Thirty Years Changes Of Benthic Algae In Intertidal Zone Of Zhangzi Island

From September 2013 to November 2015,the intertidal zone were set up 6 sampling sections,using two kinds of qualitative and quantitative way to collect benthic intertidal algae in the Island of Zhangzi,conducted a survey of intertidal algae in benthic of the Island of Zhangzi,combined with statistical analysis,explore the area in the sublittoral species economic composition,biomass,the change of algal flora in thirty years,and explore the reason of the change.There are 103 kinds of algae existing in intertidal benthic zone belongs to 4 phyla,23,species composition in Rhodophyta,including Rhodophyta 56 species,accounting for 54.4%of the total area of the algae species;2 species of Cyanophyta,accounting for 1.9% of the total;14 species were Chlorophyta,Phaeophyta also accounted for 13.6% of the total;there are 31 doors,accounting for 30.1% of the total.The number of benthic algae species with those of thirty years ago in intertidal,the total reduction of 10 species from the figures.But in fact,there are 21 kinds of original benthic algae in the past thirty years have disappeared,the emergence of a new record of 11 in the region.There are 49 kinds economic of algae,23 species of Rhodophyta,Chlorophyta accounted for 22.3%;13,12.6%;13 species of Phaeophyta,accounting for 26.5%.Thirty years ago,the specie of economic algae is 39.With the development of society,people on the sublittoral economic development and utilization value constantly,constantly discovering new economic algae,therefore,from the point of view of total economic seaweed over the number of thirty years ago has increased.Thirty years ago,intertidal algae only harmful algae(Desmarestia viridis acid(Muell.)Lamx),harmful algae in addition to the original acid algae,and strong Chaetomorpha(Chaetomorpha valida(Hooker et Harvey)Kuetzing(D.ligulata)and liguliform acid algae Lamouroux)a total of three.Because it is alien species,they multiply,the growth status of serious harm to other algae and marine organisms.The amount of seaweed greatly decreased compared to thirty years ago,a lot of the number of dominant species thirty years ago,a sharply decline,and even becomes a rare species,such as rose(Gloiopeltis fureata).This phenomenon is mainly because of climate warming,eutrophication of the sea water,sea water pH value and salinity change,destruction of the environment for the growth of benthic algae,the biomass decreased significantly.Butthe effect of seasonal variation on the algal biomass did not change,it is the same with thirty years ago.Through the analysis of temperature properties,benthic intertidal algae flora belongs to the Yellow Sea West,algae flora is temperate,warm temperate to cold temperate.This conclusion is consistent with thirty years ago.