Abundance, characteristics, and size spectra of transparent exopolymer particles and Coomassie stainable particles during spring in a large shallow lake, Taihu, China

Abundance, characteristics, and size spectra of transparent exopolymer particles (TEP) and Coomassie stainable particles (CSP) were investigated in Lake Taihu for the first time during spring. Abundance, equivalent spherical volume (ESV), and equivalent surface area (ESA) of particles were quantified by combining microscopic observation with image analysis. Average concentration of TEP in water was approximately seven-fold higher than that of CSP, and the average ESV and ESA of TEP were both greater than those of CSP. TEP abundance ranged from 5.27 × 103 to 2.3 × 104 particles/mL, with ESV from 1.09 × 106 to 7.44 × 106 μm3/mL and ESA from 3.28 × 106 to 2.23 × 107 μm2/mL. CSP abundance varied from 2.43 × 102 to 3.81 × 103 particles/mL, with ESV from 1.62 × 104 to 7.12 × 105 μm3/mL and ESA from 4.85 × 104 to 2.14 × 106 μm2/mL. During spring, small particles (equivalent spherical diameter (ESD) < 20 μm) were dominant. The size distributions of TEP and CSP in the entire lake followed a power law, with abundance of particle scaling with particle diameter. The size spectra of TEPwere also higher than that of CSP in the lake. The high abundance of TEP and CSP during spring in Lake Taihu signified not only that they could play a critical and dynamic role in nutrient cycling in this lake ecosystembut also that they are part of carbon and nitrogen storage in spring when Microcystis begins to bloom, and they could be especially important for influencing bloom outbreaks.