Carbon-fixing bacteria and sediment organic carbon response to the introduction of mangrove plant Sonneratia caseolaris

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🔬研究者:Provides mechanistic insights into microbial carbon fixation and sulfur cycling in mangrove sediments, useful for biogeochemical modeling.

🏢実務担当者:Mangrove restoration projects can use these findings to select species that maximize carbon storage and soil organic matter accumulation.

🏛政策担当者:Supports inclusion of mangrove microbial carbon sequestration in national carbon accounting and nature-based solution policies.

BACKGROUND: The fast-growing Sonneratia caseolaris has been widely used in restoration efforts to accelerate the recovery of degraded mangrove ecosystems. Carbon-fixing bacteria (CFB) are recognized as major microbial contributors to sediment carbon accumulation in the mangrove wetlands. However, the response of the CFB community and sediment organic carbon (SOC) to introduced S. caseolaris is still unknown. RESULTS: In this study, the sediment properties (especially SOC), the abundances of carbon-fixing genes (cbbL and cbbM), as well as the CFB community composition based on cbbL and cbbM functional genes and their interaction network, were compared between the introduced mangrove species (S. caseolaris) and native species (Kandelia obovata, Aegiceras corniculatum, and Acanthus ilicifolius) in the Niutianyang Mangrove Forest, Shantou, China. Our results showed that S. caseolaris markedly enhanced the SOC content and the abundances of the carbon-fixing genes (P < 0.05). The dominant CFB taxa were "purple sulfur bacteria" (PSB) (e.g., Chromatiales) and "purple nonsulfur bacteria" (PNSB) (e.g., Rhodobacterales). The relative abundances of some well-known plant growth-promoting rhizobacteria (PGPR), especially the Rhizobiales and Burkholderiales, were significantly increased (P < 0.05) by the S. caseolaris introduction. In addition, there was a more complex but less stable CFB community interaction network in the S. caseolaris sediments. It was well worth noting that a large number of the keystone taxa in the network were the sulfur-oxidizing bacteria (SOB), such as Sulfuriferula and Thioalkalivibrio, suggesting a tight connection between the carbon and sulfur cycles in mangrove wetlands, and these key genera might have decisive roles in reshaping CFB community structure and functioning. CONCLUSIONS: These findings confirmed that introduced S. caseolaris can strongly affect the CFB communities and the SOC content, and provided new insights into the microbial carbon sequestration in the mangrove wetlands.

• openalex https://doi.org/10.1186/s12915-026-02631-6first seen 2026-06-17 07:32:24