Physiological limitation of phytoplankton photosynthesis in the eastern equatorial Pacific determined from variability in the quantum yield of fluorescence

On a transect study in the eastern equatorial Pacific, from the high-nutrient, low-chlorophyll tropical waters to the oligotrophic subtropical waters, we determined the variability in the maximum change in the quantum yield of chlorophyll fluorescence (A&,) by means of a fast repetition rate fluorometer. A& is a quantitative measure of photochemical energy conversion efficiency in photosystem 2, the variability of which is determined by the functional organization of the photosynthetic apparatus. The results revealed that A&,, was relatively low throughout the nutrient-rich equatorial waters, providing unequivocal evidence for physiological limitation of photochemical energy conversion efficiency in the natural phytoplankton populations. Shipboard enrichment studies showed that A&, increased following addition of nanomolar concentrations of inorganic iron as well as aerosol dust added at similar iron concentrations. This response reflects an iron-induced repair of photosystem 2 function in the enclosed bottle community. Low A&, at the top of the Equatorial Undercurrent indicated that the amount of iron upwelled to the surface was insufficient .t,o repair photosystem 2 function. Our results strongly suggest that iron availability limits photochemrcal energy conversion efficiency and is the principal mechanism controlling rates of photosynthesis and growth in the nutrient-rich equatorial Pacific.

[1]  Hugh L. MacIntyre,et al.  Fluorescence assessment of the maximum quantum efficiency of photosynthesis in the western North Atlantic , 1993 .

[2]  D. Hutchins,et al.  Interaction of iron and major nutrients controls phytoplankton growth and species composition in the tropical North Pacific Ocean , 1993 .

[3]  P. Falkowski,et al.  Fast Repetition Rate (FRR) Fluorometer For Making In Situ Measurements Of Primary Productivity , 1992, OCEANS 92 Proceedings@m_Mastering the Oceans Through Technology.

[4]  P. Falkowski,et al.  Iron-induced changes in light harvesting and photochemical energy conversion processes in eukaryotic marine algae. , 1992, Plant physiology.

[5]  I. Vass,et al.  Molecular mechanisms behind light-induced inhibition of photosystem II electron transport and degradation of reaction centre polypeptides , 1992 .

[6]  Francisco P. Chavez,et al.  Standing stocks of particulate carbon and nitrogen in the equatorial Pacific at 150°W , 1992 .

[7]  Curtiss O. Davis,et al.  Photosynthetic characteristics and estimated growth rates indicate grazing is the proximate control of primary production in the equatorial Pacific , 1992 .

[8]  P. Falkowski,et al.  PHYSIOLOGICAL LIMITATIONS ON PHYTOPLANKTON PRODUCTIVITY IN THE OCEAN , 1992 .

[9]  P. Falkowski.  Molecular Ecology of Phytoplankton Photosynthesis , 1992 .

[10]  M. Søndergaard,et al.  Carbon-specific phytoplankton growth rates: a comparison of methods , 1992 .

[11]  Francisco P. Chavez,et al.  Regulation of primary productivity rate in the equatorial Pacific , 1991 .

[12]  F. Wilkerson,et al.  Low specific nitrate uptake rate: A common feature of high‐nutrient, low‐chlorophyll marine ecosystems , 1991 .

[13]  B. Frost.  The role of grazing in nutrient-rich areas of the open sea , 1991 .

[14]  P. Falkowski,et al.  Effect of iron limitation on photosynthesis in a marine diatom , 1991 .

[15]  C. Garside.  Shift‐up and the nitrate kinetics of phytoplankton in upwelling systems , 1991 .

[16]  P. Falkowski,et al.  Role of eddy pumping in enhancing primary production in the ocean , 1991, Nature.

[17]  W. Sunda,et al.  Low iron requirement for growth in oceanic phytoplankton , 1991, Nature.

[18]  J. H. Martin,et al.  IRON, LIEBIG'S LAW, AND THE GREENHOUSE , 1991 .

[19]  G. Krause,et al.  Chlorophyll Fluorescence and Photosynthesis: The Basics , 1991 .

[20]  Francisco P. Chavez,et al.  Phytoplankton taxa in relation to primary production in the equatorial Pacific , 1990 .

[21]  F. Morel,et al.  lron transport in marine phytoplankton: Kinetics of cellular and medium coordination reactions , 1990 .

[22]  K. Banse.  Does iron really limit phytoplankton production in the offshore subarctic Pacific , 1990 .

[23]  R. Gordon,et al.  Yes, it does: A reply to the comment by Banse , 1990 .

[24]  W. G. Harrison,et al.  Primary productivity and size structure of phytoplankton biomass on a transect of the equator at 135°W in the Pacific Ocean , 1990 .

[25]  P. Falkowski,et al.  Natural variability in photosynthetic energy conversion efficiency: A field study in the Gulf of Maine , 1990 .

[26]  M. Perry,et al.  Maximal quantum yield of photosynthesis in the northwestern Sargasso Sea , 1989 .

[27]  P. Falkowski,et al.  NITROGEN LIMITATION IN ISOCHRYSIS GALBANA (HAPTOPHYCEAE). II. RELATIVE ABUNDANCE OF CHLOROPLAST PROTEINS 1 , 1989 .

[28]  F. Chavez.  Size Distribution of phytoplankton in the central and eastern tropical Pacific , 1989 .

[29]  P. Falkowski,et al.  Effects of Growth Irradiance and Nitrogen Limitation on Photosynthetic Energy Conversion in Photosystem II. , 1988, Plant physiology.

[30]  H. Riethman,et al.  Immunological Characterization of Iron-Regulated Membrane Proteins in the Cyanobacterium Anacystis nidulans R2. , 1988, Plant physiology.

[31]  J. Raven.  The iron and molybdenum use efficiencies of plant growth with different energy, carbon and nitrogen sources , 1988 .

[32]  S. Fitzwater,et al.  Iron deficiency limits phytoplankton growth in the north-east Pacific subarctic , 1988, Nature.

[33]  F. Chavez,et al.  An estimate of new production in the equatorial Pacific , 1987 .

[34]  P. Richerson,et al.  Photoinhibition and the diurnal variation of phytoplankton photosynthesis—I. Development of a photosynthesis—irradiance model from studies of in situ responses , 1987 .

[35]  P. Falkowski,et al.  Light Harvesting and Utilization by Phytoplankton , 1986 .

[36]  Bernard Kilonsky,et al.  Mean Water and Current Structure during the Hawaii-to-Tahiti Shuttle Experiment , 1984 .

[37]  Warren L. Butler,et al.  Energy Distribution in the Photochemical Apparatus of Photosynthesis , 1978 .

[38]  H. Glover.  EFFECTS OF IRON DEFICIENCY ON ISOCHRYSIS GALBANA (CHRYSOPHYCEAE) AND PHAEODACTYLUM TRICORNUTUM (BACILLARIOPHYCEAE) 1 , 1977 .

[39]  John J. Walsh,et al.  Herbivory as a factor in patterns of nutrient utilization in the sea1 , 1976 .

[40]  W. L. Butler,et al.  Quenching of chlorophyll fluorescence and primary photochemistry in chloroplasts by dibromothymoquinone. , 1975, Biochimica et biophysica acta.

[41]  T. Parsons,et al.  A practical handbook of seawater analysis , 1968 .