Oregon State University

College of Earth, Ocean, and Atmospheric Sciences

Directory of People

Ricardo M. Letelier

Ricardo Letelier photo
Discipline: Ocean Ecology and Biogeochemistry
Office: Burt 140
Phone: 541-737-3890
Fax: 541-737-2064
Email: letelier@coas.oregonstate.edu
Vita or Résumé (PDF)

Research Interests

Scales of response of marine pelagic microorganisms, populations, and communities to environmental perturbations; the role of these responses on biogeochemical cycles, primary productivity, nitrogen fixation, photosynthesis, chlorophyll passive (solar-induced) fluorescence; and the physical and chemical factors controlling these processes.

Current Research

Scales of variability of phytoplankton productivity in the coastal environments; the interpretation of phytoplankton passive fluorescence as measured from space; seasonal, and long-term changes in pelagic community structure in the North Pacific subtropical gyre with emphasis in phytoplankton production.


BS, Universidad de Concepcion, Chile (Marine Biology), 1988
PhD, University of Hawaii at Manoa (Oceanography), 1994



2015 White, A.E., R.M. Letelier, A.L. Whitmire, B. Barone, R.R. Bidigare, M.J. Church and D.M. Karl. Phenology of particle size distributions and primary productivity in the North Pacific suntropical gyre (Station ALOHA). J. Geophys. Res. Oceans, 120 doi:10.1002/2015JC01897.

2015 Wilson, S.T., et al. Short-term variability in euphotic zone biogeochemistry and primary productivity at Station ALOHA: A case study of summer 2012. Global Biogeochem. Cycles, 29,1145-1164, doi: 10.1002/2015GB005141.

2015 Barone, B., R.R. Bidigare, M.J. Church, D.M. Karl, R.M. Letelier and A.E. White. Particle distribution and dynamics in the euphotic zone of the North Pacific Subtropical Gyre: Particle distributions at Station ALOHA. J. Geophys. Res. Oceans, 120, doi: 10.1002/2015JC010774.

2014 Kavanaugh, M.T., S.R. Emerson, B. Hales, D.M. Lockwood, P.D. Quay and R.M. Letelier. Physiochemical and biological controls on primary and net community production across northeast Pacific seascapes. Linmol. Oceanogr. 59(6): 2013-2027.

2014 Gradoville, M.R., A.E. White and R.M Letelier. Physiological response of Crocosphaera watsonii to enhanced and fluctuating carbon dioxide conditions.. PLos One 9(10): e110660. Doi10.1371/journal.pone.0110660

2014 Muller-Karger, F.E., M.T. Kavanaugh, E. Montes, W.M. Balch, M. Breitbart, F.P. Chavez, S.C. Doney, E.M. Johns, R.M. Letelier, M.W. Lomas, H.M. Sosik, and A.E. White. A framework for a marine biodiversity observing network within changing continental shelf seascapes. Oceanography 27(2):18–23, http://dx.doi.org/10.5670/oceanog.2014.56.

2014 Dore, J.E., M.J. Church, D.M. Karl, D.W. Sadler and R.M. Letelier. Paired windward and leeward biogeochemical time series reveal consistent surface CO2 trends across the Hawaiian Ridge. Geophys. Res. Let. DOI: 10.1002/2014GRL06725

2014 Böttjer, D., D.M. Karl, R.M. Letelier, D.A. Viviani, and M.J. Church. Experimental assessment of diazotroph responses to elevated pCO2 in the North Pacific Subtropical Gyre. Global Biogeochem. Cycles, 28:601-616, doi: 10.1002/2013GB004690.

2014 Laws, E.D., R.M. Letelier and D.M Karl. Estimating the compensation irradiance in the ocean: The importance of accounting for non-photosynthetic uptake of inorganic carbon.  Deep-Sea Res. I: doi: 10.1016/j.dsr.2014.07.011

2014  Gradoville, M.R., A.E. White, D. Böttjer, M.J. Church and R.M. Letelier. Diversity trumps acidification: Lack of evidence for carbon dioxide enhancement of Trichodesmium nitrogen or carbon fixation at Station ALOHA. Limnol. Oceanogr. 59(3):645-659.

