Global synthesis of temperature sensitivity of soil organic carbon decomposition: Latitudinal patterns and mechanisms

Abstract

The response of soil organic carbon (SOC) decomposition to global warming is a potentially major source of uncertainty in climate prediction. However, the magnitude and direction of SOC cycle feedbacks under climate warming remain uncertain because of the knowledge gap about the global‐scale spatial pattern and temperature sensitivity (Q10) mechanism of SOC decomposition. Here, we collected data of Q10 and corresponding soil variables from 81 peer‐reviewed papers using laboratory incubation to explore how Q10 varied among different ecosystems at the global scale and whether labile and recalcitrant SOC pools had equal Q10 values. Q10 with a global average of 2.41 substantially varied among different ecosystems, ranging from the highest in cropland soils (2.76) and the lowest in wetland soils (1.84). Hump‐shaped correlations of Q10 values with the maximum at SOC = 190 g/kg and the minimum at clay = 37% were observed. However, the main influencing factors of Q10 differed among various ecosystems. Q10 values showed a clear decrease with increasing incubation temperature but no significant decrease above 25°C. In general, labile SOC was less sensitive than recalcitrant SOC to warming. Structural equation model analyses showed that total N and SOC accounted for 53% and 46%, respectively, of the variation in Q10 of labile SOC and recalcitrant SOC. This finding suggested that Q10 values of labile and recalcitrant SOC pools had different controlling factors. Our findings highlighted the importance of Q10’s variations in ecosystem types and the response of recalcitrant SOC to warming in predicting the soil C cycling and its feedback to climate change. Therefore, ecosystem type and difference in Q10 of labile and recalcitrant SOC should be considered to precisely predict the soil C dynamics under global warming. A http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.13256/suppinfo is available for this article.

Nitrogen Addition Affects Soil Respiration Primarily through Changes in Microbial Community Structure and Biomass in a Subtropical Natural Forest

“…In our control treatment, the Q 10 value (2.07) was similar to that reported from a subtropical rehabilitated forest (2.1) [58], but lower than those from a subtropical disturbed forest (2.3) [58], a Moso bamboo forest (2.29) [6], a sweetgum forest (2.73) [59], and a larch forest (3.24) [14] across the temperate zone. This is in line with the observations of Wang et al [60], in which Q 10 showed a positive relationship with latitude in forest ecosystems. In addition, the C:N ratio is a dominant factor for regulating Q 10 , owing to the shift from C limitation to nutrient limitation with increasing latitude [60,61].…”

“…This is in line with the observations of Wang et al [60], in which Q 10 showed a positive relationship with latitude in forest ecosystems. In addition, the C:N ratio is a dominant factor for regulating Q 10 , owing to the shift from C limitation to nutrient limitation with increasing latitude [60,61]. This result may support the microbial N mining theory, which suggests that microbes decompose more SOM to obtain sufficient N at high temperature in high latitude forests with low N availability [62].…”

Climate mediates continental scale patterns of stream microbial functional diversity

“…The consistent relationships between elevation and alpha diversity for most of the functional gene families further suggest a general temperature dependence for multiple stream processes. This finding was especially noticeable for families associated with stress processes (Additional file 1: Figure S5a) and highlights the need for future research on temperature dependence to consider a wider range of ecosystem processes in addition to mere Ccycling [43].…”

The continent-scale variations in soil microbial respiration in forest ecosystems: diverged pattern and mechanism

“…As Xu et al (2017) reported, our measured Rm based on MAT may be more representative for soil microbial activity and also more useful in process modeling because MAT is near to ambient soil temperature. Furthermore, in the previous studies estimating Rm at the same incubation temperature for all soils collected from different sites may have a deviation in Rm values because Rm is generally positively related to incubation temperature (Hamdi et al, 2013;Wang et al, 2019). That is to say, Rm in high latitude biomes with low MAT (e.g., boreal forests) would be overestimated when incubation temperature was higher than their MAT, while in low latitude biomes with high MAT (e.g., tropical forests) Rm would be underestimated.…”