The Relationship Between Periphytic Algae Communities Structure And Environmental Factors In Weihe River Basin

In October2012and April2013, sixty sampling sties were investigated in weihe riverbasin. Weihe river basin can be divided into the weihe river water system, jinghe riverwater system and luohe river system. Using the MRPP, we compared the three watersystem differences. We also compared the richness, density and diversity of periphyticalage differences between wet and dry season. Using the canonical correspondenceanalysis to compare the relationship between periphytic alage assemblages andenvironmental factors at wet and dry seasons. Using periphyton Index of BiologicalIntegrity to assess stream conditions in weihe river basin, the relationship betweenperiphyton Index of Biological Integrity and environment were assessed by thePearson Correlation Test. Used IPS, TDI, IDG, IBD, DES, CEE six diatom indices toevaluate the health of weihe river basin, using the Pearson correlation analysis tocompare six diatom indices correlation and the relationship between diatom indicesand environmental factors.The results showed that5phylum,46genera and248species were observed inthe weihe river basin. The bacillariophyta had26genera and221species, whichaccount for89%of the total algae species. chlorophyta had10genera and16species,which account for6%, cyanophyta had7genera and8species, accounting for3%.The main species were Navicula cryptocephala, Cymbella ventricosa, Nitzschia palea,Cocconeis placentula, Gomphonema parvulum, Diatoma vulgare, Achnanthes minuti-ssima, Oscillatoria tenuis etc. The richness and diversity of weihe river and luoheriver system were extrmly significant differences (P<0.01) between wet and dryseasons which wet season is higher than dry season. There were no significantdifferences in jinghe river system(P>0.05). the main environmental factors in weiheriver basin were water temperature, width and conductivity in wet season, and thetotal dissolved solids, total nitrogen, potassium permanganate index were the mainfactors in dry season. The periphyton Index of Biological showed that the health siteswere in the right bank of Weihe river basin, the upstream and middle regional healthlevel is higher than the downstream areas. There were almost40%sites poor health injinghe river, the source water quality in the best health and on the left bank branch anddownstream health level is low. Luohe river system health condition is fair, the middleof hulu river tributaries, shajia river tributaries and baishui tributaries health level ishigher, Pearson correlation test showed that the P-IBI had a significantly relationshipwith water temperature, conductivity, salinity, coverage rate of forest and agriculture(P<0.05), which the forest coverage rate had a extremely significantly (P<0.01). There had a extremely significant correlation between six diatom indices in Weiheriver basin (P<0.01). Except for the TDI index, the other five diatom indices wereextremely significant related (P<0.01)with total dissolved solids and conductivity.Phosphate ions, total nitrogen and potassium permanganate index were extremelysignificant related(P<0.01) with six diatom indices, TDI index was no significantcorrelation with nitrite (P>0.05), the remaining five diatom indices were ignificantcorrelation with nitrite ion (P<0.05). There were11sites consistent among six diatomindices,33sites experienced at least one shift in narrative condition between IBIclassifications using six diatom indices.8sites experienced at least two shift innarrative condition between IBI classifications using six diatom indices. no sitesshifted three or more classes. The poor sites were accounting for61%in TDI indexresults, IDG index evaluation result showed that good and general sites number weremore than others, accounting for78%. IPS and DES indices the evaluation resultswere more close, IBD and CEE indices evaluation result was similar.