Temperature affects the response of heterotrophic bacteria and mixotrophic algae to enhanced concentrations of soil extract

Abstract

To investigate the consequences of increased temperature and enhanced input of dissolved organic matter (DOM) into lakes for heterotrophicic bacteria and for mixotrophic algae which use DOM in addition to photosynthesis, the hypotheses were tested whether (1) both bacteria and mixotrophic algae benefit from increased input of DOM, or (2) increased DOM input enhances bacterial biomass and thereby decreases algal biomass. Growth experiments in batch cultures, exudation measurements, and competition experiments in chemostats were performed at two temperature levels. Increased temperature stimulated the autotrophic growth rate of Chlorella protothecoides. Bacteria and Chlorella increased their heterotrophic growth rates at higher DOM concentration at lower temperature whereas enhanced DOM concentration hardly stimulated their growth at higher temperature. In chemostats, enhanced input of soil extract increased both bacterial and algal biomass at lower temperature whereas bacterial biomass increased only slightly and algal biomass decreased at higher temperature. Thus, the temperature determines the response of microorganisms to enhanced DOM concentration.

Efficient removal of imidacloprid from sewage by Scenedesmus sp. TXH and the effects of environmental factors on its removal

“…It is well known that the appropriate temperature for some microalgal strains is between 20 to 35 °C 40 . In addition, different temperatures in algae–bacteria system affect various biological enzyme activities, which influence the production of algae–bacteria system and the maintenance of flocculation homeostasis 41 . The results showed that Scenedesmus sp.…”

“…40 In addition, different temperatures in algae-bacteria system affect various biological enzyme activities, which influence the production of algae-bacteria system and the maintenance of flocculation homeostasis. 41 The results showed that Scenedesmus sp. TXH was efficient in removing N, P and NH 4 -N + from sewage under different temperature conditions.…”