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Home My WebLink AboutSAC presentation - Pierce - MicrocystinMicrocystin concentrations, congener profiles, and bacterial composition during multiple blooms in the Chowan River Emily Pierce, Marco Valera, Astrid Schnetzer Chowan River: •Drains into 2nd largest estuary in the U.S. •Critical nursery habitat for many species of fish, birds, invertebrates •History of severe algal problems that have begun to reemerge Map orig. produced by Natalie Chazal Data Source : NCDEQ 2020 - 2022 Introduction impact toxicity, persistence, & exposure risk Congener Low vs high Fraction particulate vs dissolved Concentration Introduction Transdermal exposure Bioaccumulation Consumption Direct Ingestion Aerosolization Drinking water IntroductionChapter I Site Full Name Date AH Arrowhead 07/16/2019 CR Colerain 07/16/2019 IR Indian River 07/31/2019 LL Leary’s Landing 07/31/2019 MC Modoc Canal 08/13/2019 CP Charlton Pier 09/11/2019 Chowan River Bloom Sites: Albemarle Sound Site: Site name: 129S Sampling period: 05/29/2019 – 10/08/2019 Sampling frequency: Methods Measurements made for every sample: •Chlorophyll-a (chl-a) •Particulate microcystin (pMC) •Dissolved microcystin (dMC) •Bacterial community composition Upstream bloom measurements: •Liquid chromatography- mass spectrometry (LC-MS) congener analysis Downstream measurements: •Solid phase adsorption toxin tracker (SPATT) deployments Enzyme linked immunosorbent assay (ELISA) Example Chowan Bloom Site Western Albemarle Sound Site Methods Upstream •High biomass & pMC •Spatiotemporal variability •No correlation between biomass and MC •MC mostly in particulate fraction Chl-a & MC Results Upstream Chl-a & MC Results Downstream Downstream SPATTS & Downstream dMC & pMC Downstream SPATTS & upstream dMC SPATT Results LA > LR > YR > RRToxicity : Chernoff et al. 2020 MC use thresholds based on more toxic MC-LR Congener profiles consistent across blooms Least toxic MC-RR was most dominant Congener Results Upstream Community Results *Order ** •Community was different between sites, Microcystis dominated •Taxa associated with Microcystis decline indicated community shifts AH CR IR LL MC CP y = 2.4e10.2x R2 = 0.99 CP: Low MC CR: High MC Most bloom communities showed similarity with exception of high MC and low MC blooms CP: Low MC CR: High MC Strong, positive exponential relationship between Microcystis abundance and MC conc. Upstream Community Results CP CP Downstream Community Results *Order * * * •Downstream community was different from upstream •Cyanobium was most abundant, in agreement with subsequent study in 2020 (Plaas et al. 2021) 1. Spatiotemporal variability during intense 2019 bloom period 2. Functional bacterial groups indicate bloom stage 3. Microcystis could be good molecular target 5. Downstream accumulated MC may point to potential transport across freshwater to marine continuum 1,140.9 µg L-1 4. Low toxicity congener dominated consistent conger profiles RR Conclusions Thanks to Input & Support from North Carolina Dept. Env. Quality- Jill Paxson, Mark Vander Borgh, Dan Wiltsie, Charlton Godwin North Carolina Sea Grant Extension- Gloria Putnam Env. Protection Agency – Blake Schaeffer Chowan Edenton Environmental Group- Colleen Karl, Steve Karl Plankton Ecology Lab Members - Emily Griffith, Aidan Smith, Miranda Hart, Madeline Anderson, Will McClure, Lucy Roussa, Barrett Rose