2014 Kavanaugh, M.T., B. Hales, M. Saraceno, Y.H. Spitz, A.E. White and R.M. Letelier. Hierarchical and dynamic seascapes: A quantitative framework for scaling pelagic biogeochemistry and ecology. Progr. Oceanogr., 120:291-304.

2013  Li, B.L., D.M. Karl, R.M. Letelier, R.R. Bidigare and M.J. Church. Variability of chromophytic phytoplankton in the North Pacific Subtropical Gyre. Deep-Sea Res. Part-II, 93:84-95.

2013 Peloquin J. et al. The MAREDAT global database of high performance liquid chromatography marine pigment measurements. Earth Syst. Sci. Data, 5:109-123.

2012 Ulloa, O., D.E. Canfield, E.F. DeLong, R.M. Letelier and F.J. Stewart. Microbial oceanography of anoxic minimum zones. Proc. Nat. Acad. Sci., 109(40):15996-16003.

2012 Hales, B., P.G. Strutton, M. Saraceno, R. Letelier, T. Takahashi, R. Feely, C. Sabine and F. Chavez. Satellite-based prediction of pCO2 in coastal waters of the eastern North Pacific. Progr. Oceanogr., 103:1-15.

2012 Saldias, G.S., M. Sobarzo, J. Largier, C. Mofffat and R.M. Letelier. Seasonal variability of turbid river plumes off central Chile based on high-resolution MODIS imagery. Rem. Sens. Environ., 123: 220-233.

2012 Guidi, L., P.H.R. Calil, S. Duhamel, K.M. Bjorkman, S.C. Doney, G.A. Jackson, B.L. Li, M.J. Church, S. Tozzi, Z.S. Kolber, K.J. Richards, A.A. Fong, R.M. Letelier, G. Gorski, L. Stemmann and D.M. Karl. Does eddy-eddy interaction control surface phytoplankton distribution and carbon export in the North Pacific Subtropical Gyre? J. Geophys. Res. Biogeosciences., doi: 10.1029/2012JG001984

2012  Karl, D.M., M.J. Church, J.E. Dore, R.M. Letelier and C. Mahaffey. Predictable and efficient carbon sequestration in the North Pacific Ocean supported by nitrogen fixation.  Proc. Nat. Acad. Sci., 109(6):1842-1848

2011 Li, B., D.M. Karl, R.M. Letelier, and M.J. Church. Size-dependent variability of photosynthesis in the North Pacific Subtropical gyre. Marine Ecology Progress Series, 440:27-40.

2011 Watkins-Brandt, K., R. M. Letelier, Y. H. Spitz, M. Church, D. Bottjer and A. E. White.(2010) Addition of inorganic or organic phosphorus enhances nitrogen and carbon fixation in the oligotrophic North Pacific. Marine Ecology Progress Series. 432:17-29.

2011 White, A. E., K. Björkman, E. Grabowski, R. M. Letelier, S. Poulos, B. Watkins, and D.M. Karl Comments on "An Open Ocean Trial of Controlled Upwelling Using Wave Pump Technology" Reply.  Journal of Oceanic and Atmospheric Technology. 28:850-851.

2010 Somes,C.J., A. Schmittner, E.D. Galbraith, M.F. Lehmann, M.A. Altabet, J.P. Montoya, R.M. Letelier, A.C. Mix, A. Bourbonnais, and M. Eby. Simulating the global distribution of nitrogen isotopes in the ocean. Global Geochemical Cycles. 24:GB4019

2010 Beversdorf, L.J., A.E. White, K.M. Bjorkman, R.M. Letelier, and D.M. Karl. Phosphonate metabolism of Trichodesmium IMS101 and the production of greenhouse gases. Limnol. Oceanogr. 55:1768-1778.

2010 White, A.E., D.M. Karl, K.M. Bjorkman, L.J. Beversdorf, and R.M. Letelier. Production of organic matter by Trichodesmium IMS101 as a function of phosphorus source. Limnol. Oceanogr. 55: 1755-1767.

