Cyanobacteria phosphorus

In this way, the near-linear chlorophyll-phosphorus relationship in lakes depends upon the outcome of a large number of interactive processes occurring in each one of the component systems in the model. One of the most intriguing aspects of those components is that the chlorophyll models do not need to take account of the species composition of the phytoplankton in which chlorophyll is a constituent. The development of blooms of potentially toxic cyanobacteria is associated with eutrophication and phosphorus concentration, yet it is not apparent that the yield of cyanobacterial biomass requires any more mass-specific contribution from phosphorus. The explanation for this paradox is not well understood, but it is extremely important to understand that it is a matter of dynamics. The bloom-forming cyanobacteria are among the slowest-growing and most light-sensitive members of the phytoplankton. ... 

In Anacystis nidulans, the intacellular PolyP level, which was manipulated by growth in the presence of various P concentrations in the medium (0.3-3 mM), increased with the Pi concentration up to 2.1 mM and decreased thereafter (Keyhani et al., 1996). Thus, the PolyP accumulation in cyanobacteria depended on the phosphorus content in the medium, as in other bacteria. The growth rate of cyanobacteria under phosphate starvation has been shown to be a function of the amount of previously accumulated PolyPs in the cells (Rhee, 1973). PolyP storage is a survival strategy under conditions of fluctuating phosphate supply characteristic of the environmental conditions, in which the cyanobacteria live (Falkner et al, 1995). 

The distribution of PolyPs between different fractions in cyanobacteria depends on culture age and growth conditions. For example, in Anabaena flos-aquae phosphorus is stored in different fractions depending on the nitrogen source. Under N2 fixing conditions, P is stored as sugar P, whereas with nitrate as the N source it is stored as PolyP (Thompson et al., 1994). 

Moisander, P. H., Steppe, T. F., Hall, N. S., Kuparinen, J., and Paerl, H. W. (2003). Variability in nitrogen and phosphorus limitation for Baltic sea phytoplankton during nitrogen-fixing cyanobacteria blooms. Mar. Ecol. Prog. Ser. 262, 81—95. 

Falcon, L. 1., Pluvinage, S., and Carpenter, E. J. (2005). Growth kinetics of marine unicellular N2-fixing cyanobacteria isolates in continuous culture in relation to phosphorus and temperature. Mar. Ecol. Prog. Ser. 285, 3-9. 

Pacific, and the North Pacific subarctic) are never completely consumed in support of primary production, because low levels of iron limit phytoplankton growth (Martin and Fitzwater, 1988 Martin et al, 1994 Coale et al, 1996 Boyd et al, 2000). Diatoms, which, unlike other dominant members of the phytoplankton, require silicon for growth, are often limited by low concentrations of silicic acid in surface waters (Brzezinski and Nelson, 1996 Nelson and Dortch, 1996). Growth of diazotrophic (N2 fixing) phytoplankton such as the cyanobacteria, Trichodes-mium, wiU be more susceptible to phosphorus and iron limitation, of course, than to nitrogen limitation. Even the concentration of dissolved CO2 in seawater (especially in the midst of a phytoplankton bloom) may limit instantaneous rates, although not ultimate levels, of primary production (RiebeseU et al, 1993 Wolf-Gladrow et al, 1999). 

Daphnia appeared after the decline of inedible cyanobacteria (Oscillatoria spp.), and thrived due to a sustained 10% decrease in its voracious predator Neomysis mercedis in 1965. The decrease in Neomysis occurred at about the same time as the introduction of longfin smelt, a predator known to specialize in eating Neomysis (Edmondson, 1994). Helped by a rapid flushing rate (2.3 yr) and stable dissolved phosphorus inputs since the end of sewage diversion (Edmondson, 1994), Lake Washington remains mesotrophic. 

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