Ocean-atmosphere exchange of aerosol particles: impact on marine ecosystems

Exchange of aerosols between the atmosphere and the oceanic surface layer is important in the biogeochemical cycling of biologically important elements and radiatively important constituents. Coastal waters receive a wide range of particles from the atmosphere, covering very different chemical forms and amount of both organic and inorganic constituents, including potentially toxic trace metals. Acting together these atmospheric multi-stressors could rapidly threaten biogeochemical cycles in coastal waters, with socio-economic costs. On the other hand, ocean-derived emissions of aerosols have an important impact on the regulation of atmospheric chemistry, cloudiness and, therefore, climate. This SOLAS Seminar is aligned with some of the research questions of both Core Theme 3: Atmospheric deposition and ocean biogeochemistry and Core Theme 4: Interconnections between marine ecosystems, aerosols, and clouds, featuring 3 keynote presentations addressing different aspects of the ocean-atmosphere exchange of aerosol particles, namely the impact of coastal pollution and anthropogenic stressors on marine ecosystems, and the abundance and properties of marine aerosols.

15:00-17:00 UTC+1, Wednesday, 19th October 2022

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Centre for Environmental and Marine Studies, University of Aveiro, Portugal
Regina Duarte (Centre for Environmental and Marine Studies, Department of Chemistry, University of Aveiro, Portugal)
Susana Loureiro (Centre for Environmental and Marine Studies, Department of Biology, University of Aveiro, Portugal)


Regina Duarte
Centre for Environmental and Marine Studies, Department of Chemistry, University of Aveiro, Portugal
Title: Impact of atmospheric stressors in coastal ecosystems: contribution from AMBIEnCE Project
Abstract: Increasing atmospheric deposition of organic and inorganic particles due to both natural and anthropogenic emission processes, combined with changing coastal water conditions (e.g., stratification, acidification), are known to induce yet unresolved feedbacks on climate and biogeochemistry of coastal waters. These changes have the potential to affect the resilience of coastal marine systems, e.g. by promoting eutrophication and high levels of organic and inorganic pollutants, or by altering marine organisms’ resilience, with direct implications on marine biodiversity and ecosystems. This presentation will show the main findings of AMBIEnCE project (PTDC/CTA-AMB/28582/2017), endorsed by SOLAS, with a focus on the structural features of fine water-soluble organic aerosols in different coastal locations, and the potential ecotoxicological effects of urban air particles deposition on marine organisms.
Khanneh Wadinga Fomba
Leibniz Institute for Tropospheric Research, Germany
Title: Atmospheric deposition of phosphorus and associated nutrient fluxes in the northeastern and southeastern Tropical Atlantic
Abstract: Aerosol-derived nutrients can be a source of nutrients to marine ecosystems in the open oceans, however, the long-term fluxes of these nutrients are not well established in the different oceanic regions. The role of atmospheric aging of aerosol particles on these nutrients due to their interaction with other atmospheric compounds (e.g. sulphates, nitrates) is less understood, especially for major nutrients such as phosphorus. This presentation will focus on the role of atmospheric processing of aerosol particles on phosphorus deposition fluxes in the northeastern and southeastern tropical Atlantic oceans, based on long-term measurements performed at the Cape Verde Atmospheric Observatory (CVAO), Cabo Verde, and Namib Desert Atmospheric Observatory (NDAO), Namibia, within the framework of the Phosphorus Speciation in Mineral Dust and Marine Aerosol Particles (PHOSDMAP) project. The effects of the nutrient deposition fluxes on the local marine ecosystem based on satellite remote sensing data will be highlighted.
Stefano Decesari
Institute of Atmospheric and Climate Sciences (ISAC) of the National Research Council of Italy, Italy
Title: Proton NMR spectroscopy for source identification of organic compounds in the sea surface microlayer in marine aerosols
Abstract: Proton Nuclear Magnetic Resonance (NMR) spectroscopy is a quasi-universal technique for characterization of organic matrices and vastly employed for the analysis of biological materials. Its application to atmospheric aerosol samples is challenged by the high degree of molecular heterogeneity and polydispersivity typical of such samples. Nevertheless, the analysis of aerosol samples collected in the marine boundary layer, and even more clearly at high latitudes, highlights compositions largely impacted by sources of biological material (metabolytes, sugars, aminoacids and fatty acids) which are rarely found that neatly in submicron aerosol samples from continental areas. This makes marine aerosol samples most suitable for techniques such as metabolomics, enabling accurate source fingerprinting and apportionment for particulate organic compounds in marine aerosols, especially when supported by the analysis of the composition of sea surface waters and sea surface microlayer samples in potential source regions. The present talk provides a survey of selected NMR results from past and ongoing field campaigns targeting the characterization of marine aerosol from seaspray and emission from the ocean. Overlaps and discrepancies with the results obtained in similar geographical areas with different techniques are finally discussed.