2010 White, A., K. Bjorkman, E. Grabowski, R. Letelier, S. Poulos, B. Watkins, and D. Karl. An open ocean trial of controlled upwelling using wave pump technology. J. Atmos. Ocean. Tech. 27(2):385-396.

2009 Whitmire, A.L., R.M. Letelier, V. Villagran,and O. Ulloa. Autonomous observations of in vivo fluorescence and particle scattering in an oceanic oxygen minimum zone. Optics Express, 17(24):21,992-22,004.

2009 Church, M.J., C. Mahaffey, R.M. Letelier, R. Lukas, J.P. Zehr, and D.M. Karl. Physical forcing of nitrogen fixation and diazotroph community structure in the North Pacific Subtropical Gyre. Global Biogeochem. Cycles. 23;GB2020.

2009 Laney, S.R., R.M. Letelier, and M.R. Abbott. Using a stochastic approach to model nonlinear dynamics in photosynthesis at the photosystem level. J. Phycol. 45:298-310.

2009 Kavanaugh, M.T., B.A. Menge, K.J. Nielsen, F.T. Chan, R.M. Letelier, and L.M. Goodrich. Experimental assessment of the effects of shade on an intertidal kelp: do phytoplankton blooms inhibit growth of open coast macroalgae? Limnol. Oceanogr. 54:276-288.

2008 Fong, A.A., D.M. Karl, R. Lukas, R.M. Letelier, J.P. Zehr, and M.J. Church. Nitrogen fixation in an anticyclonic eddy in the oligotrophic nNorth Pacific Ocean, Int. Soc. Microb. Ecol. 364:257-268.

2008 Venegas, R.M., P.T. Strub, E. Beier, R.M. Letelier, A.C. Thomas, T.Cowles, C. James, L. Soto-Mardones, and C. Cabrera. Satellite-derived variability in chlorophyll, wind stress, sea surface height, and temperature in the northern California Current system. J. Geophys. Res. 113, C03015, doi:10.1029/2007JC004481

2008 Corno, G., R.M. Letelier, M.R. Abbott, and D.M. Karl. Temporal and vertical variability of photosynthesis in the North Pacific Subtropical gyre. Limnol. Oceanogr. 53: 1252-1265.

2008 Letelier, R.M., P.G. Strutton, and D.M. Karl. Physical and Ecological uncertainties in the widespread implementation of controlled upwelling in the North Pacific Subtropical Gyre. Mar. Ecol. Prog. Ser. 371:305-308.

2008 Karl, D.M. and R.M. Letelier. Nitrogen fixation-enhanced carbon sequestration in low nitrate, low chlorophyll seascapes. Mar. Ecol. Prog. Ser. 364: 257-268.

2008 Laney, S.R. and R.M. Letelier. Artifacts in measurements of chlorophyll fluorescence transients, with specific application to fast repetition rate fluorometry. Limnol. Oceanogr.: Methods 6: 40-50.

2008 Dore, J.E., R.M. Letelier, M.J. Church, R.Lukas, and D.M. Karl. Summer phytoplankton blooms in the oligotrophic North Pacific Subtropical Gyre: Historical perspective and recent observations. Progress in Oceanography 76:2-38.

2007 Desiderio, R., S. Laney, R. Letelier, and S. Giovannoni. Using lasers to probe the transient light absorption by proteorhodopsin in marine bacterioplankton. Applied Optics. 46:7329-7336.

2007 White, A.E., Y.H. Spitz, and R.M. Letelier. What factors are driving summer phytoplankton blooms in the North Pacific subtropical gyre? J. Geophys. Res. 112(c2): C12006, doi:10.1029/2007JC004129

2007 Bane, J.M., Y.H. Spitz, R.M. Letelier, and W.T. Peterson. Jet stream intraseasonal oscillations drive dominant ecosystem variations in Oregon’s summertime coastal upwelling system. Proc. Nat. Acad. Sci. 104: 13,262-13,267.

