Particle size oceanic

Miller RJ, Smith CR, DeMaster DJ, Pomes WL (2000) Feeding selectivity and rapid particle processing by deep-sea megafaunal deposit feeders A " Th tracer approach. J Mar Res 58 653-573 Moore RM, Hunter KA (1985) Thorium adsorption in the ocean - reversibility and distribution amongst particle sizes. Geochim Cosmochim Acta 49 2253-2257 Moore RM, Millward GE (1988) The kinetics of reversible Th reactions with marine particles. Geochim Cosmochim Acta 52 113-118... 

Walter HJ, Rutgers van der Loeff MM, Hoeltzen H (1997) Etrhanced scavenging of Pa relative to h in the South Atlantic south of the Polar front Implicatiotts for the use of the Pa/ h ratio as a paleoproductivity proxy. Earth Planet Sci Lett 149 85-100 Wheatcroft RA (1992) Experimental tests for particle size-dependant biotirrbidation in the deep oceans. Linmol Oceanogr 37(1) 90-104... 

Ohta simplified the nomenclature and named the process as mechanolysis [214], The theoiy puts restrictions on the particle size, which should match with the crevices and hence it should be between 1 to 10 pm. Although mechano-catalytic water splitting is simple and does not involve any toxic materials, a major limitation is the low yield of hydrogen. Most of the work in this technique was done between 1998 and 2000 no new results based on this technique have been seen since. It does seem an intriguing way to capture the energy of ocean waves, with reaction chambers left to tumble in the ocean surf. 

Typically, the LRT smoke episodes are first detected by the increase in the PM concentration at the measurement site. If adequate real-time instruments are available, also the changes in the physical properties (e.g., particle size) and chemical composition of particles can be observed. Every PM pollution episode observed in Northern Europe is not associated with LRT smokes. Therefore, the origin of the polluted air masses must be identified, e.g., by using the backward air mass trajectory models (e.g., HYSPLIT provided by the National Oceanic and Atmospheric Administration or FLEXTRA [34]), that shows the path of air masses before arriving the measurement site. Additionally, Web Fire Mapper (http //maps. geog.umd.edu) shows the location and intensity of fires areas obtained from MODerate-resolution Imaging spectroradiometer (MODIS [10]) onboard the satellites. 

Lai, D. and Lerman, A. (1975) Size spectra of biogenic particles in ocean water and sediments./. Geophys. Res., 80, 423-430. 

Esser and Turekian (1988) estimated an accretion rate of extraterrestrial particles in ocean bottom and in varved glacial lake deposit on the basis of osmium isotope systematics and concluded a maximum accretion rate of between 4.9 x 104 and 5.6 x 104 tons/a. The discrepancy between this estimate and those derived from helium can easily be attributed to the difference in the size of the cosmic dust particles under consideration. Cosmic dusts of greater than a few ten micrometers may not be important in the helium inventory of sediments because the larger grains are likely to lose helium due to atmospheric impact heating (e.g., Brownlee, 1985). Stuart et al. (1999) concluded from studies on Antarctic micrometeorites that 50- to 1 OO-qm micrometeorites may contribute about 5% of the total flux of extraterrestrial 3He to terrestrial sediments. Therefore, the helium-based estimate deals only with these smaller particles. 

It was suggested that different particle size distributions combined to give different functionalities to the total rate or that different surface histories existed for the samples from different locations. Although the samples were taken from different ocean basins, it was Morse s (30) opinion that they should not be taken as representative of these basins, as variability within a given basin could probably be at least as large as that found in samples from different ocean basins. 

Finally, in the case of present-day aerosol nitrate isotopic measurements, samples collected as a function of particle size provide another level of detection in the resolution of sources and atmospheric transformation mechanisms. Large particles (1-10 pm) typically are crustal or oceanic sea spray, depending upon where the particular samples are collected. Small particles (less than 0.1 pm) generally are gas-to-particle conversion process products. Using combined multi-isotope ratio measurements and size-fractionated collection processes, it is possible to provide sophisticated details of atmospheric aerosol fates. 

Moore R. M. and Hunter K. A. (1985) Thorium adsorption in the ocean reversibility and distribution amongst particle sizes. Geochim. Cosmochim. Acta 49, 2253-2257. 

Wheatcroft R. A. (1992) Experimental tests for particle size-dependent bioturbation in the deep ocean. Limnol. Oceanogr. 37, 90-104. 

Aquatic suspended particles are usually characterized by a continuous particle size distribution. The distinction between particulate and dissolved compounds, conventionally made in the past by membrane filtration, does not consider organic and inorganic colloids appropriately. Colloids of iron(IIl) and manganese(III,IV) oxides, sulfur, and sulfides are often present as submicron particles that may not be retained by membrane filters (e.g., Buffle et al., 1992). Recent measurements in the ocean led to the conclusion that a significant portion of the operationally defined dissolved organic carbon may in fact be present in the form of colloid particles. 

Figure 14.3. Particle size distribution, (a) Discrete and continuous cumulative particle size distribution, (b) Discrete and continuous particle size distribution, (c) Volume distribution plotted in accordance with equation 3. (d) Particle size distributions at four depths in a calcareous sediment from west equatorial Pacific Ocean, 1°6.0 S, 161 36.6 E, box core No. 136, water depth 3848 m. (From Lerman, 1979.)...

Figure 14.4b shows predictions on the distributions obtained after 2 days for samples having an initial continuous particle size distribution with /8 = 4 and size ranging from 1 nm to 100 m where the initial mass concentration varies from 0.01 to 10 mg liter. Figure 14.4c shows the change in the mean size with concentrations under the same conditions. As can be seen, the behavior of small particles (<100 nm) is independent of particle concentration because they disappear instantaneously under all conditions. Intermediate and large particles are sensitive to changes in concentration. Obviously, open oceans, quiet rivers, and lakes, where particle concentrations are less than 5-10 mg liter" will show relatively stable size distribution patterns (Filella and... 

Woodcock (1953) as well as Moore and Mason (1954)demonstrated that the rate of bubble formation increases with increasing wind speed. In more recent work A. Meszaros and Vissy (1974) reported that over the oceans the correlation between the number of sea salt particles and the wind speed becomes gradually weaker as the particle size decreases. Thus, it is not excluded that the smallest sea salt particles (r <0.3 /on) originate from a type of bubbles the formation of which is independent of the wind speed. 

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