Under-Ice Algae Bloom: 2D Cross-Section Model

Long before open water appears, the Arctic spring bloom starts in near-darkness on the underside of the sea ice, where a thin film of ice algae photosynthesizes on whatever sunlight survives passing through snow and ice. This 2D companion renders that same light-limited production step as an edge-on cross-section: a Beer–Lambert extinction stack turns snow depth, ice thickness and sun elevation into an under-ice PAR value, a Steele-curve growth law turns that irradiance into algae biomass, and a grazing term routes the resulting energy into a copepod population that stores it as lipid reserves. A scrolling strip chart alongside the cross-section plots PAR, algae biomass and copepod population over simulated days, so the bloom's rise and fall is visible as a time series, not just an instantaneous snapshot.