Chinese Journal of Oceanology and Limnology Vol. 29 No. 3, P. 576-590, 2011 DOI: 10.1007/s00343-011-0159-7 Bacterial diversity, composition and temporal-spatial variation in sediment of Jiaozhou Bay, China* LIU Xin (刘欣) 1, 2 , XIAO Tian (肖天) 1 , LUAN Qingshan (栾青衫) 1, 2 , ZHANG Wenyan (张文燕) 1, 3 , WANG Mengqiang (王孟强) 1, 2 , YUE Haidong (岳海东) 1 1 Key Laboratory of Marine Ecology and Environment, Institute of Oceanology, Chinese Academy of Sciences, Qingdao 266071, China 2 Graduate University of Chinese Academy of Sciences, Beijing 100049, China 3 Ocean University of China, Qingdao 266003, China Received May 17, 2010; revision accepted Sep. 13, 2010 ' Chinese Society for Oceanology and Limnology, Science Press, and Springer-Verlag Berlin Heidelberg 2011 Abstract Studies on the diversity and distribution of bacterial populations will improve the overall understanding of the global patterns of marine bacteria and help to comprehend local biochemical processes and environments. We evaluated the composition and the dynamics of bacterial communities in the sediment of Jiaozhou Bay (China) using PCR-denaturing gradient gel electrophoresis (DGGE). Sediment samples were collected from 10 different sites in May, August, and November 2008 and in February 2009. There was significant temporal variation in bacterial community composition at all sites. However, the spatial variation was very small. The DGGE analyses of bacterial communities were used to divide the 10 stations into three types. Canonical correspondence analysis (CCA) revealed that the changes in bacterial communities were driven by sediment properties. Sequence analysis of DGGE band-derived 16S rRNA gene fragments revealed that the dominant bacterial groups in the sediment were of the classes γ-proteobacteria and δ-proteobacteria and phyla Bacteroidetes and Nitrospirae. Our results provide considerable insight into the bacterial community structure in Jiaozhou Bay, China. Keyword: microbial community; denaturing gradient gel electrophoresis (DGGE); sediment; Jiaozhou Bay 1 INTRODUCTION The physicochemical and structural characteristics of sediment provide microenvironments in which complex bacterial populations can evolve. One consistent finding in all sediment microbial studies is that sediment microbial communities are extremely diverse (Kemp and Aller, 2004). The taxonomic composition of benthic bacterial assemblages and their temporal and spatial dynamics in the marine environment are of major importance in determining the role bacteria play in modifying marine biogeochemistry (Castle and Kirchman, 2004). Temporal and spatial variation in bacterial community structure is a well described characteristic of sediment ecosystems (Bowman and McCuaig, 2003). Furthermore, the temporal changes in the structure of several marine bacterial communities were recently defined as predictable by Fuhrman et al. (2006) and Kan et al. (2006). These authors noted the consistency of variation in seasonal assemblages off the southern California coast and in the Chesapeake Bay, respectively. Assessing environmental factors that influence the structure of microbial communities in sediments is another way to improve our understanding of the function of these communities. The sediment microbial community structure is likely influenced by physicochemical factors such as temperature (Gonzalez-Acosta et al., 2006), salinity (Coci et al., 2005), and nutrient availability (Zhang et al., 2008). * Supported by the National High Technology Research and Development Program of China (863 Program) (No. 2007AA09Z434), the Knowledge Innovation Program of CAS (No.KZCX2-YW-213-3), the National Basic Research Program of China (973 Program) (No. 2011CB409804), and the National Natural Science Foundation of China (No. 40821004) ** Corresponding author: txiao@qdio.ac.cn