近日，香港科技大学刘易团队揭示碳酸盐风化增强了全球河流中氮的同化吸收。2025年4月28日出版的《自然—地球科学》杂志发表了这项成果。
基岩成分，特别是碳酸盐的比例，会影响河流的溶解无机碳浓度和碳酸盐化学，但其对河流氮循环的影响通常被忽视。研究组对中国珠江流域的河流进行了地球化学成分测量，结果表明，溶解有机氮（DON）与溶解无机氮呈正相关，并在雨季碳酸盐为主的地区遵循太阳辐射的变化，但在非碳酸盐为主的地区则不然。
原位培养表明，在溶解无机碳含量高、温度和太阳辐射高的地区，有机氮的产生得到了加强。由于低温对氮同化的限制，旱季DON分区不明显。研究组还报告了印度尼西亚马朗碳酸盐主导和非碳酸盐主导地区类似的DON对比。此外，通过对全球已发表数据的分析，他们发现，结合碳限制的修正Michaelis-Menten模型更适合全球DON的纬度分布。因此，研究组提出碳酸盐风化对有机氮产生的增强作用普遍存在。
附：英文原文
Title: Carbonate weathering enhances nitrogen assimilatory uptake in rivers globally
Author: Qi, Hongkai, Liu, Yi, Wang, Haoran, Kuang, Xingxing, Putra, Aditya Nugraha, Jiao, Jiu Jimmy, Gan, Jianping
Issue&Volume: 2025-04-28
Abstract: Bedrock composition, in particular the proportion of carbonate, can influence the dissolved inorganic carbon concentration and also the carbonate chemistry of rivers, but its effects on the nitrogen cycle in rivers are usually overlooked. Here we present geochemical composition measurements of rivers across the Pearl River Basin in China that show that dissolved organic nitrogen (DON) is positively correlated with dissolved inorganic nitrogen and follows the variation in solar radiation in the carbonate-dominated region during the wet season, but not in the non-carbonate-dominated region. In situ incubations show that organic nitrogen production is strengthened in the regions with high dissolved inorganic carbon and high temperature and solar radiation. DON zonation in the dry season is not obvious owing to the limitation of low temperature on nitrogen assimilation. We also report a similar DON contrast in carbonate-dominated and non-carbonate-dominated regions in Malang in Indonesia. Furthermore, from an analysis of global published data, we find that a modified Michaelis–Menten model incorporating carbon limitation provides a much better fit to the global latitudinal distribution of DON globally. Hence, we propose that carbonate weathering enhancement of organic nitrogen production occurs ubiquitously.
DOI: 10.1038/s41561-025-01680-w
Source: https://www.nature.com/articles/s41561-025-01680-w