Biogeography Of Seaweed In The Genus Ulva Of The Typical Bohai Sea

This paper is based on a important branch of the Kuroshio Current- the Yellow Sea Warm Current as well as Shandong coastal currents’ conditions. Nanhuangcheng Island,Zhangzi Island and Liugong Island were choosed as the most representative sampling sites within Huanghai and Bohai Sea. Nanhuangcheng Island and Zhangzi Island are influenced by the Yellow Sea Warm Current while Liugong Island is influenced by the Shandong coastal currents. We made a comprehensive collection of the green algae Ulva from those three islands. Morphology and molecular analysis methods were used to identify the Ulva samples in the three islands. This research based on comprehensive analysis nuclear rDNA ITS, chloroplast rbcL, elongation factor tufA and LSU, intial inqurey the differences of Ulva green algae among the three islands. This research explore the geographical differences of green algae Ulva on the three islands from the molecular level preliminary.Firstly, we used morphological observation and microsection to identify the species by special charactors such as thallus form, texture and colour; shape and form of the basal region, shape, size and arrangement of the cells,thickness of the thallus, chloroplasts location in the cell ect. We made morphological classification and identification according to the references of morphological data at home and abroad. It turns out that the algae species composition in Nanhuangcheng Island and the Zhangzi Island are basically the same, in which are distributed six Ulva green algae—Ulva linza, Ulva pertusa, Ulva compressa, Ulva prolifera, Ulva lactuca and Ulva intestinalis. The algae species composition in Liugong Island is distinction, mainly distributed with five Ulva green algae—Ulva linza, Ulva pertusa, Ulva prolifera, Ulva intestinalis and Ulva fasciata.Secondly, this research selected tufA(elongation factor Tu), ITS(internal transcribed spacer), rbcL(ribulose-1,5-bisphosphata carboxylase large / oxygenase subunit), LSU four genes to design a proper primer, PCR amplification the samples and sequencing. The sequencing results by calculate the base bias, analyze genetic distance and construct NJ phylogenetic tree. From the perspective of the precise molecular identification of the Ulva green algae in three islands, identification results coincided with the morphological identification results.. A more accurate judgment on the taxonomic status of algae samples was made to construct the NJ phylogenetic tree.Finally, this research based on the analysis of tufA(elongation factor Tu), ITS(internal transcribed spacer), rbcL(ribulose-1,5-bisphosphata carboxylase large / oxygenase subunit) and LSU, compared the differences of Ulva linza among the three islands, as well as a comprehensive analysis of the Ulva morphology on the field sampling site and their habitat, the results showing that the Nanhuagncheng Island and Zhangzi Island influenced by the Yellow Sea Warm Current are not obvious difference but there is a big difference among the Liugong Island which influenced by the Shandong coastal currents. This study provides a basis research for the biogeography of green algae, and partly supported the water cycle conditions on the Bohai Sea which influenced the geographical distribution of marine organisms.