Forensic Science International 247 (2015) 41–47

Nitrous oxide, methane and carbon dioxide dynamics fromexperimental pig graves

M. Dalva a,*, T.R. Moore a,*, M. Kalacska a, G. Leblanc b, A. Costopoulos c

a Department of Geography, McGill University, 805 Sherbrooke St. W., Montreal, QC, Canada H3A 0B9b National Research Council Canada, Flight Research Laboratory, 1920 Research Rd., Ottawa, ON, Canada K1A 0R6c Department of Anthropology, McGill University, 855 Sherbrooke Street West, Montreal, QC, Canada H3A 2T7

A R T I C L E I N F O

Article history:

Received 25 April 2014

Received in revised form 3 November 2014

Accepted 1 December 2014

Available online 8 December 2014

Keywords:

Forensic anthropology

Decomposition

Biogeochemistry

Pig carcasses

A B S T R A C T

Twelve pig carcasses were buried in single, shallow and deep (30 and 90 cm, respectively) graves at an

experimental site near Ottawa, Ontario, Canada, with three shallow and three deep wrapped in black

plastic garbage bags. An additional six carcasses were left at the surface to decompose, three of which

were bagged. Six reference pits without remains were also dug. The objective of this three-year study

was to examine the biogeochemistry and utility of nitrous oxide (N2O), methane (CH4) and carbon

dioxide (CO2) in grave detection and whether grave depth or cadaver condition (bagged versus bare)

affected soil pore air concentrations and emission of the three gases. Graves showed significantly higher

(a = 0.05) concentrations and surface fluxes of N2O and CO2 than reference pits, but there was no

difference in CH4 between graves and reference pits. While CH4 decreased with depth in the soil profiles,

N2O and CO2 showed a large increase compared to reference pits. Shallow graves showed significantly

higher emissions and pore air concentrations of N2O and CO2 than deep graves, as did bare versus bagged

carcasses.

� 2014 Elsevier Ireland Ltd. All rights reserved.

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Forensic Science International

jou r nal h o mep age: w ww.els evier . co m/lo c ate / fo r sc i in t

1. Introduction

Locating human graves is important for missing personrecovery as well as archaeological purposes. Methods to expeditelocating clandestine graves have been developed where surfaceclues are lacking and where the content of a potential grave isunknown [1–14]. Changes in soil properties have been examined[5,7,10,13,15–17] and volatile chemical compounds and odors thatcould indicate the presence of buried remains [18–24] have beenidentified. During stages of decomposition, variable amounts ofgases such as carbon dioxide (CO2), methane (CH4), nitrous oxide(N2O), ammonia, hydrogen sulfide, and many others are released[2,11,18,20,22–25].

Our study focused on the emissions, pore air concentrationsand overall detectability of CH4, CO2 and N2O in graves andwhether they can be used as indicators of graves in comparison to

* Corresponding authors. Tel.: +1 514 398 4961; fax: +1 514 398 7437.

E-mail addresses: moshe.dalva@mcgill.ca (M. Dalva), tim.moore@mcgill.ca

(T.R. Moore), margaret.kalacska@mcgill.ca (M. Kalacska),

george.leblanc@nrc-cnrc.gc.ca (G. Leblanc), andre.costopoulos@mcgill.ca

(A. Costopoulos).

http://dx.doi.org/10.1016/j.forsciint.2014.12.002

0379-0738/� 2014 Elsevier Ireland Ltd. All rights reserved.

reference sites. At a burial site of animal carcasses from a zoo inwet, heavy-textured soils, it was shown that CH4 can be used todetect the presence of graves, using atmospheric concentrations ofCH4 near the soil surface, emissions of CH4 to the atmosphere andpore air CH4 concentrations [25]. The zoo site contained a variety ofdifferent species of animals buried in comingled graves overmultiple decades with various disturbance events and thus wasmore similar to scenarios of mass graves and secondary burials inan international context [8,26], rather than individual missingpersons. Nevertheless, results suggested that trace gas biogeo-chemistry could be used to detect graves.

To better determine the effect of burial on trace gases, weburied pig (Sus scrofa domesticus) carcasses in an experimentalsetting in eastern Ontario, Canada, in a well-drained, sandy soilwith a herbaceous field. We present results on the variations in thepore air concentrations and surface emissions of CO2, CH4 and N2Owhere pigs were buried at different depths, either bare or enclosedin plastic bags, over a period of three years from burial. Plasticbag wrappings were used to simulate the burial of cadavers inplastic bags in clandestine graves. We hypothesized that theburial would increase concentrations and emissions of the threegases, compared to reference pits (ground disturbance withoutcarcasses).

