However, this cannot fully explain the relative contribution Most concentrated AAs encountered in our samples present the longestĪtmospheric lifetimes, and the less dominant ones are clearly efficiently transformed in the atmosphere, potentially explaining their low concentrations. In the cloud medium by biotic or abiotic (mainly oxidation) processes. Finally, the atmospheric aging of AAs has been evaluated byĬalculating atmospheric lifetimes considering their potential transformation
The analysis of the AA hygroscopicity also indicates a higher contribution of AAs (80 % on average) that are hydrophilic or neutral, revealing theįact that other AAs (hydrophobic) are less favorably incorporated into cloudĭroplets. AA composition of aquatic organisms (i.e., diatom species) could also explain the high concentrations of Ser in our samples. Relative distribution of AAs in biological matrices (proteins extracted fromīacterial cells or mammalian cells, for example) could explain the dominance Prevailing presence of certain AAs in the cloud samples.
We finally assessed the sources and the atmospheric processes that potentially explain the Microphysical properties' fluctuation does not explain the AA variability in our samples, confirming previous studies at the PUY. Layer, especially over the sea surface before reaching the PUY. This work shows thatĪAs are correlated with the time spent by the air masses within the boundary Variability is assessed through a statistical analysis. AA quantification in cloud water is scarce, but the results agree with the few studies that investigated AAs in this aqueous medium. TCAA constitutes between 0.5 and 4.4 % of the dissolved organic carbon measured in the cloud samples. The distribution of AAs among theĬloud events reveals high variability. To 7.7 µM, Ser (serine) being the most abundant AA (23.7 % on average) but with elevated standard deviation, followed by glycine (Gly) Total concentrations of FAAs (TCAAs) vary from 1.2 Spectrometry (LC-MS) and the standard addition method to correct for matrix effects. This quantification has been performed without concentration orĭerivatization, using liquid chromatography hyphened to mass The Puy de Dôme station (PUY – France) during 13 cloud events. Eighteen free amino acids (FAAs) were quantified in cloud water sampled at
0 kommentar(er)
