摘要:

The sea‐air interface is probably the most poorly understood of the three boundaries separating the system sea‐air‐land. However, the chemistry of the sea‐air interface is receiving increasing attention as its role in environmental problems becomes more apparent. Perhaps in no other region of the environment do microscopic physicochemical and hydrodynamic processes so profoundly affect large‐scale geophysical phenomena as they do in the transfer of material from sea to air. The solutions to many problems in air pollution and water pollution as well as a complete assessment of the geochemical cycles of many elements are critically dependent on a better understanding of sea‐surfac

ISSN:0148-0227    

DOI:10.1029/JC077i027p05059

年代:1972

数据来源: WILEY

摘要:

Air‐water interfacial films were sampled and subjected to nondestructive analysis by multiply attenuated internal reflection (MAIR) infrared spectroscopy. A field program on Lake Chautauqua in western New York correlated the buildup of oily films over the lake surface with peak boating activity and demonstrated the rapid elimination of such pollutant layers by natural mechanisms. A laboratory program to assess the relative efficiencies of various processes for film degradation included studies of the influence of ultraviolet‐visible irradiation, capillary‐wave action, bacterial activity, and bubble breaking. Bubble breaking and its concomitant ejection of film fragments into the air was by far the most efficient process, especially when simultaneous irradiation accelerated the formation of polar moieties in the films. Chemical fractionation by this mechanism has also been demonstrated, with the more polar organic components and their associated inorganic elements being stripped from the interface preferentially. Thus, air‐sea interfacial films are implicated in sea‐to‐air material transport and in the chemistry of mari

ISSN:0148-0227    

DOI:10.1029/JC077i027p05062

年代:1972

数据来源: WILEY

摘要:

A number of sea‐surface microlayer and marine atmosphere samples have been taken from sites in Hawaii over a 2‐year period from June 1969 to June 1971. The analysis of samples is reported for sodium, potassium, calcium, magnesium, strontium, copper, iron, and zinc, and some analyses of microlayer samples for marine nutrients are reported as total carbon, total phosphorus, and reactive nitrate. Data collected show chemical compositions and ion ratios of most samples to differ, often drastically, from normal sea‐water data also collected for these chemical species. Microlayer samples represent a thin film approximately 150 μ thick removed from the surface of the open ocean. These samples generally have considerably higher total carbon, phosphorus, and nitrate concentrations than samples taken at the same site but at 0.6‐meter depth. Microlayer samples are also found to be enriched to a small extent in some alkaline earth metals and to a much larger extent for the transition metals copper, iron, and zinc. The transition metals were also found to be proportionately more organically associated in the microlayer samples. Aerosol samples studied are enriched in most metals relative to sodium and to the metal to sodium ratio found in sea water. These enrichments range from values very close to zero up to unity or so for the alkali and alkaline earth metals, depending on element and particle size. Average enrichment values for the transition metals on smaller aerosols approach and exceed 3 and 4 orders of magnitude. Generally, enrichments are greatest on the smaller aerosols approaching Aitkin size; values are also pronounced for the giant aerosols, and lesser values occur for the intermediate‐sized large aerosols. It is possible to consider the data in terms of mixing of globally spread, stratospheric continental dust of long residence time and pollution aerosols with normal marine aerosols. It is also important to consider separately or in combination with this concept fractionation and enrichment of selected chemical species before their ejection from the sea surface during agitation and bubbling. A qualitative mass spectrographic study of some of the samples indicates that organic coating materials on the aerosols are more concentrated on the smalle

ISSN:0148-0227    

DOI:10.1029/JC077i027p05076

年代:1972

数据来源: WILEY

摘要:

Serratia marcescenshas been used to demonstrate that bacterial concentrations in jet drops from bursting bubbles can be much higher than the concentration in the water in which the bubbles burst. The ratio of the concentrations is the concentration factorC. A rotating tank was used to study the stripping of bacteria from the bulk air‐water interface. Values forCrange from 1 to about 100, increasing with drop size up to about 80 μm in diameter. For a given drop size,Cvaries inversely with the bacterial concentration in the bulk suspension. A bubble ‘aging tube’ has been developed in which bubbles can be aged (while suspended in a downward moving stream of water) for any given time before they rise to the surface to break. Drops from these bubbles show an increase ofCwith bubble age, indicating a time rate of change of the adsorption of bacteria to the surface of the bubble.Creaches a steady‐state value as high as 104in 10–20 sec. Surface‐active organic material is also adsorbed onto a rising bubble. This process lowers the surface‐free energy and, in turn, results in a decrease of the jet‐drop size and

