caa a22 4500 475784006 CHVBK 20180406123652.0 cr unu---uuuuu 170329e20001001xx s 000 0 eng 10.1023/A:1008151004317 doi (NATIONALLICENCE)springer-10.1023/A:1008151004317 Light-path length and population density in photoacclimation of Nannochloropsis sp. (Eustigmatophyceae) [Elektronische Daten] [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. Kluwer Academic Publishers, 2000 Nannochloropsis sp nationallicence photobioreactor nationallicence light-path nationallicence photoacclimation nationallicence chlorophyll nationallicence carotenoids nationallicence Zou Ning Microalgal Biotechnology Laboratory, The Albert Katz Department of Dryland Biotechnologies, The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, 84990, Israel aut Richmond Amos Microalgal Biotechnology Laboratory, The Albert Katz Department of Dryland Biotechnologies, The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, 84990, Israel aut Journal of Applied Phycology Kluwer Academic Publishers 12/3-5(2000-10-01), 349-354 0921-8971 12:3-5<349 2000 12 10811 https://doi.org/10.1023/A:1008151004317 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1023/A:1008151004317 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Zou Ning Microalgal Biotechnology Laboratory, The Albert Katz Department of Dryland Biotechnologies, The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, 84990, Israel aut NATIONALLICENCE 700 1- Richmond Amos Microalgal Biotechnology Laboratory, The Albert Katz Department of Dryland Biotechnologies, The Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boker Campus, 84990, Israel aut NATIONALLICENCE 773 0- Journal of Applied Phycology Kluwer Academic Publishers 12/3-5(2000-10-01), 349-354 0921-8971 12:3-5<349 2000 12 10811 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer