Abstract:During late April to early June, 2009, free-floating green algae broke out in some inner bays of Qingdao. We investigated the coastal areas with green algae and found that the estimated biomass of Ulva blooms in Qingdao Bay reached 138 t at its peak time. Through morphological and microscopic examinations, the green algae samples were preliminarily indentified as Ulva linza, though they possessed wider and longer thalli and thickened cell walls compared to the immobilized Ulva linza. PCR amplification and phylogenetic analysis of the 18S-28S rDNA internal transcribed spacer (ITS) and 5S rDNA spacer region (5SS) of the free-floating samples confirmed that the free-floating algae was Ulva linza. Morphological changes could help free-floating Ulva linza adapt to the new drifting life. This is the first time that the Ulva linza blooms in inner bays of Qingdao was reported.
