Contribution and control of microbial necromass carbon in wetland soils

IF 2 3区环境科学与生态学 Q3 ENVIRONMENTAL SCIENCES

Aquatic Sciences Pub Date : 2024-07-06 DOI:10.1007/s00027-024-01098-3

Shanshan Liao, Xiaodong Nie, Wenfei Liao, Yi Liu, Aoqi Zeng, Zhongwu Li

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Abstract

Microbial necromass carbon (MNC) has been identified as an essential component of a persistent soil carbon pool. However, the contribution of MNC to soil organic carbon (SOC) in wetlands remains unclear. This study aims to explore the contribution of MNC to SOC and the factors controlling its distribution in wetlands. The distribution pattern of MNC in drawdown areas was investigated in the inlet and center of the Dongting Wetland, China. Random forest modeling was performed to determine the relative importance of environmental variables to MNC. A partial least squares path model was performed to further explore the direct and indirect effects of environmental variables on MNC. The analyses showed that the MNC content was 2652.70–3314.64 mg kg⁻¹, accounting for 23.16–31.65% of SOC in wetland soils. Compared to bacterial necromass carbon (BNC), fungal necromass carbon (FNC) contributed more to SOC accumulation (over 70% of total MNC) in wetland soils. MNC content and the contribution of BNC to MNC increased with soil depth. In addition, MNC in wetland soils was directly affected by dissolved total nitrogen (DTN) and dissolved organic carbon (DOC)/SOC (p < 0.001; standardized total effect = 0.81). The pH indirectly affected MNC by regulating carbon and nitrogen content, with a standardized total effect of 0.48. In wetland soils, the lower MNC content and lower contribution to SOC may be supported by the slow accumulation of necromass and potential necromass mining in nutrient-poor conditions. Carbon and nitrogen availability played a crucial role in controlling the MNC turnover process in wetland soils.

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湿地土壤中微生物坏死碳的贡献与控制

微生物坏死碳（MNC）已被确定为持久性土壤碳库的重要组成部分。然而，MNC对湿地土壤有机碳（SOC）的贡献仍不清楚。本研究旨在探讨 MNC 对 SOC 的贡献及其在湿地分布的控制因素。研究人员在中国洞庭湿地的入口和中心区域调查了引水区 MNC 的分布模式。采用随机森林模型确定环境变量对 MNC 的相对重要性。采用偏最小二乘法路径模型进一步探讨了环境变量对 MNC 的直接和间接影响。分析表明，MNC 含量为 2652.70-3314.64 mg kg-1，占湿地土壤 SOC 的 23.16-31.65%。与细菌腐质碳（BNC）相比，真菌腐质碳（FNC）对湿地土壤中 SOC 积累的贡献更大（占 MNC 总量的 70% 以上）。MNC 含量和 BNC 对 MNC 的贡献随土壤深度增加而增加。此外，湿地土壤中的 MNC 直接受溶解全氮 (DTN) 和溶解有机碳 (DOC)/SOC 的影响（p < 0.001; 标准总效应 = 0.81）。pH 值通过调节碳和氮含量间接影响 MNC，标准化总效应为 0.48。在湿地土壤中，MNC 含量较低，对 SOC 的贡献也较低，这可能是因为在养分贫乏的条件下，坏死物质和潜在坏死物质的开采积累缓慢。碳和氮的供应在控制湿地土壤中的 MNC 转化过程中发挥了关键作用。

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来源期刊

Aquatic Sciences 环境科学-海洋与淡水生物学

CiteScore

3.90

自引率

4.20%

发文量

审稿时长

1 months

期刊介绍： Aquatic Sciences – Research Across Boundaries publishes original research, overviews, and reviews dealing with aquatic systems (both freshwater and marine systems) and their boundaries, including the impact of human activities on these systems. The coverage ranges from molecular-level mechanistic studies to investigations at the whole ecosystem scale. Aquatic Sciences publishes articles presenting research across disciplinary and environmental boundaries, including studies examining interactions among geological, microbial, biological, chemical, physical, hydrological, and societal processes, as well as studies assessing land-water, air-water, benthic-pelagic, river-ocean, lentic-lotic, and groundwater-surface water interactions.