2007 Corno, G., D.M. Karl, M.A. Abbott, M.J. Church, R. Lukas, and R.M. Letelier. Impact of climate forcing on ecosystem processes in the North Pacific subtropical gyre. J. Geophys. Res., 112, C04021, doi:10.1029/2006JC003730.

2007 Huyer, A., M. Kosro, R. Letelier, R.L. Smith, and P.A. Wheeler. The Newport Line off Oregon: Studies in the North East Pacific. Progress in Oceanography, doi: 10.1016/j.pocean.2007.08.003

2007 White, A. E., F.G. Prahl, R.M. Letelier, and B.N. Popp. Summer surface waters in the Gulf of California: prime habitat for biological N2 fixation..Global  Biogeochemical Cycles, 21, GB2017, doi:10.1029/2006GBC002779.

2006 Behrenfeld, M.J., R.T. O’Malley, D.A. Siegel, C.R. McClain, J.L. Sarmiento, G.C. Feldman, A.J. Milligan, P.G. Falkowski, R.M. Letelier, E.S.Boss. Climate-driven trends in contemporary ocean productivity.  Nature, 444: 752-755.

2006 White, A.E., Y.H. Spitz, and R.M. Letelier, Modeling carbohydrate ballasting by Trichodesmium spp. at Station ALOHA.  Mar. Ecol. Prog. Ser,. 323: 35-45

2006 Church, M.J., H.W. Ducklow, R.M. Letelier, and D.M. Karl. Temporal dynamics in heterotrophic picoplankton productivity in the subtropical North Pacific Ocean. Aquat. Microb. Ecol, 45: 41-53.

2006 White, A.E., Y. Spitz, D.M.  Karl, and R.M. Letelier. Ecological implications of flexible elemental stoichiometry in Trichodesmium spp. Limnol. Oceanogr. 51(4): 1777-1790

2005 Corno, G., R.M. Letelier, M.R. Abbott, and D.M. Karl. Assessing primary production variability in the North Pacific subtropical gyre: A comparison of Fast Repetition Rate fluorometry and 14C measurements. J. Phycol. 42: 51-60

2005 Laney, S.R., R.M. Letelier, and M.R. Abbott. Parameterizing the natural fluorescence kinetics of Thalassiosira weissflogii.Limnol. Oceanogr. 50(5): 1499-1510

2004 Wetz, M.S. , P.A. Wheeler, and R.M. Letelier. Light induced growth of winter phytoplankton collected from the benthic boundary layer off Oregon, USA. , Mar. Ecol. Prog. Ser. 208: 95-104.

2004 Sakamoto C, et al., Influence of Rossby waves on nutrient dynamics and plankton community structure in the North Pacific subtropical gyre. J. Geophys. Res.109: C05032

2004 Letelier, R.M., D.M. Karl, M.R. Abbott, and R.R. Bidigare.  Light driven seasonal patterns of chlorophyll and nitrate in the lower euphotic zone of the North Pacific Subtropical Gyre. Limnol. Oceanogr. 49: 508-519

2003 Hogue, F.E., P.E. Lyon, R.N. Swift, J.K. Yungel, M.R. Abbott, R.M. Letelier, W.E. Esaias. Validation of Terra-MODIS Phytoplankton Chlorophyll Fluorescence Line Height. I. Initial Airborne Lidar Results. Appl. Optics, 42(15): 2761-2771.

2002 Karl, D.M., A. Michaels, B. Bergman, D.G. Capone, E. Carpenter, R. Letelier, F. Lipschultz., H. Pearl, D. Sigma, and L. Stal. Nitrogen fixation in the world’s oceans. Biogeochemistry, 57/58: 47-98.

2002 Fennel, K., Y.H. Spitz, R.M. Letelier, and M.R. Abbott. A deterministic model for N2-fixation at the HOT site in the subtropical North Pacific. Deep-Sea Res.II, 49: 149-174.

2001 Landry, M.R., S.L. Brown, K.E. Selph, M.R. Abbott, R.M. Letelier, S. Christensen, R.R. Bidigare, and K. Casciotti, Initiation of the spring phytoplankton increase in the Antarctic Polar Front Zone at 170°W. Journal of Geophysical Research, 106: 13,903-13,915.