ISSN:0148-0227    

DOI:10.1029/JC077i027p05087

年代:1972

数据来源: WILEY

摘要:

The salts in rain, snow, and dew are considered to derive from ocean bubble spray. It was shown by laboratory bubble experiments at varying temperatures, humidities, and salt concentrations that the difference in ion ratios between the spray and the bulk of the solution that is sprayed is in agreement with the requirements of the Gibbs adsorption isotherm if the spray is derived from the surface layer of the bulk solution. Inorganic salts dissolved in ocean water are depleted in the surface of the ocean because the surface tension of their solution rises with their concentration. The gradient of this rise has a characteristic value for each salt and is independent of temperature. For sodium chloride this gradient is 1.85 and for potassium chloride it is 1.50. These and other oceanic salts were tested for changes in ion ratio in the bubble spray of their mixtures. Experiments were performed with sea water and artificial solutions at temperatures ranging from 25° to 130°C. The Gibbs theory predicts quantitatively the ratio changes found in bubble spray at equilibrium conditions only (for ocean environment near 100% humidity). When the sprayed surface is evaporated (subsaturated air, i.e., low humidity), the ratio shift is modified (e.g., enhanced in favor of potassium ions compared with sodium ions). If condensation occurs at the time of bubble spray generation, however, this change in ratio is diminishe

ISSN:0148-0227    

DOI:10.1029/JC077i027p05100

年代:1972

数据来源: WILEY

摘要:

The method of flame scintillation spectral analysis has been adopted for the determination of the size distribution of sodium‐containing particles. Near the seashore, these aerosols are identical to sea salt particles, amount to approximately 5% of the total Aitken particle count, and exhibit a power law distribution with β = 3.8. Measurements made at Mauna Loa Observatory (above the trade wind inversion) indicate a similar size distribution. However, only about 1% of the concentration is transported through the inversion, and removal efficiency tends to favor the removal of larger particl

ISSN:0148-0227    

DOI:10.1029/JC077i027p05106

年代:1972

数据来源: WILEY

摘要:

Atmospheric particles were collected over the open sea (western Mediterranean, North Atlantic, and Norwegian Sea) by air filtration and cascade impactor sampling. The observed K/Na concentration ratios exhibited marked variation and were greater than the reference ratio in bulk sea water. These concentration ratios can be related to the existence of a chemical fractionation affecting the marine aerosols produced by bubbles bursting at the sea surface. Minute amounts of terrigenous dust are found in northern hemisphere marine air in the same range of concentrations as sea‐salt particles and contain sodium and potassium of primary continental origin. The presence of this terrigenous dust in the samples raises questions as to the validity of the fractionation hypothesis. In strong support of this fractionation concept are data from our laboratory based on (a) laboratory and in situ experiments with artificially produced aerosols; (b) high‐volume air sampling over the Antarctic Ocean with controlled low loads of hydro‐insoluble dust; and (c) coastal region sampling where silicon, aluminum, iron, and potassium provide a corrective index for potassium‐rich terrigenous dust concentrations. The Cl/Na ratios measured resemble the sea‐water values, which could indicate that an enrichment of potassium takes place rather than a depletion of sodium. The Ca/Na ratios often follow the K/Na ratios and suggest identical enrichment of calcium. The enrichments seem to preferentially affect particles of small size (≤1–2 μm), and long‐range transport of fractionated marine aerosols can be hypothesized. This is supported by K/Na, Ca/Na, and Mg/Na ratios as measured in another laboratory. These ratios, observed in ice from the central part of the East Antarctic Plateau and corrected for a terrigenous influence with the iron index, suggest a geochemical fractionation at the marine source. These data further suggest that fractionated marine aerosols can be transported far from their

ISSN:0148-0227    

DOI:10.1029/JC077i027p05116

年代:1972

数据来源: WILEY

摘要:

