Changes in nutrient availability substantially alter bacteria and extracellular enzymatic activities in Antarctic...

Area of Science:

• * Environmental microbiology
• * Polar soil ecology
• * Antarctic biogeochemistry

Background:

• * Accelerated ice melt in polar regions increases nutrient runoff.
• * Short-term impacts of altered nutrient regimes on Antarctic soil microbial communities are poorly understood.
• * Antarctic soil microbiota may be resilient but their rapid response to nutrient changes is understudied.

Purpose of the Study:

• * To investigate the effects of augmented nutrients (carbon, nitrogen, moisture) on Antarctic soil microbial diversity and function.
• * To understand the shifts in microbial community structure and abundance in response to nutrient addition.
• * To identify key factors influencing microbial responses to nutrient changes in polyextreme environments.

Main Methods:

• * Construction of soil microcosms simulating augmented carbon, nitrogen, and moisture.
• * Analysis of microbial community diversity and structure using molecular techniques.
• * Assessment of extracellular enzyme activities and soil parameters.
• * Application of structural equation modeling to determine predictor variables.

Main Results:

• * Nitrogen addition significantly decreased Antarctic soil microbial diversity compared to other treatments.
• * Nitrogen addition led to distinct community structural patterns, increasing Proteobacteria and decreasing Verrucomicrobiota.
• * Extracellular enzyme activities and soil parameters were significant predictors of microbial taxa changes following nitrogen addition.
• * Nutrient source and extracellular enzyme activities positively predicted microbial diversity.

Conclusions:

• * Nitrogen addition significantly impacts Antarctic soil microbial communities, reducing diversity and altering structure.
• * Antarctic soil microbiota demonstrate rapid responses to nutrient augmentation, challenging notions of resistance.
• * Nutrient availability and associated enzymatic activities are critical drivers of microbial community dynamics in polar soils.