Spatial Variations in Surface Snow Chemistry and Stable Isotope Composition Along Different Transects of the Antarctic Coastal Zone

This study elucidated the spatial distribution characteristics of surface snow chemistry and stable isotope composition and their influencing factors in Antarctica’s coastal region. We analyzed data from eight surface snow chemical ion transects and five surface snow stable isotope transects to examine the distributions of sea-salt ions (Na+, Cl−, Mg2+, K+), non-sea-salt ions (NO3−, methanesulfonic acid (MSA), non-sea-salt sulfate (nssSO42−), non-sea-salt Ca2+ (nssCa2+)), and the stable isotope δ18O. Concentrations of chemical ions were found to exhibit distinct source signatures. Principal component analysis indicated that the ranking of ion sources in Antarctica’s coastal areas is as follows: sea-salt aerosol transport, followed by marine biological activities and crustal dust and then atmospheric chemical reactions. Data from all transects exhibited a general pattern of diminishing δ18O with increasing distance from the coast but with marked regional differences in the δ18O–distance slope (−6.84 to −1.98‰/100 km), δ18O–altitude slope (−0.97 to −0.20‰/100 m), and δ18O–temperature slope (0.61 to 1.14‰/°C). The moisture source regions and transport pathways, local orographic uplift, and local temperature field jointly affect the differentiation of δ18O in coastal areas. The findings suggest that snow chemistry and isotopic composition in Antarctica’s coastal zones are controlled by marine source transport, biogeochemical cycling, and polar topographic and climatic processes.