Diel patterns of cell division in marine Synechococcus spp. (Cyanobacteria): use of the frequency of dividing cells technique to measure growth rate

Abstract

Natural populations of the planktonic cyanobacteria Synechococcus spp. exhibit a diel pattern in the frequency of dividing cells (FDC). Based on this observation, we tested the applicability of the FDC technique for estimating growth rate of a population grown on a IighWdark cycle. In laboratory experiments, the phycoerythrin-containing strains WH7803, WH8012, WH8107, and WH8108 were grown under various light and temperature conditions and the duration of division, td, a parameter necessary for the calculation of growth rate, was determined to be 3 h. Using this td value, growth rates of oceanic populations exhibiting diel patterns in FDC were found to range from 0.42 to 0.86 d-l, and these values exceed previous estimates of phytoplankton growth rates in oligotrophic regions. In experiments conducted at a Sargasso Sea station, growth rates calculated by the FDC technique were in close agreement with calculated instantaneous growth rates. In all cases, growth rates were higher for samplesincubated at surface light intensities than at 1 % surface light intensities. Using this technique under appropriate conditions, strain-specific growth rates can b e determined.

Diel variations in frequency of dividing cells and abundance of aerobic anoxygenic phototrophic bacteria in a coral reef system of the South China Sea

“…Similar diel patterns have been reported for FDC of heterotrophic bacteria by Kuipers et al (2000). Also, FDC values of picophytoplankton were higher in the early evening in natural environments (Campbell & Carpenter 1986). These similarities indicated that the pattern of higher division rate during night might be prevalent in marine microorganisms.…”

Growth and mortality rates of Prochlorococcus and Synechococcus measured with a selective inhibitor technique

“…The highest division rates of Synechococcus were realized in early evening, i.e. 12 to 15 h after dawn (Campbell & Carpenter 1986a), whereas Prochlorococcus started cell division after sunset . Therefore, dawn-to-dusk incubations underestimate the 'true' daily growth rate, especially for Prochlorococcus.…”

“…The growth rate of Synechococcus has been studied quite intensively (Landry et al 1984, Campbell & Carpenter 1986a, b, Iturriaga & Mitchell 1986, Iturriaga & Marra 1988, Burkill et al 1993). In contrast, there are only a few recent reports of the growth rates of Prochlorococcus (Goericke & Welschmeyer 1993).…”

Importance of the Viral Shunt in Nitrogen Cycling in Synechococcus Spp. Growth in Subtropical Western Pacific Coastal Waters

“…Cells undergoing division and having a complete cross wall between daughter cells were also counted. The frequency of cells in division (FDC) was determined by dividing the cells undergoing division by the total number of cells counted (Campbell and Carpenter 1986). To obtain reliable estimates of abundance, at least 1000 virus particles, 800 bacteria, and 200 Synechococcus spp.…”