\log
The initial iteration of the documentation section of this file
and the 1992 data were provided by Lesley Smith on 24 June 1994.
Additional revisions were made to the documentation section by
RCI and the file was put under sccs control on 27 June 1994.[RCI
27 June 1994] Additional comments and revisions provided by LS
on 29 June 1994 were incorporated into the documentation section
on 1 July 1994.[RCI 1 July 1994] Trace gas plot locations surveyed
by Tim Bardsley and Mike Hartman on 6 July 1994 were added to the
comments section on 14 July 1994.[RCI 14 July 1994] A description
of the methods used was provided by Steve Schmidt on 15 July 1994
and this information and the associated citation were incorporated
into the documentation section on 20 July 1994.[RCI 20 July 1994]
Fertilization plot locations surveyed by Tim Bardsley and Mike
Hartman on 13 July and 7 September 1994 were added to the comments
section on 14 September 1994.[RCI 14 September 1994] It was determined
by Ann West that data for several of the plots from 30 July 1992
were mislabeled, and that all T1W records for that day should be
T2W, all T2W records for that day should be T3W, and that all
T3W records for that day should be T1W. The appropriate changes
were made to the data section on 21 December 1995.[MAH 21 December
1995] URL locations for related data were updated on 27 September
2000.[MAH 27 September 2000]
\doc
TITLE. Trace gas emissions from alpine tundra soils: Methane flux
data.
ABSTRACT. Trace gas samples were collected from 3 alpine tundra
vegetation community types (dry meadow, moist meadow, wet meadow)
on Niwot Ridge during the summer months of 1992 and 1993.
In addition, samples were collected from a set of control and
nitrogen amended plots in both dry and wet meadow community types.
Soil temperatures were measured in conjunction with the trace gas
sampling. Methane fluxes were calculated from the gas concentration
data.
INVESTIGATOR. Lesley Smith, EPOB, Campus Box 334, University of
Colorado, Boulder, CO 80309-0334, smithlk@spot.colorado.edu.
VARIABLES. methane emission.
KEYWORDS. methane, emission, Biogeochemistry, soil and microbial pools and fluxes.
LOCATION. The study sites were located on the Niwot Ridge Saddle.
Original data are stored in Ramaley Hall.
TIMING. begin 8 June 1992, end 18 August 1993, weekly to biweekly
(between 0900 and 1300 hrs) during the summer months.
CITATIONS. [1]Matson, P.A., S.T. Gower, C. Volkmann, C. Billow, and C.C.
Grier. 1992. Soil nitrogen cycling and nitrous oxide flux in a Rocky
Mountain Douglas-fir forest: effects of fertilization, irrigation, and
carbon addition. Biogeochemistry 18: 101-117.
COMMENTS. The raw source data for the reduced data contained in this
file can be found in the files:
http://culter.colorado.edu:1030/exec/.extracttoolA?tracegas.ss
http://culter.colorado.edu:1030/exec/.extracttoolA?soiltemp.ss
Methane fluxes were calculated as follows:
Using Lotus 1-2-3 software, a linear regression of methane concentration
(ppm) versus time (minutes) was calculated for each sample box. The
resultant r^2 was tested for significance. If the r^2 was not significant,
the corresponding data were screened for outliers, and these data were
excluded from subsequent regressions. The data immediately following
(date, plot/base number code, time code, replicate number) ultimately
were excluded from the final regressions:
090692,T1M1,T3,1
090692,T1M1,T2,2
090692,T1M3,T2,2
090692,T2M2,T1,1
090692,T2M4,T1,2
090692,T2M4,T3,2
160692,T1D1,T1,2
160692,T2D2,, {not enough data to calculate regression}
160692,T3D1,T3,1
160692,T3D4,T3,2
230692,T3M2,T3,1
240692,T2M4,T0,1
240692,T2M4,T1,1
240692,T3M2,T1,2
300692,T1D2,T3,2
300692,T1D3,T2,2
300692,T1D4,T1,1
300692,T1D4,T3,1
300692,T2D4,T3,1
300692,T3D3,T2,2
300692,T3D4,T3,1
300692,T3D4,T3,2
010792,T1M2,T0,1
010792,T2M1,T2,2
010792,T2M3,T2,1
010792,T2M4,T0,1
070792,T1W1,T2,1
070792,T1W2,T0,2
140792,T1D1,T0,2
140792,T1D3,T0,2
140792,T2D2,T2,1
150792,T1M3,T2,1
16-792,T2W4,T3,1
270792,T1D4,T3,1
270792,T2D1,T3,1
290792,T2M4,T2,2
290792,T3M2,T3,2
290792,T3M3,T0,1
300792,T2W4,T3,1
110892,T2M3,T0,1
110892,T3M1,T0,2
120892,T3D1,T2,1
250892,T3D3,T3,1
250892,T3D3,T3,2
250892,T3D4,T3,1
250892,T3D4,T3,2
260892,T1M3,T1,1
270892,T2W3,T1,1
270892,T3W1,T0,1
300992,BDN4,T2,2
Fluxes of methane and nitrous oxide are collected during non-
snow covered periods from static chambers (Matson et al. 1992).
