PDF(Pubmed)
Abstract：
Clarifying the accumulation and decomposition of soil organic carbon (SOC) is crucial for comprehending carbon cycling in terrestrial ecosystems. SOC enrichment and decomposition lead to the fractionation of stable carbon isotopes, a complex process influenced by various factors, including microbes. However, this fractionation process during early soil formation and the role of microorganisms remain poorly explored. This study investigated the relative composition of stable carbon isotopes (δ13C) of recently formed biological soil crusts (BSCs) on stabilized sand dunes in the Tengger Desert, Northern China. A notable increase in δ13C was observed during early BSC development, likely driven by cyanobacteria\'s direct fixation of CO2. Yet, δ13C values of BSCs gradually declined, approaching those of soils under native vegetation, probably linked to microbial succession within the BSCs. This finding highlights the potential microbial influence on early soil carbon turnover and underscores the effectiveness of isotope tracers for studying this process.
摘要：
明确土壤有机碳（SOC）的积累和分解对于理解陆地生态系统的碳循环至关重要。SOC富集和分解导致稳定碳同位素的分馏，一个受各种因素影响的复杂过程，包括微生物。然而,在早期土壤形成过程中的这种分馏过程和微生物的作用仍未得到充分探索。这项研究调查了腾格里沙漠稳定沙丘上最近形成的生物土壤结皮（BSC）的稳定碳同位素（δ13C）的相对组成，中国北方。在早期BSC发育过程中观察到δ13C的显着增加，可能是由蓝细菌直接固定二氧化碳驱动的。然而，BSC的δ13C值逐渐下降，接近原生植被下的土壤，可能与BSC内的微生物演替有关。这一发现强调了微生物对早期土壤碳周转的潜在影响，并强调了同位素示踪剂研究这一过程的有效性。