Fig. 2. Photograph of the site prior to set-up, looking northeast (A), and soil profiles

M. Dalva et al. / Forensic Science International 247 (2015) 41–4742

2. Site, materials and methods

2.1. Site

The site (Figs. 1 and 2A) was established at the NationalResearch Council Canada near Ottawa, Ontario (458190N, 758400W).The 30-year mean annual precipitation at the nearby MacDonaldCartier Airport comprises 732 mm rainfall and 236 mm snow.Mean monthly temperatures range from �10.8 8C in January to20.9 8C in July.

The soils in the region are mostly well-drained, sandy loams ofthe Leitrim series (Brunisols) with a parent material of shale at adepth of 1 to 2 m containing fragments of granite, gneiss, limestoneand dolomite [27]. At the burial site (Fig. 2B and C), the top 20 cm ofsoil contains medium grained to pebble sized clasts of limestone,dolomite and portions of granite. The following 17–20 cm iscomposed of poorly sorted sands with a few larger clasts (1–5 cmdiameter) and underlain by 20 cm of shale and larger clastsinterspersed with clay horizons of limited lateral extent. The pH ofthe soils ranged from 5.5 to 8.1 with a bulk density of 0.7 to1.0 g cm�3. Vegetation consisted of mixed herbaceous species.

The site, approximately 46 � 34 m, was established on July 20,2011 as part of a long-term interdisciplinary study on the detectionof clandestine graves from the biogeochemical data and remotelysensed imagery. A total of 18 pig carcasses, averaging 85 kg, werepurchased from a commercial abattoir and had not been deceasedfor more than 12 h prior to burial; to comply with provincialregulations the stomach and intestines were removed. Of these,12 carcasses were buried at one of two depths either 30 cm(shallow) or 90 cm (deep) in pits (1 � 2 m), dug by a backhoe. Thecarcasses were distributed in a randomized design within theregular grid of pits with an 8 m distance between pit centres. Six ofthe 12 buried carcasses were enclosed in black plastic garbagebags. Six additional carcasses (3 of which were bagged) were left todecompose on the surface at the northern edge of the site. Sixreference pits were dug (3 shallow and 3 deep) to the samedimensions as the graves but did not contain any remains. For each

Fig. 1. Distribution of grave and reference pits. Boxes represent locations of soil pore

air samplers. Yellow text represent pits where gas flux measurements were made.

R = reference; S = shallow; D = deep; b = bagged; G = ground (pigs left on surface).

The base image was collected August 12, 2011 at a spatial resolution of 70 cm.

Channels at 1051 nm, 1623 nm and 2121 nm are displayed as an RGB composite.

(For interpretation of the references to color in this figure legend, the reader is

referred to the web version of this article.)

from the western (B) and eastern (C) sides of the site.

of the pits the backfill was replaced with the backhoe. We refer tothe pits with the interred carcasses as graves.

2.2. Gas flux and pore air concentration measurements

Gas fluxes were measured at two reference pits (R2 and R4),two shallow (S1 and S3) and two deep graves (D1 and D3), and oneon each of shallow (Sb2) and deep (Db2) graves with baggedremains (Fig. 1). In July 2012, fluxes were measured on surfaceremains at G1 (not bagged) and Gb1 (bagged). Several attemptswere made to sample the air above the surface carcasses tocharacterize a profile of gases at different heights but as all 3 gasesshowed no variation with height, the sampling was abandonedlater in 2011.

Gas fluxes and soil pore air concentrations were measuredweekly from July to September 2011, bi-weekly from early Mayto late November 2012 and 2013. Owing to the deep snow coverand difficulty of making flux measurements, samples were nottaken during the winter periods of December to April. Carbondioxide fluxes were made only in 2013 because of instrumentproblems.

Fluxes were determined by the static chamber method, usinggrooved water-sealed collars (25 cm diameter) permanentlyplaced into the soil to a depth of 5 to 10 cm. Chambers, coveredwith aluminum foil and having a volume of 9 L, were placed onthe collars, water sealed in the groove and air samples collectedevery 15 min over 1 h, by mixing the air in the chamber with a

M. Dalva et al. / Forensic Science International 247 (2015) 41–47 43

60 mL syringe and then removing 20 mL in a syringe with a 3-waystopcock.

