The influence of salinity fluctuation on the ammonium metabolism of the marine diatom Skeletonema costatum grown in continuous culture
Rijstenbil, J.W.; Sinke, J.J. (1989). The influence of salinity fluctuation on the ammonium metabolism of the marine diatom Skeletonema costatum grown in continuous culture. J. Plankton Res. 11(2): 297-315. https://dx.doi.org/10.1093/plankt/11.2.297
In: Journal of Plankton Research. Oxford University Press: New York,. ISSN 0142-7873; e-ISSN 1464-3774, more
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| Keywords |
Aquaculture systems > Continuous culture
Chemical reactions > Photochemical reactions > Photosynthesis
Environmental effects > Salinity effects
Primary production
Properties > Chemical properties > Salinity
Skeletonema costatum (Greville) Cleve, 1873 [WoRMS]
Marine/Coastal |
| Authors | | Top |
- Rijstenbil, J.W., more
- Sinke, J.J.
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| Abstract |
Ammonium-limited cultures of Skeletonema costatum were grown at dilution rates from 0.019 to 0.038 h-1 at an average salinity of 22.4{per thousand} For a few days cultures were exposed to a freshwater pulse. When salinity was decreased to 8.6{per thousand} (average minimum) photosynthesis and cell division were inhibited. Both in vivo and DCMU-enhanced fluorescence per cell were statistically constant: photosystems I and II were not inhibited by a gradual salinity decrease. Ammonium assimilation was affected via an inhibition of carbon fixation. Ammonium concentrations increased in the continuous cultures, whereas the overcapacity of ammonium uptake declined: the nitrogen limitation was relieved. When salinity was increased again, photosynthesis and cell division were stimulated. Salinity fluctuations were accompanied by a fluctuation in the pools of aspartic acid (0.5-1.0 mM), glutamine acid (0.9-4.1 mM) and glutamine (0.5-2.0 mM). The pool of glutamic acid followed the salinity pattern (r=0.67, P<0.05). The correlation between the amino acid pool and the osmotic value of the medium was significant (r=0.72, P<0.05). Cellular glutamic acid and glutamine levels increased until the nitrogen limitation was restored. |
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