These chambers consist of 25-cm diameter PVC rings (bases) that
are 20 cm tall with a detachable ABS (acrylonitrile-butadiene-styrene)
plastic cover. The ABS cover was fitted with a single injection
port and another small port to equalize pressure during
sampling. Once the chambers were sealed, duplicate gas samples
were removed through a septum with 10-cm^3 gas-tight glass syringes
equipped with 3-way stopcocks. Gas samples were collected every
45 minutes over a 3-hour period. Samples were analyzed on gas
chromatographs.
Plot/base number codes ending with the character 'A' are for air
samples; they were not associated with specific base numbers.
The initial character in the plot/base number code is either 'T'
(transect) or 'B' (Bowman plots). The second character in the
plot/base number code is either '1', '2', or '3' (transect number)
if the initial character is a 'T', or 'D', 'M', or 'W' (community
type, i.e., dry, moist, or wet meadow) if the initial character
is 'B'. The third character in the plot/base number code is either
'D', 'M', or 'W' (community type) if the initial character is a
'T', or 'C' (control) or 'N' (nitrogen amended) if the initial
character is a 'B'. The fourth character in the plot/base number
code is the base number.
A regression was then rerun and checked for significance. If it
was still not significant, the flux was assumed to be zero. If
it was significant, the flux was calculated as follows:
(2.807.7)((P/760)/(T+273.15))(Ht)(slope)=mg CH4 m-2 d-1, where
P=barometric pressure in millibars, T=air temperature in degrees
Celsius, Ht=height of sample box (16 cm), and slope is the slope
of the line derived from the regression (ppm CH4/minute). This
equation was derived from the following relationships.
To convert ppm CH4 min-1 to molecules CH4 cm-2 min-1: n=((Y)
(1x10-6)ppm/min)(6.023x10^23 molecules/mole)[(P/760)/(82.06
cm3.atm/mol.K)(T + 273.15 K)](Ht), where Y=slope of line derived
from regression equation. Let Z=((P/760)/(T + 273.15))(Ht)(slope).
Therefore, n=7.34x10^15 molecules/cm2 s * Z. To convert molecules
CH4 cm-2 min-1 to mg CH4 m-2 d-1: (7.34x10^15 molecules/cm2 min)
(1 mole/6.023x10^23 molecules)(100^2 cm2/m2)(1440 min/d)
(16 g CH4/mole CH4)(1000 mg/g)=2807.7 * Z.
Tim Bardsley and Mike Hartman conducted a rudimentary survey of some of
the more heavily used NWT LTER research plots in 1994 in order to
reference the plots to established objects/points on Niwot Ridge.
A Silva Ranger compass was used with E declination set at 12 degrees;
the accuracy of the bearings is +/- 3 degrees. All distances were
measured across the ground surface (not at a fixed horizontal level);
such distances are accurate to +/- 2%. Each trace gas plot consisted
of an area (with an undefined outer boundary) of comparatively
heterogeneous composition (with respect to plant species composition,
or plant community type). Bearings and distances were from fixed
points of reference to the approximate center of the plots (i.e., the
center of the bases within the plot). In some cases (T1D, T2D, T1M,
T1W), bearings were taken from the approximate center of the plot to
a fixed reference point, usually because the plots were not visible
from the fixed reference point. In such cases, the reverse bearing
was calculated and, for the sake of consistency, is listed below.
