COMPARATIVE PHYSIOLOGICAL STUDY OF MARINE DIATOMS AND DINOFLAGELLATES IN RELATION TO IRRADIANCE AND CELL SIZE. II. RELATIONSHIP BETWEEN PHOTOSYNTHESIS, GROWTH, AND CARBON/CHLOROPHYLL a RATIO^1,2

Abstract

Photosynthetic rates, growth rates, cell carbon, cell protein, and chlorophyll a content of two diatom and two dinoflagellate species were measured. The microalgae were chosen to have one small and one large species from each phylogenetic group; the two size categories differed from each other by 1.5 orders of magnitude in terms of cell carbon or cell protein. The cultures for the experiments were grown under continuous light at an irradiance high enough for the light‐saturation of growth for all four species. The four species were found to have similar maximum photosynthetic rates per unit chlorophyll a. The diatom species showed lower carbon/chlorophyll a ratios and higher photosynthetic rates per unit carbon than the dinoflagellates. The higher growth rates of the diatoms were shown to be related to their higher photosynthetic rates per unit carbon. The ecological significance of the physiological difference between these two groups of microalgae is discussed.

Effects of the diatom-Emiliana huxleyi succession on photosynthesis, calcification and carbon metabolism by size-fractioned phytoplankton

“…4) agreed with the values reported for an actively growing E. huxleyi population during the 1991 North Atlantic bloom (Fernandez et al, 1993) . Our results show that the shift from a diatom-dominated assemblage to an E. huxleyidominated assemblage results in a sharp reduction of the phytoplankton standing stock and the rates of photosynthesis on a cellular carbon basis (Figs 2 and 4), which is in accordance wit the higher growth potential characteristic of diatoms as compared with non-diatom species (Chan, 1980 ;Furnas, 1990 ;Aksnes & Egge, 1991) .…”

Effect of nutrients on culture dynamics of marine phytoplankton

“…The higher C:chl a ratio of P. micans compared to the other two species is in agreement with other published fi ndings (Table 2). Under similar culture conditions, C:chl a ratio for dinofl agellates has been reported to be much higher than for diatoms (Chan, 1980). Steele and Baird (1962) reported that C:chl a ratio of S. costatum changed between 28 and 200 in the fi rst 7 d of their experiment under nitrate limitation (170 µM) and similar light conditions to our study.…”

Phytoplankton and bacterial assemblages in ballast water of U.S. military ships as a function of port of origin, voyage time, and ocean exchange practices

“…As more general observations, Forbes and Hallegraeff (1998) noted that viable diatom cells are common in ballast waters of commercial cargo ships, and various diatom species can survive extended periods in low light or darkness (e.g. Smayda and Mitchell-Innes, 1974;Chan, 1980;Lewis et al, 1999). Bacterial abundance, in contrast, was remarkably similar among the ballast tanks samples, and considerably higher ($10 11 cells m À3 ) than in the tanks studied by Ruiz et al (1999a,b; $10 6 cells m À3 ).…”