title: Ice cover extent drives phytoplankton and bacterial community structure in a large north-temperate lake: implications for a warming climate.
abstract: Mid-winter limnological surveys of Lake Erie captured extremes in ice extent ranging from expansive ice cover in 2010 and 2011 to nearly ice-free waters in 2012. Consistent with a warming climate, ice cover on the Great Lakes is in decline, thus the ice-free condition encountered may foreshadow the lakes future winter state. Here, we show that pronounced changes in annual ice cover are accompanied by equally important shifts in phytoplankton and bacterial community structure. Expansive ice cover supported phytoplankton blooms of filamentous diatoms. By comparison, ice free conditions promoted the growth of smaller sized cells that attained lower total biomass. We propose that isothermal mixing and elevated turbidity in the absence of ice cover resulted in light limitation of the phytoplankton during winter. Additional insights into microbial community dynamics were gleaned from short 16S rRNA tag (Itag) Illumina sequencing. UniFrac analysis of Itag sequences showed clear separation of microbial communities related to presence or absence of ice cover. Whereas the ecological implications of the changing bacterial community are unclear at this time, it is likely that the observed shift from a phytoplankton community dominated by filamentous diatoms to smaller cells will have far reaching ecosystem effects including food web disruptions.
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
authors.forename: B F N
authors.initials: BF
authors.lastname: Beall
authors.affiliation: Department of Biology, Clarkson University, Potsdam, NY, USA.
authors.forename: M R
authors.initials: MR
authors.lastname: Twiss
authors.affiliation: Department of Biology, Clarkson University, Potsdam, NY, USA.
authors.forename: D E
authors.initials: DE
authors.lastname: Smith
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
authors.forename: B O
authors.initials: BO
authors.lastname: Oyserman
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
authors.forename: M J
authors.initials: MJ
authors.lastname: Rozmarynowycz
authors.affiliation: Water Science & Technology Directorate, Environment Canada, Burlington, ON, Canada.
authors.forename: C E
authors.initials: CE
authors.lastname: Binding
authors.affiliation: Water Science & Technology Directorate, Environment Canada, Burlington, ON, Canada.
authors.forename: R A
authors.initials: RA
authors.lastname: Bourbonniere
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
authors.forename: G S
authors.initials: GS
authors.lastname: Bullerjahn
authors.affiliation: Sport Fish and Biomonitoring Unit, Ontario Ministry of the Environment and Climate Change, Toronto, ON, Canada.
authors.forename: M E
authors.initials: ME
authors.lastname: Palmer
authors.affiliation: Center for Water and the Environment, Natural Resources Research Institute, University of Minnesota Duluth, Duluth, MN, USA.
authors.forename: E D
authors.initials: ED
authors.lastname: Reavie
authors.affiliation: USCGC Neah Bay (WTGB 105), Cleveland, OH, USA.
authors.forename: Lcdr M K
authors.initials: LM
authors.lastname: Waters
authors.affiliation: USCGC Neah Bay (WTGB 105), Cleveland, OH, USA.
authors.forename: Lcdr W C
authors.initials: LW
authors.lastname: Woityra
authors.affiliation: Department of Biological Sciences, Bowling Green State University, Bowling Green, OH, 43403, USA.
authors.forename: R M L
authors.initials: RM
authors.lastname: McKay
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D018533:Biomass; D057231:Climate Change; D017377:Diatoms / Q000145:classification / Q000235:genetics / Q000254:growth & development*; D017753:Ecosystem; D046448:Ice Cover / Q000382:microbiology*; D060106:Lakes / Q000382:microbiology*; D010839:Phytoplankton / Q000145:classification / Q000235:genetics / Q000254:growth & development* / Q000302:isolation & purification; D012621:Seasons