2001 Nahorniak, J.S., M.R. Abbott, R.M. Letelier, and W.S. Pegau. Analysis of a method to estimate chlorophyll-a concentration from irradiance measurements at varying depths. J. Atmos. Ocean. Tech.,.18: 2063-2073.

2001 Laney, S.R., R.M. Letelier, R.A. Desiderio, M.R. Abbott, D.A. Kiefer, and C.R. Booth. Measuring the natural fluorescence of phytoplankton cultures. J. Atmos. Ocean. Tech., 18: 1924-1934.

2001 Mengelt, C., M. Abbott, R.M. Letelier, J.A. Barth, C. Measures, and S. Vink, Phytoplankton pigment distribution in relation to the physics across the Antarctic Polar Front, 170°W, Deep-Sea Res.II, 48: 4081-4100.

2001 Karl, D.M, R.R. Bidigare and R.M. Letelier, Long-term changes in plankton community structure and productivity in the subtropical North Pacific Ocean: The domain shift hypothesis, Deep-Sea Res. II, 48: 1449-1470.

2001 Karl, D.M., K.M. Björkman, J.E. Dore, L. Fujieki, D.V. Hebel, T. Houlihan, R.M. Letelier, and L.M. Tupas. Ecological Nitrogen-to-Phosphorus Stoichiometry at Station ALOHA. Deep-Sea Res. II, 48: 1529-1566.

2000 Letelier, R.M, D.M. Karl, M.R Abbott, P. Flament, M. Freilich, R. Lukas, and T. Strub, Role of late winter mesoscale events in the biogeochemical variability of the upper water column of the North Pacific Subtropical Gyre, Journal of Goephysical Research, 105: 28,723-28,740. Correction in Journal of Goephysical Research, 106: 7181-7182.

2000 Abbott, M.R., J.G. Richman, R.M. Letelier, and J.S. Bartlett. The spring bloom in the Antarctic Polar Frontal Zone as Observed from a Mesoscale Array of Bio-optical Sensors, Deep-Sea Res. II, 47: 3285-3314.

1998 Karl, D.M, D. Hebel, K. Bjorkman, and R.M. Letelier. The role of dissolved organic matter exudation in the productivity of the oligotrophic North Pacific Ocean. Limnology and Oceanography, 43(6): 1270-1286.

1998 Abbott, M.R. and R.M. Letelier.  Decorrelation scales of chlorophyll as observed from bio-optical drifters in the California Current. Deep-Sea Res., 45: 1639-1668.

1998  Letelier, R.M. and D.M. Karl. Trichodesmium spp.  physiology and nutrient fluxes in the North Pacific subtropical gyre. Aquatic Microbial Ecology 15(3): 265-276.

1998 Essaias, W. et al. An overview of MODIS capabilities for ocean science observations. IEEE Transactions of Geoscience and Remote Sensing 36(4):1250-1265.

1997 Letelier, R.M., M.R. Abbott, and D.M. Karl. Chlorophyll natural fluorescence response to upwelling events in the Southern Ocean. Geophysical Research Letters  24(4): 409-412.

1997 Karl, D.M., R.M. Letelier, L. Tupas, J. Dore, J. Christian, and D. Hebel. The role of nitrogen fixation in biogeochemical cycling in the subtropical North Pacific Ocean. Nature 387: 533-538.

1996 Letelier, R.M. and M.R. Abbott. An analysis of chlorophyll fluorescence algorithms for the Moderate Resolution Imaging Spectrometer (MODIS). Rem. Sens. Environ. 58: 215-223.

1996 Letelier, R.M, D.M.  Karl. The role of Trichodesmium spp. in the productivity of the subtropical North Pacific Ocean.. Mar. Ecol. Prog. Ser. 133:263-273.

1996 Letelier, R.M., J.E. Dore, C.D. Winn, and D.M. Karl. Seasonal and interannual variations in autotrophic carbon assimilation at Station ALOHA . Deep-Sea Res. 43:467-490.

