Study On The Correlation Between Community Characteristics Of Protozoa And Water Quality In The Lhasa Section Of The Lhasa River

Protozoan species diversity, community structure characteristics and its relationship with the water environment were studied with 108 water samples colleceted in May to Decembein year 2015 from Lhasa River Lhasa section by setting up nine sampling sites with three phases(Average water period,High water period,Low water period).The results are as following:1)A total of 97 specise of protozoa were identified, including 31 species of Flagellates(belonging to 1 subphylum, 2 classes, 4 orders, 7 families and 14 genera and 1unidentified), 66 species of Ciliates(3 calass, 12 Orders, 28 families, 36 genera and 2 unidentified) and the dominance degree of Flagellates is 32%, in which Euglenida and Kinetoplastida are the dominant groups with 29.03% and 32.26% dominance degree respectively and the scandary dominance group is Chrysomonadida with dominance group of 19.35%, Pelobiontida is uncommon group with 1 specise, and the dominance degree of Cilate is 68%, in which Prostomatida and Hypotrichida are the dominant groups with 18.18% and 31.82% dominance degree respectively and the scandary dominance group is Colpodida and Scuticociliatida with dominance group of 9.09% and 10.6%, Synhymeniida and Heterotrichida are uncommon group with 1 specise.2)There are no significant differencs in dominant group between the same sampling point of different water phases and the same water phase of different sampling points, and the dominant species found in the some of sampling poits at the same water phase. The dominant species in Lhasa section of Lhasa River included Bodo minimus, Oxytricha muscorum and Aspidisca sultata. This indicates that some of the sampling poits havebeen polluted in same degrees.3)Specise richness index of Flagellates at three water phases and different sampling points are ranging between 0-1.02, the diversity index ranging between 0-1.61, and Specise richness index of Ciliate at threewater phases and different sampling points are ranging bteween 0.33-2.89 richness, the diversity index ranging between 0-2.4. Relatively low richness index and diversity index suggest that community structure of protozoan is relatively simple in Lhasa river Lhasa section.4)The water environment quality of Lhasa River Lhasa section was evaluated by using the characteristic parameters of protozoan community combining with the main physical and chemical factors of water body. The result showed that there is a significant correlation between Protozoan community characteristic parameters and water environmental factors and these water environmental factors impact on community stucture of protozoa in Lhasa River Lhasa section.5)Comprehensive evaluation of water quality results showed that the Lhasa river Lhasa section have been polluted in some degrees, the polluted degrees from upstream to downstream is 1 #, 2 #, 3 # inliner with Os-β-ms, 4 #, 5 #, 6 # samples inline with β-ms-α-msand 7 #, 8 #, 9 # samples inline withα-ms. The evaluation result and that of water physical and chemical indexes are basically consistent, and accord with the actual situation of the pollution of the river along the section.