摘要：More than 90% of marine dissolved organic matter (DOM) is biologically recalcitrant. This recalcitrance has been attributed to intrinsically refractory molecules or to low concentrations of molecules, but their relative contributions are a long-standing debate. Characterizing the molecular composition of marine DOM and its bioavailability is critical for understanding this uncertainty. Here, using different sorbents, DOM was solid-phase extracted from coastal, epipelagic, and deep-sea water samples for molecular characterization and was subjected to a 180-day incubation. 1H nuclear magnetic resonance spectroscopy and ultra-high-resolution mass spectrometry (UHRMS) analyses revealed that all of the DOM extracts contained refractory carboxyl-rich alicyclic molecules, accompanied with minor bio-labile components, for example, carbohydrates. Furthermore, dissolved organic carbon concentration analysis showed that a considerable fraction of the extracted DOM (86-95%) amended in the three seawater samples resisted microbial decomposition throughout the 180-day heterotrophic incubation, even when concentrated threefold. UHRMS analysis revealed that DOM composition remained mostly invariant in the 180-day deep-sea incubations. These results underlined that the dilution and intrinsic recalcitrance hypotheses are not mutually exclusive in explaining the recalcitrance of oceanic DOM, and that the intrinsically refractory DOM likely has a relatively high contribution to the solid-phase extractable DOM in the ocean.

关键字：recalcitrant DOM; bioavailability; molecular composition; microbial incubation

ISSN号：0013-936X

卷、期、页：卷56期23: 17420-17429

发表日期：2022-12-06

影响因子：9.028500

期刊分区（SCI为中科院分区）：一区

收录情况：SCI（科学引文索引印刷版）,SCIE（科学引文索引网络版）

发表期刊名称：ENVIRONMENTAL SCIENCE & TECHNOLOGY

参与作者：郑晓暄,蔡阮鸿,姚宏伟,郑强,焦念志

通讯作者：禚笑村

第一作者：何晨,史权

论文类型：期刊论文

论文概要：郑晓暄,蔡阮鸿,姚宏伟,禚笑村,何晨,郑强,史权,焦念志，Experimental Insight into the Enigmatic Persistence of Marine Refractory Dissolved Organic Matter，ENVIRONMENTAL SCIENCE & TECHNOLOGY，2022，卷56期23: 17420-17429

论文题目：Experimental Insight into the Enigmatic Persistence of Marine Refractory Dissolved Organic Matter