INTERACTIONS BETWEEN MICROPLASTICS AND CYANOBACTERIAL: GROWTH, TOXIN PRODUCTION, FATE AND TRANSPORT

Increases in runoff contribute to cyanobacterial harmful algal bloom (cHAB) formation by stimulating growth of cHAB causing species with nutrient and pollutant inputs. Microplastics are being detected at increasing concentrations in this runoff and downstream in lakes and surrounding watersheds. The effect of microplastics on cHAB formation, toxin production, and transport are largely unknown. To address this, we use Statistical Design of Experiments to elucidate microbe-plastic interactions in vitro with cyanobacteria obtained from a HAB events in the Great Lakes. This experiment measured the impact of differing sizes, concentrations, and UV-ageing times of polyethylene, polypropylene, and cellulose fibers on the chlorophyll-a content of Trichormus variabilis and Microcystis aeruginosa and microcystin-LR content in M. aeruginosa. The results suggest that polymer type and size decreased chlorophyll content over the course of four weeks.  The trend was inverted for polypropylene polymers which underwent photooxidation prior to inoculation. Members of these microbial communities displayed adhesion to the polymers during this study.  To complement these findings, we have designed a turbulence tank capable of mimicking environmental wave motion to further investigate microbial adhesion to microplastics and determine the influence of this complex formation on fate and transport. Initial testing has found that biofilms on neutrally buoyant particles causes them to sink consistently, while biofilm formation on negatively buoyant particles slows their terminal settling velocity.

Presentation Preference: Either

Primary Presenter: Fuad Shatara, UW-Madison (shatara@wisc.edu)

Authors:

Fuad Shatara, UW-Madison  (shatara@wisc.edu)

Erica Majumder, UW-Madison  (emajumder@wisc.edu)

Kiyoko Yokota, SUNY Oneonta  (kiyoko.yokota@oneonta.edu)

Nimish Pujara, UW-Madison  (npujara@wisc.edu)

James Rice, UW-Madison  (jrice4@wisc.edu)

Saaurabh Gupta, UW-Madison  (sgupta278@wisc.edu)