Lan Shubin, Wu Li, Adessi Alessandra, Hu Chunxiang
Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China.
School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan, 430070, China.
Environ Microbiol. 2022 Jan;24(1):66-81. doi: 10.1111/1462-2920.15853. Epub 2021 Nov 23.
Biocrusts provide numerous ecological functions in drylands. Recovering biocrusts via cyanobacterial inoculation recently gathered interest for ecological restoration, yet it still lacks long-term experiments to unravel biocrust community dynamics. To examine how cyanobacterial inoculants influenced local microbial community and biocrust development, we observed a 2 km (Qubqi Desert, China) inoculation experiment after 10 and 15 years, following biocrust formation. Our results revealed that biocrust development was in line with ecological regime shift, providing evidence for biocrust community succession, from cyanobacteria- to moss-dominated types. Associated with biocrust development, microbial communities differed significantly with less specialists compared to shifting sands. Cyanobacterial community analysis showed that Microcoleus vaginatus and Scytonema javanicum are an ideal inoculating model, as they were still dominating the community after 15 years since inoculation, while other nitrogen-fixing cyanobacteria occurred profusely with biocrust development. Biocrust community composition combined with thickness, Chl-a and exopolysaccharide measurements revealed the large variation of cyanobacterial ecological functions along biocrust development, suggesting a main function shift: from carbon fixation associated with exopolysaccharide secretion in bare sandy soils to nitrogen fixation in developed biocrusts. This large-scale field study verifies that cyanobacterial inoculation accelerates biocrust development and forwards succession, shaping the biocrust community composition over a long time.
生物结皮在旱地发挥着多种生态功能。通过接种蓝细菌来恢复生物结皮最近在生态恢复方面受到关注，但仍缺乏长期实验来揭示生物结皮群落动态。为了研究蓝细菌接种剂如何影响当地微生物群落和生物结皮发育，我们在生物结皮形成后的10年和15年，对一个2公里（中国库布齐沙漠）的接种实验进行了观测。我们的结果表明，生物结皮的发育与生态状态转变一致，为生物结皮群落演替提供了证据，即从以蓝细菌为主导的类型向以苔藓为主导的类型转变。与生物结皮发育相关，微生物群落与流动沙地相比有显著差异，专性物种较少。蓝细菌群落分析表明，鞘丝藻和爪哇伪枝藻是理想的接种模型，因为接种15年后它们仍在群落中占主导地位，而随着生物结皮的发育，其他固氮蓝细菌大量出现。生物结皮群落组成结合厚度、叶绿素a和胞外多糖测量结果表明，随着生物结皮的发育，蓝细菌生态功能存在很大差异，这表明其主要功能发生了转变：从裸沙地中与胞外多糖分泌相关的碳固定转变为发育成熟的生物结皮中的氮固定。这项大规模的田间研究证实，蓝细菌接种加速了生物结皮的发育并推动了演替，长期塑造了生物结皮群落组成。
