Virulence and biodegradation potential of dynamic microbial communities associated with decaying Cladophora in Great Lakes

Chan Lan Chun, Julie R. Peller, Dawn Shively, Muruleedhara N. Byappanahalli, Richard L. Whitman, Christopher Staley, Qian Zhang, Satoshi Ishii, Michael J. Sadowsky

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


Cladophora mats that accumulate and decompose along shorelines of the Great Lakes create potential threats to the health of humans and wildlife. The decaying algae create a low oxygen and redox potential environment favoring growth and persistence of anaerobic microbial populations, including Clostridium botulinum, the causal agent of botulism in humans, birds, and other wildlife. In addition to the diverse population of microbes, a dynamic chemical environment is generated, which involves production of numerous organic and inorganic substances, many of which are believed to be toxic to the sand and aquatic biotic communities. In this study, we used 16S-rDNA-based-amplicon sequencing and microfluidic-based quantitative PCR approaches to characterize the bacterial community structure and the abundances of human pathogens associated with Cladophora at different stages (up to 90 days) of algal decay in laboratory microcosms. Oxygen levels were largely depleted after a few hours of incubation. As Cladophora decayed, the algal microbial biodiversity decreased within 24 h, and the mat transitioned from an aerobic to anaerobic environment. There were increasing abundances of enteric and pathogenic bacteria during decomposition of Cladophora, including Acinetobacter, Enterobacter, Kluyvera, Cedecea, and others. In contrast, there were no or very few sequences (< 0.07%) assigned to such groups in fresh Cladophora samples. Principal coordinate analysis indicated that the bacterial community structure was dynamic and changed significantly with decay time. Knowledge of microbial communities and chemical composition of decaying algal mats is critical to our further understanding of the role that Cladophora plays in a beach ecosystem's structure and function, including the algal role in trophic interactions. Based on these findings, public and environmental health concerns should be considered when decaying Cladophora mats accumulate Great Lakes shorelines.

Original languageEnglish (US)
Pages (from-to)872-880
Number of pages9
JournalScience of the Total Environment
StatePublished - Jan 1 2017

Bibliographical note

Funding Information:
This work was supported, in part, by a grant from the U.S. Environmental Protection Agency ( EPAR5-GL2010-1 ) to MJS and CLC. Next-generation sequence data was processed and analyzed using the resources of Minnesota Supercomputing Institute. Any use of trade, product, or firm names is for descriptive purposes only and does not imply endorsement by the US Government.

Publisher Copyright:
© 2016 Elsevier B.V.


  • 16S rRNA
  • Cladophora
  • Decomposition
  • Dynamics
  • Great Lake
  • Microbiota
  • Pathogens

PubMed: MeSH publication types

  • Journal Article


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