Periphy Algae Communities Structure Of Hun River And Analysis Of Influence Factors

Periphy algae are important component of aquatic ecological system. They areprimary producers and an important foundation of many stream food webs. Their celldensity and species affected by water quality and habitat. So periphy algae are usefulecological indicators to monitor and assess water quality.The cell density, species, chlorophyll a and diversity of periphy algae in fivesections were investigated in Hun River from a methodical approach which combinefield study with indoor culture in2011. Temporal and spatial differences of periphyalgae communities were discussed, as well as the environmental factors of periphyalgae communities structure were studied. Several researches were carried out:（1）A total of7phyla,9classes,17orders,28families,55genera wereidentified during indoor culturing from low flow period to level period. Periphy algaecommunities of every period was dominated by Bacillariophyta, fowlled byChlorophyta. The percent of Cyanophyta, Euglenophyta, Pyrrophyta, Cryptophytaand Xanthophyta were little.（2）The algae commmunities in different period reached peak bioamss withdifferent growth rate. Flood period had the fastest growth rate, and level period theslowest; low flow period were intermediate. The growth rate was determined bywater quality and temperature. The spatial differences in the same period were onlyrelative with water quality, meanwhile the temporal differences in the same secitionswere only relative with water quality and temperature.（3）Periphy algae of Hun River were divided into four taxon, includingprostrate, erect, stalker and chain forming taxa based on behavious and morphollgy.The analyses showed a shift from a community dominated by prostrate and erect taxato another dominated by stalker and chain forming taxa during coloinzation, as aresult become a complex community uniform distributed by four taxon.（4）Redundancy analysis (RDA) showed quantitative relationships between celldensity of dominated species and environmental variables. The results indicated that the environmental variables existed differences when they influenced the growth anddevelopment of periphy algae communities during each period. Generally speaking, itshowed facilitation caused by nutrient such as TN and TP, and inhibitory actioncaused by organic pollution, as well as facilitation from a certain range velocity ofwater.