title: Invasive dreissenid mussels and benthic algae in Lake Michigan: characterizing effects on sediment bacterial communities.
abstract: Dreissenid mussels have invaded the Laurentian Great Lakes causing dramatic changes to benthic-pelagic interactions. Despite research on food web impacts, there is limited data on mussel effects on benthic bacterial communities. This study examined effects of dreissenid mussels and benthic algae on sediment bacterial community composition and diversity. Triplicate experimental sediment plus lake water microcosms were used and either mussels, benthic algae or both were added. Changes in water nutrient chemistry and sediment bacterial communities were monitored using 16S rRNA amplicon sequencing, over 21 days. When mussels were present, nitrate and soluble reactive P increased significantly as the dominant N and P forms. Bacterial diversity increased in all microcosms, although bacterial community composition was distinct between treatment. Higher nitrate in mussel microcosms was accompanied by increases in nitrifying taxa (Nitrospira, Nitrosomonas), which are important in oxidizing mussel-excreted ammonium. Microcosms with algal additions showed increases in bacterial taxa capable of degrading algal cellulose, and Pelagibacter (SAR11) disappeared from all but control microcosms. This study suggests that bacterial communities in lake sediments respond to mussels and algae. Functional analysis of bacterial communities provides insights into changes in microbially mediated benthic nutrient transformations associated with invasive dreissenid mussels and benthic algae in lake ecosystems.
authors.affiliation: Department of Biological Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave., Milwaukee, WI 53201, USA.
authors.forename: Philip O
authors.initials: PO
authors.lastname: Lee
authors.affiliation: The School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA.
authors.forename: Sandra L
authors.initials: SL
authors.lastname: McLellan
authors.affiliation: Department of Botany, University of Wisconsin-Madison, 430 Lincoln Drive, Madison, WI 53706 USA.
authors.forename: Linda E
authors.initials: LE
authors.lastname: Graham
authors.affiliation: Department of Biological Sciences, University of Wisconsin-Milwaukee, 3209 N. Maryland Ave., Milwaukee, WI 53201, USA The School of Freshwater Sciences, University of Wisconsin-Milwaukee, 600 E. Greenfield Ave., Milwaukee, WI 53204, USA ebyoung@uwm.edu.
authors.forename: Erica B
authors.initials: EB
authors.lastname: Young
mesh_terms: D000818:Animals; D001419:Bacteria / Q000235:genetics; D001483:Base Sequence; D044822:Biodiversity; D049872:Bivalvia / Q000382:microbiology*; D004269:DNA, Bacterial / Q000235:genetics; D017753:Ecosystem; D020387:Food Chain; D005618:Fresh Water; D019015:Geologic Sediments / Q000382:microbiology*; D060106:Lakes; D059013:Microbial Consortia; D009566:Nitrates / Q000378:metabolism; D010944:Plants / Q000382:microbiology*; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA; D014481:United States
chemical_list: D004269:DNA, Bacterial; D009566:Nitrates; D012336:RNA, Ribosomal, 16S
keywords: 16S rRNA; Cladophora; bacteria; diversity; dreissenid mussels; microcosm; phosphorus; pyrosequencing