Cyanotoxin Bloom Reactor (2D)

This simulator models a cyanobacterial harmful algal bloom as a coupled system: cell population growth driven by phosphorus loading and temperature, an intracellular microcystin toxin pool that grows under nutrient/thermal stress, and a dissolved-toxin pool in the water that fills when cells lyse and empties through photolysis and microbial decay. A top-down 2D lake view renders the live cell population as scattered particles with a toxin haze tinting the water — pan by dragging and zoom with the scroll wheel — while a live strip chart tracks population (as % of carrying capacity) against dissolved toxin, and a WHO-guideline risk readout tracks whether the dissolved toxin sits in the safe, moderate, or high-risk band. An "apply algaecide treatment" control demonstrates a real and counter-intuitive risk-management lesson: killing the bloom chemically detonates its stored toxin into the water in one pulse, briefly spiking dissolved microcystin even as the visible bloom disappears — which is why treated waterbodies are monitored for dissolved toxin, not cell counts, after any intervention.