Elemental composition of Microcystis aeruginosa under conditions of lake nutrient depletion
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
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| Keywords |
Algae
Analytical techniques > Spectroscopic techniques > X-ray spectroscopy > X-ray emission analysis
Chemical elements > Nonmetals > Phosphorus
Water bodies > Inland waters > Lakes
Microcystis aeruginosa (Kützing) Kützing, 1846 [WoRMS]
Fresh water |
| Authors | | Top |
- Krivtsov, V.
- Bellinger, E.G.
- Sigee, D.C.
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| Abstract |
Electron probe X-ray microanalysis (XRMA) was used to determine the elemental composition of the blue-green alga, Microcystis aeruginosa, in a stratified freshwater lake during the late summer. Colonies of this alga were initially observed in mid-July, at a time when phosphorus concentration in the lake water had decreased to minimal levels (total P 0.04 mg l−1). The P quota of these cells was high (mean concentration 132 mmol kg−1 dry weight) with a cell P to lake water P concentration ratio of 105. The elemental concentrations of Microcystis remained relatively stable throughout the sampling period (July–September), with mean cell concentrations of Mg, P, S and Ca showing no significant changes. Mean elemental ratios and the ratio of monovalent/divalent cations were also relatively constant (SE <10% mean). The pattern of cell elemental associations, determined by Factor and Pearson correlation analysis, was consistent throughout – with Mg, P, K and S forming a core tetrad of inter-correlated elements. The relative constancy of cell composition seen in Microcystis would be expected of an alga with a K-selection strategy. The continued high P quota over a period of nutrient depletion in lake water is consistent with the ability of this alga to sink to nutrient-rich lower regions of the water column. |
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