Soil, plant, and transport influences on methane in a subalpine forest under high ultraviolet irradiance

Abstract. Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH4 was high, with observed values in the range 1790 to 1910 nmol mol−1. High CH4 was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soils were moderately dry during the study. Vertical gradients of CH4 were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH4 sink. Using scalar similarity with CO2, the magnitude of the summer soil CH4 sink was estimated at ~1.7 mg CH4 m−2 h−1, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m−2. Gradients and means of CO2 within the canopy under daytime conditions showed net uptake of CO2 due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH4 source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season.

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Soil and plant contributions to the methane flux balance of a subalpine forest under high ultraviolet irradiance

Biogeosciences Discussions ◽

10.5194/bgd-6-4765-2009 ◽

2009 ◽

Vol 6 (3) ◽

pp. 4765-4801

Author(s):

D. R. Bowling ◽

J. B. Miller ◽

M. E. Rhodes ◽

S. P. Burns ◽

R. K. Monson ◽

...

Keyword(s):

Methane Flux ◽

High Elevation ◽

Subalpine Forest ◽

Atmospheric Methane ◽

Vegetation Canopy ◽

Conifer Forest ◽

Uv Irradiance ◽

Plant Foliage ◽

Net Uptake ◽

Ultraviolet Irradiance

Abstract. Recent studies have demonstrated direct methane emission from plant foliage under aerobic conditions, particularly under high ultraviolet (UV) irradiance. We examined the potential importance of this phenomenon in a high-elevation conifer forest using micrometeorological techniques. Vertical profiles of methane and carbon dioxide in forest air were monitored every 2 h for 6 weeks in summer 2007. Day to day variability in above-canopy CH4 was high, with observed values in the range 1790 to 1910 nmol mol−1. High CH4 was correlated with high carbon monoxide and related to wind direction, consistent with pollutant transport from an urban area by a well-studied mountain-plain wind system. Soil moisture was moderately dry during the study. Vertical gradients of CH4 were small but detectable day and night, both near the ground and within the vegetation canopy. Gradients near the ground were consistent with the forest soil being a net CH4 sink. Using scalar similarity with CO2, the magnitude of the summer soil CH4 sink was estimated at ~1.7 mg CH4 m−2 h−1, which is similar to other temperate forest upland soils. The high-elevation forest was naturally exposed to high UV irradiance under clear sky conditions, with observed peak UVB irradiance >2 W m−2. Gradients and means of CO2 within the canopy under daytime conditions showed net uptake of CO2 due to photosynthetic drawdown as expected. No evidence was found for a significant foliar CH4 source in the vegetation canopy, even under high UV conditions. While the possibility of a weak foliar source cannot be excluded given the observed soil sink, overall this subalpine forest was a net sink for atmospheric methane during the growing season.

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Postglacial vegetation dynamics at high elevation from Fairy Lake in the northern Greater Yellowstone Ecosystem, Montana, USA

Quaternary Research ◽

10.1017/qua.2019.9 ◽

2019 ◽

Vol 92 (2) ◽

pp. 365-380 ◽

Cited By ~ 1

Author(s):

James V. Benes ◽

Virginia Iglesias ◽

Cathy Whitlock

Keyword(s):

Fire History ◽

Late Glacial ◽

High Elevation ◽

Subalpine Forest ◽

Greater Yellowstone Ecosystem ◽

Southwestern Montana ◽

History Of ◽

Greater Yellowstone ◽

High Elevations ◽

Early Late

AbstractThe postglacial vegetation and fire history of the Greater Yellowstone Ecosystem is known from low and middle elevations, but little is known about high elevations. Paleoecologic data from Fairy Lake in the Bridger Range, southwestern Montana, provide a new high-elevation record that spans the last 15,000 yr. The records suggest a period of tundra-steppe vegetation prior to ca. 13,700 cal yr BP was followed by open Picea forest at ca. 11,200 cal yr BP. Pinus-Pseudotsuga parkland was present after ca. 9200 cal yr BP, when conditions were warmer/drier than present. It was replaced by mixed-conifer parkland at ca. 5000 cal yr BP. Present-day subalpine forest established at ca. 2800 cal yr BP. Increased avalanche or mass-wasting activity during the early late-glacial period, the Younger Dryas chronozone, and Neoglaciation suggest cool, wet periods. Sites at different elevations in the region show (1) synchronous vegetation responses to late-glacial warming; (2) widespread xerothermic forests and frequent fires in the early-to-middle Holocene; and (3) a trend to forest closure during late-Holocene cooling. Conditions in the Bridger Range were, however, wetter than other areas during the early Holocene. Across the Northern Rockies, postglacial warming progressed from west to east, reflecting range-specific responses to insolation-driven changes in climate.

