Molecular composition of dissolved organic matter across diverse ecosystems: Preliminary implications for biogeochemical cycling.
Molecular composition of dissolved organic matter across diverse ecosystems: Preliminary implications for biogeochemical cycling.
复制标题
DOI：
10.1016/j.jenvman.2023.118559
复制
发表时间：
2023-07
影响因子：
8.7
通讯作者：
Chen He;Y. Yi;Ding He;Ruanhong Cai;Chunmao Chen;Q. Shi
中科院分区：
文献类型：
--
作者：
Chen He;Y. Yi;Ding He;Ruanhong Cai;Chunmao Chen;Q. Shi
傅里叶变换离子回旋共振质谱（FT-ICR MS）已广泛应用于表征不同生态系统中溶解有机物（DOM）的分子组成。以往的研究大多集中于一个或几个生态系统探索DOM的分子组成，这阻碍了我们追踪不同来源的DOM分子组成并进一步探索其跨生态系统的生物地球化学循环。本研究采用负离子电喷雾电离 FT-ICR MS 对土壤、湖泊、河流、海洋和地下水等 67 个 DOM 样品进行了分析。结果表明，不同生态系统中 DOM 的分子组成差异很大。具体而言，森林土壤 DOM 表现出最强的陆地分子特征，而海水 DOM 显示出最丰富的生物顽抗成分，例如，深海水中富含羧基的脂环族分子。陆源有机质在沿着河流-河口-海洋连续体的运输过程中逐渐降解。盐湖DOM表现出与海洋DOM相似的DOM特征，并且封存了丰富的顽固性DOM。通过比较这些 DOM 提取物，我们发现人类活动可能导致 DOM 中含硫和含氮杂原子含量增加，这种现象常见于水稻土、污染河流、富营养化湖泊和酸性矿山排水 DOM 样品中。总体而言，本研究比较了从不同生态系统中提取的 DOM 的分子组成，提供了 DOM 指纹的初步比较，并为不同生态系统的生物地球化学循环提供了视角。因此，我们主张使用 FT-ICR MS 在更广泛的生态系统中开发全面的 DOM 分子指纹数据库。这将使我们能够更好地理解生态系统之间独特特征的普遍性。
Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR MS) has been widely applied to characterize the molecular composition of dissolved organic matter (DOM) in different ecosystems. Most previous studies have explored the molecular composition of DOM focused on one or a few ecosystems, which prevents us from tracing the molecular composition of DOM from different sources and further exploring its biogeochemical cycling across ecosystems. In this study, a total of 67 DOM samples, including soil, lake, river, ocean, and groundwater, were analyzed by negative-ion electrospray ionization FT-ICR MS. Results show that molecular composition of DOM varies dramatically among diverse ecosystems. Specifically, the forest soil DOM exhibited the strongest terrestrial signature of molecules, while the seawater DOM showed the most abundant of biologically recalcitrant components, for example, the carboxyl-rich alicyclic molecules were abundant in the deep-sea waters. Terrigenous organic matter is gradually degraded during its transport along the river-estuary-ocean continuum. The saline lake DOM showed similar DOM characteristics with marine DOM, and sequestrated abundant recalcitrant DOM. By comparing these DOM extracts, we found that human activities likely lead to an increase in the content of S and N-containing heteroatoms in DOM, this phenomenon was commonly found in the paddy soil, polluted river, eutrophic lake, and acid mine drainage DOM samples. Overall, this study compared molecular composition of DOM extracted from various ecosystems, providing a preliminary comparison on the DOM fingerprint and an angle of view into biogeochemical cycling across different ecosystems. We thus advocate for the development of a comprehensive molecular fingerprint database of DOM using FT-ICR MS across a wider range of ecosystems. This will enable us to better understand the generalizability of the distinct features among ecosystems.