Publication Date:
2024-04-10
Description:
Carbohydrates, originating from marine microorganisms, enter the atmosphere as part of sea spray
aerosol (SSA) and can influence fog and cloud microphysics as cloud condensation nuclei (CCN) or icenucleating
particles (INP). Particularly in the remote Arctic region, significant knowledge gaps persist about
the sources, the sea-to-air transfer mechanisms, atmospheric concentrations, and processing of this substantial
organic group. In this ship-based field study conducted from May to July 2017 in the Fram Strait, Barents Sea,
and central Arctic Ocean, we investigated the sea-to-air transfer of marine combined carbohydrates (CCHO)
from concerted measurements of the bulk seawater, the sea surface microlayer (SML), aerosol particles and
fog. Our results reveal a wide range of CCHO concentrations in seawater (22–1070 μg L-1), with notable variations
among different sea-ice-related sea surface compartments. Enrichment factors in the sea surface microlayer
(SML) relative to bulk water exhibited variability in both dissolved (0.4–16) and particulate (0.4–49) phases, with
the highest values in the marginal ice zone (MIZ) and aged melt ponds. In the atmosphere, CCHO was detected
in super- and submicron aerosol particles (CCHOaer;super: 0.07–2.1 ngm-3; CCHOaer;sub: 0.26–4.4 ngm-3) and
fog water (CCHOfog;liquid: 18–22 000 μg L-1; CCHOfog;atmos: 3–4300 ngm-3). Enrichment factors for sea–air
transfer varied based on assumed oceanic emission sources. Furthermore, we observed rapid atmospheric aging
of CCHO, indicating both biological/enzymatic processes and abiotic degradation. This study highlights
the diverse marine emission sources in the Arctic Ocean and the atmospheric processes shaping the chemical
composition of aerosol particles and fog.
Repository Name:
EPIC Alfred Wegener Institut
Type:
Article
,
isiRev
Format:
application/pdf