Antarctic sea ice region as a source of biogenic organic nitrogen in aerosols

DALLOSTO, M.; OVADNEVAITE, J.; PAGLIONE, M.; BEDDOWS, D.; CEBURNIS, D.; CREE, CH.; CORTÉS, P; ZAMANILLO, M.; O. NUNES, S; PÉREZ, G. L.; SIMÓ, R.

SCIENTIFIC REPORTS

Nature Publishing Group

Lugar: Londres; Año: 2017

2045-2322

<!-- /* Font Definitions */@font-face{font-family:Arial;panose-1:2 11 6 4 2 2 2 2 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536859905 -1073711037 9 0 511 0;}@font-face{font-family:Arial;panose-1:2 11 6 4 2 2 2 2 2 4;mso-font-charset:0;mso-generic-font-family:auto;mso-font-pitch:variable;mso-font-signature:-536859905 -1073711037 9 0 511 0;} /* Style Definitions */p.MsoNormal, li.MsoNormal, div.MsoNormal{mso-style-unhide:no;mso-style-qformat:yes;mso-style-parent:"";margin:0cm;margin-bottom:.0001pt;mso-pagination:widow-orphan;font-size:12.0pt;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman";mso-ansi-language:EN-GB;mso-fareast-language:EN-GB;}.MsoChpDefault{mso-style-type:export-only;mso-default-props:yes;font-size:10.0pt;mso-ansi-font-size:10.0pt;mso-bidi-font-size:10.0pt;}@page WordSection1{size:612.0pt 792.0pt;margin:70.85pt 3.0cm 70.85pt 3.0cm;mso-header-margin:36.0pt;mso-footer-margin:36.0pt;mso-paper-source:0;}div.WordSection1{page:WordSection1;}-->Polar sea ice is one of the largest ecosystems on Earth, composed of a complexmultiphase environment with a variety of organisms tolerating extremeconditions (Arrigo 2014). Asclimate warming is rapidly amplifying in the polar regions (Holland andBitz 2003), with associated changes in seaice, understanding biogeochemical processes occurring across the air-ocean-iceinterfaces is crucial to pinpoint climate feedbacks. Although marine aerosolsare recognised as a key climate component (Browse et al. 2014), currently there is a serious lack ofaerosol data throughout the Southern Ocean, and particularly over the Antarcticsea ice region. Here we show field and laboratory results from amultidisciplinary Antarctic expedition where coupled oceanic and atmosphericmeasurements were conducted. We found an enhancement of secondary aerosol nitrogencomponents (namely low molecular weight alkyl-amines) in sea-ice influenced airmasses. Concomitant sulphur secondary species (methanesulphonic acid andnon-sea-salt sulphate) and newly formed particles (1-3 nm in size) supportedthe dominance of gas-to-particle conversion mechanisms. Besides, aerosols generatedby deliberate bubbling of melted sea ice showed enrichment of organic nitrogen,suggesting sea ice also contributes primary aerosol nitrogen through water-icefloe interactions. Chemical and biological analyses of sea ice and surroundingsea water confirmed the biogenic origin of both primary and secondary aerosolnitrogen components. The sea ice and the sea ice-influenced microbiota, therefore,are a previously unknown source of aerosol-forming, atmospheric organic nitrogen.The resulting effects on cloud formation and brightness must have importantconsequences on the surface energy balance and ice melt, thereby supporting a biosphere-climatefeedback involving sea ice and clouds.