近日，天津大学陈春梅团队进行了全球滨海湿地亚稳铁矿物富集研究。2025年8月7日出版的《自然—地球科学》杂志发表了这项成果。
滨海湿地是陆地-海洋有机碳储存的重要界面。据推测，活性低结晶或短程有序的铁矿物增强了有机碳的积累和持久性。然而，这些亚稳矿物容易快速还原溶解，增加了它们的丰度和对沿海湿地碳循环影响的不确定性，在缺氧通常普遍存在的地方。
研究组结合了约23,000个观测数据的全球数据库和中国海岸线的全国调查。研究表明，与高地相比，沿海湿地优先富集低结晶或短程有序的铁矿物，而不是高结晶相。M Ssbauer谱分析显示，水合铁、纳米针铁矿和高度无序相在滨海湿地的氧化铁池中占主导地位，并具有少量的结晶形式，挑战了反应性亚稳态矿物在缺氧条件下优先被去除的观点。
研究组发现活性亚稳铁在热带湿地最为丰富，而在热带高地，晶体矿物占主导地位。尽管亚稳铁矿物的丰度更高，但沿海湿地与氧化铁相关的总有机碳的比例（约13%）与高地相似。此外，这些广泛存在的亚稳铁矿物没有显示出沿海湿地有机碳饱和的证据，这突出了通过管理实践促进这种有机碳汇的潜力。
附：英文原文
Title: Enrichment of metastable iron minerals in global coastal wetlands
Author: Ma, Hua, Thompson, Aaron, Hall, Steven J., Wang, Jialin, Xiao, Yanqi, Liu, Cong-Qiang, Chen, Chunmei
Issue&Volume: 2025-08-07
Abstract: Coastal wetlands are important land–ocean interfaces for organic carbon storage. It was assumed that reactive poorly crystalline or short-range-ordered iron minerals enhance organic carbon accrual and persistence. However, these metastable minerals are prone to rapid reductive dissolution, raising uncertainties about their abundance and impact on carbon cycling in coastal wetlands, where anoxia typically prevails. Here we combine a global database of ~23,000 observations and a national survey across China’s coastline. We show that coastal wetlands are enriched preferentially in poorly crystalline or short-range-ordered iron minerals over well-crystalline phases, compared with uplands. Mssbauer spectroscopy reveals that ferrihydrite, nanogoethite and highly disordered phases dominated the iron oxide pool in coastal wetlands, with minor crystalline forms, challenging the notion that reactive metastable minerals are removed preferentially under anoxic conditions. We find that reactive metastable iron was most abundant in tropical wetlands, in contrast with tropical uplands where crystalline minerals predominate. Despite a higher abundance of metastable iron minerals, coastal wetlands had a similar fraction of total organic carbon associated with iron oxides (~13%) to uplands. Furthermore, these widespread metastable iron minerals show no evidence of organic carbon saturation in coastal wetlands, highlighting potential for boosting this rusty carbon sink through management practices.
DOI: 10.1038/s41561-025-01764-7
Source: https://www.nature.com/articles/s41561-025-01764-7