Chemical fate and settling of mineral dust in surface seawater after atmospheric deposition observed from dust seeding experiments in large mesocosms

Abstract. We report here the elemental composition of sinking particles in sediment traps and in the water column following four artificial dust seeding experiments (each representing a flux of 10 g m−2). Dry or wet dust deposition were simulated during two large mesocosms field campaigns that took place in the coastal water of Corsica (NW Mediterranean Sea) representative of oligotrophic conditions. The dust additions were carried out with fresh or artificially aged dust (i.e., enriched in nitrate and sulfate by mimicking cloud processing) for various biogeochemical conditions, enabling us to test the effect of these parameters on the chemical composition and settling of dust after deposition. The rates and mechanisms of total mass, particulate organic carbon (POC) and chemical elements (Al, Ba, Ca, Co, Cu, Fe, K, Li, Mg, Mn, Mo, N, Nd, P, S, Sr and Ti) transfer from the mesocosm surface to the sediment traps installed at the base of the mesocosms after dust deposition show that (1) 15% of the initial dust mass was dissolved in the water column in the first 24 h after seeding. Except for Ca, S and N, the elemental composition of dust particles was constant during their settling, showing the relevance of using interelemental ratios, such as Ti/Al as proxy of lithogenic fluxes. (2) Whatever the type of seeding (using fresh dust to simulate dry deposition or artificially aged dust to simulate wet deposition), the particulate phase both in the water column and in the sediment traps was dominated by dust particles. (3) Due to the high Ba content in dust, Ba/Al cannot be used as productivity proxy in the case of high dust input in the sediment traps. Instead, our data suggests that the ratio Co/Al could be a good productivity proxy in this case. (4) After 7 days, between 30 and 68% of added dust was still in suspension in the mesocosms. This difference in the dust settling was directly associated with a difference in POC export, since POC fluxes were highly correlated to dust lithogenic fluxes signifying a ballast effect of dust. The highest fraction of remaining dust in suspension in the mesocosm at the end of the experiment was found inversely correlated to Chl a increase. This suggests that the fertilizing effect of dust on autotrophs organisms, the ballast effect, and POC fluxes are strongly correlated. (5) Our data emphasize a typical mass ratio Lithogenic/POC fluxes around 30 which could be used as reference to estimate the POC export triggered by wet dust deposition event.

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Chemical fate and settling of mineral dust in surface seawater after atmospheric deposition observed from dust seeding experiments in large mesocosms

Biogeosciences Discussions ◽

10.5194/bgd-11-4909-2014 ◽

2014 ◽

Vol 11 (3) ◽

pp. 4909-4947 ◽

Cited By ~ 4

Author(s):

K. Desboeufs ◽

N. Leblond ◽

T. Wagener ◽

E. B. Nguyen ◽

C. Guieu

Keyword(s):

Water Column ◽

Elemental Composition ◽

Mineral Dust ◽

Sediment Traps ◽

Dust Particles ◽

Marine Biota ◽

Dust Deposition ◽

Chl A ◽

Poc Export ◽

Fertilizing Effect

Abstract. We report here the elemental composition of sinking particles in sediment traps and in the water column following 4 artificial mineral dust seedings (representing a flux of 10 g m−2) in mesocosms, simulating dry or wet dust deposition into oligotrophic marine waters. These data were used to examine the rates and mechanisms of total mass, particulate organic carbon (POC) and elemental (Al, Ba, Ca, Co, Cu, Fe, K, Li, Mg, Mn, Mo, N, Nd, P, S, Sr and Ti) transfer from the surface to the sediment traps after dust deposition. The dust additions were carried out with fresh or artificially aged dust (i.e. enriched in nitrate and sulfate by mimicking cloud processing) for various biogeochemical conditions, enabling us to test the effect of these parameters on the chemical evolution and settling of dust after deposition. Whatever the type of seeding (using fresh dust to simulate dry deposition or artificially aged dust to simulate wet deposition), the dust was predominant in the particulate phase in the sediment traps at the bottom of mesocosms and within the water column during each experiment. 15% of initial dust mass was dissolved in the water column in the first 24 h after seeding. For artificially aged dust, this released fraction was mainly nitrate, sulfate and calcium and hence represented a significant source of new N for the marine biota. Except for Ca, S and N, the elemental composition of dust particles was constant during their settling, showing the relevance of using interelemental ratios, such as Ti/Al or Ba/Al as proxy of lithogenic fluxes or of productivity. After 7 days, between 30 and 68% of added dust was still in suspension in the mesocosms depending on the experiment. This difference in the dust settling was directly associated to a difference in POC export, since POC fluxes were highly correlated to dust lithogenic fluxes signifying a ballast effect of dust. The highest fraction of remaining dust in the mesocosm at the end of the experiment was found when the lowest chl a increase was observed, and inversely. This suggests a high interaction between a fertilizing effect of dust, a ballast effect, and POC fluxes. Our data emphasize a typical ratio Lithogenic/POC fluxes around 30 which could be used as reference to estimate the POC export triggered by wet dust deposition event. The elemental fluxes associated to the dust settling presented in this paper constitute also an original database on the export of atmospheric metals in a case of dry or wet dust deposition event.

