A Study On The Fundamental Biology And Ecological Restoration Of Zostera Japonica Along The Coastlines Of Shandong Province, China

Zostera japonica Ascherson&Graebner is one of the most common seagrassesalong the temperate coastlines of China. However, continuously distributed dwarfeelgrass dominated beds are rarely seen now and the related survey and research arelacking. Consequently, the objective of this study is to investigate the fundamentalbiological and ecological characteristics of Z. japinica populations, including theirmajor fouling plants, in the northern areas of China; also to explore one effectivetransplant measure to restore Z. japonica beds; and to evaluate the genetic variation ofZ. japnica between the northern and southern part of China.An annual survey in Swan Lake was conducted from September2011to January2013. The dwarf eelgrass bed in Swan Lake distributed continuously and covered ca.2.7×104m2. The growth of Z. japonica exhibited seasonal variation. The maximumshoot density of9880±2786shoots m–2and maximum total biomass of199g DW m–2occurred in August, and the flowering period was from July to November. The meanC/N atomic ratio of leaf was13.73±1.66, and the mean C/P ratio was230.28±29.62,respectively. The annual mean maximum C, N, and P standing stocks of Z. japonica inSwan Lake were calculated to be68.1g C m–2,5.17g N m–2, and0.72g P m–2,respectively. Water temperature is the key environmental factor that impacts theseasonal variation in this species. Compared to the Swan Lake, the dwarf eelgrass inHuiquan Bay showed a growth varied more gently among seasons.Main fouling plants in the seagrass beds in Swan Lake were Cladophorafascicularis and Ulva pertusa. The macroalgae C. fascicularis grew rapidly from Mayto July, but the maximum biomass was observed in January for the reason of storms.The macroalgae U. pertusa explosively grew from April to June, and got themaximum biomass1511+555g DW m^-2in June.From May to October2012, a field test was design to investigate the relationshipbetween the growth of Z. japonica and water depth. It was observed that Z. japonicagrowing in the depth of2m was in the best condition. Z. japonica could survive in a depth of6m or8m for a relatively short period of time （1-2months）, with lightavailability being a main limited factor. A small scale of Z. japonica transplant in theintertidal zone of Swan Lake got a high survival of100%, which demonstrated thefeasibility to restore Z. japonica beds in a large scale through transplanting.The sequence analysis based on cpDNA of matK and microstellite analysis offour Z. japonica populations （Weihai, Qingdao, Guangxi, and HongKong）, showedthat the former two and the latter two populations shared one cluster respectively. Itmeans that Z. japonica from the northern and southern part of China have significantgenetic differentiation, which was probably caused by the geographic isolationbetween those locations.