Elevated atmospheric CO{sub 2}, soil microorganisms and the flow of N within the soil system

Journal Article · Thu Jun 01 04:00:00 EDT 1995 · Bulletin of the Ecological Society of America

OSTI ID:95851

Mikan, C J; Zak, D R; Randlett, D L ^[1]

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1. Univ. of Michigan, Ann Arbor, MI (United States)

Elevated atmospheric CO{sub 2} and soil N availability are potent modifiers of plant production and belowground allocation. In a recent experiment, we observed that fine-root production and turnover were greatest under elevated atmospheric CO{sub 2} and high soil N availability. We reasoned that greater belowground plant production under these conditions could alter soil C availability and the flow of N within the soil system. In a laboratory experiment, we used {sup 15}N to trace the flow of NH{sub 4}+ and NO{sub 3}- in the soils of Populus tremuloides grown under two levels of atmospheric CO{sub 2} (ambient and twice-ambient) and two levels of soil N availability (low and high). Gross and net rates of N mineralization as well as the N content of microbial biomass were not significantly influenced by atmospheric CO{sub 2}, but all displayed large differences related to soil N availability. Gross rates of nitrification differed significantly at ambient (205 ng g{sup -1} d{sup -1}) and twice-ambient (301 ng g{sup -1} d{sup -1}) CO{sub 2}. However, greater rates of gross nitrification under twice-ambient CO{sub 2} were offset by a significant increase in NO{sub 3}- immobilization, producing equivalent rates of net nitrification at ambient and twice-ambient CO{sub 2}. We found no evidence to suggest that greater rates of belowground plant production under elevated atmospheric CO{sub 2} will slow rates of N transformations in soil.

• OSTI ID: 95851
• Report Number(s): CONF-9507129--
• Journal Information: Bulletin of the Ecological Society of America, Journal Name: Bulletin of the Ecological Society of America Journal Issue: 2 Vol. 76; ISSN BECLAG; ISSN 0012-9623
• Country of Publication: United States
• Language: English

Related Subjects

54 ENVIRONMENTAL SCIENCES
56 BIOLOGY AND MEDICINE
APPLIED STUDIES
BIOLOGICAL AVAILABILITY
BIOLOGICAL EFFECTS
CARBON DIOXIDE
ECOLOGICAL CONCENTRATION
ENVIRONMENTAL EFFECTS
MICROORGANISMS
NITROGEN
NITROGEN CYCLE
SOILS