Section of Microbial Ecology, Department of Biology, Lund University, Lund, Sweden.
School of Forestry, Northeast Forestry University, Harbin, China.
Ecology. 2024 Jan;105(1):e4210. doi: 10.1002/ecy.4210. Epub 2023 Dec 8.
The microbial use of resources to sustain life and reproduce influences for example, decomposition and plant nutrient provisioning. The study of "limiting factors" has shed light on the interaction between plants and their environment. Here, we investigated whether carbon (C), nitrogen (N), or phosphorus (P) was limiting for soil microorganisms in a subarctic tundra heath, and how changes in resource availability associated with climate change affected this. We studied samples in which changes in resource availability due to climate warming were simulated by the addition of birch litter and/or inorganic N. To these soils, we supplied factorial C (as glucose), N (as NH NO ), and P (as KH PO /K HPO ) additions ("limiting factor assays," LFA), to determine the limiting factors. The combination of C and P induced large growth responses in all soils and, combined with a systematic tendency for growth increases by C, this suggested that total microbial growth was primarily limited by C and secondarily by P. The C limitation was alleviated by the field litter treatment and strengthened by N fertilization. The microbial growth response to the LFA-C and LFA-P addition was strongest in the field-treatment that combined litter and N addition. We also found that bacteria were closer to P limitation than fungi. Our results suggest that, under a climate change scenario, increased C availability resulting from Arctic greening, treeline advance, and shrubification will reduce the microbial C limitation, while increased N availability resulting from warming will intensify the microbial C limitation. Our results also suggest that the synchronous increase of both C and N availability might lead to a progressive P limitation of microbial growth, primarily driven by bacteria being closer to P limitation. These shifts in microbial resource limitation might lead to a microbial targeting of the limiting element from organic matter, and also trigger competition for nutrients between plants and microorganisms, thus modulating the productivity of the ecosystem.
微生物利用资源来维持生命和繁殖，例如，分解和植物养分供应。对“限制因素”的研究揭示了植物与其环境之间的相互作用。在这里，我们调查了在亚北极苔原荒地中，土壤微生物是否受到碳 (C)、氮 (N) 或磷 (P) 的限制，以及气候变化引起的资源可用性变化如何影响这种限制。我们研究了由于气候变暖导致资源可用性变化的样本，这些变化通过添加桦木落叶和/或无机 N 来模拟。对于这些土壤，我们提供了葡萄糖（C）、硝酸铵（N）和磷酸二氢钾/磷酸氢二钾（P）的因子添加（“限制因素测定”，LFA），以确定限制因素。C 和 P 的组合在所有土壤中引起了大量的生长反应，并且由于 C 的生长增加呈系统趋势，这表明总微生物生长主要受 C 限制，其次受 P 限制。田间落叶处理缓解了 C 限制，氮施肥则加强了 C 限制。LFA-C 和 LFA-P 添加的微生物生长响应在结合了落叶和 N 添加的田间处理中最强。我们还发现细菌比真菌更接近 P 限制。我们的结果表明，在气候变化情景下，北极绿化、林线推进和灌木化导致的 C 可用性增加将减少微生物的 C 限制，而变暖导致的 N 可用性增加将加剧微生物的 C 限制。我们的结果还表明，C 和 N 可用性的同步增加可能导致微生物生长的渐进性 P 限制，主要由细菌更接近 P 限制驱动。微生物资源限制的这些变化可能导致微生物从有机物中靶向限制元素，并引发植物和微生物之间对养分的竞争，从而调节生态系统的生产力。
