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 gas-phase 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.
The capabilities of filament-induced breakdown spectroscopy for the analysis of the elemental composition of aqueous aerosols were estimated. The diameter of aqueous aerosol droplets in the ...atmosphere was 0.8–2.0 μm. The emission lines of the chemical elements were excited by fi lamentation of femtosecond laser pulses (60 fs, 800 nm, 4.4 mJ) in weak focusing mode by a lens with a focal length of 500 mm. The obtained limits of detection for Al (396.15 nm), Ba (553.35 nm), Ca (422.67 nm), Mg (285.21 nm), Na (588.99 nm), and Mn (403.08 nm) in an aqueous aerosol were 12.1, 41.7, 10.0, 7.3, 0.7, and 32.3 mg/L, respectively.
The dependence of the intensity of Ca (393.3, 396.8, 422.6 nm), Mg (383.6 nm), and Na (589 nm) emission lines on the laser pulse duration in the method of filament-induced breakdown spectroscopy is ...studied. A filament was excited in seawater aerosol droplets 0.8–2 μm in size by laser pulses of 70, 230, 500, and 900 fs duration at a constant pulse energy of 3.0 mJ. The intensities of the emission lines of the elements under study are shown to increase with the laser pulse duration, except for the magnesium line. Optimal laser pulse durations for the excitation of Ca, Mg, and Na lines in seawater aerosol are derived.
We analyzed the distribution of the ordering parameter of raft-like microdomains in the mitochondrial membranes of halophytes, which differ in the type of salt tolerance:
Salicornia perennans, ...Halocnemum strobilaceum
, and
Artemisia santonica
. The packing density of the membrane lipids (lipid order) was assessed by measuring generalized polarization (GP) of the Laurdan fluorescence. In the mitochondrial membrane material of
S. perennans, H. strobilaceum
, and
A. santonica
, in the range of 15 and 25% of the sucrose density gradient, the GP distributions contain 4–6 components presumably related to the raft structures. Lipids isolated from ordered domains are enriched in sterols, cerebrosides, and saturated fatty acids; the quantitative content of raft-forming lipids depends on the salt tolerance strategy of halophytes.
A relatively simple fiber sensor system for high-power electromagnetic field measurements is presented. The system utilizes an all-dielectric fiber tip sensor head with CdTe electro optic (EO) ...crystal as an electric field transducer. The fiber sensor of small size converts electric field strength into modulation of light power. The rise time of the EO sensor is measured and evaluated theoretically. The system can be used for ultra-wideband high-power electric field measurements.
Laser technologies that are used for the development of sensor elements for Remotely Operated Vehicles (ROVs) are presented, as well as the latest developments in underwater robotics where laser ...spectroscopy methods are applied to environmental monitoring. A submersible laser spectrometer unit intended for studying Raman scattering and laser-induced fluorescence (LIF) spectra is presented. The spectrometer was developed as an element of an ROV sensor system for remote detection and measurements of organic matter concentrations in sea water and underwater objects. The results of environmental tests of the submersible LIF spectrometer in various marine areas, including the Arctic, are described.
We analysed the relationship between the chemical complex (concentration of dissolved ions, nutrients, pH) and biological parameters (primary production, biomass of phytoplankton, abundance and ...activity of bacterial communities) at estuaries of rivers and coastal waters of Southern Baikal during the under-ice period. Correlation network analysis revealed CO2 to be the main limiting factor for the development of algae and microbial communities in the coastal zone of Lake Baikal. This study indicates that primarily reverse synthesis of bicarbonate and carbonate ions associated with the development of phytoplankton and accumulation of dissolved CO2 during photosynthesis regulates pH in the Baikal water. We did not detect the anthropogenic factors that influence the change in pH and acidification. Near the Listvyanka settlement (Lake Baikal, Listvennichnaya Bay), there was a great number of organotrophs and thermotolerant bacteria with low bacterioplankton activity and high concentration of organic carbon. This evidences eutrophication due to the influx of organic matter having an anthropogenic source. Nutrients produced during the bacterial destruction of this matter may explain the changes in bottom phytocenoses of Listvennichnaya Bay.
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The dependence of the limits of detection of Mg, Mn, Sr, Pb, Al, and B in aqueous solutions on the laser pulse repetition rate is studied by femtosecond laser induced breakdown spectroscopy for the ...laser pulse repetition rate from 50 to 1000 Hz. The limit of detection is shown to be the best at a laser pulse repetition rate of 166 Hz for all the elements under study, other experimental conditions being the same.
We present the results of devising new techniques and technical means for utilizing small-sized unmanned aerial vehicles (UAVs) in ecological monitoring of marine water basins in compliance with the ...MARPOL 73/78 international convention. The development of a hardware-software complex is described for the system of recognizing oil spills using elements of artificial intelligence. The laboratory experiments on identifying oil spills by laser induced fluorescence (LIF) methods are presented, as well as the methods of recording the spectrum of upward solar radiation.
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Two techniques for multielement analysis of liquid-droplet aerosol are compared, which are based on the spectral analysis of the radiation of a laser plasma generated in a laser breakdown (LIBS) or ...during laser pulse filamentation in a liquid droplet aerosol (R-FIBS). A liquid-droplet aerosol containing Na solution is used. It is shown that there are optimal delay times of the start of signal recording relative to the start of plasma generation, at which the signal-to-noise ratio is maximal, for both techniques. The dependence of the signal-to-noise ratio is derived for different laser radiation focusing deep into a liquid-droplet cloud for LIBS. The Na detection limits are determined for both methods.
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