An ecosystem of epiphytes in Cladophora

Session: Poster session

Meredith Nevers, U.S. Geological Survey - Great Lakes Science Center, [email protected]
Murulee Byappanahalli, U.S. Geological Survey, Great Lakes Science Center, [email protected]
Kasia Kelly, USGS-Lake Michigan Ecological Research Station, [email protected]
Aaron Aunins, U.S. Geological Survey, [email protected]

Abstract

Cladophora in the Great Lakes has reached nuisance proportions, with attached, floating, and stranded algae creating economic and recreational hardship.  The sheer amount of Cladophora biomass has not surprisingly become a component of the nearshore ecosystem, but the role of associated epiphytic organisms in nutrient cycling and food webs has not been fully explored.  We collected samples of attached, live Cladophora from four locations in southern Lake Michigan (Wisconsin, Illinois, Indiana) on three occasions and analyzed alga-associated community using metagenomic analysis.  Algae were briefly rinsed, drained, and centrifuged, and DNA was extracted from the resulting pellets using commercial kits.  Results of 18S rRNA sequencing revealed 14 eukaryotic phyla.  Dominant taxa include Stramenopiles (diatoms, golden and brown algae), Metazoa (zooplankton, macroinvertebrates), Viridiplantae (green algae), Fungi, and Alveolata (protists, dinoflagellates).  Differences in taxonomic composition were more pronounced spatially than seasonally: Bacillariophyta dominated at one site while Arthropoda dominated one site for two months. A high number of unclassified taxa limits complete description of the eukaryotic community and highlights the need for improving public databases.  The highly diverse eukaryotic community associated with Cladophora begs further investigation into its role in interrupted nutrient flows in the lake system, altered food webs, and benthification.

1. Keyword
Cladophora

2. Keyword
phytoplankton

3. Keyword
genetics