Genetic diversity and its seasonal variation of Jiaozhou Bay phytoplankton determined by rbcL gene sequencing

Ribulose-1, 5-bisphosphate carboxynase/oxygenase large subunit gene (rbcL) of Jiaozhou Bay phytoplankton was amplified from spring, summer and autumn surface seawater DNAs and cloned respectively.About 50 clones were randomly selected from each library and sequenced.If identical amino acid sequences are considered as the same operational taxonomy unit (OTU), 61 OTUs are identified according to inferred amino acid sequences, among them, 21 from spring seawater, 15 from summer seawater and 25 from autumn seawater.Shannon index calculated from OTU abundances reflects the genetic diversity of a community.The indexes of spring, summer and autumn surface seawater phytoplankton are 2.69, 2.44 and 2.76 respectively, indicating that phytoplankton genetic diversity of autumn seawater is the richest.Seasonal variation of phytoplankton community is significant; the community compositions of three seasons are almost completely different except for the two OTUs shared by summer and autumn.Surface seawater phytoplankton communities are possibly metacommunities different spatially and temporally.