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Nature and origins of acidity in bogs

Thesis/Dissertation ·
OSTI ID:5875514
To elucidate the causes of acidity in bogs, all of the processes generating and consuming acidity in a small peat bog in northern Minnesota were measured. These processes include ion exchange, plant nutrient uptake, atmospheric deposition, decomposition, organic acid production, sulfate reduction, and denitrification. Organic acid production was found to be the dominant source of acidity, responsible for the low pH of bog waters and the high acidity in the outflow. Net biological uptake (NBU) is the next largest source of acidity. Ion exchange accounts for only about 40% of the NBU-acidity. Plant uptake and ion exchange are much larger sources of acidity on an annual basis, but much of this acidity is neutralized by decomposition. Sulfate reduction and denitrification are quantitatively unimportant at this site because inputs (NO/sub 3//sup -/ and SO/sub 4/=) are low. Bog water samples and peat cores from bogs across northeastern North America were analyzed to determine if geographic trends in the rates of acidity-generating and -consuming processes exist. Rates of organic acid production varied little across the transect. Higher values of NBU-acidity were observed in maritime bogs than in midcontinental bogs. The effects of transformations of sulfur and nitrogen on the hydrogen-ion cycle were examined in detail. Nitrate appears to be taken up by bryophytes and little is lost to denitrification. Alkalinity from nitrate uptake is low. In contrast, there is a dynamic cycle of oxidation and reduction of sulfur within bogs. Inorganic forms of sulfur are not important storage pools in peat; 35% of the total sulfur input is accumulated as organic S.
Research Organization:
Minnesota Univ., Minneapolis (USA)
OSTI ID:
5875514
Country of Publication:
United States
Language:
English