Effects of light on Microcystis spp.: Pigments, cell growth, photosynthetic parameters, and toxins

Session: Harmful Algal Blooms: From Ecosystem Drivers to Ecosystem Impacts (3)

Dominique Derminio, SUNY, College of Environmental Science & Forestry, [email protected]
Gregory Boyer, SUNY-ESF, [email protected]

Abstract

Microcystis is a genus of cyanobacteria that can cause cyanobacterial harmful algal blooms (cHABs). cHABs generally occur during late summer where there is higher intensity light. To gather light, cyanobacteria use a phycobilisome consisting of three major pigment-proteins: allophycocyanin, phycocyanin (PC) and phycoerythrin (PE). These latter two proteins, PC and PE, form the light gathering antenna complex. To understand how this antenna changes with light intensity, a 4-day experiment was conducted difference strains of Microcystis in culture under four difference light irradiations. Light intensity, cyanobacteria biomass as both cell number and pigment fluorescence, photosynthetic parameters, and toxicity were measured at 4-hr intervals for 16 hours, then once a day afterward. Cell numbers significantly changed over time based on the light level. Also, pigments (chl-a, PC, and PE) significantly varied with time. Photosynthetic parameters varied under different light intensities. This study will improve our fundamental understanding of how Microcystis pigments and toxin concentrations respond to changing light fields.