Characterization of Photosynthetic Rhythms in Marine Dinoflagellates

Abstract

Diurnal periodicity in photosynthetic capacity (Pmax)2 has been documented during the last 20 years for several groups of algae and mixed populations of phytoplankton (6,12,13,21). In these organisms, maximal productivity is restricted to a short time each day, and thus the periodic nature of photosynthesis complicates field measurements of primary production. It ap pears clear from the extensive data now available that environmental variables significantly affect the magnitude of photosynthesis, but have little or no effect on the timing of the photosynthetic maximum each day. Recently, Stross and his co-workers (2, 22) demonstrated a coincidence between the daily maximum in photosynthesis in Euglena and that in the rates of phosphate uptake in phosphorous-sufficient cultures. It appears unlikely that phosphorous availability serves to regulate the timing of the photosynthetic periodicity, since the maximal phosphate uptake rates occurred 6 hr after that in photosynthesis, when cultures were phosphorous-limited (3).A few marine algae have been examined extensively for endogenous features which might account for their photosynthetic rhythm (4,8,9,14,18,19,21,(25)(26)(27)(28). Although several of these studies demonstrate a daily periodicity in various photosynthetic parameters correlated with the cell cycle of synchronized cultures (4,17,18,28), it is not clear that these organisms divide either once a day or in synchrony in natural populations.

Circadian Changes in Ribulose-1,5-Bisphosphate Carboxylase/Oxygenase Distribution Inside Individual Chloroplasts Can Account for the Rhythm in Dinoflagellate Carbon Fixation

“…We have measured the mean oxygen consumption rate of cells in darkness as 62% (SD ϭ 11, n ϭ 15) of the oxygen evolution rate of illuminated cells (300 E·m Ϫ2 ·sec Ϫ1 cool-white light), averaged from several different times during a light/ dark cycle. These values represent the high end of the range reported previously for this organism (30 to 60%; Prezelin et al, 1977). Given the spherical geometry of the cells, more photosynthetically produced oxygen should diffuse out into the medium than in toward the cell center.…”

Characterization of diurnal photosynthetic rhythms in the marine diatom Skeletonema costatum grown in synchronous culture under ambient and elevated CO2

“…Figure 6 showed that the apparent carboxylating efficiencies (ACE) of the alga rhythmically changed and reached a maximum at 3 h of the light period, and the ACE was markedly higher at the low CO 2 than at the high CO 2 . Prézelin et al (1977) reported that the photosynthetic pigment (chlorophyll a and c 2 ) contents in marine dinoflagellates Glenodinium sp. and Ceratium furca were constant over circadian cycles, but Jacquet et al (2001) showed that the chlorophyll contents for three marine Prochlorococcus spp.…”

Photosynthesis–irradiance parameters of marine phytoplankton: synthesis of a global data set

“…In highly stratified and stable seas such as the oligotrophic gyres this may be the case, yet in more dynamic ocean conditions such as the Beaufort Sea, optical depth has been shown to have no more predictive skill, and sometimes less, than using depth alone (Huot et al, 2013). It is important to note that diel changes in the P-E parameters were not taken into account in this meta-analysis due to a lack of information on the time of sample collection in a significant number of observations, which can be a significant source of variability (MacCaull and Platt, 1977;Prézelin and Sweeney, 1977;Prézelin et al, 1986;Harding et al, 1983;Cullen et al, 1992;Bruyant et al, 2005). However, as noted in the study of Babin and co-authors (1996) such diel and day-to-day variability in the P-E parameters is likely to be far smaller when compared with differences across biogeochemical provinces subject to markedly different environmental forcing.…”