Long‐term observations of carbonaceous aerosols in the Austral Ocean are reported here for the first time from almost 5 years of continuous filter sampling performed at Amsterdam Island (37°48′S, 77°34′E). Black carbon concentrations determined by optical method were among the lowest reported for marine atmosphere, with monthly mean levels ranging from 2–5 ng C/m3 during summer to 7–13 ng C/m3 during winter. A clear seasonal pattern was also observed for organic aerosols, but in opposite phase, with maximum values during the austral summer period (>250 ng C/m3) and minimum concentrations (100 ng C/m3) during winter. This seasonal variation of organic concentration was found to be almost entirely related to the water‐insoluble organic carbon fraction, suggesting a primary origin for these organics, most probably through bubble bursting processes. Moreover, this summer maximum observed for organic aerosols was found to be correlated with satellite‐derived chlorophyll a concentrations averaged over an oceanic region upwind of the sampling site and characterized by relatively high biogenic activity. This oceanic region being located at 1000–2000 km far away from the monitoring station, atmospheric ageing may have played a significant role on the levels and size‐resolved properties of marine organics collected at Amsterdam Island. This biogenic marine organic source of primary origin in the Austral Ocean is fully consistent with similar observations previously reported for the Northern Atlantic Ocean and brings further evidences of the major role of marine organic emissions over remote oceanic regions.

Total and dissolved inorganic phosphorus (IP) was measured in both rainwater and aerosol samples collected from two remote coastal areas: on the island of Crete (Greece) and at Erdemli (Turkey). Particle size distributions of P, as well as total deposition were also measured. Wet and dry deposition of dissolved inorganic phosphorus (DIP) from Crete are compared with simultaneously obtained dissolved inorganic nitrogen (DIN) and with productivity data from the literature. Our results indicate that (1) in both wet and dry deposition, the DIN/DIP molar ratio ranges between 63 and 349, exceeding by a factor of up to 22 the N/P ratio observed in seawater (ranging from 25 to 28) and (2) atmospheric deposition of DIP could reasonably account for a significant part of the new production (up to 38%) observed during the summer and autumn period (i.e., when water stratification is at its maximum).

Abstract. Long-term (5-year) measurements of Elemental Carbon (EC) and Organic Carbon (OC) in bulk aerosols are presented here for the first time in the Mediterranean Basin (Crete Island). A multi-analytical approach (including thermal, optical, and thermo-optical techniques) was applied for these EC and OC measurements. Light absorbing dust aerosols were shown to poorly contribute (+12% on a yearly average) to light absorption coefficient (b abs ) measurements performed by an optical method (aethalometer). Long-range transport of agricultural waste burning from European countries surrounding the Black Sea was shown for each year during two periods (March-April and July-September). The contribution of biomass burning to the concentrations of EC and OC was shown to be rather small (20 and 14%, respectively, on a yearly basis), although this contribution could be much higher on a monthly basis and showed important seasonal and interannual variability. By removing the biomass burning influence, our data revealed an important seasonal variation of OC, with an increase by almost a factor of two for the spring months of May and June, whereas BC was found to be quite stable throughout the year. Preliminary measurements of Water Soluble Organic Carbon (WSOC) have shown that the monthly mean WSOC/OC ratio remains stable throughout the year (0.45±0.12), suggesting that the partitioning between water soluble and water insoluble organic matter is not significantly affected by biomass burning and secondary organic aerosol (SOA) formation. A chemical mass closure performed in the fine mode (Aerodynamic Diameter, A.D.<1.5µm) showed that the mass contribution of organic matter (POM) was found to be essentially invariable during the year (monthly average of 26±5%).