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Effects of dust deposition on iron cycle in the surface Mediterranean Sea: results from a mesocosm seeding experiment

Biogeosciences ◽

10.5194/bg-7-3769-2010 ◽

2010 ◽

Vol 7 (11) ◽

pp. 3769-3781 ◽

Cited By ~ 54

Author(s):

T. Wagener ◽

C. Guieu ◽

N. Leblond

Keyword(s):

Water Column ◽

Sediment Traps ◽

Dust Particles ◽

Dust Deposition ◽

Dissolved Iron ◽

Surface Ocean ◽

Batch Dissolution ◽

Particulate Iron ◽

Dust Events ◽

Scavenging Ratio

Abstract. Soil dust deposition is recognized as a major source of iron to the open ocean at global and regional scales. However, the processes that control the speciation and cycle of iron in the surface ocean after dust deposition are poorly documented mainly due to the logistical difficulties to investigate in-situ, natural dust events. The development of clean mesocosms in the frame of the DUNE project (a DUst experiment in a low Nutrient low chlorophyll Ecosystem) was a unique opportunity to investigate these processes at the unexplored scale of one dust deposition event. During the DUNE-1-P mesocosm seeding experiment, iron stocks (dissolved and particulate concentrations in the water column) and fluxes (export of particulate iron in sediment traps) were followed during 8 days after an artificial dust seeding mimicking a wet deposition of 10 g m−2. The addition of dust at the surface of the mesocosms was immediately followed by a decrease of dissolved iron [dFe] concentration in the 0–10 m water column. This decrease was likely due to dFe scavenging on settling dust particles and mineral organic aggregates. The scavenging ratio of dissolved iron on dust particles averaged 0.37 ± 0.12 nmol mg−1. Batch dissolution experiments conducted in parallel to the mesocosm experiment showed a increase (up to 600%) in dust iron dissolution capacity in dust-fertilized waters compared to control conditions. This study gives evidences of complex and unexpected effects of dust deposition on surface ocean biogeochemistry: (1) large dust deposition events may be a sink for surface ocean dissolved iron and (2) successive dust deposition events may induce different biogeochemical responses in the surface ocean.

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Effects of dust deposition on iron cycle in the surface Mediterranean Sea: results from a mesocosm seeding experiment

Biogeosciences Discussions ◽

10.5194/bgd-7-2799-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 2799-2830 ◽

Cited By ~ 1

Author(s):

T. Wagener ◽

C. Guieu ◽

N. Leblond

Keyword(s):

