Oceanography The Official Magazine of
The Oceanography Society
Volume 21 Issue 04

View Issue TOC
Volume 21, No. 4
Pages 90 - 107

Why is the Northern End of the California Current System So Productive?

Barbara M. Hickey Neil S. Banas
Article Abstract

Although scientists have long believed that, in an eastern boundary current system, alongcoast wind stress is responsible for the upwelling of deep nutrients that initiates phytoplankton blooms, the California Current System (CCS) presents a challenge to this idea. Seasonally averaged chlorophyll concentrations are several times higher along the Washington/southern British Columbia coast than off northern California, where alongcoast wind stress is several times greater. The high chlorophyll concentration is reflected in higher trophic levels, such as zooplankton and fish density in the northern CCS. This article discusses potential reasons for this apparent paradox. The analysis suggests that the northern CCS has several mechanisms that can produce upwelled nutrient concentrations comparable to those in regions with much greater wind stress, including a persistent nutrient supply through the dynamics of the Strait of Juan de Fuca and local upwelling enhancement by submarine canyons. Large-scale upwelling resulting from coastal-trapped waves forced in the areas with stronger wind stress is also likely an important factor, as is iron input by the Columbia River. In addition, in contrast to other parts of the CCS, the high-productivity northern latitudes have numerous physical features that give phytoplankton blooms time to develop fully and to be retained on the shelf, including wide shelves, coastlines without large capes, a large bank, wind intermittency, and density fronts related to the Columbia River.


Hickey, B.M., and N.S. Banas. 2008. Why is the northern end of the California Current System so productive? Oceanography 21(4):90–107, https://doi.org/10.5670/oceanog.2008.07.


Allen, S.E. 1996. Topographically generated, subinertial flows within a finite length canyon. Journal of Physical Oceanography 26:1,608–1,632.

Allen, J.S., P.A. Newberger, and J. Frederiuk. 1995. Upwelling circulation on the Oregon Continental Shelf. Part I. Response to idealized forcing. Journal of Physical Oceanography 25:1,843–1,866.

Bakun, A. 1973. Coastal upwelling indices, west coast of North America, 1946–71. NOAA Technical Report NMFS Special Scientific Report, Fisheries-671, US Dept. of Commerce, Washington DC. 103 pp.

Banas, N.S., E.J. Lessard, R.M. Kudela, P. MacCready, T.D. Peterson, B.M. Hickey, and E. Frame. In review. Planktonic growth and grazing in the Columbia River plume region: A biophysical model study.

Banas, N.S., P. MacCready, and B.M. Hickey. 2008. The Columbia River plume as cross-shelf exporter and along-coast barrier. Continental Shelf Research doi:10.1016/j.csr.2008.03.011.

Barnes, C.A., A.C. Duxbury, and B.-A. Morse. 1972. Circulation and selected properties of the Columbia River effluent at sea. Pp. 5–80 in The Columbia River Estuary and Adjacent Ocean Waters, A.T. Pruter and D.L. Alverson, eds., University of Washington Press, Seattle, WA.

Barth, J.A., and R.L. Smith. 1996. Separation of a coastal upwelling jet and pathways for cross-shelf exchange: A Lagrangian perspective. Eos Transactions, American Geophysical Union, Ocean Sciences Meeting Supplement 77(3):130, OS130.

Barth, J.A., B.A. Menge, J. Lubchenco, F. Chan, J.M. Bane, A.R. Kirincich, M.A. McManus, K.J. Nielsen, S.D. Pierce, and L. Washburn. 2007. Delayed upwelling alters nearshore coastal ocean ecosystems in the Northern California Current. Proceedings of the National Academy of Sciences of the United States of America 104(10):3,719–3,724.

Battisti, D., and B.M. Hickey. 1984. Application of remote wind-forced coastal trapped wave theory to the Oregon and Washington coasts. Journal of Physical Oceanography 14(5):887–903.

Botsford, L.W., C.A. Lawrence, E.P. Dever, A. Hastings, and J.L. Largier. 2006. Effects of variable winds on biological productivity on continental shelves in coastal upwelling systems. Deep-Sea Research Part II 53(25–26):3,116–3,140: doi:10.1016/j.dsr2.2006.07.011.

