Meltwaters

One of the major effects of acidic deposition is felt by aquatic ecosystems in mountainous terrain, where considerable precipitation occurs due to orographic lifting. The maximum effect is felt where there is little buffering of the acid by soil or rock structures and where steep lakeshore slopes allow little time for precipitation to remain on the ground surface before entering the lake. Maximum fish kills occur in the early spring due to the "acid shock" of the first meltwater, which releases the pollution accumulated in the winter snowpack. This first melt may be 5-10 times more acidic than rainfall. 

Wemer M, Mikolajewicz U, Hoffmann G, Heimann M (2000) Possible changes of in precipitation caused by a meltwater event in the North Atlantic. J Geophys Res 10 10161-10167 Whitehead NE, Ditchbmn RG, Wilhams PW, McCabe WJ (1999) Pa and contamination at zero age a possible hmitation on U/Th series dating of speleothem material. Chem Geol 156 359-366 Wigley TML, Plummer LN, Pearson FJ (1978) Mass transfer and carbon isotope evolntion in natural water systems. Geochim Cosmochim Acta 42 1117-1140... 

Most of the snow is collected from nearby streets. If necessary, snow guns are used to produce additional snow. In April the snow deposit is thermally insulated by 0.2 m of wood chips. Some meltwater is evaporated through the sawdust, which gives an evaporative cooling effect that corresponds to 25% of the extracted cold. The wood chips in Sundsvall are reused several seasons before being burnt in a nearby cogeneration plant. 

Bertine KK, Keene JB (1975) Laurentide ice sheet meltwater recorded in Gulf of Mexico deep-sea cores. Science 188 147-152... 

Small amounts of salt are commonly occluded in sea ice. Not all of the ions are incorporated to the same degree. This alters the ion ratios in the remaining brine, leading to deviations from the Rule of Constant Proportions during freezing. Likewise, meltwater from sea ice can contain ions in ratios that deviate from average open ocean water. 

The glacial till deposits consist of poorly sorted to unsorted, nonstratified till ranging from muddy gravel to sandy coarse gravel. Pebbles and small cobbles are dominant. Surface morphology commonly includes morainal ridges, dry and water-filled kettle depressions, and meltwater channels (Hamilton 2007). 

Fig. 2 ARISE categories based on Glacial (Distributed), Quickflow (Dilute meltwater) and Groundwater contributions (see Table 1 for details of categories A-I)...

Johannessen M, Henriksen A (1978) Chemistry of snow meltwater changes in concentration during melting. Water Resour Res 14 615... 

Besides temperature, a variable isotopic composition of the ocean is another factor responsible for variations in foraminifera. A crucial control is salinity ocean waters with salinities greater than 3.5% have a higher 0 content, because 0 is preferentially depleted in the vapor phase during evaporation, whereas waters with salinities lower than 3.5% have a lower content due to dilution by fresh waters, especially meltwaters. The other factor which causes variations in the isotopic composition of ocean water is the volume of low- 0 ice present on the continents. As water is removed from the ocean during glacial periods, and temporarily stored on the continents as 0-depleted ice, the ratio of the global ocean increases... 

NADW flows southward the ongoing oxidation of organic matter results in a progressive C-depletion down to less than 0.4%c in the Southern Ocean. Reductions in observed in many cores from the North-Atlantic (Samtheim et al. 2001 Elliot et al. 2002) have been interpreted as meltwater input to the surface ocean (Heinrich events), which caused changes in deep water circulation. 

Bums, R.G. (1994) Schwertmannite on Mars Deposition of this ferric oxyhydroxysulfate mineral in acidic saline meltwaters. Lunar Planetary Sd. 25, Part 1 203-204... 

Higher pH of meltwater may act to lessen the effects of acid rain and snow. 

Paalme et al. (1990) studied the bulk deposition chemistry in the environment around the Estonian oil shale combustion area (Fig. 11 see also Kirso et al. 2002). Cations (i.e., calcium, potassium, sodium), anions (i.e., chloride, sulphate, nitrate), and - he x an e-e x t ractable PAHs were analysed in snow meltwater samples collected from 21 sampling stations in northeastern Estonia. It was found that the characteristic products of oil shale combustion, that is, Ca2+ and SC>4, accounted for over 92% of the major cations and 90% of the major anions in the snow. Correlation coefficients of r = 0.86 and 0.92 were noted for Ca2+ vs. SO - and Ca2+ vs. (SO2 - + 20 ), respectively. A high degree of correlation (r = 0.83) was also noted between Ca2+ vs. total PAHs in snow samples taken 150 km to the south of the thermal power plants. The deposition fluxes of Ca2+ and PAHs decreased with distance from the power plants. The average Ca2+ deposition flux 90 km... 

Boil the water only until the ice cube melts. As it melts, remove the meltwater with the sponge. 

In 1978, other Russian scientists proposed that meltwater (from freshly melted snows) carries certain biological properties not known in ordinary water. The Russian scientists theorized that meltwater retains some of the order that is characteristic of frozen water and that this increased order alters vital reaction rates within cells. This tends to tie in with the concept of structured water discussed briefly later. 

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