Increased Temperature Due to Global Warming Alters the Respiratory Potential in Aquatic Organisms from an Oligotrophic Lake.

The influence of elevated temperature was studied on the respiratory potential of a microplankton community, two macrophytes species ( Myriophyllum spicatum and Chara aspera), and sediments, all from an oligotrophic lake, in order to estimate their susceptibility to temperature change. Samples collected in winter, spring, summer and autumn were incubated at three different temperatures. The respiratory potential, measured as electron transport system (ETS) activity at a standard temperature of 20 °C was, in average, greater at higher incubation temperatures for 117% in microplankton and for 30% in sediments, indicating that elevated temperature influenced the respiratory capacity of the microbial communities for mineralization of organic matter through respiration. The large increases of respiratory potential in winter microplankton community (for 184% at the highest incubation temperature compared to the temperatures of the multiyear period) and spring microplankton community (190%), and in spring sediment (64%) reveal that those communities are most susceptible to elevated temperatures during the coldest period of a year and at the beginning of lake warming. The respiratory activity of Myriophyllum spicatum was independent of incubation temperature, indicating its wide physiological tolerance. The lower respiratory potential at higher temperatures in Chara aspera optimized the use of energy in plants. (© 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]