Algal blooms modulate organic matter remineralization in freshwater sediments: A new insight on priming effect
Algal blooms modulate organic matter remineralization in freshwater sediments: A new insight on priming effect
复制标题
藻华调节淡水沉积物中的有机物再矿化：关于启动效应的新见解
DOI：
10.1016/j.scitotenv.2021.147087
复制
发表时间：
2021
影响因子：
9.8
通讯作者：
Ngwenya Bryne Tendelo
中科院分区：
文献类型：
--
作者：
Wang Yarui;Feng Muhua;Wang Jianjun;Chen Xinfang;Chen Xiangchao;Du Xian;Xun Fan;Ngwenya Bryne Tendelo
本研究为基于启动效应的藻源有机物（AOM）调控沉积物有机质（SOM）降解提供了新的视角。我们利用化合物特异性稳定同位素（δ13C）技术跟踪了沉积物中添加低密度和高密度藻屑后SOM矿化产物和途径的动态变化，以及启动效应（PE）。藻类碎屑增加了总碳氧化速率，导致反硝化和甲烷生成为主的有机质矿化。而铁还原和硫酸盐还原在藻类积累初期起着重要作用。改良处理的总碳氧化速率和厌氧速率均高于对照组。分析表明，藻屑对SOM矿化具有正PE作用，导致初始阶段矿化加剧，80%以上的溶解无机碳来源于SOM降解。由启动效应推断的SOM总碳氧化速率（rtco - pe）与随机好氧相似，进一步表明SOM矿化是最终产物的重要来源。这些发现偏离了AOM分解的因果焦点，证实了AOM的富集是SOM矿化的促进因素。本研究提供了经验证据，进一步完善了传统的AOM对SOM成矿作用的看法。
This study provides a novel insight into the degradation of sediment organic matter (SOM) regulated by algae-derived organic matter (AOM) based on priming effect. We tracked the dynamics of SOM mineralization products and pathways, together with priming effects (PE) using the compound-specific stable isotope (δ13C) technique following addition of low- and high-density algal debris in sediments. We found that algal debris increased the total carbon oxidation rate, and resulted in denitrification and methanogenesis-dominated SOM mineralization. While iron reduction and sulphate reduction played important roles in the early period of algal accumulation. Total carbon oxidation rate and anaerobic rates (Ranaerobic) were higher in the amended treatments compared with that in the control. Analysis indicated that algal debris had a positive PE on SOM mineralization, which caused an intensified mineralization in the initial phase with over 80% of dissolved inorganic carbon deriving from SOM degradation. Total carbon oxidation rate of SOM deduced from priming effect (RTCOR-PE) was similar to Ranaerobic, further indicating SOM mineralization was a critical source of the end products. These findings deviate the causal focus from the decomposition of AOM, and confirm the accumulation of AOM as the facilitator of SOM mineralization. Our study offers empirical evidences to advance the traditional view on the effect of AOM on SOM mineralization.