The relative abundance of marine and subsurface associated archaea, rather than soil archaea, increased with temperature. Nevertheless, Leininger et al. showed that the quantity of crenarchaeota population is only slightly affected by temperature in the soil ecosystem. The relationships between environmental factors and the ecological ML 289 distribution of AOA and AOB have mainly been investigated in soil and marine ecosystems so far. However, the knowledge gaps about the responses of AOA and AOB to temperature in lake ecosystems need to be filled. In the present study, lake microcosms under different temperatures were constructed in the laboratory. The main objective of this research was to investigate the effects of temperature on the abundances and community compositions of AOA and AOB in lake sediments. Lake microcosms were constructed in cylindrical plexiglass containers, which included the lake water and sediment samples. To simulate the natural lake environment and to facilitate the collection of sediment for subsequent analysis, the top 20 cm of the collected sediment cores were sectioned into 1-cm intervals, and samples at the same depth were pooled together. Sediments were then sieved with a 0.6-mm mesh to SCH 442416 remove the macrofauna and large particles. The sieved sediment samples were fully homogenized and placed into plexiglass tubes with 1-cm intervals corresponding to their original depths. Lake water was filtered and added into the plexiglass tubes using intravenous needles. The top 1 cm sediment was collected as the 0 d sample. Then, the cylindrical containers were remained under dark environment and stored in the 15uC, 25uC and 35uC incubators for 40 d, respectively. Each temperature group had three replicates. Oxygen concentrations in the overlying water were monitored by a glass electrode to ensure the oxic environment during the incubations. After the incubation, the top 1 cm sediment samples were collected and transferred to sterile centrifuge tubes. The samples were stored at 270uC until further analysis. In the present study, the abundances of archaeal amoA gene showed positive correlations with the temperature. Cao et al. investigated the abundances of archaeal and bacterial amoA genes in surface sediments from the coastal Pearl River estuary to the South China Sea. No significant correlation was found between the temperature and the abundances of both archaeal and bacterial amoA genes.