Big Chemical Encyclopedia

Chemical substances, components, reactions, process design ...

Articles Figures Tables About

Acid lakes

Water birds have not been shown to be directly affected by acidification. However, the prey of waterbirds may be of concern as these lower food-chain organisms may have elevated levels of toxic metals related to acidification of their habitat. Moreover, most water birds rely on some component of the aquatic food-chain for their high protein diet. Invertebrates that normally supply caJcium to egg-laying birds or their growing chicks are among the first to disappear as lakes acidify. As these food sources are reduced or eliminated due to acidification, bird habitat is reduced and reproductive rate of the birds is affected. The Common Loon is able to raise fewer chicks, or none at all, on acidic lakes where fish populations are reduced 37 and 5S). However, in some isolated cases, food supplies can be increased when competitive species are eliminated (e.g.. Common Goldeneye ducks can better exploit insects as food when competition from fish is eliminated). The collective influences of acidification are difficult to quantify on a specific area basis but for species that rely on a healthy aquatic ecosystem to breed, acidification remains a continuing threat in thousands of lakes across eastern North America 14). [Pg.56]

Ideally, lakes and streams have a pH between 6 and 8. However, according to the National Surface Water Survey (NSWS) conducted by the U.S. Environmental Protection Agency between 1984 and 1986, the most acidic lake in the country, Little Echo Pond in Franklin, New York, had a pH of 4.2. According to the same survey, the Pine Barrens region of New Jersey also has a very high percentage of acidic rivers. More than 90% of the streams in that area are considered acidic. This is very bad news for the fish that live in these lakes and streams. [Pg.96]

Arctic char, Salvelinus alpinus Austria acidic lake 19.n nvv Oft ... [Pg.264]

Lakes that have been acidified cannot support the same variety of life as healthy lakes. As a lake becomes more acidic, crayfish and clam populations are the first to disappear, then various types of fish. Many types of plankton—minute organisms that form the basis of the lake s food chain—are also affected. As fish stocks dwindle, so do populations of loons and other water birds that feed on them. The lakes, however, do not become totally dead. Some life forms actually benefit from the increased acidity. Lake-bottom plants and mosses, for instance, thrive in acid lakes. So do blackfly larvae. [Pg.333]

Naphthalenesulfonic acid lake pigments are based on naphthalenesulfonic acid as a coupling component introduction of an additional S03H function as part of the diazo component is possible. [Pg.7]

Phelps TJ, Zeikus JG. 1984. Influence of pH on terminal carbon metabolism in anoxic sediments from a mildly acidic lake. Appl Environ Microbiol 48 1088-95. [Pg.189]

Decomposition rates of some organic substrates are reduced. Substantial changes in the species composition of primary producers occur. The richness of phytoplankton species is reduced, while biomass and productivity of phytoplankton are not reduced by acidification. The biomass of herbivorous and predaceous zooplankton is probably reduced because of reductions in numbers of organisms and/or reduction in their average size. Many benthic invertebrates such as species of snails, clams, crayfish, amphipods, and various aquatic insects are intolerant of low pH and are seldom found in acidic lakes. However, certain large aquatic insects such as water boatmen and gyrinids are very acid tolerant and may become the top predators in some acidified lakes. Acidification of aquatic systems has major effects on fish population. [Pg.124]

Calculating the bicarbonate concentrations with (3), it is possible to plot the measured average pH values of Table 2 against the calculated loglHCOs ]. The result is shown in Fig. 5a. For pH >5.5 a linear relationship, very close to that reported in the literature, can be observed (pH = loglHCOa ] + 11.2). However, for acid lakes the calculated bicarbonate concentrations seem to be too low. It is reported that at pH<6 the release of metals from soils or sediments as a consequence of weathering processes becomes more and more important. Consequently aluminium hydroxides can influence alkalinity. In [18] the equation for calculating alkalinity was modified as follows ... [Pg.129]

