|Are marine diatoms favoured by high Si:N ratios?|
Sommer, U. (1994). Are marine diatoms favoured by high Si:N ratios? Mar. Ecol. Prog. Ser. 115: 309-315
In: Marine Ecology Progress Series. Inter-Research: Oldendorf/Luhe. ISSN 0171-8630, more
Biomass; Competition; Dominant species; Experimental research; Light intensity; Nitrates; Nutrients (mineral); Phytoplankton; Silicates; Chrysochromulina polylepis Manton & Parke, 1962 [WoRMS]; Dunaliella tertiolecta Butcher, 1959 [WoRMS]; Pseudo-nitzschia pungens (Grunow ex Cleve) G.R.Hasle, 1993 [WoRMS]; Rhodomonas Karsten, 1898 [WoRMS]; Stephanopyxis palmeriana (Greville) Grunow, 1884 [WoRMS]; Marine
Competition experiments were performed first with 4, then with 11 species of marine phytoplankton at various ratios of silicate: nitrate and various light intensities. Diatoms became dominant at Si:N ratios >25:1 while flagellates were the superior competitors at lower ratios. The light supply did not influence the competitive position of diatoms and non-siliceous flagellates in general, while it was important in determining the outcome of competition at the species level. In the 11 species experiments, Stephanopyxis palmeriana was the dominant diatom at high light intensities. It shared dominance with Lauderia annulata at medium and low light intensities and high Si:N ratios. Pseudonitzschia pungens was the dominant diatom at low light intensities and relatively low Si:N ratios. The green alga Dunaliella tertiolecta was the dominant flagellate at high light intensities, while at low light intensities the prymnesiophycean Chrysochromulina polylepis and the cryptophyte Rhodomonas were also important.