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Temperature Effect on Exploitation and Interference Competition among Microcystis aeruginosa, Planktothrix agardhii and, Cyclotella meneghiniana.

Gomes AM, de Oliveira e Azevedo SM, Lürling M - ScientificWorldJournal (2015)

Bottom Line: The temperature did not influence exploitation competition between MIJAC and other competitors and it was the best competitor in both temperatures.The growth of MIJAC was favored in strains exudates at 30°C, while CCAP was favored at 18°C, revealing that the optimum growth temperature was important to establish the competitive superiority.Therefore, we can propose two hypotheses: (i) different temperatures may results in production of distinct compounds that influence the competition among phytoplankton species and (ii) the target species may have different vulnerability to these compounds depending on the temperature.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Ecofisiologia e Toxicologia de Cianobactérias, IBCCF, Universidade Federal do Rio de Janeiro, CCS, Bloco G, 21949-900 Rio de Janeiro, RJ, Brazil ; Laboratório de Botânica, Instituto de Recursos Naturais, Universidade Federal de Itajubá, Avenida BPS 1303, Pinheirinho, 37500-903 Itajubá, MG, Brazil.

ABSTRACT
We studied the effect of temperature (18 and 30°C) on growth and on the exploitation and interference competition of three species: Microcystis aeruginosa (MIJAC), Planktothrix agardhii (PAT), and Cyclotella meneghiniana (CCAP). Coculturing the organisms in batch systems allowed for the examination of both competitive interactions, while the interference competition was studied in cross-cultures. The experiments were done during 10-12 days, and samples were taken for chlorophyll-a analysis, using PHYTO-PAM. The temperature did not influence exploitation competition between MIJAC and other competitors and it was the best competitor in both temperatures. PAT presented higher growth rates than CCAP in competition at 18 and 30°C. The temperature influenced the interference competition. The growth of MIJAC was favored in strains exudates at 30°C, while CCAP was favored at 18°C, revealing that the optimum growth temperature was important to establish the competitive superiority. Therefore, we can propose two hypotheses: (i) different temperatures may results in production of distinct compounds that influence the competition among phytoplankton species and (ii) the target species may have different vulnerability to these compounds depending on the temperature. At last, we suggest that both the sensitivity and the physiological status of competing species can determine their lasting coexistence.

No MeSH data available.


Chlorophyll-a-based growth rate of M. aeruginosa, P. agardhii, and C. meneghiniana cross-culture at two different temperatures (18°C and 30°C). Different letters represent significant differences at p < 0.05.
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fig7: Chlorophyll-a-based growth rate of M. aeruginosa, P. agardhii, and C. meneghiniana cross-culture at two different temperatures (18°C and 30°C). Different letters represent significant differences at p < 0.05.

Mentions: Differences in responses of target species suggest that the competitor organisms may produce multiple compounds that vary in their allelopathic potential as a function of species, strains, or even environmental factor [9, 29]. Our study indicated that temperature was also an important factor in the interference competition. The growth of M. aeruginosa was favored by all competitor exudates at 30°C (Figures 7(a) and 7(b)), which is frequently described as its optimum growth temperature [25]. C. meneghiniana was also stimulated by M. aeruginosa, P. agardhii, and three-culture exudates at its optimum growth temperature (18°C; Figures 7(e) and 7(f)). However, M. aeruginosa was not clearly influenced at 18°C and neither C. meneghiniana at 30°C. No pattern of response was observed for P. agardhii (Figures 7(c) and 7(d)). We cannot determine the exact mechanism responsible for stimulatory effect of competitor exudates on M. aeruginosa and C. meneghiniana, but it seems that at their optimum growth temperature, these species can make better use of the available resources. The ability of M. aeruginosa to use better the available resources should explain its competitive superiority, which is supposed to be able to take up organic matter from the extracellular medium and these compounds favor its development. Many phytoplankton species are capable of using dissolved organic compounds [30, 31]. Cyanobacteria produce many bioactive secondary metabolites, which phytoplankton may utilize for their own metabolism [32]. In the study of Carey and Rengefors [7], the cyanobacterium Gloeotrichia stimulated the growth of other phytoplankton, including Microcystis and Cyclotella species. They suggest that the positive effect may be by released nutrients, such as stored phosphorus and nitrogen. In our study, all species exudates had similar nutrient concentration, not justifying different responses (Table 2). Another possibility suggested was antibacterial and antifungal compounds production by cyanobacteria, which may benefit other phytoplankton species [7, 9].