Water Column ◽

Sediment Traps ◽

Dust Particles ◽

Dust Deposition ◽

Dissolved Iron ◽

Surface Ocean ◽

Batch Dissolution ◽

Particulate Iron ◽

Dust Events ◽

Scavenging Ratio

Abstract. Soil dust deposition is recognized as a major source of iron to the open ocean at global and regional scales. However, the processes that control the speciation and cycle of iron in the surface ocean after dust deposition are poorly documented mainly due to the logistical difficulties to investigate in-situ, natural dust events. The development of clean mesocosms in the frame of the DUNE project (a DUst experiment in a low Nutrient low chlorophyll Ecosystem) was a unique opportunity to investigate these processes at the unexplored scale of one dust deposition event. During the DUNE1 mesocosm seeding experiment, iron stocks (dissolved and particulate concentrations in the water column) and fluxes (export of particulate iron in sediment traps) were followed during 8 days after an artificial dust seeding mimicking a wet deposition of 10 g m−2. The addition of dust at the surface of the mesocosms was immediately followed by a decrease of dissolved iron [dFe] concentration in the 0–10 m water column. This decrease was likely due to dFe scavenging on settling dust particles and mineral organic aggregates. The scavenging ratio of dissolved iron on dust particles averaged 0.37 ± 0.12 nmol mg−1. Batch dissolution experiments conducted in parallel to the mesocosm experiment showed a increase (up to 600%) in dust iron dissolution capacity in dust-fertilized waters compared to control conditions. This study gives evidences of complex and unexpected effects of dust deposition on surface ocean biogeochemistry: (1) large dust deposition events may be a sink for surface ocean dissolved iron and (2) successive dust deposition events may induce different biogeochemical responses in the surface ocean.

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Introduction to project DUNE, a DUst experiment in a low Nutrient, low chlorophyll Ecosystem

Biogeosciences ◽

10.5194/bg-11-425-2014 ◽

2014 ◽

Vol 11 (2) ◽

pp. 425-442 ◽

Cited By ~ 35

Author(s):

C. Guieu ◽

F. Dulac ◽

C. Ridame ◽

P. Pondaven

Keyword(s):

Atmospheric Deposition ◽

Surface Waters ◽

Wet Deposition ◽

Initial Conditions ◽

Sediment Traps ◽

Saharan Dust ◽

Dust Particles ◽

Dust Deposition ◽

Mesocosm Experiments ◽

Atmospheric Inputs

Abstract. The main goal of project DUNE was to estimate the impact of atmospheric deposition on an oligotrophic ecosystem based on mesocosm experiments simulating strong atmospheric inputs of eolian mineral dust. Our mesocosm experiments aimed at being representative of real atmospheric deposition events onto the surface of oligotrophic marine waters and were an original attempt to consider the vertical dimension after atmospheric deposition at the sea surface. This introductory paper describes the objectives of DUNE and the implementation plan of a series of mesocosm experiments conducted in the Mediterranean Sea in 2008 and 2010 during which either wet or dry and a succession of two wet deposition fluxes of 10 g m−2 of Saharan dust have been simulated based on the production of dust analogs from erodible soils of a source region. After the presentation of the main biogeochemical initial conditions of the site at the time of each experiment, a general overview of the papers published in this special issue is presented. From laboratory results on the solubility of trace elements in dust to biogeochemical results from the mesocosm experiments and associated modeling, these papers describe how the strong simulated dust deposition events impacted the marine biogeochemistry. Those multidisciplinary results are bringing new insights into the role of atmospheric deposition on oligotrophic ecosystems and its impact on the carbon budget. The dissolved trace metals with crustal origin – Mn, Al and Fe – showed different behaviors as a function of time after the seeding. The increase in dissolved Mn and Al concentrations was attributed to dissolution processes. The observed decrease in dissolved Fe was due to scavenging on sinking dust particles and aggregates. When a second dust seeding followed, a dissolution of Fe from the dust particles was then observed due to the excess Fe binding ligand concentrations present at that time. Calcium nitrate and sulfate were formed in the dust analog for wet deposition following evapocondensation with acids for simulating cloud processing by polluted air masses under anthropogenic influence. Using a number of particulate tracers that were followed in the water column and in the sediment traps, it was shown that the dust composition evolves after seeding by total dissolution of these salts. This provided a large source of new dissolved inorganic nitrogen (DIN) in the surface waters. In spite of this dissolution, the typical inter-elemental ratios in the particulate matter, such as Ti / Al or Ba / Al, are not affected during the dust settling, confirming their values as proxies of lithogenic fluxes or of productivity in sediment traps. DUNE experiments have clearly shown the potential for Saharan wet deposition to modify the in situ concentrations of dissolved elements of biogeochemical interest such as Fe and also P and N. Indeed, wet deposition yielded a transient increase in dissolved inorganic phosphorus (DIP) followed by a very rapid return to initial conditions or no return to initial conditions when a second dust seeding followed. By transiently increasing DIP and DIN concentrations in P- and N-starved surface waters of the Mediterranean Sea, wet deposition of Saharan dust can likely relieve the potential P and/or N limitation of biological activity; this has been directly quantified in terms of biological response. Wet deposition of dust strongly stimulated primary production and phytoplanktonic biomass during several days. Small phytoplankton (< 3 μm) was more stimulated after the first dust addition, whereas the larger size class (> 3 μm) significantly increased after the second one, indicating that larger-sized cells need further nutrient supply in order to be able to adjust their physiology and compete for resource acquisition and biomass increase. Among the microorganisms responding to the atmospheric inputs, diazotrophs were stimulated by both wet and dry atmospheric deposition, although N2 fixation was shown to be only responsible for a few percent of the induced new production. Dust deposition modified the bacterial community structure by selectively stimulating and inhibiting certain members of the bacterial community. The microbial food web dynamics were strongly impacted by dust deposition. The carbon budget indicates that the net heterotrophic character (i.e., ratio of net primary production to bacteria respiration < 1) of the tested waters remained (or was even increased) after simulated wet or dry deposition despite the significant stimulation of autotrophs after wet events. This indicates that the oligotrophic tested waters submitted to dust deposition are a net CO2 source. Nonetheless, the system was able to export organic material, half of it being associated with lithogenic particles through aggregation processes between lithogenic particles and organic matter. These observations support the "ballast" hypothesis and suggest that this "lithogenic carbon pump" could represent a major contribution of the global carbon export to deep waters in areas receiving high rates of atmospheric deposition. Furthermore, a theoretical microbial food web model showed that, all other things being equal, carbon, nitrogen and phosphorus stoichiometric mismatch along the food chain can have a substantial impact on the ecosystem response to nutrient inputs from dusts, with changes in the biomass of all biological compartments by a factor of ~ 2–4, and shifts from net autotrophy to net heterotrophy. Although the model was kept simple, it highlights the importance of stoichiometric constrains on the dynamics of microbial food webs.