The original Bardsley/Hartman field notes contain crude diagrams
indicating the relative orientation of and distances between the
bases within a plot; bases were generally within 4 m of the center
of the plot. This information is not reported here but these notes
are on file with the NWT LTER data manager. The plot code, bearing
(degrees) from indicated reference point to center of plot,
distance (meters) from indicated reference point to center of the
plot, and number of bases in plot follow:
T1D,192 (wind turbine centerline),146.1 (wind turbine SW corner),4
T2D,30 (Saddle grid stake 60A),28.60 (Saddle grid stake 60A),4
T3D,40 (Saddle grid stake 78),50.5 (Saddle grid stake 78),5
T1M,254 (wind turbine centerline),48.8 (wind turbine SW corner),4
T2M,87 (Saddle grid stake 59),24.25 (Saddle grid stake 59),4
T3M,41 (Saddle grid stake 77),33.44 (Saddle grid stake 77),8
T1W,220 (wind turbine centerline),153.20 (wind turbine SW corner),4
T2W,230 (Saddle grid stake 67),17.3 (Saddle grid stake 67),4
T3W,25 (Saddle grid stake 77),23.20 (Saddle grid stake 77),4
The fertilized wet meadow plots were surveyed on 13 July 1994 using
the same methodology. The bearing from the northwest corner of the c1
wet meadow plot to the centerline of the wind turbine was 202 degrees.
Thus, the bearing from the centerline of the wind turbine to the
northwest corner of the c1 wet meadow plot was 22 degrees. The
distance form the northwest corner of the c1 wet meadow plot to the
southwest corner of the base of the wind turbine was 278.2 meters. A
crude map of the relationships among the dry meadow plots was provided
by Bill Bowman and that map is on file with the LTER data manager.
Plot n1 was oriented west and south of c1. Plot np1 was approximately
due south of c1. The following plots were approximately due west of
np1 (with the most proximal listed first): np2, p1, c2, p2, c3, p3, c4,
np4, and c5. The bearing from the northwest corner of c1 to the
northwest corner of c5 was 309 degrees. South of this row, and oriented
approximately from west to east were plots n2, n3, np5, np4, n4, np3,
n5, and p5. The plots n2, n5, and p5 were slightly out of line with the
other plots in the row; the bearings from the northwest corner of c1 to
the northwest corner of these plots were 292, 249, and 239 degrees,
respectively. Note that a band of willows (approximately L-shaped)
separates plots n5 and p5 from c2, p1, and np2. The distances (meters)
reported below are between the northwest corner of c1 and the northwest
corner of the given plot:
n1,3.55
np1,3.27
np2,6.19
p1,8.51
c2,12.65
p2,15.59
c3,18.84
p3,22.75
c4,24.89
p4,27.09
c5,29.55
n2,32.39
n3,28.45
np5,26.20
np4,23.63
n4,19.95
np3,15.55
n5,15.00
p5,16.75
Tim Bardsley and Mike Hartman conducted a rudimentary survey of the
fertilized dry meadow plots on 7 September 1994. A less sophisticated
compass was used for this survey and, consequently, all bearings
reported below are for magnetic, not true, north; a declination of
11.5 degrees should be added to the former to convert to the latter.
The bearing from the northeast corner of the c1 dry meadow plot to
the centerline of the wind turbine was 345 degrees. Thus, the
bearing from the centerline of the wind turbine to the northeast
corner of the c1 dry meadow plot was 165 degrees. The distance from
the northeast corner of the c1 dry meadow plot to the southwest
corner of the base of the wind turbine was 231.0 meters. The bearings
(degrees) and distances (meters) reported below are from the
northeast corner of the c1 dry meadow plot to the northeast corner of
the given plot:
np1,259,3.37
p1,178,3.12
n1,209,6.90
np2,192,10.46
p2,212,10.83
c2,222,12.20
n2,239,13.58
n3,232,17.41
np3,246,19.26
c3,199,31.47
p3,211,31.62
c4,214,32.50
np4,221,33.41
p4,228,34.60
c5,232,36.48
n4,234,39.07
p5,206,35.55
n5,207,37.74
np5,205,39.20
Note that the plot code nomenclature used in the surveys is slightly
different than the plot code nomenclature used elsewhere in this
file. The code BDN4, for example, would be equivalent to n4 in the
second of the 2 listings for the fertilized plot locations above.
