title: Response of bacterioplankton communities to cadmium exposure in coastal water microcosms with high temporal variability.
abstract: Multiple anthropogenic disturbances to bacterial diversity have been investigated in coastal ecosystems, in which temporal variability in the bacterioplankton community has been considered a ubiquitous process. However, far less is known about the temporal dynamics of a bacterioplankton community responding to pollution disturbances such as toxic metals. We used coastal water microcosms perturbed with 0, 10, 100, and 1,000 μg liter(-1) of cadmium (Cd) for 2 weeks to investigate temporal variability, Cd-induced patterns, and their interaction in the coastal bacterioplankton community and to reveal whether the bacterial community structure would reflect the Cd gradient in a temporally varying system. Our results showed that the bacterioplankton community structure shifted along the Cd gradient consistently after a 4-day incubation, although it exhibited some resistance to Cd at low concentration (10 μg liter(-1)). A process akin to an arms race between temporal variability and Cd exposure was observed, and the temporal variability overwhelmed Cd-induced patterns in the bacterial community. The temporal succession of the bacterial community was correlated with pH, dissolved oxygen, NO3 (-)-N, NO2 (-)-N, PO4 (3-)-P, dissolved organic carbon, and chlorophyll a, and each of these parameters contributed more to community variance than Cd did. However, elevated Cd levels did decrease the temporal turnover rate of community. Furthermore, key taxa, affiliated to the families Flavobacteriaceae, Rhodobacteraceae, Erythrobacteraceae, Piscirickettsiaceae, and Alteromonadaceae, showed a high frequency of being associated with Cd levels during 2 weeks. This study provides direct evidence that specific Cd-induced patterns in bacterioplankton communities exist in highly varying manipulated coastal systems. Future investigations on an ecosystem scale across longer temporal scales are needed to validate the observed pattern.
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China 2011 Center of Modern Marine Aquaculture of East China Sea, Ningbo, China.
authors.forename: Kai
authors.initials: K
authors.lastname: Wang
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China 2011 Center of Modern Marine Aquaculture of East China Sea, Ningbo, China zhangdemin@nbu.edu.cn.
authors.forename: Demin
authors.initials: D
authors.lastname: Zhang
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China 2011 Center of Modern Marine Aquaculture of East China Sea, Ningbo, China.
authors.forename: Jinbo
authors.initials: J
authors.lastname: Xiong
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China.
authors.forename: Xinxin
authors.initials: X
authors.lastname: Chen
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China.
authors.forename: Jialai
authors.initials: J
authors.lastname: Zheng
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China.
authors.forename: Changju
authors.initials: C
authors.lastname: Hu
authors.affiliation: School of Marine Sciences, Ningbo University, Ningbo, China.
authors.forename: Yina
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Faculty of Architectural, Civil Engineering and Environment, Ningbo University, Ningbo, China.
authors.forename: Jianlin
authors.initials: J
authors.lastname: Zhu
mesh_terms: D001419:Bacteria / Q000145:classification* / Q000187:drug effects*; D058448:Biota / Q000187:drug effects*; D002104:Cadmium / Q000633:toxicity*; D004269:DNA, Bacterial / Q000737:chemistry / Q000235:genetics; D004275:DNA, Ribosomal / Q000737:chemistry / Q000235:genetics; D008969:Molecular Sequence Data; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000737:chemistry* / Q000382:microbiology*; D017422:Sequence Analysis, DNA
chemical_list: D004269:DNA, Bacterial; D004275:DNA, Ribosomal; D012336:RNA, Ribosomal, 16S; D002104:Cadmium