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Impact of surface contamination on elemental composition of Sanguinea (Pall.) leaves

BIO Web of Conferences ◽

10.1051/bioconf/20213800105 ◽

2021 ◽

Vol 38 ◽

pp. 00105

Author(s):

Valentina A. Sagaradze ◽

Elena Y. Babaeva ◽

Yulia V. Zagurskaya ◽

Tatyana I. Siromlya

Keyword(s):

Elemental Composition ◽

Plant Material ◽

Chemical Elements ◽

Raw Materials ◽

Ash Content ◽

Surface Contamination ◽

Dust Particles ◽

Fine Dust ◽

Visual Condition ◽

The Impact

The leaves of C. sanguinea Pall. have the potential to accumulate dust on the surface. As the fine dust particles contain various chemical elements (ChEs), we studied the ChE composition in the leaves with different degrees of dust contamination to assess the impact on assay results. The samples of C. sanguinea leaves collected in the Kemerovo region (Russia) were divided into two groups based on the visual condition of plant material: clean leaves and dust contaminated leaves. The total ash assay revealed higher ash content, exceeding pharmacopoeial standards in the dust contaminated group. Dust contaminated leaf samples demonstrated significantly higher concentrations of many ChE: Si, Fe, Al, Na, Ti, Ni, Zr, Cr, V, Pb, La, Ga, Y, Sc and Yb comparing to non-contaminated plant material. The values of potentially hazardous ChEs were significantly lower than the maximum levels specified for medicinal raw materials in all studied samples.

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Particulate barium tracing significant mesopelagic carbon remineralisation in the North Atlantic

10.5194/bg-2017-400 ◽

2017 ◽

Cited By ~ 2

Author(s):

Nolwenn Lemaitre ◽

Hélène Planquette ◽

Frédéric Planchon ◽

Géraldine Sarthou ◽

Stéphanie Jacquet ◽

...

Keyword(s):

