Evaluation of simulated acid precipitation effects on forest microcosms. Final report
Microcosms were treated for a 30-month period with simulated precipitation acidified to four pH levels (5.7, 4.5, 4.0, and 3.5) to evaluate the impact of acid precipitation on foliar leaching, plant nutrient content, soil leaching, soil nutrient content, and litter decomposition. Direct effects of acid precipitation on diameter growth, bud break, leaf senescence, chlorophyll content, stomatal size, stomatal density, photosynthesis, respiration, transpiration, and cuticle erosion were evaluated on tulip poplar, white oak, and Virginia pine seedlings growing as mixed stands in the microcosms. None of the plant physiological or morphological parameters evaluated responded in a statistically significant manner as a result of treatment. A significant treatment canopy interaction was observed in the form of a 60 percent increase in calcium input in throughfall in response to the pH 3.5 treatment. Foliar nutrient content did not change in response to treatment nor did field measurements of decomposer activity. Soil analysis indicated a significantly lower concentration of exchangeable calcium and magnesium in the top 3.5 cm of the mineral soil in association with the pH 3.5 treatment. Soil leachate concentrations exhibited significant increases at both the 25 and 50 cm depths. However, at the 100 cm depth no significant response in concentration or elemental loss from the system was observed. Laboratory respiration measurements indicated a small, but statistically significant reduction in decomposer activity in the lower litter (02) horizon. This reduction was masked in the field measurements of decomposer activity due to the relatively small contribution of the 02 to total soil respiration. 38 references, 12 figures, 18 tables.
- Research Organization:
- Tennessee Valley Authority, Muscle Shoals, AL (USA). Div. of Air and Water Resources
- OSTI ID:
- 6827908
- Report Number(s):
- EPRI-EA-3500; ON: TI84920329
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
ACID RAIN
BIOLOGICAL EFFECTS
SIMULATION
FOREST LITTER
DECOMPOSITION
FORESTS
MICROCOSMS
LEAVES
LEACHING
SOILS
AMMONIA
BUDS
CALCIUM
CHLORIDES
CHLOROPHYLL
MAGNESIUM
NITRATES
NUTRIENTS
OAKS
PH VALUE
PHOSPHATES
PHOTOSYNTHESIS
PINES
POTASSIUM
STOMATA
SULFATES
TRANSPIRATION
TREES
ALKALI METALS
ALKALINE EARTH METALS
ATMOSPHERIC PRECIPITATIONS
BIOLOGICAL MATERIALS
CARBOXYLIC ACIDS
CHEMICAL REACTIONS
CHLORINE COMPOUNDS
CONIFERS
DISSOLUTION
ELEMENTS
HALIDES
HALOGEN COMPOUNDS
HETEROCYCLIC ACIDS
HETEROCYCLIC COMPOUNDS
HYDRIDES
HYDROGEN COMPOUNDS
MATERIALS
METALS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
OPENINGS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHORUS COMPOUNDS
PHOTOCHEMICAL REACTIONS
PHYTOCHROMES
PIGMENTS
PLANTS
PORPHYRINS
RAIN
SEPARATION PROCESSES
SULFUR COMPOUNDS
SYNTHESIS
500200* - Environment
Atmospheric- Chemicals Monitoring & Transport- (-1989)
510200 - Environment
Terrestrial- Chemicals Monitoring & Transport- (-1989)
560303 - Chemicals Metabolism & Toxicology- Plants- (-1987)