The structure of water at the interface between a solid and an aqueous phase is different from the structure of bulk water. Somewhat surprisingly, structural similarities have been found between water adjacent to a purely hydrophobic surface and water adjacent to a hydrophilic surface. In the presence of an insoluble monolayer on water, the vicinal water structure resembles the structure near a water‐solid interface. Anomalies in the thermal properties of vicinal water are frequently observed and interpreted as higher order phase transitions in the structured entities at the interface. Water structures near a solid surface (or near an insoluble monolayer) may be stabilized by an ‘energy delocalization effect.’ At the pure air‐water interface, no such stabilization is likely to occur; hence the surface tension of pure water is not expected to reveal thermal anomalies. This explanation reconciles previous anomalous results with more recent accurate measurements of surface tension carried out by Gittens, by Johanssen and Eriksson, and by Cini and his co‐workers. A notable anomaly in interfacial properties of water occurs at around 29°–32°C. Assuming that natural sea water may be partially (or completely) covered by an insoluble monolayer, we expect that the air‐sea interfacial properties may, therefore, also show an anomaly in this temperature range. The large surface entropy of vicinal water probably reflects an increased number of monomeric molecules. This anomaly is reflected both in the viscosity and the mechanical disjoining pressure of water between two solid surfaces (Peschel and Adlfinger) and in the ‘mechanical coupling’ between a solid surface and the vicinal water (data by Forslind and by Kerr and Drost‐Hansen). We tentatively propose that this phenomenon may affect the rate of vaporization of sea water from a partially or completely covered air‐sea interface. It is interesting to note that hurricanes appear to be spawned in the tropical ocean where the surface temperature exceeds approximately 30°C! A cause and effect relationship between this observation and the anomaly in surf

ISSN:0148-0227    

DOI:10.1029/JC077i027p05132

年代:1972

数据来源: WILEY

摘要:

A series of determinations was made of the concentration of airborne chloride particles at heights between approximately 1 and 15 meters above the ocean surface, using the sloopNis Randersas the sampling platform. Analyses were done by the membrane filter technique of J. P. Lodge (1954), which yields both number concentration and particle size. Samples were taken in the general area between Santa Barbara, California, and Santa Catalina Island. As Y. Toba (1965) predicted, there is no clear gradient in concentration over the height interval measured. Number count, geometric mean, and geometric standard deviation were all extremely similar at all heights. Geometric standard deviation was small, rarely exceeding 2.0, and was often as low as 1.5. Geometric mean diameter, expressed as the diameter of an equivalent sphere of pure sodium chloride, was approximately 2 μm. Concentrations ranged over a wide span from a few thousand to a few million particles per cubic meter. Because of the complex geography of the San Pedro channel and adjacent waters, there was no obvious relationship between local wind velocity and particle concentration. A contributing factor may be the difficulty in making measurements in a small boat at wind velocities that cause significant local surface generation of salt particles. Simultaneous collections of smaller particles for electron microscopy showed phosphate to be a consistent minor ingredient, and sulfuric acid and sulfates to be a surprisingly predominant one numerically

ISSN:0148-0227    

DOI:10.1029/JC077i027p05147

年代:1972

数据来源: WILEY

摘要:

Interactions between marine aerosols and polluted continental air were studied at a coastal sampling station in the Los Angeles basin. Material was collected on filters and salt‐sensitive impaction slides over a vertical distance of 30 meters in order to contrast differences between fresh aerosols generated in the surf and aged aerosols entering the basin from the open ocean. The diurnal onshore‐offshore flow of air was monitored to characterize short‐term interactions between heavily polluted air and the marine environment. In the absence of well‐defined scavenging mechanisms, the removal of nonmarine aerosols and the addition of sea salt during the 12‐ to 16‐hour residence time over the ocean at night was minimal. Analysis of cascade impactor samples collected in relatively clear air indicated a deficiency of chloride in the smaller marine aerosols due to the inclusion of nonchloride particulates from continental sources or other mechanisms. The formation of a highly conductive acid species in these aged aerosols was noted. Large‐scale mixing of nitrogen dioxide from continental air is postulated with reactions between salt particles and the gas leading to the formation of nitric acid and the loss of hydrogen chloride in the gas phase. The use of the term ‘maritime aerosol’ is suggested for mixtures of marine and continental aerosols in

ISSN:0148-0227    

DOI:10.1029/JC077i027p05152

年代:1972

数据来源: WILEY