Temperature Effect on Exploitation and Interference Competition among Microcystis aeruginosa, Planktothrix agardhii and, Cyclotella meneghiniana.

Gomes AM, de Oliveira e Azevedo SM, Lürling M - ScientificWorldJournal (2015)

Chlorophyll-a-based growth rate of M. aeruginosa, P. agardhii, and C. meneghiniana cross-culture at two different temperatures (18°C and 30°C). Different letters represent significant differences at p < 0.05.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4561989&req=5

fig7: Chlorophyll-a-based growth rate of M. aeruginosa, P. agardhii, and C. meneghiniana cross-culture at two different temperatures (18°C and 30°C). Different letters represent significant differences at p < 0.05.
Mentions: Differences in responses of target species suggest that the competitor organisms may produce multiple compounds that vary in their allelopathic potential as a function of species, strains, or even environmental factor [9, 29]. Our study indicated that temperature was also an important factor in the interference competition. The growth of M. aeruginosa was favored by all competitor exudates at 30°C (Figures 7(a) and 7(b)), which is frequently described as its optimum growth temperature [25]. C. meneghiniana was also stimulated by M. aeruginosa, P. agardhii, and three-culture exudates at its optimum growth temperature (18°C; Figures 7(e) and 7(f)). However, M. aeruginosa was not clearly influenced at 18°C and neither C. meneghiniana at 30°C. No pattern of response was observed for P. agardhii (Figures 7(c) and 7(d)). We cannot determine the exact mechanism responsible for stimulatory effect of competitor exudates on M. aeruginosa and C. meneghiniana, but it seems that at their optimum growth temperature, these species can make better use of the available resources. The ability of M. aeruginosa to use better the available resources should explain its competitive superiority, which is supposed to be able to take up organic matter from the extracellular medium and these compounds favor its development. Many phytoplankton species are capable of using dissolved organic compounds [30, 31]. Cyanobacteria produce many bioactive secondary metabolites, which phytoplankton may utilize for their own metabolism [32]. In the study of Carey and Rengefors [7], the cyanobacterium Gloeotrichia stimulated the growth of other phytoplankton, including Microcystis and Cyclotella species. They suggest that the positive effect may be by released nutrients, such as stored phosphorus and nitrogen. In our study, all species exudates had similar nutrient concentration, not justifying different responses (Table 2). Another possibility suggested was antibacterial and antifungal compounds production by cyanobacteria, which may benefit other phytoplankton species [7, 9].

Bottom Line: The temperature did not influence exploitation competition between MIJAC and other competitors and it was the best competitor in both temperatures.The growth of MIJAC was favored in strains exudates at 30°C, while CCAP was favored at 18°C, revealing that the optimum growth temperature was important to establish the competitive superiority.Therefore, we can propose two hypotheses: (i) different temperatures may results in production of distinct compounds that influence the competition among phytoplankton species and (ii) the target species may have different vulnerability to these compounds depending on the temperature.

View Article: PubMed Central - PubMed

Affiliation: Laboratório de Ecofisiologia e Toxicologia de Cianobactérias, IBCCF, Universidade Federal do Rio de Janeiro, CCS, Bloco G, 21949-900 Rio de Janeiro, RJ, Brazil ; Laboratório de Botânica, Instituto de Recursos Naturais, Universidade Federal de Itajubá, Avenida BPS 1303, Pinheirinho, 37500-903 Itajubá, MG, Brazil.

ABSTRACT
We studied the effect of temperature (18 and 30°C) on growth and on the exploitation and interference competition of three species: Microcystis aeruginosa (MIJAC), Planktothrix agardhii (PAT), and Cyclotella meneghiniana (CCAP). Coculturing the organisms in batch systems allowed for the examination of both competitive interactions, while the interference competition was studied in cross-cultures. The experiments were done during 10-12 days, and samples were taken for chlorophyll-a analysis, using PHYTO-PAM. The temperature did not influence exploitation competition between MIJAC and other competitors and it was the best competitor in both temperatures. PAT presented higher growth rates than CCAP in competition at 18 and 30°C. The temperature influenced the interference competition. The growth of MIJAC was favored in strains exudates at 30°C, while CCAP was favored at 18°C, revealing that the optimum growth temperature was important to establish the competitive superiority. Therefore, we can propose two hypotheses: (i) different temperatures may results in production of distinct compounds that influence the competition among phytoplankton species and (ii) the target species may have different vulnerability to these compounds depending on the temperature. At last, we suggest that both the sensitivity and the physiological status of competing species can determine their lasting coexistence.

No MeSH data available.