This research was supported by the Environmental Protection
Agency (R819448-01-1).
Other trace gas data can be found in the files:
http://culter.colorado.edu:1030/exec/.extracttoolA?fertflux.jn
http://culter.colorado.edu:1030/exec/.extracttoolA?methemis.ls
http://culter.colorado.edu:1030/exec/.extracttoolA?subnflux.pb
http://culter.colorado.edu:1030/exec/.extracttoolA?tracegas.ss
\type
statistical.
\header
COL1. label=plot/base number code, type=string, units=none, missing
value indicator, minimum=, maximum=, precision=
COL2. label=date(ddmmyy), type=string, units=none, missing value
indicator=, minimum=0800692, maximum=, precision=
COL3. label=methane flux, type=real, units=mg/m2*d, missing value
indicator=99.99, minimum=-1.63, maximum=18.46, precision=+/-2%
{*********************************************************************
If the data section below contains no data then you will need to
obtain permission from the investigator listed in the documentation
section of this file. If you have obtained permission or if the data
are already contained in this file, include the following
acknowledgment (in addition to an acknowledgment of the investigator)
in any published use of these data: "Logistical support
and/or data were provided by the Niwot Ridge Long-Term Ecological
Research project (NSF DEB 0423662) and the Mountain Research Station
(BIR 9115097)." Please send 4 reprints or high-quality copies of any
such publications to Todd Ackerman, NWT LTER data manager,
INSTAAR, CB 450, University of Colorado, Boulder, CO, 80309-0450.
The data contained in these files have many sources. Generally,
data collected prior to 1993 would have been subjected to quality
control standards imposed by the investigator. Data after 1992
were likely to have been manually entered and/or processed in the
NWT LTER central data management laboratory. Detailed information
on the quality control protocols and programs associated with any
data routed through the NWT LTER data management laboratory will
be supplied upon request. The user of these data should be aware
that, while efforts have been taken to ensure that these data are
of the highest quality, there is no guarantee of perfection for
the data contained herein and the possibility of errors exists.
If you encounter questionable data, please contact the NWT LTER
data manager (todda@culter.colorado.edu; (303) 492-4771) so that
the data can be corrected or qualified. Thus, these data should
be considered dynamic in that past data may be modified and future
data will be appended.
******************************************************************}
\data
T1D1,080692,-0.15
T1D2,080692,-0.21
T1D3,080692,-0.35
T1D4,080692,-0.45
T2D1,080692,-0.38
T2D2,080692,-0.46
T2D3,080692,-0.34
T2D4,080692,-0.64
T3D1,080692,-0.70
T3D2,080692,0.00
