Biology subjects

Elser, J. J.

Publications and source records attributed to Elser, J. J..

4 recordsLinked to original sources

bioRxiv2026

Elevation shapes alpine snow algal blooms and their influence on albedo reduction

Snow algae darken snowpacks and accelerate melt worldwide. Although elevation strongly structures the physical conditions of mountain snowfields, its influence on snow algal traits and their effects on snowpack reflectance remains unclear. Here, we investigated snow algal composition, cellular traits, and optical properties in summer blooms across an elevational range of 1,059-3,423 m a.s.l. in the western United States, spanning two elevational gradients in the Cascade Range (CA, OR, WA) and the Rocky Mountains (UT, WY, MT). Across all samples (n = 294), snow albedo declined strongly with increasing algal cell density, indicating that total biomass, rather than pigment composition, is the dominant driver of albedo reduction. However, within Sanguina-dominated blooms (117 of 206 samples bloom samples identified across the dataset), neither relative abundance nor algal cell density varied systematically with elevation. Instead, mean cell size increased with elevation, while per-cell pigment concentrations declined, leading to higher astaxanthin:chlorophyll-a ratios driven primarily by reductions in chlorophyll-a per cell. These elevation-dependent shifts in cell size and pigment balance were consistent across both mountain ranges, indicating phenotypic acclimation to increasing environmental stress with elevation. Together, these findings link cellular-scale acclimation of a widespread snow alga to radiative processes shaping mountain snowpacks.

microbiology↗

bioRxiv2025

Taxonomy-driven variations in snow algae color modulate albedo and energy balance in a single snow patch

In this study, we examined the reflectance, pigment composition, and community composition of three snow algae blooms showing distinct colors in the same snowfield in Glacier National Park (USA). Each color bloom was dominated by a different algae, each exhibiting a unique pigment signature but with astaxanthin as the predominant pigment across all three blooms. The spectral reflectance of red snow algae was consistently lower than that of green algae, while orange algae had intermediate reflectance values. Specifically, red algae reduced reflectance by approximately 55% across the PAR range, while green algae reduced reflectance by 25%. Red algae also demonstrated the highest radiative forcing, double that of green algae, leading to increased energy re-emission into the surrounding environment, which likely contributes to the localized melting of adjacent ice crystals. The high absorbance around 680 nm in cells with high astaxanthin content, such as the orange algae, suggests that semi-automatic detection methods could effectively identify these algae, as their spectral features remain distinct despite the presence of secondary carotenoids. Our data demonstrate the impact of snow algae taxonomic and pigment composition on the radiative balance of snowfields, underscoring taxonomy as a key determinant of bloom color under similar environmental conditions

microbiology↗

bioRxiv2024

Laboratory experiments suggests limited impact of increased nitrogen deposition on snow algae blooms

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 that is likely contributing is nutrient availability, specifically nitrogen (N) and phosphorus (P). However, the nutrient requirements of the taxa responsible for these blooms is 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 N and P. After 38 days of incubation, we measured total biomass and cell size and estimated their effective albedo reduction surface (EARS). Snow algal strains tended to respond similarly and achieved bloom-like cell densities over a wide range of NP conditions. However, the molar ratio of N:P at which maximum biomass was achieved was between 4 and 7. Our data indicate a high requirement for P for snow algae and suggest that additional N inputs into the ecosystem may not significantly impact the productivity and abundance of snow algae blooms. This highlights P availability as a critical factor influencing the frequency and extent of snow algae blooms and their potential contribution to snow melt through altered albedo.

microbiology↗

bioRxiv2019

Genomic adaptations in information processing underpin trophic strategy in a whole-ecosystem nutrient enrichment experiment

Several universal genomic traits affect the capacity, cost, and efficiency of biochemical information processing underpinning metabolism and reproduction. We analyzed their role in mediating planktonic microbial community responses to nutrient enrichment in an oligotrophic, phosphorus-deficient pond in Cuatro Cienegas, Mexico--one of the first whole-ecosystem experiments involving replicated metagenomic assessments. As predicted assuming oligotrophy favors lower information-processing costs whereas copiotrophy favors higher processing rates, mean bacteria genome size was higher in the fertilized treatment, as were GC content, total number of tRNA genes, total number of rRNA genes and codon usage bias in ribosomal protein sequences. However, contrasting changes in trait variances also suggested differences between traits in mediating assembly under oligotrophic versus copiotrophic conditions. Tradeoffs in information-processing traits are apparently sufficiently pronounced to play a role in community assembly and all different components of metabolism-- information, energy, and nutrient requirements--are fine-tuned to an organisms growth and trophic strategy.

ecology↗