Can Saharan Dust Intrusions Alter the Isotopic Composition of Atmospheric Methane and Carbon Dioxide?

first_pagesettingsOrder Article Reprints Open AccessArticle Can Saharan Dust Intrusions Alter the Isotopic Composition of Atmospheric Methane and Carbon Dioxide? by Isabella Zaccardo 1,2,*ORCID,Antonella Buono 1,2,*ORCID,Teresa Laurita 1ORCID,Benedetto De Rosa 1,Francesco D’Amico 3,4ORCID,Davide Amodio 1ORCID,Francesco Cardellicchio 1ORCID,Canio Colangelo 1ORCID,Gianluca Di Fiore 1,Giuseppe Gargano 1ORCID,Aldo Giunta 1ORCID,Emilio Lapenna 1ORCID,Ermann Ripepi 1ORCID,Marco Rosoldi 1,Donato Summa 1ORCID,Serena Trippetta 1ORCID,Claudia Roberta Calidonna 3ORCID,Alcide Giorgio di Sarra 5ORCID,Guido Masiello 2ORCID andLucia Mona 1ORCID 1 Institute of Methodologies for Environmental Analysis, National Research Council of Italy (CNR-IMAA), Contrada Santa Loja, Tito Scalo, I-85050 Potenza, Italy 2 Department of Engineering, University of Basilicata (Unibas DiING), Via dell’Ateneo Lucano 10, I-85100 Potenza, Italy 3 Institute of Atmospheric Sciences and Climate, National Research Council of Italy (CNR-ISAC), Area Industriale Comparto 15, Lamezia Terme, I-88046 Catanzaro, Italy 4 Department of Biology, Ecology and Earth Sciences, University of Calabria (Unical DiBEST), Via Pietro Bucci Cubo 15B, Rende, I-87036 Cosenza, Italy 5 Italian National Agency for New Technologies, Energy and Sustainable Economic Development (ENEA), Via Enrico Fermi 45, Frascati, I-00044 Rome, Italy * Authors to whom correspondence should be addressed. Environments 2026, 13(3), 145; https://doi.org/10.3390/environments13030145 Submission received: 7 February 2026 / Revised: 2 March 2026 / Accepted: 4 March 2026 / Published: 6 March 2026 (This article belongs to the Topic Atmospheric Chemistry, Aging, and Dynamics) Downloadkeyboard_arrow_down Browse Figures Versions Notes Abstract This study investigates the potential influence of Saharan dust intrusions on the stable carbon isotopes of methane (CH4) and carbon dioxide (CO2), using continuous in situ measurements from the ICOS (Integrated Carbon Observation System) atmospheric station at the CNR-IMAA Atmospheric Observatory (CIAO) in Tito, Basilicata, southern Italy. The analysis builds upon the recent investigation of a two-month isotopic dataset (20 February–20 April 2025), which identified anomalous isotopic behavior in March, coinciding with three distinct dust events. The observations reveal shifts in δ13C–CH4 values that align temporally with the dust intrusions, accompanied by a decrease in CH4 mole fractions. Such patterns could suggest fractionation processes affecting CH4, potentially driven by enhanced oxidation promoted by mineral aerosols. At the same time, δ13C–CO2 shows a gradual decline, deviating from the typical springtime enrichment associated with intensified photosynthetic uptake of 12CO2. This unexpected decrease suggests that dust-related radiative effects, particularly the attenuation of incoming solar radiation, may inhibit photosynthesis, thereby altering the isotopic composition of atmospheric CO2. Consistently, CO2 mole fractions exhibit a modest increase during periods of declining δ13C–CO2, reinforcing the interpretation of reduced photosynthetic activity. These findings provide new observational data beyond existing studies from Atlantic regions and highlight the need for further research on the role of mineral dust in shaping greenhouse gas isotopic variability in the Mediterranean, where such events are frequent and climatically relevant.