T3D3,080692,-0.71
T3D4,080692,-0.76
T1D1,160692,-0.43
T1D2,160692,-0.24
T1D3,160692,-0.45
T1D4,160692,-0.64
T2D1,160692,-0.52
T2D2,160692,-0.45
T2D3,160692,99.99
T2D4,160692,-0.42
T3D1,160692,-0.75
T3D2,160692,-0.75
T3D3,160692,-0.22
T3D4,160692,-0.92
T1D1,230692,99.99
T1D2,230692,-0.79
T1D3,230692,-0.30
T1D4,230692,-0.27
T2D1,230692,99.99
T2D2,230692,99.99
T2D3,230692,99.99
T2D4,230692,99.99
T3D1,230692,-0.84
T3D2,230692,-0.91
T3D3,230692,-0.75
T3D4,230692,-0.98
T1D1,300692,99.99
T1D2,300692,-0.74
T1D3,300692,-0.62
T1D4,300692,-0.54
T2D1,300692,-0.48
T2D2,300692,-0.96
T2D3,300692,-0.82
T2D4,300692,-0.82
T3D1,300692,-0.70
T3D2,300692,-1.05
T3D3,300692,-0.40
T3D4,300692,-1.53
T1D1,140792,-0.33
T1D2,140792,-0.58
T1D3,140792,-0.50
T1D4,140792,-0.78
T2D1,140792,-0.88
T2D2,140792,-1.15
T2D3,140792,-1.28
T2D4,140792,-1.57
T3D1,140792,-0.85
T3D2,140792,-1.12
T3D3,140792,-0.67
T3D4,140792,-1.10
T1D1,270792,-0.69
T1D2,270792,-0.68
T1D3,270792,-0.77
T1D4,270792,-0.86
T2D1,270792,-1.04
T2D2,270792,-1.14
T2D3,270792,-0.86
T2D4,270792,-0.74
T3D1,270792,-0.80
T3D2,270792,-1.05
T3D3,270792,0.00
T3D4,270792,-0.91
T1D1,120892,-0.70
T1D2,120892,-0.80
T1D3,120892,-0.92
T1D4,120892,-1.06
T2D1,120892,-0.90
T2D2,120892,-1.17
T2D3,120892,-1.15
T2D4,120892,-0.99
T3D1,120892,-0.95
T3D2,120892,-1.25
T3D3,120892,-0.93
T3D4,120892,-1.09
T1D1,250892,-0.72
T1D2,250892,-0.85
T1D3,250892,-0.97
T1D4,250892,99.99
T2D1,250892,-0.98
T2D2,250892,-1.19
T2D3,250892,-1.10
T2D4,250892,-1.10
T3D1,250892,-0.78
T3D2,250892,-1.22
T3D3,250892,-1.00
T3D4,250892,-1.38
T1D1,230992,-0.78
T1D2,230992,99.99
T1D3,230992,-0.86
T1D4,230992,-0.93
T2D1,230992,-0.82
T2D2,230992,-0.46
T2D3,230992,-1.13
T2D4,230992,99.99
T3D1,230992,99.99
T3D2,230992,99.99
T3D3,230992,99.99
T3D4,230992,99.99
T1M1,090692,-0.68
T1M2,090692,-0.22
T1M3,090692,-0.54
T1M4,090692,-0.38
T2M1,090692,0.00
T2M2,090692,-0.08
T2M3,090692,-0.24
T2M4,090692,0.00
T3M1,090692,-0.19
T3M2,090692,-0.17
T3M3,090692,-0.31
T3M4,090692,-0.16
T1M1,170692,-1.24
T1M2,170692,-0.59
T1M3,170692,-1.06
T1M4,170692,-0.88
T2M1,170692,99.99
T2M2,170692,-0.18
T2M3,170692,-0.71
T2M4,170692,-0.13
T3M1,170692,-0.35
T3M2,170692,0.00
T3M3,170692,0.00
T3M4,170692,0.00
T1M1,240692,99.99
T1M2,240692,99.99
T1M3,240692,99.99
T1M4,240692,99.99
T2M1,240692,0.00
T2M2,240692,-0.19
T2M3,240692,-0.79
T2M4,240692,-0.17
T3M1,240692,-0.30
T3M2,240692,-0.18
T3M3,240692,0.00
T3M4,240692,-0.26
T1M1,010792,-1.63
T1M2,010792,-1.33
T1M3,010792,-1.32
T1M4,010792,-1.23
T2M1,010792,-0.11
T2M2,010792,-0.26
T2M3,010792,-0.38
T2M4,010792,-0.40
T3M1,010792,-0.21
T3M2,010792,-0.32
T3M3,010792,-0.29
T3M4,010792,99.99
T1M1,150792,-0.94
T1M2,150792,-1.47
T1M3,150792,-0.95
T1M4,150792,-0.86
T2M1,150792,-0.58
T2M2,150792,-0.63
T2M3,150792,-0.46
T2M4,150792,-0.62
T3M1,150792,-0.34
T3M2,150792,-0.20
T3M3,150792,-0.21
