Molecular Insights into Dissolved Organic Matter in Natural Dew Water: Biogrime Films on Leaf Surfaces
Molecular Insights into Dissolved Organic Matter in Natural Dew Water: Biogrime Films on Leaf Surfaces
复制标题
天然露水中溶解有机物的分子洞察：叶片表面的生物炭膜
DOI：
10.1021/acsearthspacechem.1c00445
复制
发表时间：
2022-03-17
影响因子：
3.4
通讯作者：
O'Brien, Rachel E.
中科院分区：
文献类型：
--
作者：
Dibley, Monica;Jaffe, Aron;O'Brien, Rachel E.
露水是溶解的有机分子的临时储存库，这些分子在早晨露水蒸发时释放出来。许多地方允许阳光在早晨直接照射露水，这增加了光解驱动化学反应的可能性。大多数研究露水化学成分的现有工作都是针对清洁表面（如特氟隆）上新沉积的露水。然而，露水中溶解的有机物质是夜间沉积的化合物的混合物，以及已经存在于表面的水溶性化合物。在这里，我们分析了2020年秋天在弗吉尼亚州东南部的草地和灌木树叶表面收集的六个独立的露水或霜水样本，并发现了水溶性表面污垢层的证据，我们称之为雨雾。使用傅里叶变换离子回旋共振质谱，离线气溶胶质谱和紫外/维斯光谱的混合物的化学组成和光活性进行了探测。复杂的有机混合物被发现在所有的样品中，共有类似的9600个确定的分子式，包含C，H，N，O，S和P.许多样品在可见光区有很强的吸收，并显示出最初的快速光衰减。不同样品的组成不同，可能的来源包括植物吐出物和微生物废物以及大气有机气溶胶颗粒、土壤颗粒和雾滴的沉积。有机分子的组成，结合它们的光活性，表明露水在蒸发时可能是水溶性气体的复杂来源。
Dew water serves as a temporary reservoir of dissolved organic molecules that are released in the morning when the dew evaporates. Many locations allow for direct sunlight on the dew water in the morning, raising the possibility for photolysis-driven chemical reactions. The majority of prior works looking at dew water chemical composition has targeted freshly deposited dew on clean surfaces like Teflon. However, the dissolved organic material in dew is a mixture of compounds deposited during the night, as well as water-soluble compounds already present on the surface. Here, we analyzed six separate dew or frost water samples collected off grass and bush leaf surfaces in Southeast Virginia in the fall of 2020 and found evidence for a water-soluble surface grime layer that we term biogrime. The chemical composition and photoactivity of the mixtures were probed using Fourier transform ion cyclotron resonance mass spectrometry, offline-aerosol mass spectrometry, and UV/vis spectroscopy. Complex organic mixtures were found in all the samples with a total of similar to 9600 identified molecular formulae containing C, H, N, O, S, and P. Many samples had strong absorption in the visible region, and all showed an initially rapid photodecay. The composition varied between samples with possible sources including plant guttation and microbial waste as well as deposition of atmospheric organic aerosol particles, soil particles, and fog droplets. The composition of organic molecules, combined with their photoactivity, suggests that dew water may be a complex source for water-soluble gases as it evaporates.