Fig 3 - uploaded by Maria van Leeuwe
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The 14 C incorporation into the biochemical pools ( A ) glucan, ( B ) amino acids, ( C ) proteins, ( D ) lipids and ( E ) polysaccharides during long- term (24 h) incubations with natural phytoplankton populations of the APF at low and high photon irradiance, with and without the addition of iron. Error bars indicate standard deviations ( n = 5). HL, high light; LL, low light. Dashed bars indicate the dark period.
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not found in spite of differences in phytoplankton species composition: at the Antarctic Polar Front, biomass was dominated by a diatom population of Fragilariopsis kerguelensis, whereas smaller cells, including chrysophytes, were relatively more abundant in the Antarctic Circumpolar Current beyond the influence of frontal systems. Because mixing w...
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Context 1
... diurnal carbon incorporation rate in incubations performed with phytoplankton sampled at the APF was strongly dependent on irradiance but did not change in response to Fe addition for any of the pools ( Figure 3A-E). The net diurnal production rate of glucan was almost 6 times higher at high compared with low irradiance (Table II). ...
Context 2
... long-term incubations (filled circles), 43% of the newly assimilated carbon was incorporated into glucan at the end of the light period and 7% into amino acids; 30% was incorporated into proteins, 18% into polysaccharides and lipids contrib- uted only 2%. The contributions of glucan and amino acids fractions were relatively low compared with con- tributions in the natural phytoplankton populations that were kept at the comparable irradiance (Figure 3, HL, open circles). The amount of carbon incorporated into the glucan fraction decreased strongly during the dark period ( Figure 6A), stronger than during the experiments with the natural populations ( Figure 3A). ...
Context 3
... contributions of glucan and amino acids fractions were relatively low compared with con- tributions in the natural phytoplankton populations that were kept at the comparable irradiance (Figure 3, HL, open circles). The amount of carbon incorporated into the glucan fraction decreased strongly during the dark period ( Figure 6A), stronger than during the experiments with the natural populations ( Figure 3A). As observed for the natural populations, protein synthesis continued during the dark period and lipid synthesis stopped ( Figure 6C,D). ...
Context 4
... comparing the strong decrease in radioactivity in the glucan fraction during the dark period in the C. brevis cultures with the more modest decrease in radioactivity in the field experiments ( Figures 3A and 6A), one might wonder why the relative proportions of the modelled diur- nal and nocturnal respiration rate (R d and R n ) and the The growth rate applied to fit the model to the field data was based on two 6 day experiments under similar experimental conditions, during which cells were counted with a flow cytometer every 2 days (Van Leeuwe and Van Oijen, 2000). b The model was fitted to the 14 C data using the equation editor of Sigmaplot 8.0. ...