1996 Karl, D.M., J.R. Christian, J.E. Dore, D.V. Hebel, R.M. Letelier, L.M. Tupas, and C.D. Winn. Seasonal and interannual variability in primary production and particle flux at station ALOHA. Deep-Sea Res. 43:539-568.

1995 Karl, D.M., R.M. Letelier, D. Hebel, L. Tupas, J. Dore, J. Christian, and C. Winn. Ecosystem changes in the North Pacific subtropical gyre attributed to the 1991-1992 El Niño. Nature 373:230-234.

1995 Winn, C.D., L. Campbell, J.R. Christian, R.M. Letelier, D.V. Hebel, J.E. Dore, L. Fujieki, and D.M. Karl. Seasonal variability in the phytoplankton community of the North Pacific Subtropical Gyre. Global Biogeochem. Cycles 9:605-620.

1993 Letelier, R.M,  R.R. Bidigare, D.V. Hebel, M. Ondrusek, C.D. Winn, and D.M. Karl. Temporal variability of phytoplankton community structure based in pigment analysis. Limmnol. Oceanogr. 38:1420-1437.


2011. Hixon, M., Gregory, S. Robinson, W.D., Baker, S, Batchelder, H., Epps, C. Garcia, T.S., Haig, S. Letelier, R., Lytle, D., Menge, B., Miller, J., Noakes, D. Peterson, W. Rice, J., Rumrill, S., Schreck, C., Suryan, R., Systma, M. and White, A. (2010) Oregon's Fish and Wildlife in a Changing Climate. In: Oregon Climate Change Research Institute, The Oregon Climate Assessment Report K.D. Dello and P.W. Mote (eds). College of Oceanic and Atmospheric Sciences, Oregon State University, Corvallis, Oregon.

2010 Karl, D.M. and R.M. Letelier. Seascapes microbial ecology: Habitat, structure, biodiversity and ecosystem function.  In: S.E. Levin (ed.), Guide to Ecology, Princeton University Press.

2009 Karl, D.M. and R.M. Letelier.  Marine habitats. Pp. 258-277. In: M. Schaechter (ed.), Encyclopedia of Microbiology, 3rd Edition, Elsevier.

2002 Karl, D.M., R. Bidigare, and R.M. Letelier. Sustained Seasonal and Interannual Variability of Phytoplankton Processes in the North Pacific Subtropical Gyre. In: P.J. Le B. Williams, D.N. Thomas, and C. Reynolds (eds.), Phytoplankton Productivity: Carbon Assimilation in Marine and Freshwaters Ecosystems, p. 222-264, Blackwell Science Ltd., Oxford, U.K.

1997 Abbott, M.R. and R.M. letelier. Going with the Flow - The use of Optical Drifters to Study Phytoplankton Dynamics. In: Mati Kahru and C. W. Brown (eds.), Monitoring Algal Blooms: New Techniques for Detecting Large-Scale Environmental Change, pp. 143-168, Landes Bioscience, USA.

1996 Karl, D.M., J.R. Christian, J.E. Dore, and R.M. Letelier. Microbial oceanography in the region west of the Antarctic Peninsula: Microbial Dynamics, Nitrogen Cycle and Carbon Flux. In: R.R. Ross et al.  (eds.), Foundations for Ecological Research West of the Antarctic Peninsula , pp. 303-332, American Geophysical Union, Antarctic Research Series 70.

1992 Karl, D.M., R.M. Letelier, D.V. Hebel, D.F. Bird, and C.V. Winn. Trichodesmium blooms and new nitrogen in the North Pacific gyre, In: E.J. Carpenter et al. (eds.), Marine Pelagic Cyanobacteria: Trichodesmium and Other Diazotrophs, pp. 219-237, Kluwer Academic Publishers, Netherlands.

1991 Lee, C., S. Henrichs, and R. Letelier. Organic inventories workshop report. In: D.C. Hurd and D.W. Spencer (eds), Marine Particles: Analysis and Characterization, pp. 101-117. American Geophysical Union, Geophysical Monograph 63.

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