美国明尼苏达大学Liang, Guopeng和Reich, Peter B.团队研究了北方森林土壤湿度调节下土壤呼吸对十年变暖的响应。相关论文于2024年8月20日发表在《自然—地球科学》杂志上。

据研究人员介绍，长期气候变暖对森林土壤呼吸及其驱动因素的影响尚不清楚，森林储存了全球约40%的土壤碳。

研究人员在两个森林地块进行了长达13年的气候变化实验。该研究处理包括在不同降雨情景(夏季降雨量的100%和60%)下，进行地上和地下同时升温(环境温度，+1.7°C和+3.3°C)，以及对比树冠层开放度(开放和封闭)的变化。

在+1.7°C和+3.3°C升温条件下，土壤呼吸分别增加了7%和17%，这是所有地点、处理方式和年份的平均升温值。这些呼吸作用的增加高于之前仅有的两个长期但仅限土壤的森林变暖实验的每一度变暖的影响。

此外，变暖对土壤呼吸的影响随时间变化显著。在几乎所有条件下，湿润土壤都比干燥土壤表现出更大的呼吸增加来响应变暖。研究结果表明，在预测变暖对土壤呼吸的影响时，应该考虑到一系列现实的预期条件，包括地上和地下的温度和湿度。

附：英文原文

Title: Soil respiration response to decade-long warming modulated by soil moisture in a boreal forest

Author: Liang, Guopeng, Stefanski, Artur, Eddy, William C., Bermudez, Raimundo, Montgomery, Rebecca A., Hobbie, Sarah E., Rich, Roy L., Reich, Peter B.

Issue&Volume: 2024-08-20

Abstract: The effects of long-term climate warming on soil respiration and its drivers remain unclear in forests, which store approximately 40% of global soil carbon. Here we conducted a climate change experiment for 13years in forest plots planted with tree juveniles at two southern boreal forest sites. Treatments included simultaneous above- and below-ground warming (ambient, +1.7°C and +3.3°C) under different rainfall scenarios (100% and 60% of summer rainfall) and contrasting overstory canopy openness (open and closed). Soil respiration increased by 7% and 17% under +1.7°C and +3.3°C warming, respectively, averaged across all sites, treatments and years. These increases in respiration were higher than impacts per degree warming of the only two prior long-term, but soil-only, forest warming experiments. Moreover, warming effects on soil respiration varied significantly over time. Under almost all conditions, moist soil exhibited a greater increase in respiration in response to warming than dry soil. Our results suggest that a realistic range of anticipated conditions, including both above- and below-ground temperature and moisture, should be accounted for when predicting warming effects on soil respiration.

DOI: 10.1038/s41561-024-01512-3

Source: https://www.nature.com/articles/s41561-024-01512-3