The Swiss law for water protection does not indicate a concentration hmit for aluminium in surface waters. Therefore, in order to better assess the measured aluminium concentrations, we compared them with the concentration limits existing in the US. The chronic US National Ambient Water Quality Criteria [19] for total aluminium at a pH of 6.5-9 is 87 pg 1, indicating that the average value over 4 days should not exceed this value more than once every 3 years. However, since aluminium seems to be more toxic at low pH s the result is that in acidic waters the acceptable chronic value of total aluminium may be even lower. We conclude that aluminium concentrations in our three most acid lakes are probably high enough to cause toxic effects on organisms. [Pg.130]

Liming an acidic lake is similar to the process many people use to maintain a pH balance in their soil for lawn maintenance. Plants have an optimum pH range in which they strive. Acidic conditions often develop in soils for several reasons. Rain tends to leach away basic ions, weak organic acids develop from the carbon dioxide produced by decaying organic matter, and strong acids, such as nitric acid, can form when ammonium fertilizers oxidize. To neutralize these acids, different forms of lime such as quicklime, CaO, and slaked lime, Ca(OH)2, are used to neutralize the acid and increase the pH of the soil. Table 13.9 shows how much fertilizer is wasted when applied to... [Pg.166]

Arctic char, Salvelinus alpinus] Austria acidic lake with 0.5 pg Pb/L kidney... [Pg.264]

About 25% of the Hg deposited to the terrestrial catchment is transported to the various lakes, probably in association with organic acids. Lakes with larger catchments (relative to their surface area) receive proportionally higher Hg loading. Among the seven lakes studied, between 40 and 80% of Hg inputs were made directly to the lake surface. [Pg.69]

In addition, aluminum ions (Al3+, AlOH2+, and AlOH2+) must be considered in some acidic lakes. Soluble Fe2+ and Mn2+ forms may contribute significantly to the ion balance in anoxic hypolimnia of some lakes. [Pg.142]

It has been estimated that 1.4-7.4 times as many streams in the eastern United States undergo episodic acidification than are chronically acidic (108). Similarly, the number of episodically acidic Adirondack lakes is estimated to be 3 times higher than the number of chronically acidic lakes (108). Wigington et al. (109) reported that acidic episodes occur in a wide range of geographic locations in the northeastern, southeastern, and western United States, as well as in Scandinavia, Europe, and Canada. [Pg.248]

Some evidence does exist that mechanisms other than atmospheric deposition contribute to N03" episodes, at least on a small scale. Rascher et al. (43), for example, showed that mineralization of organic matter in the soil during the winter months and subsequent nitrification contribute substantially to snowmelt N03 concentrations at one site in the Adirondacks. Schaefer and Driscoll (83) suggested that a similar phenomenon contributes to N03 pulses during snowmelt at 11 Adirondack lakes and that the contribution from mineralization is greater in low-ANC and acidic lakes. Murdoch and Stoddard (127) presented similar results for streams in the Catskill Mountains. Stottlemyer and Toczydlowski (184) also reported that mineralization contributes to snowmelt NO3" at a site on the upper peninsula of Michigan. It is not currently known how widespread this phenomenon is. [Pg.273]

Pore-water profiles are frequently interpreted according to this concept. For example, White et ah (35) described a conceptual model of biogeo-chemical processes of sediments in an acidic lake (cf. Figure 4). They discussed the numbered points in Figure 4 as follows Diffusion of dissolved oxygen across the sediment-water interface leads to oxidation of ferrous iron and to an enrichment of ferric oxide (point 1). Bacterial reductive dissolution of the ferric oxides in the deeper zones releases ferrous iron (point 2). The decrease in sulfate concentration stems from sulfate reduction, which produces H2S to react with ferrous iron to form mostly pyrite in the zone below the ferric oxide accumulation (point 3). [Pg.379]

