Dust, continental

Fluxes of continental dust preserved in ice cores of Greenland and Antarctica suggest a 30-fold increase in dust flux during the last Glacial Maximum. Dramatic increases in new biological production in the HNLC regions may have resulted, resulting in the draw-down of atmospheric CO2 (Martin, 1990). 

Most of the non-gaseous impurities in ice were once atmospheric aerosols. Atmospheric aerosols raining onto an ice sheet are of two types primary aerosols, which are incorporated directly into the atmosphere as aerosols (these include continental dust and sea spray), and secondary aerosols which form in the atmosphere from gases. In addition to aerosol-derived impurities, some soluble gases in the atmosphere (HNO3 HCl, H2O2, and NH3) adsorb directly onto ice, and so are measured in a core... 

Hammer, C. U., Clausen, H. B., Dansgaard, W. et al. (1987). Dating of Greenland ice cores by flow models, isotopes, volcanic debris, and continental dust. /. Glacial. 20,3-26. 

The annual singularity in continental dust concentrations has already been applied to cross-check the dating uncertainties of 0-isotope oscillations in several Greenland cores [8,9]. About... 

The usefulness of continental dust concentration variations in dating snow from the Antarctic plateau is unclear. Boutron [11] found an insignificant variance in A1 concentrations as a function of depth at South Pole, while Thompson and Thompson [24] found an annual peak in microparticle concentrations. 

Deciphering the cause(s) of the Late Wisconsin dust interval will be the subject of many future studies, but the interval serves as a useful time marker at present. Koerner and Fisher [34] have used elevated microparticle concentrations in the Devon Island ice core as an indicator of Wisconsin-aged ice. Similarly high continental dust concentrations are expected in the recently recovered cores from the East Antarctic plateau. 

One particular type of source that should be studied carefully Is entrained soil. As shown above, this Is often the greatest contributor of TSP In urban areas. As there Is so much of It present, we need to know concentrations of all measured elements quite well to make an accurate determination of the residual amounts left to be accounted for by other sources. The composition of selved soil Is often used for the soil component, but there may be considerable fractionation Imposed by entrainment, e.g., preferential selection of very fine clay mineral particles. Such fractionation has been demonstrated In the very limited studies of entrainment of particles from soil of known composition (e.g.. Refs. 21, 49). These studies can probably best be done In controlled environments such as wind tunnels. One cannot simply collect ambient particles In the countryside and consider it to be soil, as there are anthropogenic contributions even at great distances from cities ( ). There Is further confusion betwen clean, "continental" dust and "urban" dust. The latter, which Is usually collected near city streets (21, 50), typically has a composition of soil contaminated by anthropogenic emissions, especially from motor vehicles. 

Cooper and Watson (21) reported finding about 0.1% manganese in both the fine (<2 pm) and coarse ( 2 pm) particle fractions, respectively, of urban dust in Portland and 0.2% and 0.085% in the fine and coarse fractions, respectively in continental dust. Thus, it should be possible to use this element in RSP samples as a soil tracer in New York City. However, during part of the period of this investigation, methylcyclopentadienyl tricarbonyl (MMT) was used as an octane booster for unleaded gasoline ( ). ... 

Continental dust flux is the main natural source of chromium in the atmosphere volcanic dust and gas flux are minor natural sources of chromium in the atmosphere (Fishbein 1981). Chromium is released into the atmosphere mainly by anthropogenic stationary point sources, including industrial, commercial, and residential fuel combustion, via the combustion of natural gas, oil, and coal. Other important anthropogenic stationary point sources of chromium emission to the atmosphere are metal industries. It... 

Another point is that the western part of Honshu Is. is relatively susceptible to acid precipitation especially on the Japan sea side, thus this should be watched carefully because this area is at down wind of the Continental dust. 

One of the major inputs of iron to the ocean comes from the dissolution of Fe(II) from wind-borne continental dust deposited on the surface of the ocean (Zhuang et al, 1990). In oxygenic environments, such as surface ocean waters, Fe(II)... 

Figure 7 Accumulation rates of total mass, opal, and the eolian component (continental dust) of North Pacific sediments recovered at ODP Sites 885/886. Accumulation rates derived by (a) Rea et al. (1998) using an age model based on biostratigraphic and paleomagnetic age control points and (b) Higgins et al. (submitted) by...

Higgins S. M., Anderson R. F., Marcantonio F., Schlosser P., Stute M., Schwarz B., Frank M., and Strobl C. Fluxes of Extraterrestrial He, continental dust, and opal in North Pacific sediments over the past 7 Ma. Paleoceanography (submitted for publication). 

Vanadium was discovered in 1830. It is present at 0.01% in earth s crust. Vanadium is released naturally into the air through the formation of continental dust, marine aerosols, and volcanic emissions. The natural release of vanadium into water and soils occurs primarily as a result of weathering of rocks and soil erosion. Anthropogenic sources include the combustion of fossil fuels, particularly residual fuel oils, which constitute the single largest overall release of vanadium to the atmosphere. Deposition of atmospheric vanadium is also an important source... 

The presence of heavy metals in the atmospheric particulate matter in Antarctica can be attributed to different sources, both natural and anthropogenic. Some authors state that almost all natural sources of heavy metals in Antarctica are generally situated in the southern hemisphere (4, 14, 15). The natural sources are normally volcanic activities, erosive processes, continental dusts, marine spray from the ocean, low-temperature biological processes, etc. (7, 10, 16-18). Important local human sources of heavy metal emissions into the Antarctic atmosphere are presumed to be the Antarctic stations and their activities, especially all kinds of transport, power plants, waste burning (incinerators), etc. (10, 12, 15, 19). 

Natural sources of atmospheric vanadium include continental dust, marine aerosol, and volcanic emissions (Byerrum et al. 1974 Van Zinderen Bakker and Jaworski 1980 Zoller et al. 1973). The quantities entering the atmosphere from each of these sources are uncertain however continental dust is believed to account for the largest portion of naturally emitted atmospheric vanadium followed by marine aerosols. Contributions from volcanic emissions are believed to be negligible when compared with the other two sources (Zoller et al. 1973). 

This leads to the suggestion that the dust in the atmosphere may play an important role, catalytically and photocatalytically cleaning the atmosphere from harmful compounds. Large desert areas, which are the main generators of continental dust, possibly play the role of the kidneys of the planet. 

The HNTC areas were enigmatic until the discovery of the role of iron in phytoplankton production. In the three main HNTC areas—the equatorial Pacific, subarctic Pacific and Southern Ocean—the phytoplanktonic communities are generally dominated by picoplankton. There are also periodic diatom blooms, from which a large proportion of the detritus sinks out of the euphotic zone, so silicate levels are also often low (Dugdale et al. 1995). Iron concentrations are very low, which in the subarctic Pacific and Southern Ocean may be due to the low aeolian contribution in the form of continental dust (Martin et al. 1991). 

Patterson DB, Fmley KA, Norman MD (1999) He-4 as a tracer of continental dust A 1.9 million yem record of aeohanflux to the west eqttatorial Pacific Ocean. Geochim Cosmochim Acta 63 615-625 Pearson Jr. FJ, Balderer W, Loosli HH, Lehman BE, Matter A, Peters T, Schmassmarm H, Gautschi A... 

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