瑞典默奥大学Strack, M.团队报道了变暖冻原生态系统呼吸增加的环境驱动因素。相关论文发表在2024年4月17日出版的《自然》杂志上。

研究人员综合了来自28个北极和高山冻原站点的56个开顶室原位变暖实验的136个数据集，这些实验已经运行了到1至25年。研究发现，空气温度平均上升1.4°C[置信区间(CI) 0.9-2.0°C ]和土壤温度平均上升0.4°C [置信区间0.2-0.7°C ]，导致生长期生态系统呼吸增加30% [置信区间22-38% (n=136)]。结果表明，生态系统呼吸的刺激是由于植物相关呼吸和微生物呼吸的增加(n=9)，并持续至少25年(n=136 )。

气候变暖对呼吸作用的影响程度主要受气候变暖引起的局部土壤条件变化(即总氮浓度和pH值的变化)，和土壤条件的空间变化(特别是总氮浓度和碳氮比)驱动。氮限制较强的冻原地点和变暖刺激了植物和微生物养分周转的地区，似乎对变暖的呼吸反应特别敏感。研究结果强调了当地土壤条件及其变暖引起的变化，对未来气候对呼吸的影响的重要性。

据了解，北极和高山冻原生态系统是有机碳的大型储存库。气候变暖可能会刺激生态系统的呼吸作用，并将碳释放到大气中。这种刺激的强度和持续性以及驱动其变化的环境机制仍不确定，阻碍了全球陆地碳—气候反馈预测的准确性。

附：英文原文

Title: Environmental drivers of increased ecosystem respiration in a warming tundra

Author: Maes, S. L., Dietrich, J., Midolo, G., Schwieger, S., Kummu, M., Vandvik, V., Aerts, R., Althuizen, I. H. J., Biasi, C., Bjrk, R. G., Bhner, H., Carbognani, M., Chiari, G., Christiansen, C. T., Clemmensen, K. E., Cooper, E. J., Cornelissen, J. H. C., Elberling, B., Faubert, P., Fetcher, N., Forte, T. G. W., Gaudard, J., Gavazov, K., Guan, Z., Gumundsson, J., Gya, R., Hallin, S., Hansen, B. B., Haugum, S. V., He, J.-S., Hicks Pries, C., Hovenden, M. J., Jalava, M., Jnsdttir, I. S., Juhanson, J., Jung, J. Y., Kaarlejrvi, E., Kwon, M. J., Lamprecht, R. E., Le Moullec, M., Lee, H., Marushchak, M. E., Michelsen, A., Munir, T. M., Myrsky, E. M., Nielsen, C. S., Nyberg, M., Olofsson, J., skarsson, H., Parker, T. C., Pedersen, E. P., Petit Bon, M., Petraglia, A., Raundrup, K., Ravn, N. M. R., Rinnan, R., Rodenhizer, H., Ryde, I., Schmidt, N. M., Schuur, E. A. G., Sjgersten, S., Stark, S., Strack, M.

Issue&Volume: 2024-04-17

Abstract: Arctic and alpine tundra ecosystems are large reservoirs of organic carbon. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain. This hampers the accuracy of global land carbon–climate feedback projections. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1year up to 25years. We show that a mean rise of 1.4°C [confidence interval (CI) 0.9–2.0°C] in air and 0.4°C [CI 0.2–0.7°C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22–38%] (n=136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n=9) and continued for at least 25years (n=136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

DOI: 10.1038/s41586-024-07274-7

Source: https://www.nature.com/articles/s41586-024-07274-7