Acidity peat bogs

Figure 5. Comparison of TA100 mutagenic activities of XAD-2/ethyl ether extracts of treated water and chlorinated model compounds. O, treated water , amino acids A, humic acids (Fluka AG) , humic acids (aquatic) and A, humic acids (peat bogs). (Reproduced with permission from reference 16. Copyright 1986 Water Research Centre.)...

Archaeological remains are limited to skeletons in most areas of the world. However, where climatic or local conditions permit, dried tissues may be preserved in the form of mummies. Furthermore, wet sites such as peat bogs often yield macroscopically well-preserved material. However, the likelihood of retrieval of DNA is dependent on factors such as the pH of the water. Thus, acid peat bogs of Europe have yet to yield any DNA from human remains, whereas two samples from the neutral peat bogs of Florida5,6 have shown that DNA may be preserved in the presence of persistent standing water. The above materials yield DNA that goes back in time approximately 40,000 years. Theoretical considerations indicate that should be about the upper limit for the preservation of DNA when water is present.7 However, under some circumstances DNA may survive for several millions of years in plant compression fossils (the interested reader is referred to Refs. 8 and 9 for information on DNA from plant fossils). 

Terrestrial burial environments also are variable and may have microenvironments. Preserved wood is commonly found in acid peat bogs, but rarely found in shell middens. Is this because of different degradation rates or different use patterns of past human environments We have to be cautious in our interpretations. 

Bales of waste tyres have been used for many years in large construction projects, and this method of re-use was the subject of a report published by the UK Department of the Enviromnent, Food and Rural Affairs (DEFRA) in 2001 [74]. This report reviewed the international literature that was available on baled tyres, in particular the long-term behaviour and stability of the tyres and the metal that binds them together, when used in marine environments (e.g., artificial reefs), watery environments (e.g., flood defence or river management) or acid peat bogs, in order to assess their environmental impact. The scope of the review also included examining baled tyres encased in concrete. As dictated by the waste protocols, tyres may be baled... 

Analysis of pollen and spores preserved in acid soils and peat bogs has given rise to palynology. This approach is based on the assumption that the type of tree and plants growing in a particular terrestrial region are indicator of the climate. Morphological characteristics of the specimens are observed with the help of light and electron microscopes [64]. 

Gaud V., Disc N., and Fowler D. (2002) Controls on suppression of methane flux from a peat bog subjected to simulated acid rain sulfate deposition. Global Biogeochem. Cycles 16, 4-1-4-12. 

Decrease in alkalinity (acidification and cation depletion in soils) occurs whenever the production of organic matter (assimilation of NH ) is larger than the decomposition. This takes place, for example, when peat bogs or forest peats are formed these systems are very acidic. The harvest of crops on agricultural and forest land often causes discrepancies between production and decomposition. ... 

Volo Bog is a small, glaciated, sedge peat bog in northern Illinois. The bog has no surface inlet or outlet, and the water is at pH 4-5 with low nutrient concentrations. Saganashkee Slough drains into the Calumet Sag Channel and into the Des Plaines River in northern Illinois. It is at pH 7 and has a higher nutrient content than the bog. The Lake Bradford samples, collected near Tallahassee, Florida had a pH of 5-6. Humic and fulvic acids fi-om this lake have been used in radionuclide binding studies (18). The lake is fed by a spring and by surface runoff... 

Peat-bog waters have a great Insufficiency of calcium, they are strongly acidic and contain mostly humic substances and carbonic acids. In such waters, algae (Desmidiaceae), less frequently cyanobacteria Chroococcus turgidus) and protozoa Rhizopoda) can be found. 

When both acidic and anaerobic conditions prevail, as occurs in many peat bogs prior to drainage and cultivation, almost all decomposition can be stopped. In such cases the constant formation of organic acids and other end products of anaerobic decomposition, such as methane, hydrogen sulfide and hydrogen, suppress the growth of nearly all... 

A newly-reclaimed peat bog is usually an unsatisfactory medium in which to grow cultivated crops. The reasons include lack of aeration and oxidation, especially of the lower layers. Peat bogs have been under anaerobic conditions for centuries, and the roots of cultivated plants do not thrive in, or even penetrate, such an environment. This is due in part to lack of adequate oxygen, but often also to the presence of toxic amounts of such substances as ferrous iron, manganese compounds, sulfuric acid, and possibly soluble aluminum. Methane, hydrogen and sulfides are also likely to be present at least in traces initially, but are no longer formed when oxygen is abundant. 

Scientists have discovered the remains of dead organisms in peat bogs that are well preserved after hundreds or even thousands of years. Tannic acid, a compound found in peat bogs, slows the breakdown of the dead organisms tissues, although it usually destroys the DNA in the tissues. However, the DNA is protected from destruction if the area contains limestone, a mineral made of calcium carbonate (CaCOj). Explain how calcium carbonate protects DNA. (Hint Refer to Table 19-2 in your textbook.)... 

The Duluth-Superior Harbor (St. Louis River) contains HS from upstream peat bogs, which explains its tea-colored waters. The pH of its waters is also in the neutral range. Figure 32.12 (Stevenson, 1982) illustrates the range of colors associated with HS and how these colors are related to molecular weight, carbon content, oxygen content, acidity, and solubility. 

A type of wetland that accumulates peat deposits they are less acidic than bogs, deriving most of their water from groundwater rich in calcium and magnesium. 

Peat is formed when dead vegetation is saturated with water which prevents the action of aerobic bacteria. Thus, most of the carbon of the cellulosic matter is retained, and with ageing, peat is formed. It accumulates at an average rate of 0.7 mm/year or worldwide at 210 Mt of carbon. Canada (40%) and Russia (36%) have more than 3/4 of the world s peat land (320 Mha or 150 x 10 Mt of carbon). In Russia, peat deposits occupy about 1/10 of the total country s terrain. It is a spongy watery mass when first obtained from the peat bog. Six toimes of dry peat yield about 1 t of fuel. A commercial grade of peat contains about 25% water. Air-dried peat has a heating value of about 16.3 MJ/kg. Peat is rich in bitumens, carbohydrates, and humic acids, and as a chemical source, it can yield waxes, paraffins, resins, and oils. Peat also is a source of pharmaceutical and curative preparations as well as a livestock-feed supplement. 

The formation of soluble iron or fulvic acid chelates, represented in general as FeFA (Equation 9.8), has been shown to be responsible for soluble iron in runoff from humic-substance-rich peat bog leachate earrying iron into coastal seawater off North Scotland. ... 

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