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Attributes of Atmospheric Carbon Monoxide Oxidation by Maine Forest Soils

Applied and Environmental Microbiology ◽

10.1128/aem.65.12.5257-5264.1999 ◽

1999 ◽

Vol 65 (12) ◽

pp. 5257-5264 ◽

Cited By ~ 34

Author(s):

G. M. King

Keyword(s):

Co Oxidation ◽

Forest Soils ◽

Inhibitory Effect ◽

Atmospheric Methane ◽

Methyl Fluoride ◽

Co Concentration ◽

Net Uptake ◽

Atmospheric Carbon Monoxide ◽

Nitrite Inhibition ◽

Water Contents

ABSTRACT CO, one of the most important trace gases, regulates tropospheric methane, hydroxyl radical, and ozone contents. Ten to 25% of the estimated global CO flux may be consumed by soils annually. Depth profiles for 14CO oxidation and CO concentration indicated that CO oxidation occurred primarily in surface soils and that photooxidation of soil organic matter did not necessarily contribute significantly to CO fluxes. Kinetic analyses revealed that the apparentKm was about 18 nM (17 ppm) and theV max was 6.9 μmol g (fresh weight)−1 h−1; the apparentKm was similar to the apparentKm for atmospheric methane consumption, but theV max was more than 100 times higher. Atmospheric CO oxidation responded sensitively to soil water regimes; decreases in water content in initially saturated soils resulted in increased uptake, and optimum uptake occurred at water contents of 30 to 60%. However, extended drying led to decreased uptake and net CO production. Rewetting could restore CO uptake, albeit with a pronounced hysteresis. The responses to changing temperatures indicated that the optimum temperature for net uptake was between 20 and 25°C and that there was a transition to net production at temperatures above 30°C. The responses to methyl fluoride and acetylene indicated that populations other than ammonia oxidizers and methanotrophs must be involved in forest soils. The response to acetylene was notable, since the strong initial inhibition was reversed after 12 h of incubation; in contrast, methyl fluoride did not have an inhibitory effect. Ammonium did not inhibit CO uptake; the level of nitrite inhibition was initially substantial, but nitrite inhibition was reversible over time. Nitrite inhibition appeared to occur through indirect effects based on abiological formation of NO.

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Comparisons of Estimated Economic Burdens due to Insufficient Solar Ultraviolet Irradiance and Vitamin D and Excess Solar UV Irradiance for the United States

Photochemistry and Photobiology ◽

10.1562/2005-01-24-ra-424 ◽

2005 ◽

Vol 81 (6) ◽

pp. 1276 ◽

Cited By ~ 77

Author(s):

William B. Grant ◽

Cedric F. Garland ◽

Michael F. Holick

Keyword(s):

United States ◽

Vitamin D ◽

The United States ◽

Uv Irradiance ◽

Solar Uv ◽

Ultraviolet Irradiance ◽

Solar Uv Irradiance ◽

Solar Ultraviolet

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The contribution of beneath-snow soil respiration to total ecosystem respiration in a high-elevation, subalpine forest

Global Biogeochemical Cycles ◽

10.1029/2005gb002684 ◽

2006 ◽

Vol 20 (3) ◽

pp. n/a-n/a ◽

Cited By ~ 72

Author(s):

Russell K. Monson ◽

Sean P. Burns ◽

Mark W. Williams ◽

Anthony C. Delany ◽

Michael Weintraub ◽

...

Keyword(s):

Soil Respiration ◽

Ecosystem Respiration ◽

High Elevation ◽

Subalpine Forest ◽

Total Ecosystem Respiration

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The Temporal Dynamics of Carbon Dioxide under Snow in a High Elevation Rocky Mountain Subalpine Forest and Meadow

Arctic Antarctic and Alpine Research ◽

10.1657/1523-0430(2005)037[0527:ttdocd]2.0.co;2 ◽

2005 ◽

Vol 37 (4) ◽

pp. 527-538 ◽

Cited By ~ 27

Author(s):

R. C. Musselman ◽

W. J. Massman ◽

J. M. Frank ◽

J. L. Korfmacher

Keyword(s):

Carbon Dioxide ◽

Temporal Dynamics ◽

Rocky Mountain ◽

High Elevation ◽

Subalpine Forest

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Carbon sequestration in a high-elevation, subalpine forest

Global Change Biology ◽

10.1046/j.1365-2486.2002.00480.x ◽

2002 ◽

Vol 8 (5) ◽

pp. 459-478 ◽

Cited By ~ 279

Author(s):

R. K. Monson ◽

A. A. Turnipseed ◽

J. P. Sparks ◽

P. C. Harley ◽

L. E. Scott-Denton ◽

...