Figure 4. A generalized profile of Fe and S chemistry in sediment pore waters from an acidic lake. Numbered points are discussed in the text. (Reproduced with permission from reference 35. Copyright 1989 American Geochemical... Figure 4. A generalized profile of Fe and S chemistry in sediment pore waters from an acidic lake. Numbered points are discussed in the text. (Reproduced with permission from reference 35. Copyright 1989 American Geochemical...
Acid rain primarily affects sensitive bodies of water, that is, those that rest atop soil with a limited ability to neutralize acidic compounds (called buffering capacity ). Many lakes and streams examined in a National Surface Water Survey (NSWS) suffer from chronic acidity, a condition m which water lias a constant low (acidic) pH level. The survey investigated tlie effects of acidic deposition in over 1,000 lakes larger than 10 acres and in thousands of miles of streams believed to be sensitive to acidification. Of the lakes and streams surveyed in the NSWS, arid rain has been determined to cause acidity in 75 percent of the acidic lakes and about 50 percent of tlie acidic streams. Several regions in the U.S. were identified as containing many of the surface waters sensitive to acidification. They include, but are not limited to, the Adirondacks. the mid-Appalachian highlands, the upper Midwest, and the high elevation West. [Pg.9]

Acidification is also a problem in surface wafer populations that were not surveyed in federal research projects. For example, although lakes smaller than 10 acres were not included in the NSWS. there are from one to four times as many of these small lakes as there are larger lakes. In the Adirondacks, tlie percentage of acidic lakes is significantly higher when it includes smaller lakes (26 percent) than when it includes only the target size lakes (14 percent). [Pg.9]

For example, approximately 70 percent of sensitive lakes in the Adirondacks are at risk of episodic acidification. This amount is over three limes the amount of chronically acidic lakes. In the mid-Appalachians, approximately 30 percent of sensitive streams are likely to become acidic during an episode. This level is seven times the number of chronically acidic streams in that area,... [Pg.9]

Among the many dramatic effects of acid rain are the extinction of fish from acidic lakes throughout parts of the northeastern United States, Canada, and Scandinavia, the damage to forests throughout much of central and eastern Europe, and the deterioration everywhere of marble buildings and statuary. Marble is a form of calcium carbonate, CaC03, and, like all metal carbonates, reacts with acid to produce C02. The result is a slow eating away of the stone. [Pg.365]

Heit M, Tan Y, Klusek C, et al. 1981. Anthropogenic trace elements and polycyclic aromatic hydrocarbon levels in sediment cores from two lakes in the Adirondack acid lake region. Water Air Soil Pollut 15 441-464. [Pg.147]

Collienne, R. H. 1983. Photoreduction of iron in the epilimnion of acidic lakes. Limnology and Oceanography 28 83-100. [Pg.208]

Sulzberger, B., J. L. Schnorr, R. Giovanoli, J. G. Hering, and J. Zobrist. 1990. Biogeochemistry of iron in an acidic lake. Aquatic Sciences 52 56-74. [Pg.213]


See other pages where Acid lakes is mentioned: [Pg.127]    [Pg.739]    [Pg.241]    [Pg.363]    [Pg.334]    [Pg.342]    [Pg.6]    [Pg.198]    [Pg.389]    [Pg.390]    [Pg.414]    [Pg.137]    [Pg.138]    [Pg.117]    [Pg.130]    [Pg.241]    [Pg.363]    [Pg.161]    [Pg.22]   
See also in sourсe #XX -- [ Pg.197 , Pg.198 ]




SEARCH



Acid mine drainage lakes

Acid mine waste lakes

Acid-sensitive lakes and streams

Acidic lake

Acidic lakes/ponds/water

Carbon acid mining lakes

Lakes dissolved free amino acids

Lakes fulvic acid

Mangrove Lake humic acids from sediments

Naphthalene sulfonic acid pigment lake

Weathering acidic lakes

Why are some lakes more acidic than others

© 2024 chempedia.info