Bruland, K.W., M.C. Lohan, A.M. Aguilar-Islas, G.J. Smith, B. Sohst, and A. Baptista. 2008. Factors influencing the chemistry of the near-field Columbia River Plume: Nitrate, silicic acid, dissolved Fe and dissolved Mn. Journal of Geophysical Research doi:10.1029/2007JC004702.

Chase, Z., B. Hales, and T. Cowles. 2005. Distribution and variability of iron input to Oregon waters during the upwelling season. Journal of Geophysical Research 110(C10S12): doi:10.1029/2004JC002590.

Conomos, T.J., M.G. Gross, C.A. Barnes, and F.A. Richards. 1972. River-ocean nutrient relations in summer. Pp. 151–175 in The Columbia River Estuary and Adjacent Ocean Waters, A.T. Pruter and D.L. Alverson, eds, University of Washington Press, Seattle, WA.

Crawford, W.R., and R.K. Dewey. 1989. Turbulence and mixing: Sources of nutrients on the Vancouver Island continental shelf. Atmosphere–Ocean 27(2):428–442.

Denman, K.L., D.L. Mackas, H.J. Freeland, M.J. Austin, and S.H. Hill. 1981. Persistent upwelling and mesoscale zones of high productivity off the west coast of Vancouver Island, Canada. Pp. 514–521 in Coastal Upwelling. F.A. Richards, ed., American Geophysical Union, Washington, DC.

Dugdale, R.C., F.P. Wilkerson, A. Marchi, and V.E. Hogue. 2006. Nutrient controls on new production in the Bodega Bay, California, coastal upwelling plume. Deep-Sea Research Part II 53(25–26):3,049–3,062: doi:10.1016/j.dsr2.2006.07.009.

Fisher, J., A. Ammann, J. Orsi, J. Piccolo, M. Trudel, C. Bucher, J. Harding, J. Morris, R. Brodeur, E. Casillas, and others. 2007. Regional comparisons of distribution and abundance of juvenile salmon along the West Coast of North America. American Fishery Society Symposium 57:31–80.

Foreman, M.G.G., W. Callendar, A. MacFadyen, B.M. Hickey, R.E. Thompson, and E. Di Lorenzo. 2008. Modeling the generation of the Juan de Fuca Eddy. Journal of Geophysical Research 113(C03006): doi:10.1029/2006JC004082.

Freeland, H.J., and K.L. Denman. 1982. A topographically controlled upwelling center off southern Vancouver Island. Journal of Marine Research 40:1,069–1,093.

Gan, J., and J.S. Allen. 2005. Modeling upwelling circulation off the Oregon coast. Journal of Geophysical Research 110(C10S07): doi:10.1029/2004JC002692.

Garcia-Berdeal, I., B.M. Hickey, and M. Kawase. 2002. Influence of wind stress and ambient flow on a high discharge river plume. Journal of Geophysical Research 107(C9):3,130: doi:10/1029/2001JC000932

Geier, S.L., B.M. Hickey, S.R. Ramp, P.M. Kosro, N.B. Kachel, and F. Bahr. 2006. Interannual variability in water properties and velocity in the U.S. Pacific Northwest coastal zone. Eos Transactions, American Geophysical Union, Ocean Sciences Meeting Supplement 87(36):121, OS36D-23.

Hales, B., J.N. Moum, P. Covert, and A. Perlin. 2005. Irreversible nitrate fluxes due to turbulent mixing in a coastal upwelling system. Journal of Geophysical Research 110(C10S11): doi:10.1029/2004JC002685.

Henson, S.A., and A.C. Thomas. 2007. Phytoplankton scales of variability in the California Current system: 2. Latitudinal variability. Journal of Geophysical Research 112(C07018): doi:10.1029/2006JC004040.

Hickey, B.M. 1979. The California Current system—Hypotheses and facts. Progress in Oceanography 8:191–279.

Hickey, B.M. 1989. Patterns and processes of shelf and slope circulation. Pp. 41–115 in Coastal Oceanography of Washington and Oregon. M.R. Landry and B.M. Hickey, eds, Elsevier Science, Amsterdam, The Netherlands.

Hickey, B.M. 1997. Response of a narrow submarine canyon to strong wind forcing. Journal of Physical Oceanography 27(5):697–726.

