title: An approach to analyzing spatial patterns of protozoan communities for assessing water quality in the Hangzhou section of Jing-Hang Grand Canal in China.
abstract: BACKGROUND
  In order to evaluate water quality of a canal system, the spatial pattern of protozoan communities in response to physicochemical variables was studied in the Hangzhou section of the Grand Canal, northern China during a 1-year cycle (February 2008-January 2009).
  
  
  METHODS
  Protozoan samples were monthly collected at six sampling stations with a spatial gradient of environmental status. Physicochemical parameters, e.g., water temperature, dissolved oxygen, chemical oxygen demand (COD), biological oxygen demand, total nitrogen (TN), and total phosphorus (TP), were measured synchronously for comparison with biotic parameters.
  
  
  RESULTS
  The protozoan community structures represented significant differences among the six sampling stations. The spatial patterns of protozoan communities were significantly correlated with the changes of chemical variables, especially COD, either alone or in combination with TP and/or TN. Of 88 protozoan taxa recorded over the study period, ten species (e.g., Carchesium polypinum, Colpidium campylum, Prorodon teres, Vorticella putrina, Zoothamnium arbuscula, Euglena spp., and Phacus spp.) were significantly related to COD, either alone or in combination with TP and/or TN.
  
  
  CONCLUSIONS
  These findings suggest that protozoa can be used as a robust bioindicator of water quality in freshwater river systems.
authors.affiliation: Hangzhou Key Laboratory for Animal Science and Technology, Hangzhou Normal University, Hangzhou 310036, China. shixl56@163.com
authors.forename: Xinlu
authors.initials: X
authors.lastname: Shi
authors.forename: Xiaojiang
authors.initials: X
authors.lastname: Liu
authors.forename: Guijie
authors.initials: G
authors.lastname: Liu
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Sun
authors.forename: Henglong
authors.initials: H
authors.lastname: Xu
mesh_terms: D057919:Biological Oxygen Demand Analysis; D055598:Chemical Phenomena; D002681:China; D002923:Cilia / Q000378:metabolism; D016798:Ciliophora / Q000145:classification / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D016822:Euglenida / Q000145:classification / Q000166:cytology / Q000235:genetics / Q000302:isolation & purification*; D005407:Flagella / Q000378:metabolism; D005618:Fresh Water / Q000737:chemistry / Q000469:parasitology*; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis / Q000737:chemistry; D010758:Phosphorus / Q000032:analysis; D010802:Phylogeny; D025341:Principal Component Analysis; D045483:Rivers / Q000737:chemistry / Q000469:parasitology; D012621:Seasons; D012995:Solubility; D013696:Temperature; D060753:Water Quality
chemical_list: D010758:Phosphorus; D009584:Nitrogen; D010100:Oxygen