Keyword(s):

Carbon Sequestration ◽

High Elevation ◽

Subalpine Forest

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Effect of clear cutting on nutrient fluxes in a subalpine forest at Fraser, Colorado

Hydrology and Earth System Sciences ◽

10.5194/hess-1-333-1997 ◽

1997 ◽

Vol 1 (2) ◽

pp. 333-344 ◽

Cited By ~ 16

Author(s):

J. O. Reuss ◽

R. Stottlemyer ◽

C. A. Troendle

Keyword(s):

Nitrogen Loss ◽

Water Flux ◽

Base Cations ◽

High Elevation ◽

Control Plot ◽

Subalpine Forest ◽

Nutrient Fluxes ◽

Exchange Reactions ◽

Clear Cutting ◽

Nitrogen Inputs

Abstract. Nutrient fluxes were investigated on a forested and a clearcut plot in a mixed conifer high elevation (2900 m) forest at the Fraser Experimental Forest in Fraser, Colorado, USA. Plots were located on a coarse loamy mixed Dystric Cryochrept with relatively high base saturation (30-90%) and underlain by an impermeable clay subsoil. Following harvest in late 1984, annual mean NO3 concentrations of 195 to 198 μmol l-1 were observed from 1988 through 1990 and concentrations were still above reference levels in 1993. Total nitrogen loss attributable to leaching following harvest was estimated at 48kg ha-1 over 8 years. Over this same period, atmospheric nitrogen inputs exceeded annual outflow of NH4 plus NO3 from the control plots by approximately 11 kg N ha-1. A slight enrichment Of SO4 and Cl was observed from the harvested plot in 1986 but concentrations later fell below control plot levels, apparently due to dilution by the increased discharge from the harvested plot which was three to four times that from the control plot. Elevated Ca, Mg, and Na concentrations followed a similar pattern to NO3 due to exchange reactions, while a depression in alkalinity of about one-third the amount of NO3 found was also observed. Enrichment of K occurred primarily in water collected at less than 1 m depth. Increases in base cation loss due to leaching after harvest were about twice the amount that can be accounted for by the increased flux of NO3, SO4, and Cl anions. The excess reflects the increased water flux and consequent leaching of base cations in association with HCO3 and organic anions.

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Effect of clear cutting on snow accumulation and water outflow at Fraser, Colorado

Hydrology and Earth System Sciences ◽

10.5194/hess-1-325-1997 ◽

1997 ◽

Vol 1 (2) ◽

pp. 325-332 ◽

Cited By ~ 20

Author(s):

C. A. Troendle ◽

J. O. Reuss

Keyword(s):

High Elevation ◽

Snow Accumulation ◽

Conifer Forest ◽

Mixed Conifer ◽

Post Harvest ◽

Clear Cutting ◽

Mixed Conifer Forest ◽

The Mean ◽

Zero Discharge ◽

Water Outflow

Abstract. This paper compares of snowpack accumulation and ablation, evapotranspiration, and water outflow from clearcut and forested plots within a high elevation (2900 m) mixed conifer forest at the Fraser Experimental Forest near Fraser, Colorado, USA. Also presented is a method for defining contributing area where outflow is measured from unbounded plots. Plots were monitored from 1980 to 1990 and again in 1993. The clearcut plot was harvested in late 1984. Evapotranspiration (ET) of the forested plot at zero discharge (ETo) was estimated at 426 mm while the ET was 500 mm at the mean precipitation of 596 mm. ET was dependent on precipitation with about 28% of precipitation input in excess of 426 mm contributing to increased ET, while the remainder contributed to increased outflow. During the six monitored post-harvest years, Peak Water Equivalent of the snowpack averaged 36% higher on the cut plot than on the control, and the mean discharge increased from 85 mm to 356 mm. Area estimates were obtained from the slopes of the regression of outflow on precipitation inputs. Hydrologic parameters corresponded closely to those previously determined at Fraser Experimental Forest using other methods, lending credence to the validity of the area estimates.

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