Hickey, B.M. 1998. Coastal Oceanography of Western North America from the tip of Baja California to Vancouver Island. Pp. 345–393 in The Sea, Volume 11. K.H. Brink and A.R. Robinson, eds., Wiley and Sons, Inc., New York, NY.

Hickey, B.M., and N.S. Banas. 2003. Oceanography of the Pacific Northwest coastal ocean and estuaries with application to coastal ecosystems. Estuaries 26(48):1,010–1,031.

Hickey, B., S. Geier, N. Kachel, and A. MacFadyen. 2005. A bi-directional river plume: The Columbia in summer. Continental Shelf Research 25(14):1,631–1,656.

Hickey, B., A. MacFadyen, W. Cochlan, R. Kudela, K. Bruland, and C. Trick. 2006. Evolution of chemical, biological and physical water properties in the northern California current in 2005: Remote or local wind forcing? Geophysical Research Letters 33(L22S02): doi:10.1029/2006GL026782.

Hickey, B.M., R. McCabe, S. Geier, E. Dever, and N. Kachel. 2008. Three interacting freshwater plumes in the northern California Current System. Journal of Geophysical Research doi: 10.1029/2008JC004907.

Hickey, B.M., R.E. Thomson, H. Yih, and P.H. LeBlond. 1991. Velocity and temperature fluctuations in a buoyancy-driven current off Vancouver Island. Journal of Geophysical Research 96(C6):10,507–10,538.

Hill, E.D., B.M. Hickey, F.A. Shillington, P.T. Strub, E.D. Barton, and K. Brink. 1998. Eastern Boundary Current Systems of the World. Pp. 21–62 in The Sea, Volume 12. K.H. Brink and A.R. Robinson, eds, Wiley and Sons, Inc., New York, NY.

Hutchins, D.A., and K.W. Bruland. 1998. Iron-limited diatom growth and Si:N uptake ratios in a coastal upwelling regime. Nature 393:561–564.

Huyer, A. 1983. Coastal upwelling in the California Current system. Progress in Oceanography 12(3):259–284.

Huyer, A., J.H. Fleischbein, J. Keister, P.M. Kosro, N. Perlin, R.L. Smith, and P. Wheeler. 2005. Two coastal upwelling domains in the northern California Current system. Journal of Marine Research 63:901–929.

Huyer, A., E.J.C. Sobey, and R.L. Smith. 1979. The spring transition in currents over the Oregon continental shelf. Journal of Geophysical Research 84(C11):6,995–7,011.

Kudela, R.M., N. Garfield, and K.W. Bruland. 2006. Bio-optical signatures and biogeochemistry from intense upwelling and relaxation in coastal California. Deep-Sea Research Part II 53(25–26):2,999–3,022: doi:10.1016/j.dsr2.2006.07.010.

Landry, M.R., J.R. Postel, W.K. Peterson, and J. Newman. 1989. Broad-scale patterns in the distribution of hydrographic variables. Pp. 1–41 in Coastal Oceanography of Washington and Oregon. M.R. Landry and B.M. Hickey, eds., Elsevier Press, Amsterdam, The Netherlands.

Legaard, K., and A.C. Thomas. 2006. Spatial patterns of seasonal and interannual variability in chlorophyll and surface temperature in the California Current. Journal of Geophysical Research 111(C06032): doi:10.1029/2005JC003282.

Lentz, S.J. 1992. The surface boundary layer in coastal upwelling regions. Journal of Physical Oceanography 22(12):1,517–1,539.

MacCready, P., N.S. Banas, B.M. Hickey, E.P. Dever, and Y. Liu. 2008. A model study of tide- and wind-induced mixing in the Columbia River estuary andplume. Continental Shelf Research: doi:10.1016/j.csr.2008.03.015.

MacFadyen, A., B.M. Hickey, and M.G.G. Foreman. 2005. Transport of surface waters from the Juan de Fuca Eddy region to the Washington coast: Implications for HABs. Continental Shelf Research 25(16):2,008–2,021: doi:10.1016/j.csr.2005.07.005.

