Year-end Sale % OFF 
Abstract
Stable carbon isotope ratios in marine aerosol collected over the Southern Indian Ocean revealed δ13C values ranging from −20.0‰ to −28.2‰. The isotope ratios exhibited a strong correlation with the fractional organic matter (OM) enrichment in sea spray aerosol. The base-level isotope ratio of −20.0‰ is characteristic of an aged Dissolved Organic Matter (DOM) pool contributing a relatively homogeneous background level of DOM to oceanic waters. The range of isotope ratios, extending down to −28.2‰, is characteristic of more variable, stronger, and fresher Particulate Organic Matter (POM) pool driven by trophic level interactions. We present a conceptual dual-pool POM-DOM model which comprises a ‘young’ and variable POM pool which dominates enrichment in sea-spray and an ‘aged’ but invariant DOM pool which is, ultimately, an aged end-product of processed ‘fresh’ POM. This model is harmonious with the preferential enrichment of fresh colloidal and nano-gel lipid-like particulate matter in sea spray particles and the observed depleted δ13C ratio resulting from isotope equilibrium fractionation coupled with enhanced plankton photosynthesis in cold water (−2 °C to +8 °C). These results re-assert the hypothesis that OM enrichment in sea-spray is directly linked to primary production and, consequently, can have implications for climate-aerosol-cloud feedback systems.
Highlights
Stable carbon isotope ratios in marine aerosol collected over the Southern Indian Ocean revealed δ13C values ranging from −20.0‰ to −28.2‰
Chlorophyll-a has been demonstrated to be a valid proxy for organic matter (OM) source parameterisations[3], but there has been a significant debate whether such a proxy can reproduce seasonal variability across all the world oceans
Long-term studies of marine aerosol organic matter spanning several years of continuous measurements[4,5] revealed a profound seasonality linked to an apparent biological activity[6], while short-term ship-born campaigns were unable to reproduce the relationship between organic matter fraction in sea spray and phytoplankton abundance parameterised by chlorophyll-a proxy[7]
Summary
The aerosol samples were collected at Amsterdam Island (37.48°S, 77.34°E), which is located approximately 3000 km from Antarctica and Australia and 5000 km from Africa and India. Carbon isotope ratio (δ13C) measurements were performed using a stable Isotope Ratio Mass Spectrometer (IRMS) calibrated by the Vienna Pee Dee Belemnite (VPDB) standard[30]. The filters were analysed with the elemental analyzer FlashEA 1112 connected to the stable isotope ratio mass spectrometer Thermo Finnigan Delta Plus Advantage following the analytical procedure detailed in Ceburnis et al.[11]. The calibration CO2 gas was delivered to the mass spectrometer until the isotopic ratio uncertainty was better than 0.15% and three replicates of each sample were analysed. Δ13C values were corrected for blank and standard HCO3− content in sea water using isotope mixing equations. Duplicate injections were performed for all filtered extracts and the agreement of 5% was achieved for all ions, except MSA and oxalate (10%)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
