Project description:Characteristics of nirK-type denitrifier communities in the surface sediments from the South Yellow Sea and northern East China Sea
Project description:Characteristics of nirK-type ammonia-oxidizing archaeal communities in the surface sediments from the South Yellow Sea and northern East China Sea
Project description:Characteristics of bacterial, archaeal, and denitrifying microbial communities in the surface sediments from the South Yellow Sea and northern East China Sea
Project description:This study examined archaeal lipidome of a total of 48 sediment and soil samples across a wide range of environmental gradients, including sediment from hot springs in Tengchong, Yunan Province, sediment from acid mine drainages in Anhui and Guangdong provinces, permafrost soil from Tibet Plateau, soil from Western Sichuan Plateau, surface sediment of cold seeps and sediment core material from the South China Sea, and sediment from the East China Sea.
Project description:Coastal marine sediments, as locations of substantial fixed nitrogen loss, are very important to the nitrogen budget and to the primary productivity of the oceans. Coastal sediment systems are also highly dynamic and subject to periodic natural and anthropogenic organic substrate additions. The response to organic matter by the microbial community involved in nitrogen loss processes was evaluated using mesocosms of Chesapeake Bay sediments. Over the course of a 50-day incubation, rates of anammox and denitrification were measured weekly using 15N tracer incubations, and samples were collected for genetic analysis. Rates of both nitrogen loss processes and gene abundances associated with them corresponded loosely, probably because heterogeneities in sediments obscured a clear relationship. The rates of denitrification were stimulated more by the higher organic matter addition, and the fraction of nitrogen loss attributed to anammox slightly reduced. Furthermore, the large organic matter pulse drove a significant and rapid shift in the denitrifier community as determined using a nirS microarray, indicating the diversity of these organisms plays an essential role in responding to anthropogenic inputs. We also suggest that the proportion of nitrogen loss due to anammox in these coastal estuarine sediments may be underestimated due to temporal dynamics as well as from methodological artifacts related to conventional sediment slurry incubation approaches.
