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Abstract. We presented the results of expedition measurements of the set of physical-chemical characteristics of atmospheric aerosol in areas of the Arctic and Far East seas, performed onboard RV Akademik Fedorov (17 August-22 September 2013) and RV Professor Khljustin (24 July-7 September 2013). The specific features of spatial distribution and time variations of aerosol optical depth (AOD) of the atmosphere in the wavelength range of 0.34-2.14 µm and boundary layer height, aerosol and black carbon mass concentrations, and disperse and chemical composition of aerosol are discussed. Over the Arctic Ocean (on the route of RV Akademik Fedorov) there is a decrease in aerosol and black carbon concentrations in a northeastern direction: higher values were observed in the region of Spitsbergen and near the Kola Peninsula; and minimum values were observed at northern margins of the Laptev Sea. Average AOD (0.5 µm) values in this remote region were 0.03; the aerosol and black carbon mass concentrations were 875 and 22 ng m −3 , respectively. The spatial distributions of most aerosol characteristics over Far East seas show their latitudinal decrease in the northern direction. On transit of RV Professor Khljustin from the Japan Sea to the Chukchi Sea, the aerosol number concentration decreased on average from 23.7 to 2.5 cm −3 , the black carbon mass concentration decreased from 150 to 50 ng m −3 , and AOD decreased from 0.19 to 0.03. We analyzed the variations in the boundary layer height, measured by ship-based lidar: the average value was 520 m, and the maximal value was 1200 m. In latitudinal distribution of the boundary layer height, there is a characteristic minimum at a latitude of ∼ 55 • N. For water basins of eight seas, we present the chemical compositions of the water-soluble aerosol fraction (ions, elements) and small gasphase species, as well as estimates of their vertical fluxes. It is shown that substances are mainly (75-89 %) supplied from the atmosphere to the sea surface together with gas-phase species. The deposited ions account for from 11 to 24.5 %, and trace elements account for 0.2-0.4 % of the total sum of water-soluble components. The average vertical fluxes of aerosol substance are a factor of 4-7 larger in the Japan Sea than in the water basins of Arctic seas.

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543.423;533.9 The spectral and temporal characteristics of plasmas produced by femtosecond laser pulses acting on seawater surfaces are studied. The time dependence of the decay in the intensities of emission lines and the continuum are determined and the electron density is estimated using the three-body recombination time. It is shown that an atomic line with a low excitation potential is the most sensitive for femtosecond laser induced breakdown spectroscopy.Introduction. The increasing anthropogenic effect on the world's oceans has created a need for the development of new methods for monitoring marine ecosystems. Laser induced breakdown spectroscopy (LIBS) is definitely one such operational technique. LIBS does not require advanced preparation of samples, can be used for spectral analysis in real time, is a contactless, remote analysis technique, and can be used to determine the concentrations of a wide range of elements with relatively small sample sizes. The use of LIBS for determining the elemental composition of seawater was first proposed in [1,2]. Further studies have established the optimal parameters for detection of the emission lines of the elements dissolved in seawater with breakdown by nanosecond laser pulses [3-10]. The detection limits for elements by this method of laser plasma excitation is ~10

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