Competition ability of two planktic diatoms under different vertical light gradients, mixing-depth and -frequencies: An experimental approach

Summary

Dependence of specific growth rates on daily light dosage (integral PFD per day) of Stephanodiscus minutulus (Kütz.) Cleve & Möller and Nitzschia acicularis W. Smith were estimated at very different daylengths and corresponding integral daylengths resulting from interrupted illumination periods (L/D = 12.5/12.5 min.) within a 12 h photoperiod per day. St. minutulus exhibits higher growth potential (μm) at very short daylength (3 h) and higher growth rates under strong light limitation, especially under short integral light supply, imitating turbulent mixing well below the compensation depth. N. acicularis is favoured under continuous and non-limiting light supply prevailing under at least temporary stratification. Both exhibit higher growth rates than Planktothrix agardhii and Limnothrix redekei even under light limitation.