title: Temperature Effect on Exploitation and Interference Competition among Microcystis aeruginosa, Planktothrix agardhii and, Cyclotella meneghiniana.
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.
authors.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.
authors.forename: Andreia Maria da Anunciação
authors.initials: AM
authors.lastname: Gomes
authors.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.
authors.forename: Sandra Maria Feliciano
authors.initials: SM
authors.lastname: de Oliveira e Azevedo
authors.affiliation: Aquatic Ecology & Water Quality Management Group, Department of Environmental Sciences, Wageningen University, 6708 PB Wageningen, Netherlands ; Department of Aquatic Ecology, Netherlands Institute of Ecology (NIOO-KNAW), 6708 PB Wageningen, Netherlands.
authors.forename: Miquel
authors.initials: M
authors.lastname: Lürling
mesh_terms: D018929:Cell Culture Techniques; D002734:Chlorophyll / Q000031:analogs & derivatives / Q000096:biosynthesis; D000458:Cyanobacteria / Q000502:physiology*; D017377:Diatoms / Q000502:physiology*; D008027:Light; D056265:Microbial Interactions; D046931:Microcystis / Q000502:physiology*; D010839:Phytoplankton / Q000502:physiology*; D013696:Temperature
chemical_list: D002734:Chlorophyll; C085815:chlorophyll a'