| Porphyra yezoensis is the main marine economic aver in our country, and we often meet many problems like disease during cultivating. The biological diversity of the Phytoplankton and Planktobacteria in the water environment could reflect current status of that. It’s eutrophication also determines the biological diversity of the Phytoplankton and Planktobacteria, while cultivating P.yezoensis and manual intervention activities make changes of initial conditions of the water environment. This paper does primary research in the following five aspects and is surrounded by cultivating P.yezoensis makes influence on the biological diversity of Phytoplankton and Planktobacteria in proper sea position, which is systematically based on summarising the planktonic algae and bacteria ecology research progress at home and abroad. Effects of P.yezoensis cultivation on phytoplankton biodiversityFrom November to December, 2012, we separately set four sampling dot in P. yezoensis cultivation and non-cultivation area in HaizhouBay, Jiangsu Province. Then, we collect water from sea-surface and research on rbcL gene in P.yezoensis cultivation and non-cultivation area firstly, then study the influence of the biological diversity by cultivating P.yezoensis; There are 8 kind of marine microalgae in P.yezoensis non-farming area,among which Cryptomonas accounts for 22% of the total number of coloning and the dominance. while Thalassiosira and Skeletonema costatum accounts for 6% and 2% respectively;however, there are 10 kind of Eu alga in farming area, among which Heterothrix debilis accounts for 22%. Only 3 kind of Eu alga were found in both area(Chlorella、Cryptomonas and S. costatum). It show strikingly difference in plankton community structure from laver cultivating and non-cultivating area. The Planktonic algae shannon index in P.yezoensis non-cultivating area is 3.273.the index in cultivating area is 3.654. Evenness index value was 1.090 and 1.040, respectively. it shows that plankton genetic diversity in the cultivating area is more abundant. While the maturity and stabiliy of community is more high in non-cultivating area. Effects of P. yezoensis cultivation on planktobacteria biodiversityThis paper fistly research on the influence on the biological diversity of Planktobacteria by cultivating P.yezoensis with high-throughput sequencing technique. Four sampling dots are separately set up in P.yezoensis cultivation and non-cultivation area. Through identified, the planktonic bacteria belongs to 15 doors, 141 generas in total, 253 species of planktonic bacteria and some undetermined. The dominant fungi in culture area are Proetobacteria(44%)、Bacteroidetes(41%)、Firmicutes(9%)while in uncultured area are Proetobacteria(32%)、Bacteroidetes(25%)、Firmicute(38%)、Fusobacteria(5%);Proetobacteria、Bacteroidetes、Firmicutes take hold in the whole sea area bacteria flora structure. And that Verrucomicrobia 、Actinobacteria、Cyanobacteria are only found in cultivate area which consist 5% total bacterium. The study confirms that planktonic bacteria in laver farming areas is higher than non-farming areas, and there is strong correlation between them. But the coverage in non-farming areas is higher than farming.so is the maturity and stability of the flora. Allelopathy of Marinobacter adhaerens HY-3 and Skeletonema costatum Allelopathy is a complex physiological ecological phenomenon. Diatom often adhere to P.yezoensis, leading P.yezoensis sicking and decline in quality. According to reports in the literatures, Marinobacter adhaerens and diatom has interaction. A marine bacteria strains were isolated from seawater, identified as M.adhaerens HY-3. We choose S. costatum as object of study to research the Allelopathy of Marinobacter adhaerens HY-3 and S. costatum.Studies have shown that when bacterier concentration is above 10-4,it would produced growth inhibition on costatum. 10 days later, the algae growth of 10-4,10-6,10-8 is 70%,23%,22% as control group, respectively. and the chlorophyll synthesis is 88%,62%,60% as control group. addtionally, the inhibition effect is increasing as the growth of bacterier concentration. But when add bacterial extracellular metabolites had no effect on the growth of S. costatum. This paper has builded quantitative relation that M.adhaerens HY-3 has inhibiting effect on skeletonema costatum. For Allelopathic effect is acted by bacteria-alga direct cotact or metabolin existing allelopathy factors, further research is needed until drawig the scientific conclusion. Isolation and identification of endophytic bacteria from cultivating P.yezoensis in Haizhou BayIsolation and identification of endophytic bacteria from cultivating P.yezoensis in Haizhou Bay,Jiangsu Province, study it’s growth promoting effect. Four endophytic bacteria separated from P. yezoensis thallus identified by morphological, physiological, biochemical test, and 16 s ribosomal DNA sequence analysis. The 4 endophytic bacteria strains, named ZCN-I, ZCN-II, ZCN-III, ZCN-IV, all belong to bacillus sp. ZCN-I and ZCN-III are classified to Bacillus licheniformis and Paenibacillus barcinonensissp, respectively. They also were evaluated for their ability to promote the growth of P. yezoensis. ZCN-I and ZCN-II could promote P.yezoensis growth significantly, which could reach as high as 2.5 times and 1.9 times compared with the control. ZCN-IV didn’t have this effect. Results demonstrates a potential application of endophytic bacteria in P. yezoensis, which has certain growth promoting effect. Isolation and identification of pathogen of yellow spot disease from cultivating P.yezoensis in Haizhou BayWith analysising the pathogen of yellow spot disease and separating it’s pathogenic bacteria, multiplicity infection reactivation combined with morphological observation、physiological and biochemical identification and 16 SrRNA sequence alignment, the main pathogenic bacterium of the yellow spot disease is Pseudoalteromonas tetraodonis. Some basic control methods are listed.During cultivating P.yezoensis, organic pollutant would be in high concentration and the degree of eutrophication could enhance due to metabolism of the Nori growth process、the algae secreting and human activities, which influence the biological diversity of the Phytoplankton and Planktobacteria. Allelopathy is proceed by bactiria and algae contacting, metabolin doesn’t exist allelopathy factors. the main pathogenic bacterium of the yellow spot disease is P. tetraodonis. |
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