Department of Plant and Microbial Biology, University of Minnesota, St. Paul, Minnesota, USA.
Flathead Lake Biological Station, University of Montana, Polson, Montana, USA.
Environ Microbiol Rep. 2024 Dec;16(6):e70052. doi: 10.1111/1758-2229.70052.
Snow algal blooms decrease snow albedo and increase local melt rates. However, the causes behind the size and frequency of these blooms are still not well understood. One factor likely contributing is nutrient availability, specifically nitrogen and phosphorus. The nutrient requirements of the taxa responsible for these blooms are not known. Here, we assessed the growth of three commercial strains of snow algae under 24 different nutrient treatments that varied in both absolute and relative concentrations of nitrogen and phosphorus. After 38 days of incubation, we measured total biomass and cell size and estimated their effective albedo reduction surface. Snow algal strains tended to respond similarly and achieved bloom-like cell densities over a wide range of nutrient conditions. However, the molar ratio of nitrogen to phosphorus at which maximum biomass was achieved was between 4 and 7. Our data indicate a high requirement for phosphorus for snow algae and highlights phosphorus availability as a critical factor influencing the frequency and extent of snow algae blooms and their potential contribution to snow melt through altered albedo. Snow algae can thrive across a range of nitrogen (N) and phosphorus (P) conditions, with a higher P requirement for optimal growth. Our study suggests that increased N deposition may have a limited impact on snow algae bloom occurrence and size, emphasising P as a key factor influencing these blooms and their potential to accelerate snow melt by lowering albedo.
雪藻水华会降低雪面反照率并增加当地融雪速率。然而，这些水华大小和频率的成因仍不甚清楚。一个可能的促成因素是营养物质的可利用性，特别是氮和磷。导致这些水华的分类群的营养需求尚不清楚。在这里，我们评估了三种商业雪藻菌株在 24 种不同营养处理下的生长情况，这些处理在氮和磷的绝对和相对浓度上均有所不同。经过 38 天的孵育，我们测量了总生物量和细胞大小，并估计了它们的有效反照率降低表面。雪藻菌株的反应趋于相似，并在广泛的营养条件下达到了类似水华的细胞密度。然而，达到最大生物量的氮磷摩尔比在 4 到 7 之间。我们的数据表明，雪藻对磷的需求很高，并强调磷的可利用性是影响雪藻水华发生频率和范围及其通过改变反照率对融雪潜在贡献的关键因素。雪藻可以在一系列氮 (N) 和磷 (P) 条件下茁壮成长，对最佳生长有更高的磷需求。我们的研究表明，增加的氮沉积可能对雪藻水华的发生和规模影响有限，强调磷是影响这些水华及其降低反照率从而加速融雪潜力的关键因素。
