Journal of Applied Phycology

, Volume 12, Issue 3–5, pp 349–354 | Cite as

Light-path length and population density in photoacclimation of Nannochloropsis sp. (Eustigmatophyceae)

  • Ning Zou
  • Amos Richmond


Photoacclimation in the marine eustigmatophyte Nannochlropsis sp., used extensively as a food chaincomponent in aquaculture, was studied both in thelaboratory and outdoors. Cell-chlorophyll andcarotenoids were used as markers to assessphotoacclimation to strong light, as well as todecreasing growth irradiance due to cellproliferation. Focusing on practical aspects involvedin mass cultivation, three different approaches wereused as follows: (a) cultures initially exposed to lowlight (150 μmol photon m-2 s-1) thentransferred to strong light (1000 to 3000 μmolphoton m-2 s-1); (b) initially low celldensity cultures grown in reactors of differentlight-paths, exposed to strong PFD, in the laboratoryand outdoors; (c) initially low or high cell densitycultures exposed to strong light. As has already beenestablished in many reports, cell-chlorophyllrepresented a sensitive parameter in assessing cellresponse to changes in the intensity of the lightsource as well as to modifications in the light regimeto which the cells were exposed. Cell-chlorophyllconcentration sharply decreased initially upontransferring the culture from low PFD cell-1 tohigh PFD cell-1 due to either culture dilution(i.e. decrease in cell density and mutual shading) orto an increase in PFD. After some 7 days ofphotoacclimating to 2000 and 3000 μmol photonm-2 s-1, chlorophyll a content began to riseat a much faster rate than cell number, which alsoincreased in response to the higher irradiance.Cell-chlorophyll in the culture exposed to 2000μmol photon m-2 s-1 increased afteracclimation earlier and at a faster rate than in theculture exposed to 3000 μmol photon m-2s-1, indicating the later irradiance affected astronger stress. The length of the reactor's lightpath exerted a decisive effect on cell response tostrong light through its influence on the light regimein the culture. Upon a sharp increase in PFD,carotenoids in the 1-cm reactor increased in muchhigher rate than chlorophyll, compared with the 3-cmlight path reactors. This marked difference in cellresponse to a shift-up in light was attributed to thevast variations in the light regime associated withdifferences in the length of the light path and areal density. Growth oflow cell density cultures ceased temporarily upontransfer to strong light, in contrast with high celldensity cultures transferred to strong light, whichcontinued growth without a lag.

Nannochloropsis sp. photobioreactor light-path photoacclimation chlorophyll carotenoids 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Davis AE, Dedrick J, French CS, Milner HW, Myers J, Smith JHC, Spoehr HA (1953) Laboratory experiments on Chlorella culture at the Carnegie Institution of Washington Dept. of Plant Biology. In Burlew JS (ed.), Algae Culture from Laboratory to Pilot Plant. Publ. No. 600, Carnegie Institution of Washington, Washington DC, pp. 105-153.Google Scholar
  2. Falkowski PG, LaRoche J (1991) Acclimation to spectral irradiance in algae. J. Phycol. 27: 8-14.Google Scholar
  3. Falkowski PG, Owens TG (1980) Light-shade adaptation. Plant Physiol. 66: 592-595.Google Scholar
  4. Fisher T, Minnaard J, Dubinsky Z (1996) Photoacclimation in the marine alga Nannochloropsis sp. (Eustigmatophyte): a kinetic study. J. Plankton Res. 18: 1797-1818.Google Scholar
  5. Fisher T, Berner T, Iluz D, Dubinsky Z (1998) The kinetics of the photoacclimation response of Nannochloropsis sp. (Eustigmatophyte): a study of changes in ultrastructure and PSU density. J. Phycol. 34: 818-824.Google Scholar
  6. Hu Q, Richmond A (1994) Optimizing the population density in Isochrysis galbana grown outdoors in a glass column photobioreactor. J. appl. Phycol. 6: 391-396.Google Scholar
  7. Hu Q, Guterman H, Richmond A (1996) A flat inclined modular photobioreactor for outdoor mass cultivation of photoautotrophs. Biotechnol. Bioengng 51: 51-60.Google Scholar
  8. Hu Q, Zarmi Y, Richmond A (1998) Combined effects of light intensity, light-path and culture density on output rate of Spirulina platensis (Cyanobacteria). Eur. J. Phycol. 33: 165-171.Google Scholar
  9. Renaud SM, Parry DL, Thinh LV, Kuo C, Padovan A, Sammy N (1991) Effect of light intensity on the proximate biochemical and fatty acid composition of Isochrysis sp. and Nannochloropsis oculata for use in tropical aquaculture. J. appl. Phycol. 3: 43-53.Google Scholar
  10. Richmond A (1996) Efficient utilization of high irradiance for production of photoautotrophic cell mass: a survey. J. appl. Phycol. 8: 381-387.Google Scholar
  11. Sukenik A, Carmeli Y, Berner T (1989) Regulation of fatty acid composition by irradiance level in the Eustigmatophyte Nannochloropsis sp. J. Phycol. 25: 686-692.Google Scholar
  12. Vonshak A, Guy R (1988) Photoinhibition as a limiting factor in outdoor cultivation of Spirulina platensis. In Stadler T, Mollion J, Verdus M-C, Karamanos Y, Morvan H, Christiaen D (eds), Algal Biotechnology, Elsevier Applied Science Publishers, London: 365-370.Google Scholar

Copyright information

© Kluwer Academic Publishers 2000

Authors and Affiliations

  • Ning Zou
    • 1
  • Amos Richmond
    • 1
  1. 1.Microalgal Biotechnology Laboratory, The Albert Katz Department of Dryland Biotechnologies, The Jacob Blaustein Institute for Desert ResearchBen-Gurion University of the NegevIsrael

Personalised recommendations