Distribution of Nitrogen Fixed in Desert Algal-Crusts1
- H. F. Mayland and
- T. H. McIntosh2
Fixation of isotopically labeled N2 by desert algal crust organisms was very rapid after initial wetting of crusts. After 8 days of incubation, a steady rate of fixation was reached which continued for 152 days.
The initial distribution of N was 4% extracellular NH4, 16% acid-hydrolyzable NH4 (included extracellular NH4), 41% α amino acid, 4% hexosamine, 29% acid-hydrolyzable but unidentified, and 11% non-hydrolyzable. After 21 days of incubation the distribution of total N was 2, 18, 42, 2, 29 and 11%, respectively. The distribution of excess N15 after 21 days of incubation was trace, 12, 51, 2, 29 and 7% for the respective fractions. Continued incubation had little effect on the relative distribution of N in the several fractions.Please view the pdf by using the Full Text (PDF) link under 'View' to the left.
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