title: Effects of Hypoxia on the Phylogenetic Composition and Species Distribution of Protists in a Subtropical Harbor.
abstract: Tolo Harbor, a subtropical semi-enclosed coastal water body, is surrounded by an expanding urban community, which contributes to large concentrations of nutrient runoff, leading to algal blooms and localized hypoxic episodes. Present knowledge of protist distributions in subtropical waters during hypoxic conditions is very limited. In this study, therefore, we combined parallel 454 pyrosequencing technology and denaturing gradient gel electrophoresis (DGGE) fingerprint analyses to reveal the protist community shifts before, during, and after a 2-week hypoxic episode during the summer of 2011. Hierarchical clustering for DGGE demonstrated similar grouping of hypoxic samples separately from oxic samples. Dissolved oxygen (DO) concentration and dissolved inorganic nitrogen:phosphate (DIN:PO4) concentrations significantly affected OTU distribution in 454 sequenced samples, and a shift toward a ciliate and marine alveolate clade II (MALV II) species composition occurred as waters shifted from oxic to hypoxic. These results suggest that protist community shifts toward heterotrophic and parasitic tendencies as well as decreased diversity and richness in response to hypoxic outbreaks.
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Emma
authors.initials: E
authors.lastname: Rocke
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.|Sanya Institute of Deep-Sea Science and Engineering, Chinese Academy of Sciences, Sanya, 572000, China.
authors.forename: Hongmei
authors.initials: H
authors.lastname: Jing
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong.
authors.forename: Xiaomin
authors.initials: X
authors.lastname: Xia
authors.affiliation: Division of Life Science, Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong. liuhb@ust.hk.
authors.forename: Hongbin
authors.initials: H
authors.lastname: Liu
mesh_terms: D044822:Biodiversity; D018441:Biofilms; D016798:Ciliophora / Q000145:classification* / Q000302:isolation & purification; D016000:Cluster Analysis; D058645:Denaturing Gradient Gel Electrophoresis; D056890:Eukaryota / Q000145:classification* / Q000302:isolation & purification; D006723:Hong Kong; D000860:Hypoxia / Q000378:metabolism*; D009584:Nitrogen / Q000032:analysis; D010100:Oxygen / Q000032:analysis; D010710:Phosphates / Q000032:analysis; D010802:Phylogeny; D012623:Seawater / Q000737:chemistry / Q000382:microbiology; D017422:Sequence Analysis, DNA; D013045:Species Specificity
chemical_list: D010710:Phosphates; D009584:Nitrogen; D010100:Oxygen
keywords: DGGE; Hypoxia; Protists; Pyrosequencing