T3M4,150792,-0.66
T1M1,290792,-1.20
T1M2,290792,-1.08
T1M3,290792,-1.05
T1M4,290792,-1.05
T2M1,290792,-0.97
T2M2,290792,-0.91
T2M3,290792,-0.70
T2M4,290792,-0.78
T3M1,290792,-0.62
T3M2,290792,-0.18
T3M3,290792,-0.44
T3M4,290792,-0.92
T1M1,110892,-1.06
T1M2,110892,-1.41
T1M3,110892,-1.37
T1M4,110892,-1.28
T2M1,110892,-0.71
T2M2,110892,-0.60
T2M3,110892,-0.86
T2M4,110892,-0.54
T3M1,110892,0.00
T3M2,110892,-0.45
T3M3,110892,-0.27
T3M4,110892,-0.57
T1M1,260892,0.00
T1M2,260892,-0.93
T1M3,260892,-0.80
T1M4,260892,-1.42
T2M1,260892,0.00
T2M2,260892,0.00
T2M3,260892,0.00
T2M4,260892,-0.69
T3M1,260892,-0.28
T3M2,260892,-0.26
T3M3,260892,-0.61
T3M4,260892,-0.18
T1M1,230992,-0.18
T1M2,230992,-1.19
T1M3,230992,-0.88
T1M4,230992,99.99
T2M1,230992,99.99
T2M2,230992,99.99
T2M3,230992,99.99
T2M4,230992,99.99
T3M1,230992,-0.58
T3M2,230992,99.99
T3M3,230992,99.99
T3M4,230992,0.72
T1W1,100692,0.00
T1W2,100692,0.00
T1W3,100692,0.00
T1W4,100692,99.99
T2W1,100692,5.63
T2W2,100692,18.46
T2W3,100692,3.83
T2W4,100692,9.16
T3W1,100692,0.00
T3W2,100692,0.00
T3W3,100692,0.00
T3W4,100692,0.00
T1W1,180692,0.00
T1W2,180692,99.99
T1W3,180692,0.00
T1W4,180692,0.00
T2W1,180692,1.04
T2W2,180692,2.79
T2W3,180692,0.00
T2W4,180692,1.38
T3W1,180692,0.00
T3W2,180692,0.00
T3W3,180692,0.00
T3W4,180692,0.00
T1W1,250692,99.99
T1W2,250692,0.00
T1W3,250692,0.00
T1W4,250692,0.00
T2W1,250692,8.86
T2W2,250692,0.63
T2W3,250692,7.47
T2W4,250692,6.43
T3W1,250692,0.00
T3W2,250692,0.00
T3W3,250692,0.00
T3W4,250692,0.00
T1W1,070792,-0.14
T1W2,070792,-0.15
T1W3,070792,0.00
T1W4,070792,0.00
T2W1,070792,3.12
T2W2,070792,1.60
T2W3,070792,4.56
T2W4,070792,4.67
T3W1,070792,-0.28
T3W2,070792,0.00
T3W3,070792,0.00
T3W4,070792,0.56
T1W1,160792,0.00
T1W2,160792,0.012
T1W3,160792,0.00
T1W4,160792,0.029
T2W1,160792,5.12
T2W2,160792,1.32
T2W3,160792,4.46
T2W4,160792,11.4
T3W1,160792,0.00
T3W2,160792,0.00
T3W3,160792,0.047
T3W4,160792,0.89
T1W1,300792,-0.32
T1W2,300792,0.00
T1W3,300792,-0.11
T1W4,300792,0.00
T2W1,300792,12.2
T2W2,300792,0.94
T2W3,300792,7.54
T2W4,300792,17.70
T3W1,300792,0.00
T3W2,300792,0.16
T3W3,300792,0.00
T3W4,300792,1.53
T1W1,270892,0.00
T1W2,270892,0.00
T1W3,270892,-0.31
T1W4,270892,-0.55
T2W1,270892,25.6
T2W2,270892,1.16
T2W3,270892,14.0
T2W4,270892,18.1
T3W1,270892,-0.28
T3W2,270892,0.00
T3W3,270892,0.00
T3W4,270892,0.19
T1W1,230992,99.99
T1W2,230992,99.99
T1W3,230992,99.99
T1W4,230992,99.99
T2W1,230992,0.96
T2W2,230992,99.99
T2W3,230992,1.10
T2W4,230992,3.98
T3W1,230992,0.00
T3W2,230992,-0.66
T3W3,230992,99.99
T3W4,230992,-0.10
BWC1,300992,-1.12
BWC2,300992,-0.69
BWC3,300992,-0.45
BWC4,300992,-0.72
BWN1,300992,0.00
BWN2,300992,-0.71
BWN3,300992,-0.79
BWN4,300992,-0.87
BDC1,300992,-1.51
BDC2,300992,-0.79
BDC3,300992,-1.00
BDC4,300992,-1.11
BDN1,300992,-0.55
BDN2,300992,-0.42
BDN3,300992,-0.46
BDN4,300992,-0.79