Carbon Sequestration ◽

North Atlantic ◽

Deep Convection ◽

Sediment Traps ◽

Chl A ◽

Physical Forcing ◽

The North ◽

Poc Export ◽

Order Of Magnitude ◽

The North Atlantic

Abstract. The remineralisation of sinking particles by prokaryotic heterotrophic activities is important for controlling oceanic carbon sequestration. Here, we report mesopelagic particulate organic carbon (POC) remineralisation fluxes in the North Atlantic along the GEOTRACES-GA01 section (GEOVIDE cruise; May–June 2014) using the particulate biogenic barium (excess barium; Baxs) proxy. Important mesopelagic (100–1000 m) Baxs differences were observed along the transect depending on the intensity of past blooms, the phytoplankton community structure and the physical forcing, including downwelling. The subpolar province was characterized by the highest mesopelagic Baxs content (up to 727 pmol L−1), which was attributed to an intense bloom averaging 6 mg Chl-a m−3 between January and June 2014 and by an intense 1500 m-deep convection in the central Labrador Sea during the winter preceding the sampling. This downwelling could have promoted a deepening of the prokaryotic heterotrophic activity, increasing the Baxs content. In comparison, the temperate province, characterized by the lowest Baxs content (391 pmol L−1), was sampled during the bloom period and phytoplankton appear to be dominated by small and calcifying species, such as coccolithophorids. The Baxs content, related to an oxygen consumption, was converted into a remineralisation flux using an updated relationship, proposed for the first time in the North Atlantic. The estimated fluxes were in the same order of magnitude than other fluxes obtained by independent methods (moored sediment traps, incubations) in the North Atlantic. Interestingly, in the subpolar and subtropical provinces, mesopelagic POC remineralisation fluxes (up to 13 and 4.6 mmol C m−2 d−1, respectively) were equalling and occasionally even exceeding upper ocean POC export fluxes, highlighting the important impact of the mesopelagic remineralisation on the biological carbon pump with a near-zero, deep (> 1000 m) carbon sequestration efficiency in spring 2014.

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Impact of surface contamination on elemental composition of Crataegus sanguinea (Pall.) leaves

BIO Web of Conferences ◽

10.1051/bioconf/20213800145 ◽

2021 ◽

Vol 38 ◽

pp. 00145

Author(s):

Valentina A. Sagaradze ◽

Elena Y. Babaeva ◽

Yulia V. Zagurskaya ◽

Tatyana I. Siromlya

Keyword(s):

Elemental Composition ◽

Plant Material ◽

Chemical Elements ◽

Raw Materials ◽

Ash Content ◽

Surface Contamination ◽

Dust Particles ◽

Fine Dust ◽

Visual Condition ◽

The Impact

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Dust Deposition on the Gulf of California Caused by Santa Ana Winds

Atmosphere ◽

10.3390/atmos11030275 ◽

2020 ◽

Vol 11 (3) ◽

pp. 275 ◽

Cited By ~ 1

Author(s):

Christian A. Álvarez ◽

José N. Carbajal ◽

Luis F. Pineda-Martínez ◽

José Tuxpan ◽

David E. Flores

Keyword(s):

Gulf Of California ◽

Dust Emission ◽

Positive Influence ◽

Dust Particles ◽

Weather Research And Forecasting ◽

Western Coast ◽

Emission Rates ◽

Dust Deposition ◽

Santa Ana ◽

Santa Ana Winds

Numerical simulations revealed a profound interaction between the severe dust storm of 2007 caused by Santa Ana winds and the Gulf of California. The weather research and forecasting model coupled with a chemistry module (WRF-CHEM) and the hybrid single-particle Lagrangian integrated trajectory model (HYSPLIT) allowed for the estimation of the meteorological and dynamic aspects of the event and the dust deposition on the surface waters of the Gulf of California caused by the erosion and entrainment of dust particles from the surrounding desert regions. The dust emission rates from three chosen areas (Altar desert, Sonora coast, and a region between these two zones) and their contribution to dust deposition over the Gulf of California were analyzed. The Altar Desert had the highest dust emission rates and the highest contribution to dust deposition over the Gulf of California, i.e., it has the most critical influence with 96,879 tons of emission and 43,539 tons of dust deposition in the gulf. An increase of chlorophyll-a concentrations is observed coinciding with areas of high dust deposition in the northern and western coast of the gulf. This kind of event could have a significant positive influence over the mineralization and productivity processes in the Gulf of California, despite the soil loss in the eroded regions.

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Programmed cell death in diazotrophs and the fate of organic matter in the western tropical South Pacific Ocean during the OUTPACE cruise

Biogeosciences ◽

10.5194/bg-15-3893-2018 ◽

2018 ◽

Vol 15 (12) ◽

pp. 3893-3908 ◽

Cited By ~ 9

Author(s):

Dina Spungin ◽

Natalia Belkin ◽

Rachel A. Foster ◽

Marcus Stenegren ◽

Andrea Caputo ◽

...

