Elevated atmospheric CO[sub 2] increases microbial nitrogen-demand, but plants outcompete microbes for inorganic N

Conference · Wed Jun 01 04:00:00 EDT 1994 · Bulletin of the Ecological Society of America; (United States)

OSTI ID:7264938

Hungate, B A; Canadell, H; Zhong, H; Chapin, III, F S ^[1]; Holland, E A ^[2]

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1. Univ. of California, Berkeley, CA (United States)
2. National Center for Atmospheric Research, Boulder, CO (United States)

Soil microbial biomass C increased after 3 months of exposure to elevated atmospheric CO[sub 2] in serpentine and sandstone annual grasslands, but microbial biomass N did not change. We suggest that C:N ratio is plastic within the soil microbial community, shifting in response to the relative availability of C and N. The observed increases in C:N ratio indicates decreased C- and increased N-limitation of microbes, consistent with the increase in microbial N-immobilization we found for the same samples in laboratory incubations. When both plants and microbes were given equal access to 15NH4 in the field, however, plant uptake increased under elevated CO[sub 2], but microbial immobilization did not charge. This suggests that elevated CO[sub 2] increases plant N-demand more strongly than microbial N-demand.

• OSTI ID: 7264938
• Report Number(s): CONF-940894--
• Conference Information: Journal Name: Bulletin of the Ecological Society of America; (United States) Journal Volume: 75:2
• Country of Publication: United States
• Language: English

Related Subjects

560300* -- Chemicals Metabolism & Toxicology
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
AVAILABILITY
BIOLOGICAL EFFECTS
CARBON COMPOUNDS
CARBON DIOXIDE
CARBON OXIDES
CHALCOGENIDES
ECOLOGICAL CONCENTRATION
ELEMENTS
GROWTH
MICROORGANISMS
NITROGEN
NONMETALS
OXIDES
OXYGEN COMPOUNDS
PLANT GROWTH
PLANTS