NITRATE TRANSFORMATIONS IN SOUTHERN ONTARIO STREAM SEDIMENTS1 |
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Authors: | M. D. Wyer A. R. Hill |
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Affiliation: | 1. Graduate Student, Department of Geography, York University, Downsview, Ontario, Canada M3J 1P3.;2. Associate Professor, Department of Geography, York University, Downsview, Ontario, Canada M3J 1P3. |
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Abstract: | The transformation of nitrate was investigated in diverse stream sediments from six areas of Southern Ontario, Canada. Laboratory Experiments conducted with intact 0-5 cm depth sediment cores overlain with aerated 5 mg/l nitrate-N solution reveald considerable nitrate depletion during a six-day period as a resuit of denitrification and nitrate reduction to ammonium. Nitrification and ammonification also occurred simultaneously with nitrate reduction in many stream sediments. Mixed 0-5 cm depth sediments collected from 81 stream sites were used to examine the relationship between microbial nitrate removal and sediment characteristics. Rates of nitrate-N loss from aerated 5 mg/l nitrate-N solutions overlying these sediments ranged between 11 and 171 mg/m2/day for a 24-hour incubation period. Rates of nitrate loss for the 24-hour period exhibited a significant positive correlation (r=0.72) with sediment ammonium content. Organic carbon, total nitrogen and sediment texture also had significant but weak correlations with nitrate loss. |
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Keywords: | denitrification nitrate transformations sediments streams water quality. |
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