DM Checkley. 2008. Influence of ocean winds on the pelagic ecosystem in upwelling regions. Proc. Nat. Acad. Sci. USA. 105:1965-1970. Link. Copy.

Rykaczewski BONGO tow for zooplankton, CCE-LTER, CalCOFI
BONGO towing for zooplankton
Photo courtesy of Andrew L. King