Limits...
The outcome of competition between the two chrysomonads Ochromonas sp. and Poterioochromonas malhamensis depends on pH.

Moser M, Weisse T - Eur. J. Protistol. (2011)

Bottom Line: Results were compared to growth rates measured earlier in single species experiments over the same pH range.We tested the hypothesis that the acidotolerant species benefits from competitive release under conditions of acid stress.Adverse effects mediated via allelopathy, either directly on the competing flagellate or indirectly by affecting its bacterial food, might also have affected the outcome of competition.

View Article: PubMed Central - PubMed

Affiliation: Institute for Limnology of the Austrian Academy of Sciences, Herzog Odilostraße. michael.moser@assoc.oeaw.ac.at

Show MeSH

Related in: MedlinePlus

LN-transformed cell numbers of Ochromonas sp. (circles) and Poterioochromonas malhamensis (triangles) in the course of the competition experiments at pH 2.5 (A), pH 3.5 (B), pH 5.0 (C), and pH 7.0 (D). Symbols represent mean values of triplicates; the error bars denote 1 SD. A linear regression (dashed line) was calculated over the exponential growth of each strain.
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC3117142&req=5

fig0005: LN-transformed cell numbers of Ochromonas sp. (circles) and Poterioochromonas malhamensis (triangles) in the course of the competition experiments at pH 2.5 (A), pH 3.5 (B), pH 5.0 (C), and pH 7.0 (D). Symbols represent mean values of triplicates; the error bars denote 1 SD. A linear regression (dashed line) was calculated over the exponential growth of each strain.

Mentions: Irrespective of pH, cell numbers of both flagellate species decreased during the first 24 h of the experiments. In the experiment conducted at pH 2.5, cell numbers of both strains were similar and relatively constant during the initial 4 days (Fig. 1A), ranging from 40,000 to 65,000 cells ml−1. Beginning on day 4 of the experiment, the abundance of Ochromonas sp. increased exponentially until the end of the experiment. The slope of the regression line corresponded to an average μ of 0.39 d−1 during days 3–8, i.e. growth of Ochromonas sp. in the competition experiment was not statistically different from when grown alone at pH 2.5 (Fig. 2A). The final abundance of Ochromonas sp. was close to 300,000 cells ml−1, while the final abundance of P. malhamensis was lower than at the beginning of the experiment.


The outcome of competition between the two chrysomonads Ochromonas sp. and Poterioochromonas malhamensis depends on pH.

Moser M, Weisse T - Eur. J. Protistol. (2011)

LN-transformed cell numbers of Ochromonas sp. (circles) and Poterioochromonas malhamensis (triangles) in the course of the competition experiments at pH 2.5 (A), pH 3.5 (B), pH 5.0 (C), and pH 7.0 (D). Symbols represent mean values of triplicates; the error bars denote 1 SD. A linear regression (dashed line) was calculated over the exponential growth of each strain.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3117142&req=5

fig0005: LN-transformed cell numbers of Ochromonas sp. (circles) and Poterioochromonas malhamensis (triangles) in the course of the competition experiments at pH 2.5 (A), pH 3.5 (B), pH 5.0 (C), and pH 7.0 (D). Symbols represent mean values of triplicates; the error bars denote 1 SD. A linear regression (dashed line) was calculated over the exponential growth of each strain.
Mentions: Irrespective of pH, cell numbers of both flagellate species decreased during the first 24 h of the experiments. In the experiment conducted at pH 2.5, cell numbers of both strains were similar and relatively constant during the initial 4 days (Fig. 1A), ranging from 40,000 to 65,000 cells ml−1. Beginning on day 4 of the experiment, the abundance of Ochromonas sp. increased exponentially until the end of the experiment. The slope of the regression line corresponded to an average μ of 0.39 d−1 during days 3–8, i.e. growth of Ochromonas sp. in the competition experiment was not statistically different from when grown alone at pH 2.5 (Fig. 2A). The final abundance of Ochromonas sp. was close to 300,000 cells ml−1, while the final abundance of P. malhamensis was lower than at the beginning of the experiment.

Bottom Line: Results were compared to growth rates measured earlier in single species experiments over the same pH range.We tested the hypothesis that the acidotolerant species benefits from competitive release under conditions of acid stress.Adverse effects mediated via allelopathy, either directly on the competing flagellate or indirectly by affecting its bacterial food, might also have affected the outcome of competition.

View Article: PubMed Central - PubMed

Affiliation: Institute for Limnology of the Austrian Academy of Sciences, Herzog Odilostraße. michael.moser@assoc.oeaw.ac.at

Show MeSH
Related in: MedlinePlus