MacFadyen, A., B.M. Hickey, and W.P. Cochlan. 2008. Influences of the Juan de Fuca Eddy on circulation, nutrients, and phytoplankton production in the northern California Current System. Journal of Geophysical Research 113(C08008): doi:1029/2007JC004412.

MacIsaac, J.J., R.C. Dugdale, R.T. Barber, D. Blasco, and T.T. Packard. 1985. Primary production cycle in an upwelling center. Deep-Sea Research 32:503–529.

Mackas, D.L., G.C. Louttit, and M.J. Austin. 1980. Spatial distribution of zooplankton and phytoplankton in British Columbian coastal waters. Canadian Journal of Fisheries and Aquatic Sciences 37(10):1,476–1,487.

Mackas, D.L., W.T. Peterson, M.D. Ohlman, and B.E. Lavaniegos. 2006. Zooplankton anomalies in the California Current system before and during the warm conditions of 2005. Geophysical Research Letters 33(L22S07): doi:10.1029/2006GL027930.

McCabe, R., B. Hickey, and P. MacCready. 2008. Observational estimates of entrainment and vertical salt flux behind the frontal boundary of a spreading river plume. Journal of Geophysical Research, 113(C08027): doi:10.1029/2007JC004361.

McCreary, J.P., P.K. Kundu, and S. Chao. 1987. On the dynamics of the California Current system. Journal of Marine Research 45(1):1–32.

Newell, C.L., and T.J. Cowles. 2006. Unusual gray whale Eschrichtius robustus feeding in the summer of 2005 off the central Oregon coast. Geophysical Research Letters 33(L22S11): doi:10.1029/2006GL027189.

Pierce, D.P., J.A. Barth, R.E. Thomas, and G.W. Fleischer. 2006. Anomalously warm July 2005 in the northern California Current: Historical context and the significance of cumulative wind stress. Geophysical Research Letters 33(L22S04): doi:10.1029/2006GL027149.

She, J., and J.M. Klinck. 2000. Flow near submarine canyons driven by constant winds. Journal of Geophysical Research 105(C12):28,671–28,694.

Smith, R.L. 1981. A comparison of the structure and variability of the flow field in the three coastal upwelling regions: Oregon, Northwest Africa, and Peru. Pp. 107–118 in Coastal Upwelling. F.A. Richards, ed., American Geophysical Union, Washington, DC.

Spitz, Y.H., J.S. Allen, and J. Gan. 2005. Modeling of ecosystem processes on the Oregon shelf during the 2001 summer upwelling. Journal of Geophysical Research 110(C10S17): doi:10.1029/2005JC002870.

Strub, P.T., and C. James. 1988. Atmospheric conditions during the spring and fall transitions in the coastal ocean off western United States. Journal of Geophysical Research 93(C12):15,561–15,584.

Strub, P.T., and C. James. 2000. Altimeter-derived variability of surface velocities in the California Current System: 2. Seasonal circulation and eddy statistics. Deep-Sea Research Part II 47(5–6):831–870.

Strub, P.T., J.S. Allen, A. Huyer, and R.L. Smith. 1987. Large scale structure of the spring transition in the coastal ocean off western North America. Journal of Geophysical Research 92:1,527–1,544.

Strub, P.T., P.M. Kosro, and A. Huyer. 1991. The nature of cold filaments in the California Current system. Journal of Geophysical Research 96(C8):14,743–14,768.

Trainer, V.L., B.M. Hickey, W.P. Cochlan, E.J. Lessard, C.G. Trick, M.L. Wells, J. Herndon, A. MacFadyen, and S.K. Moore. In press. Seasonal and interannual variability of Pseudo-nitzschia and domoic acid in the Juan de Fuca Eddy region and its adjacent shelves. Limnology and Oceanography.

Ware, D.M., and R.E. Thomson. 2005. Bottom-up ecosystem trophic dynamics determine fish production in the Northeast Pacific. Science 308(5726):1,280–1,284: doi:10.1126/science,1109049.

Wilkerson, F.P., A.M. Lassiter, R.C. Dugdale, A. Marchi, and V.E. Hogue. 2006. The phytoplankton bloom response to wind events and upwelled nutrients during the CoOP–WEST Study. Deep-Sea Research II Part II 53(25–26):3,023–3,048: doi:10.1016/j.dsr2.2006.07.007.