Study On Phytoplankton Communityin The Marine Ranching Area In Summerof Zhangzi Island Waters

Marine ranchingwas a new ecological Marine fisheries production system, and constructedin our countryto alleviate the phenomenon of fishery resources recession and environment degradation. Zhangzi Islandwhich located in 39 degreesnorth latitude has built the largestmarine ranching of our China based on the good environmental conditions. The article study on phytoplanktoncommunity characteristics in the marine ranching area at costal Zhangzi Island through investigation, sampling, identification, analysis,etc.and the investigation time we chosen in 2010 summer, 2011 summer, 2012 summer, 2014 summer, 2015 summer, respectively.Species composition and dominant species: A total of 73 phytoplankton species was detected, which belonged to 39 genera, 3 phyla in 5 surveys, among them, the Bacillariophyta including 58 species belonged to 30 generaand accounted for 79.45% of the total species, the Pyrrophyta including 14 species belonged to 8 genera and accounted for 19.18% of the total, the Chrysophyta including 1 species belonged to 1 genera and accounted for 1.37% of the total. The Bacillariophytacurrencied dominate with percentage of 74.07%-80.77%, and the Pyrrophyta was the second largest phyla with percentage of 16.67%-24.24%, the Chrysophyta was the least with percentage of 0%-4.17%. The dominant species: there are 4 species which belonged to the Bacillariophyta in 2010; there are 3 species which belonged to the Bacillariophyta in 2011; there are4 species belonged to the Bacillariophyta and 2 species belonged to the Pyrrophyta in 2012; there are 3 species belonged to the Bacillariophyta and 3 species belonged to the Pyrrophyta in 2014; there are2 species belonged to the Bacillariophyta and 2 species belonged to the Pyrrophyta in 2015.Phytoplankton abundance and space distribution: the phytoplankton abundance range in 1.5880×104 cells/m3-142.6286×104cells/m3 with mean value of 34.3415×104cells/m3, and the minimum appeared in the ZZD07 stationof 2014 survey, the maximum value appeared in the ZZD09 stationof 2010 survey. The bigger phytoplankton abundance appeared in the northwestern water area of Zhangzi Island, the costal water area off Dalian Island, the northern and northwestern water area of Dahao Island; the smaller phytoplankton abundance appeared in the middle water area of three Island(Zhangzi Island, Dalian Island and Dahao Island), the southern water area of Zhangzi Island, the southern water area of Dahao Island.Phytoplankton biomass and space distribution:the phytoplankton biomass range in 0.0023g/m3-34.8442 g/m3 with mean value of 3.8041 g/m3, and the minimum appeared in the ZZD06 stationof 2010 survey, the maximum value appeared in the ZZD02 stationof 2015 survey.There wasbig difference among the phytoplankton communitys space distribution of ten stations.Diversity index and the space distribution: the Shannon-Wiener index(H’) range in 0.4885-1.9624 with mean value of 1.3241 in 5 surveys, among them, the maximum H’ appeared in 2012 summer and the minimum H’ appeared in 2015 summer; the Pielou eveness index(J’) range in 0.1583-0.9671 with mean value of 0.5740 in 5 surveys, among them, the maximum J’ appeared in 2012 summer and the minimum J’appeared in 2015 summer; the margalef richness index(D) range in 0.8820-4.9221 with mean value of 2.3518 in 5 surveys, among them, the maximum D appeared in 2015 summer and the minimum D appeared in 2010 summer.There was big difference among the phytoplankton communitys of 5 years of H’,J’ and D.The correlationof community indexes and space distribution:the phytoplankton abundance was fond to be significantly(P < 0.05) positive correlate to the phytoplankton biomass, the phytoplankton bioamass was fond to be significantly(P < 0.05) positive correlate to the phytoplankton J’, and the phytoplankton abundance was fond to be significantly(P < 0.05) positive correlate to the phytoplankton J’ or D some of years.The Phytoplankton community similarity analysis: the phytoplankton community of ZZD05, ZZD06, ZZD07, ZZD08 have higher community similarityamong 10 ten stations, and the rest stations have higher similarity.Some of environmental factors have significant effect on phytoplankton Community: they are the water temperature, salinity, pH, dissolved oxygen(DO), chemical oxygen demand(COD), oil, nitrate, ect.