Emission of biogenic volatile organic compounds from warm and oligotrophic seawater in the Eastern Mediterranean
<p>Biogenic volatile organic compounds (BVOCs) from terrestrial vegetation and marine organisms contribute to photochemical pollution and affect the radiation budget, cloud properties and precipitation via secondary organic aerosol formation. Their emission from both marine and terrestrial eco...
Main Authors: | , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2020-11-01
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Series: | Atmospheric Chemistry and Physics |
Online Access: | https://acp.copernicus.org/articles/20/12741/2020/acp-20-12741-2020.pdf |
Summary: | <p>Biogenic volatile organic compounds (BVOCs) from terrestrial vegetation and
marine organisms contribute to photochemical pollution and affect the
radiation budget, cloud properties and precipitation via secondary organic
aerosol formation. Their emission from both marine and terrestrial
ecosystems is substantially affected by climate change in ways that are
currently not well characterized. The Eastern Mediterranean Sea was
identified as a climate change “hot spot”, making it a natural laboratory
for investigating the impact of climate change on BVOC emissions from both
terrestrial and marine vegetation. We quantified the mixing ratios of a
suite of volatile organic compounds (VOCs), including isoprene, dimethyl
sulfide (DMS), acetone, acetaldehyde and monoterpenes, at a mixed vegetation
site <span class="inline-formula">∼4</span> km from the southeastern tip of the Levantine Basin,
where the sea surface temperature (SST) maximizes and ultra-oligotrophic
conditions prevail. The measurements were performed between July and October
2015 using a proton transfer reaction time-of-flight mass spectrometer
(PTR-ToF-MS). The analyses were supported by the Model of Emissions of Gases
and Aerosols from Nature (MEGAN v2.1). For isoprene and DMS mixing ratios,
we identified a dominant contribution from the seawater. Our analyses
further suggest a major contribution, at least for monoterpenes, from the
seawater. Our results indicate that the Levantine Basin greatly contributes
to isoprene emissions, corresponding with mixing ratios of up to
<span class="inline-formula">∼9</span> ppbv several kilometers inland from the sea shore. This
highlights the need to update air quality and climate models to account for
the impact of SST on marine isoprene emission. The DMS mixing ratios were 1 to 2 orders of magnitude lower than those measured in 1995 in the same
area, suggesting a dramatic decrease in emissions due to changes in the
species composition induced by the rise in SST.</p> |
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ISSN: | 1680-7316 1680-7324 |