| Seaweeds mainly including marine red algae, brown algae and green algae (macro-blue algae are not included in this study) are important components of marine ecological system, which contribute about 10% primary production within only 1% marine area.Under the pressure of global change and human activities, there were 2 main changes in diversity and distribution of seaweeds:first, due to the substitution of artificial shoreline to the natural shoreline in large areas, the former distribution pattern of seaweeds had changed; second, most seaweeds intent to gather in several islands which were seldom effected by human activities.Bohai Sea and Yellow Sea were important areas for seaweed study. According to the above 2 main changes,3 typical sites including the boundary areas of seaweed flora, artificial shoreline areas and island seaweed bed were selected to study the seaweed biographical distribution in this broad area. A new species of Protomonostroma was discovered and identified during the above investigations, and systematic studies were carried out both in morphological and molecular methods. In order to positively control the seaweeds distribution and protect the seaweed biodiversity in Bohai Sea and Yellow Sea, this paper proposed a seaweed-exporting protection method. The main study contents were as below.Investigation of the flora boundary areas was carried out in Yalu River mouth and Yangtse River mouth seperately. According to the trends of temperature variation in these areas, the scope of seaweed flora in Bohai Sea and Yellow Sea intent to change in the coming decades, and this change might be first reflected in boundary areas. Since the soft substrate was not suitable for seaweed living, there were little historical records of seaweeds in these areas. We studied 2 islands in Yalu River mouth and most of Jiangsu shoreline including Yangtse River mouth (exept for Lianyungang city), collected and identified 7 and 8 species in the 2 areas separately. In Yalu River mouth, the 7 species (6 red ones and 1 green one) included 2 cold temperate species,3 warm temperate species and 2 subtropic species. While in Yangtse River mouth and nearby areas, the 8 species (all are green ones) included 3 cold temperate species,4 warm temperate species and 1 tropic species.The species diversity was much lower than in Lianyungang City (about 70 species) which was next to the study areas. According to the temperature character of seaweeds, the 2 flora boundary areas were still within the flora unit of Western Yellow Sea and had no obviouse changes in seaweeds construction and distribution at present. Although there were very few seaweed species distributed in the 2 areas, it was necessary to carry out substantial research due to the dramatic environmental changes, not only the raise of the SSTs in summer made the northward movement of warm species possible, but also the recent supplement of artificial hard substrates made it possible for seaweed to be introduced from nearby floras and live in the new habitat. These environmental changes increased the chance for seaweeds construction and distribution to change within the flora boundary areas, and these changes were also critical to evaluate changes in the whole flora scope.Investigation of typical artificial shoreline was carried out in 3 types of shoreline with the length of 1km separately in Dalian Bay, which included 2 typical artificial shorelines: channel and seawall, and a natural shoreline as control. We recorded 34 species in all, which included 33 species recorded in historical data, and a new species. The results showed an obvious low level of seaweed species construction in artificial shoreline than in natural shoreline (13:32). Since the public species in both types of shorelines were 11 which accounted for 85% of the total species in artificial shoreline, it suggested that the artificial shoreline species construction mainly came from the nearby natural shoreline.Within the two artificial shorelines, the 2 species recorded in channel were all wide-spread green ones. While in seawall there were 13 species including 5 red ones,3 brown ones and 5 green ones. Since both artificial shoreline sites were of the similar building material and age, the differences in species construction mainly came from difference in topological structure and surrounding water environment. Besides, the reservation of some natural shorelines closing to the artificial shoreline was helpful to recover the seaweed diversity level. Above all, the main effect of artificial shoreline on seaweeds was the reduction of diversity level. This level was decided by multiple characters of artificial shoreline, thus positive human effects could be imposed accordingly to promote the restoration proceeding and improve the restoration level.Investigation of seaweed bed was carried out in Nanhuangcheng Island. This study investigates the seaweed biodiversity and biomass of seaweed bed around Nanhuangcheng Island (N 37°56’, E 120°41’). This seaweed bed was about 48.6h with biomass of 7.79 kg·m2. Laminaria japonica, Undaria pinnatifida, Sargassum siliquastrum and Desmarestia viridis were the main constructive species. Since this island is merely 70 km away from the Bohai oil spilling site, the seaweed bed surrounded is critical in the oil pollution study. As a control, Temple Island(N 38°21’-22’, E 120°53’-54’)which was also about 70km away from the oil spilling site was studied. This island was 50 km away from Nanhuangcheng Island and was surrounded by a seagrass bed of 68.3ha, which mainly consisted of Zostera marina with biomass of 18.3 kg·m2. Both of the above 2 flora types were valuable in the oil pollution and recovery study due to the sensitivity of their species composition, area size and biomass to oil pollution. Above all, due to the high seaweed diversity level and the seaweed bed surrounded, Nanhuangcheng Island was an ideal candidate for a new marine protected area (MPA) of seaweed, which was critical in seaweed biogeography study and the coming ecological restoration in Bohai Sea.A new green seaweed species named Promonostroma leptophyllum Liu et Wang, sp. nov. was discovered and identified in the investigation of Dalian Bay and Zhangzi Island. However, the phylogenetic analysis result including 3 molecular markers ITS, rbcL-5P and rbcL-3P was conflicted with morphological identification result and showed that these samples were much closer to Monostroma grevillei. The differences in identification results probably came from the close phylogenetic relationship between the 2 genuses. Besides, there were very few sequences of the 2 close genuses Protomonostroma and Monostroma in Genebank. Thus more molecular sequences with reliable morphological identification were needed to obtain the authentic analysis result of the phylogenetic relationships and species identification in the 2 genuses.According to the change in algal diversity and distribution in Bohai Sea and Yellow Sea, a strategy of seaweed-exporting protection was proposed to export seaweeds from areas with high diversity level to the areas with low level such as artificial shoreline. The time period for natural distribution of seaweeds would be shortened and the adaption of seaweed to new environment would be accelerated. This strategy aimed to sustain the stability of seaweed species composition of a flora and promote the proceeding of eco-restoration of environment in artificial shoreline.In the seaweed-exporting protection strategy, environmental evaluation of the target sites was an essential premise. A preliminary study of biomarker for environmental evaluation was carried out. Compared to normal chemical detections, biomarker was more sensitive and suitable for more environmental factors. As the convenience in culture and manipulation, microalgae were the more proper organism than macroalgae to develop biomarker. Heat shock proteins (HSPs), a highly conserved molecular chaperone, played key roles in defense responses against various environmental stresses both in microalgae and seaweeds. Chlorella vulgaris, a wide spread microalgae which could be find both in sea water and fresh water was proper for anti-adversity research than seaweed since it was much easier to culture and operate. In this study, we cloned the cDNA of Chlorella vulgaris HSP90 (named CvHSP90) by combining homology cloning with rapid amplification of cDNA ends (RACE). Sequence analysis indicated that CvHSP90 was a cytosolic member of the HSP90 family. Quantitative RT-PCR was applied to determine the expression level of messenger RNA (mRNA) in CvHSP90 under different stress conditions including different heat shock time, heat shock temperature and salinity. Results showed that CvHSP90 was a potential biomarker to monitor environment changes. And it might be useful in the target sites selection in seaweed-exporting protection. |
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