Nitrogen budget of alpine and aeolian Rocky Mountain sites. Doctoral thesis

Technical Report · Tue Jan 01 04:00:00 EST 1985

OSTI ID:6111917

Boston, P J

Sources of nitrogen were measured for five Rocky Mountain sites including intrinsic biological N/sub 2/-fixation and atmospheric sources. Total snow, rain and dry deposition of nitrogen for a two-year period were extrapolated from direct measurements. Significant quantities of nitrogen come to these sites from external sources. Atmospheric inputs are higher than background levels for pristine areas. Agricultural and industrial sources undoubtedly contribute to this. Based on acetylene-reduction measurements (1982/1983 and 1983/1984 seasons), only 14-46% of yearly total nitrogen input was provided by biological fixation (as microbial biomass). Over half of the nitrogen (as NO/sup 3 -/ and NO/sup 4 +/) came from precipitation and dry deposition. The ultimate source may be either atmospherically fixed nitrogen or nitrogen biologically or industrially fixed elsewhere and transported to the sites by air movements. All sites are water-limited, particularly late in the growing season. This restricts microbial nitrogen fixation. Total bacterial counts are depressed by dryness. Snowpack melting inhibits densities of nitrogen fixers, nitrifiers, and denitrifiers at the barren sites. High-altitude sites are subject to wide fluctuations in all environmental parameters both seasonally and yearly. Long-term studies will be essential.

• Research Organization: National Center for Atmospheric Research, Boulder, CO (USA)
• OSTI ID: 6111917
• Report Number(s): PB-86-119914/XAB; NCAR/CT-90
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ALPS
ATMOSPHERIC CHEMISTRY
ATMOSPHERIC PRECIPITATIONS
CHEMISTRY
ECOLOGY
MICROORGANISMS
MOUNTAINS
NITROGEN CYCLE
NITROGEN FIXATION
RAIN
ROCKY MOUNTAINS