Climate warming impacts on soil organic carbon fractions and aggregate stability in a Tibetan alpine meadow

“…Up to now, some studies have examined the responses of SOC stocks to experimental warming on the Tibetan Plateau, however, previous studies mainly concentrated on the absolute SOC content and labile SOC fractions, such as microbial biomass and dissolved organic C (Luo et al, 2009;Yu, Shen, Zhang, Sun, & Fu, 2014;Zhou et al, 2013). As a consequence, experimental evidence about warming effects on SOM molecular composition is still limited (Guan et al, 2018;Jia et al, 2019). Particularly, no study has yet addressed warming-induced changes in SOM molecular composition and the associated mechanisms across Tibetan permafrost ecosystems.…”

Section: Introductionmentioning

confidence: 99%

Warming alters surface soil organic matter composition despite unchanged carbon stocks in a Tibetan permafrost ecosystem

Peng

Chen

et al. 2019

Functional Ecology

View full text Add to dashboard Cite

Climate warming can alter ecosystem carbon (C) balance and also the composition of soil organic matter (SOM), with important local and global implications. However, the extent to which rising temperature affects SOM composition in permafrost ecosystems remains poorly understood. Here, we experimentally warmed a permafrost ecosystem by open‐top chambers (OTCs) on the Tibetan Plateau for 4 years to quantify the responses of C inputs via vegetation production, C losses via soil respiration and soil organic carbon (SOC) stocks in the top 30 cm. We also characterized the molecular composition of SOM using 13C nuclear magnetic resonance (NMR) and biomarker analyses. The results indicated that warming treatment significantly increased root biomass, soil respiration, heterotrophic respiration and its contribution to soil respiration by 16.7%, 49.0%, 63.2% and 9.5% respectively. While we observed no change in SOC stocks, warming altered SOM composition in the 0–10 cm layer during the fourth experimental year. Warming increased the abundance of the alkyl C component (3.9%) and decreased aromatic C (5.1%), primarily lignin. The decrease in lignin‐derived compounds was attributable to the increased soil phenol oxidase activity. Overall, the substantial increase in heterotrophic respiration and rapid degradation of relatively recalcitrant C components such as lignin demonstrate that Tibetan SOC stocks are vulnerable to climate warming, which could trigger positive C–climate feedback in a warmer world. A free Plain Language Summary can be found within the Supporting Information of this article.

show abstract

“…The mean monthly rainfall and air and soil temperatures at 5 cm depth inside/outside the OTCs recorded during the experimental period were given in detail in our previous study (Guan et al 2018). On average, warming increased the annual soil temperature by 1.3°C and decreased soil moisture by 4.70% (v/v).…”

Section: Resultsmentioning

confidence: 99%

“…Thus, from the point of view of soil aggregates, we might reveal the intrinsic mechanisms of nutrient retention and release in soil. However, to our knowledge, little information was obtained on the dynamics of C, N and P associated with soil aggregates under climate warming scenarios (Guan et al 2018).…”

mentioning

confidence: 99%

Warming impacts on carbon, nitrogen and phosphorus distribution in soil water-stable aggregates

Guan¹,

An²,

Liu³

et al. 2018

PLANT SOIL ENVIRON

View full text Add to dashboard Cite

A five-year (2010–2015) field experiment was conducted to investigate warming impacts on organic carbon (OC), total nitrogen (TN) and total phosphorus (TP) contents and their ratios in bulk soil and soil water-stable aggregates in an alpine meadow of the Tibetan Plateau. Compared with unwarmed control, warming had no significant effects on OC, TN and TP contents and their ratios in bulk soil. The contents of OC, TN and TP associated with macroaggregates and microaggregates decreased, whereas those associated with silt + clay fractions significantly increased. The C:N and C:P ratios in macro- and microaggregates and silt + clay fractions decreased, with significant differences for C:P ratio in microaggregates and C:N and C:P ratios in silt + clay fractions. The results indicated that C, N and P were protected chemically in silt- and clay-size fractions under warming, which offset the loss of C, N and P protected physically by macro- and microaggregates. Both physically and chemically protected C decomposition proceeded relatively more rapidly or accumulated relatively more slowly than did N and P. Our results suggest that C, N and P distributions within soil aggregate size fractions influence their net changes in bulk soil under future climate change scenarios.

show abstract

Climate warming impacts on soil organic carbon fractions and aggregate stability in a Tibetan alpine meadow

Cited by 120 publications

References 84 publications

Characteristic, changes and impacts of permafrost on Qinghai-Tibet Plateau

Characteristic, changes and impacts of permafrost on Qinghai-Tibet Plateau

Warming alters surface soil organic matter composition despite unchanged carbon stocks in a Tibetan permafrost ecosystem

Warming impacts on carbon, nitrogen and phosphorus distribution in soil water-stable aggregates

Contact Info

Product

Resources

About