Phosphate Enrichment From Wildlife Inputs Shapes the Distribution and Pigmentation of Green and Red Snow Algae Along the West Antarctic Peninsula
Journal Article
Overview
abstract
Abstract; ; Snow algae darken snow through biomass accumulation and pigmentation, yet nutrient controls on algal abundance and pigment composition in Antarctic snowfields remain poorly constrained. Along the West Antarctic Peninsula (WAP), coastal snowfields receive nutrient inputs from marine and wildlife sources that may influence bloom development. We analyzed 111 snow samples collected from nine coastal WAP sites during the 2024–2025 austral summer to assess the relationships between dissolved nutrients and algal cell density, pigment concentration, and pigment composition across red, green, and clean snow. In green snow, median phosphate (PO; 4; 3−; ) concentrations were tenfold higher (114 μM) relative to red snow (11.4 μM), and ∼70‐fold higher than clean snow (1.54 μM). High‐phosphate samples, composed primarily of green snow, exhibited higher cell densities and per‐cell pigment concentrations than low‐phosphate samples, consistent with enhanced biomass and cellular pigment accumulation under phosphate‐rich conditions. These results identify green snow as a bloom state strongly associated with elevated phosphate availability. Green snow was also characterized by lower ratios (NO; 3; −; + NO; 2; −; : PO; 4; 3−; ) and increased photoprotective carotenoids relative to red snow, suggesting that dense green blooms rapidly drawdown bioavailable nitrogen relative to excess phosphate, creating a distinct post‐uptake stoichiometric signature in wildlife‐influenced regimes. Phosphate concentrations were positively associated with wildlife influence (Spearman's; r; = 0.54,; p; < 0.001), indicating ornithogenic inputs as a key phosphorus source. Collectively, these results link phosphate availability to snow algal biomass and cellular pigment composition and suggest that wildlife‐mediated nutrient inputs may intensify algal‐driven surface darkening.;
