Phosphorus uptake and growth of blue‐green alga, Microcystis aeruginosa

Abstract

The specific uptake rate Q(p) of orthophosphate (expressed throughout as phosphorus) and the specific growth rate mu of Microcystis aeruginosa were measured using batch-precultured cells, whose growth phase, and intracellular and extracellular phosphorus concentrations f(p) and P, respectively, had been changed. When the cells from phosphorus-rich precultures were used, smaller values of Q(p) (0.1-0.3 microg P mg dry wt. (-1) h (-1)) were observed. However, if phosphorusstarved cells were used, the initial value of Q(p) was enhanced to more than ten times those smaller values referred to above, but declined rapidly with time after the transfer. Q(p) leveled off at around t = 4 h, when f(p) approached the maximum value, even if phosphorus was still available in the medium. A new correlation was presented here with respect to Q(p) as a function of P and f(p) as follows: [Qp = Qp,max P/Kp + P (fp,max-fp)/fp,max-fp)] Although numerical values of parameters involved in the equation depend on physiological state (or preculture history) of the cells, the above equation could account not only for phosphorus uptake, during which changes in phosphorus content in the cells were observed, but also for initial rates of uptake presented previously by other workers. mu Values were confirmed to be a hyperbolic function of f(p) as has been suggested by previous workers.

Quantitative studies on phosphorus transference occuring between Microcystis aeruginosa and its attached bacterium (Pseudomonas sp.)

“…When the intracellular phosphorus content of M. aeruginosa was luxury, it grew by utilization of the intracellular phosphorus in its lag and exponential phases (Okada & Sudo, 1982), thus, only 20% of intracellular phosphorus was released form M. aeruginosa to aqueous solution and to Pseudomonas. However, M. aeruginosa released a lot of phosphorus in its stationary and decline phases while it could simultaneously provide Pseudomonas with organic carbon and trace elements (Sommaruga & Robarts, 1997;Worm, 1998;Brunberg, 1999).…”

Comparative studies on physiological responses to phosphorus in two phenotypes of bloom-forming Microcystis

“…Under these conditions, the Microcystis biomass was restricted to some extent and the protein content per cell in vivo decreased (Ou et al, 2005). The initial specific uptake rate of P i in P-starved Microcystis cells was 10 times higher than that in the cells from P-rich precultures (Okada et al, 1982). Due to high V max and low P content, Microcystis outcompeted Oscillatoria in P-limited conditions that restricted the growth rate (Kromkamp et al, 1989).…”

The Importance of Cellular Phosphorus in Controlling the Uptake and Toxicity of Cadmium and Zinc in Microcystis Aeruginosa, A Freshwater Cyanobacterium

“…Microcystis aeruginosa also can develop adaptive strategies to cope with P‐limited conditions. With a sufficient supply of P, the P‐deficient M. aeruginosa cells take up P 10fold faster than P‐replete cells do [1]. The cells can store P as polyphosphate bodies under P‐sufficient conditions, and the polyphosphate bodies are then reused to sustain normal physiological processes when the cells become P‐limited [2].…”