Keyword(s):

Cell Death ◽

Organic Matter ◽

Pacific Ocean ◽

Programmed Cell Death ◽

South Pacific ◽

Sediment Traps ◽

Vertical Flux ◽

Filamentous Cyanobacterium ◽

Chl A ◽

South Pacific Ocean

Abstract. The fate of diazotroph (N2 fixers) derived carbon (C) and nitrogen (N) and their contribution to vertical export of C and N in the western tropical South Pacific Ocean was studied during OUTPACE (Oligotrophy to UlTra-oligotrophy PACific Experiment). Our specific objective during OUTPACE was to determine whether autocatalytic programmed cell death (PCD), occurring in some diazotrophs, is an important mechanism affecting diazotroph mortality and a factor regulating the vertical flux of organic matter and, thus, the fate of the blooms. We sampled at three long duration (LD) stations of 5 days each (LDA, LDB and LDC) where drifting sediment traps were deployed at 150, 325 and 500 m depth. LDA and LDB were characterized by high chlorophyll a (Chl a) concentrations (0.2–0.6 µg L−1) and dominated by dense biomass of the filamentous cyanobacterium Trichodesmium as well as UCYN-B and diatom–diazotroph associations (Rhizosolenia with Richelia-detected by microscopy and het-1 nifH copies). Station LDC was located at an ultra-oligotrophic area of the South Pacific gyre with extremely low Chl a concentration (∼ 0.02 µg L−1) with limited biomass of diazotrophs predominantly the unicellular UCYN-B. Our measurements of biomass from LDA and LDB yielded high activities of caspase-like and metacaspase proteases that are indicative of PCD in Trichodesmium and other phytoplankton. Metacaspase activity, reported here for the first time from oceanic populations, was highest at the surface of both LDA and LDB, where we also obtained high concentrations of transparent exopolymeric particles (TEP). TEP were negatively correlated with dissolved inorganic phosphorus and positively coupled to both the dissolved and particulate organic carbon pools. Our results reflect the increase in TEP production under nutrient stress and its role as a source of sticky carbon facilitating aggregation and rapid vertical sinking. Evidence for bloom decline was observed at both LDA and LDB. However, the physiological status and rates of decline of the blooms differed between the stations, influencing the amount of accumulated diazotrophic organic matter and mass flux observed in the traps during our experimental time frame. At LDA sediment traps contained the greatest export of particulate matter and significant numbers of both intact and decaying Trichodesmium, UCYN-B and het-1 compared to LDB where the bloom decline began only 2 days prior to leaving the station and to LDC where no evidence for bloom or bloom decline was seen. Substantiating previous findings from laboratory cultures linking PCD to carbon export in Trichodesmium, our results from OUTPACE indicate that nutrient limitation may induce PCD in high biomass blooms such as displayed by Trichodesmium or diatom–diazotroph associations. Furthermore, PCD combined with high TEP production will tend to facilitate cellular aggregation and bloom termination and will expedite vertical flux to depth.

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About the possibility of identification of articles from steels, aluminum, copper and alloys on their basis on the expanded micro-impurity elemental composition

Chernye Metally ◽

10.17580/chm.2021.02.09 ◽

2021 ◽

pp. 51-56

Author(s):

Yu. B. Sazonov ◽

D. Yu. Ozherelkov ◽

R. Sh. Latypov ◽

E. E. Gorshkov

Keyword(s):

Spectral Analysis ◽

Chemical Composition ◽

Elemental Composition ◽

Chemical Elements ◽

Copper Alloys ◽

Minimal Amount ◽

Elementary Composition ◽

Geometric Size ◽

The Common

Possibility of determination of the fragments and articles made of different grades of steel aluminium and copper alloys and their affiliation to the common melt was examined via the methods of photoelectric spectral analysis based on composition of micro-impurities. Chemical elements with micro-impurities were revealed; they allow to determine affiliation of metal fragments to one melt. Ultimately possible deviations of micro-impurities within one melt were obtained. The technique allowing to establish affiliation of fragments to the common melt based on their elementary composition of micro-impurities with minimal amount of measurements was suggested based on the obtained results. The minimal geometric size of a sample available for analysis was determined; it allows to classify the examined fragments to one melt based on the results of investigation of expanded elementary composition of micro-impurities. Practical opportunities of this technique were displayed on the example of the alloys with different chemical composition.

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