Freshwater lakes

Twelve distribution compartments are distinguished air, rivers, freshwater lakes, freshwater lake sediments, salt lakes, salt lake sediments, natural, agricultural and urban soil, groundwater, sea water, and sea water sediments. In contrast... 

Robinson, N., Cranwell, P.A., and Eglinton, G (1987) Sources of the lipids in the bottom sediments of an English oligomesotrophic lake. Freshwater Biol. 17, 15-33. 

Engle, D. L., and J. M. Melack. 1990. "Floating meadow epiphyton Biological and chemical feamres of epiphytic material in an Amazon floodplain lake." Freshwater Biology 23 479-494. 

Lenz, P. H., J. M. Melack, B. Robertson, and E. A. Hardy. 1986. "Ammonium and phosphate regeneration by the zooplankton of an Amazon floodplain lake." Freshwater Biology 16 821-830. 

Stratification in estuaries is in some respects similar to stratification in lakes, although in estuaries the density difference is primarily due to the difference in salinity between freshwater and ocean water, instead of being primarily due to temperature differences, as in most lakes. Freshwater has a density of approximately 1.00 g/cm3, whereas ocean water has a density of approximately 1.03 g/cm3 due to dissolved salts [primarily sodium (Na+), chloride (Cl-), calcium (Ca2+), and sulfate (SO4 ). This is a much larger density difference than that which occurs due to temperature differences in surface waters hence, the stratification may be very strong. Whatever its cause, stratification always inhibits the vertical transfer of dissolved chemicals from layer to layer. 

Description Body fusiform, streamlined, laterally compressed, usually 18 to 24 in. (457 to 610 mm) in length and 8 to 12 lb in weight as marine adults and 10.8 to 25.8 in. (279 to 656 mm) fork length in Great Lakes freshwater populations body depth moderate, greater in breeding males. 

P.A. Bukaveckas, M. Robbins-Forbes (2000). Role of dissolved organic carbon in the attenuation of photosynthetically active and ultraviolet radiation in Adirondack lakes. Freshwat. Biol., 43, 339-354. 

Cage, M.A. and Gorham, E. (1985) Alkaline phosphatase activity and cellular phosphorus as an index of the phosphorus status of phytoplankton in Minnesota lakes. Freshwater Biology 15, 227-233. 

Shapiro, J., The role of carbon dioxide in the initiation and maintenance of blue-green dominance in lakes, Freshwater Biol., 37, 307, 1997. 

Edmundson, J.A. and A. Mazumder. 2002. Regional and hierarchical perspectives of thermal regimes in subarctic, Alaskan lakes. Freshwater Biol. 47 1-17. 

In hydrological studies, the transfer of water between reservoirs is of primary interest. The magnitudes of the main reservoirs and fluxes (volume per time) are given in Figure 7. The oceans hold ca 76% of all the earth s water. Most of the remainder, ie, ca 21%, is contained in pores of sediments and in sedimentary rocks. A Httle more than 1% (or 73% of freshwater) is locked up in ice. The other freshwater reservoir of significant size is groundwater. Lakes, rivers, and the atmosphere hold a surprisingly small fraction of the earth s water. 

Freshwater is withdrawn from various sources (rivers, lakes, groundwater, etc) and used many times before its discharge to the ocean. Water uses can generally be classified as follows pubHc water supply (domestic) industrial commercial and institutional, eg, restaurants, schools agricultural and hve stock. 

Obstacles attend this new solution of the freshwater problem, which magnify those familiar to the chemical engineer in purifying other cheap or worthless raw materials into valuable products by treatment with chemicals or thermal or electrical energy. These obstacles are quite different from the previous main problem of water supply, ie, the factor of happenstance in finding a river or lake nearby or of making a fortunate geological strike. 

Asiatic clams are freshwater moUusks. They probably origiaated ia China or eastern Asia and were iatroduced iato North America and Europe ia the past century. They were originally found ia warm water but their territory now extends to Minnesota. They have not yet been seen ia Canadian rivers or lakes. 

The main deposits of freshwater diatomite were laid down in large lakes. Many of these deposits in the western United States formed during glacial times, when the local climate was wetter. Several tens of square kilometers in Nevada west of Tonopah are covered with diatomite as are other large areas in the Great Basin. 

The principal marine deposits were formed during the Tertiary period and more particularly the upper Miocene epoch. Deposits of freshwater origin date from the PHocene to Miocene epochs to more recent times, dating to as late as 100,000 years ago. U.S. commercial deposits are at or comparatively near the surface. Bog deposits are exploited and lake beds are dredged for use in other parts of the world. 

The most evident damage from acid depositions is to freshwater lake and stream ecosystems. Acid depositions can lower the pH of the water, with potentially serious consequences for fish, other animal, and plant life. Lakes in areas with soils containing only small amounts of calcium or magnesium carbonates that could help neutralize acidified rain are especially at risk. Few fish species can survive the sudden shifts in pH (and the effects of soluble... 

Surface freshwater lakes contain 1.25 x 10 km of water, more than half of which... 

A number of freshwater lakes were surveyed for concentrations of plutonium, the ratio of its upper to lower oxidation states, pH, and the concentration of dissolved organic carbon (DOC), which are shown in Table 11(11). 

Fig. 14-4 Schematic representation of the transport of P through the terrestrial system. The dominant processes indicated are (1) mechanical and chemical weathering of rocks, (2) incorporation of P into terrestrial biomass and its return to the soil system through decomposition, (3) exchange reactions between soil interstitial waters and soil particles, (4) cycling in freshwater lakes, and (5) transport through the estuaries to the oceans of both particulate and dissolved P.

Hampton SE, Izmest eva LR, Moore MV, Katz SL, Dennis B, Silow EA (2008) Sixty years of environmental change in the world s largest freshwater lake - Lake Baikal, Siberia. Global Change Biol 14 1947-1958... 

As noted earlier, OPs are known to be highly toxic to aquatic invertebrates and to fish. This has been demonstrated in field studies. For example, malathion applied to watercress beds caused lethal intoxication of the freshwater shrimp Gammarus pulex located downstream (Crane et al. 1995). Kills of marine invertebrates have been reported following the application of OPs. Accidental release of OPs into rivers, lakes, and bays has sometimes caused large-scale fish kills (see Environmental Health Criteria 63). 

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