Acid rain and soil microbial activity: effects and their mechanisms

Journal Article · · J. Environ. Qual.; (United States)

DOI:https://doi.org/10.2134/jeq1983.00472425001200010024x· OSTI ID:6446822

Killham, K; Firestone, M K; McColl, J G

In this investigation, the aim was to determine if acid rain affects soil microbial activity and to identify possible mechanisms of observed effects. A Sierran forest soil (pH 6.4) planted with Ponderosa pine seedings was exposed to simulated rain (pH 2.0, 3.0, 4.0, and 5.6) with ionic composition reflecting that found in northern California, corresponding to 15 cm of precipitation over a 12-week period. After exposure, the soils were collected in two samples (top 1 cm and 4 to 5 cm), which were assayed separately for respiration and enzyme activities (urease, phosphatase, dehydrogenase, and arylsulfatase). Changes in microbial activity were most significant in surface soils. Only the pH 2.0 input caused inhibition of both respiration and enzyme activities. The overall microbial response to the pH 3.0 and 4.0 acid regimes was one of simulation, although the response of individual enzymes was more varied. In surface soils receiving the pH 3.0 input, for example, urease activity was unaffected while arylsulfatase and phosphatase were increased and decreased respectively. Therefore, individual microbial processes will have different sensitivities to acid rain. Although changes in C-availability in the exposed soils are documented, changes in the supply of N are evaluated as the major mechanism through which simulated acid rain affects soil microbial activity.

• Research Organization: Univ. of California, Berkeley
• OSTI ID: 6446822
• Journal Information: J. Environ. Qual.; (United States), Journal Name: J. Environ. Qual.; (United States) Vol. 12:1; ISSN JEVQA
• Country of Publication: United States
• Language: English

Related Subjects

500200* -- Environment
Atmospheric-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
ACID RAIN
AMIDINASES
ATMOSPHERIC PRECIPITATIONS
BIODEGRADATION
BIOLOGICAL EFFECTS
CARBON
CHEMICAL REACTIONS
CONIFERS
DECOMPOSITION
ECOSYSTEMS
ELEMENTS
ENZYMES
ESTERASES
FORESTS
HYDROLASES
NITROGEN
NON-PEPTIDE C-N HYDROLASES
NONMETALS
OXIDOREDUCTASES
PH VALUE
PHOSPHATASES
PINES
PLANTS
RAIN
SEEDLINGS
SIMULATION
SOILS
TERRESTRIAL ECOSYSTEMS
TREES
UREASE