Metatranscriptomics of Lake Erie Planktothrix blooms

Session: 15. - Environmental 'omics: New Tools for Aquatic Ecosystem Science and Management

Michelle Neudeck, Bowling Green State University, [email protected]
Robert (Mike) McKay, Bowling Green State University , [email protected]
Katelyn McKindles, Bowling Green State University, [email protected]
Timothy Davis, Bowling Green State University, [email protected]
George Bullerjahn, Bowling Green State University, [email protected]

Abstract

Whereas much attention has been devoted to studying Microcystis harmful algal blooms (HABs), tributary sites are often affected by persistent blooms of Planktothrix, a filamentous microcystin-producing cyanobacterium. Our lab is examining the factors that allow these two organisms to occupy different ecological niches. Regarding Planktothrix, HABs are typically of longer duration (May-October), routinely yielding microcystin levels in excess of 20 ppb.  In agreement with prior studies on the Planktothrix bloom in Grand Lake St. Marys (OH), Sandusky Bay (Lake Erie) dissolved inorganic N concentrations often fall below detection due to denitrification, and enhancement of bloom conditions is dependent on N additions, rather than P. We hypothesize that N availability is a driver of Planktothrix dominance.  The success of Planktothrix in an N-limited system is notable given that this genus is not an N fixer, but metatranscriptomic analyses reveal a minor cyanobacterial community of N fixers contributing new N into the system. Metatranscriptomics also indicate that the synthesis of the N storage polymer cyanophycin occurs when N is abundant, and that cyanophycin is degraded in Planktothrix following N depletion. These data indicate that Planktothrix success is in part driven by luxury uptake and storage of N.

1. Keyword
cyanophyta

2. Keyword
nutrients

3. Keyword
Lake Erie

4. Additional Keyword
HABs