Soil pore air samples were taken from 6 mm diameterstainless steel tubes installed permanently at depths from 10 to100 cm (Fig. 1). The tubes had �1 mm diameter holes drilledalong the bottom 4–5 cm which were covered with Nytexmesh to prevent clogging during sampling. The top of thetubes were fitted with Tygon tubing and 2-way stopcocks tofacilitate sample withdrawal. Three sets of tubes were placed onthe grave, at each end and the middle. For shallow gravesthis would generally mean tubes at 10, 20, 30 and 50 cm at theends, and 25 or 30 cm and a 50 cm tube in the middle. Thesame procedures were used in the deep graves but withdepths going to 100 cm. Tubes were also placed at referencelocations and between graves. Additional soil pore air samplingwas established in August 2011 at 33 (Sb2), 34 (D1), 35 (Db2)and 36 (S1).

Gas samples were analyzed within 24 to 72 h after collection.Methane was analyzed using a Shimadzu-Mini 2 flame ionizationdetector with ultra high purity nitrogen as the carrier gas and aPorapaq-Q column (80/100 mesh). Column and detector tem-peratures were 55 and 100 8C, respectively, and standards of5.01 and 2000 ppm were used for calibration. Carbon dioxide wasmeasured with a Qubit Systems S151 infrared gas analyzer usingultra high purity nitrogen as the carrier and zero gas and1996 ppm CO2 as the span gas. Nitrous oxide was measured with aShimadzu 14-A electron capture detector and a Ni63 radioisotopesource with column and detector temperatures of 55 and 325 8C,respectively. The GC was fitted with Porapaq-Q and Hayesep-Ncolumns (both 80/100 mesh) and a pre-column that was backflushed to vent with a carrier gas of ultra high purity nitrogen.Compressed air (0.3 ppm N2O) and 1.0 ppm N2O were used forcalibration. The fluxes were calculated from the slopes of linearregressions between concentration and time and expressed asmg m�2 d�1. Fluxes were rejected if regressions were non-linearand when r2 values were <0.5: the rejection rate was approxi-mately 10%.

2.3. Statistical methods

As part of the data were normally distributed and part were not,we used non-parametric tests such as Mann–Whitney U-tests forIndependent samples and Wilcoxon signed rank test using SPSS toanalyze for differences in gas fluxes and concentrations betweengrave and reference pits at a significance level of 0.05 and a 95%confidence interval. Linear regressions were used to test forrelationships between gases.

Table 1Statistics of CH4 and N2O flux (2011–2013, mg m�2 d�1) and CO2 flux (2013, g m�2 d�1) for

R = reference; S = shallow; D = deep; b = bagged; G = ground (pigs left on surface).

Plot CH4 N2O

Mean Median S.D. Min. Max. n Mean Median S.D

R2 �0.67 �0.49 0.83 �3.19 �0.03 12 �0.1 �0.02 0

R4 0.42 �0.21 2.8 �5.49 8.42 23 �0.1 0.05 0

S1 1.18 �0.13 2.76 �1.78 9.12 24 20.02 17.07 12

S2 �1.09 �0.77 1.14 �4.49 �0.17 12 9.18 9.81 5

S3 �0.7 �0.57 0.37 �1.75 0.16 25 16.65 15.87 10

Sb2 �0.61 �0.52 1.23 �6.03 1.5 25 2.54 2.73 1

D1 �0.57 �0.57 0.32 �1.17 0.16 25 4.69 4.09 3

D3 �0.98 �0.49 1.41 �5.79 0.32 22 1.53 1.22 1

Db1 �0.27 �0.36 1.16 �3.13 2.35 17 1.08 0.8 0

Db2 �0.5 �0.44 0.3 �1.35 �0.02 24 0.98 1 0

G1 �0.93 �1.01 0.75 �2.68 0.79 21 4.55 0.53 7

Gb1 �0.04 �0.23 1.05 �1.78 2.38 21 1.65 1.43 1

3. Results

3.1. CH4, N2O and CO2 fluxes

Mean CH4 flux ranged from �0.77 (uptake by soil) to 0.54(emission from soil) mg m�2 d�1. Both references and gravesshowed CH4 consumption, with the exception of a slight emissionof 0.54 and 0.41 mg m�2 d�1 from the shallow grave S1 andbagged surface remains at Gb1, respectively (Table 1). There wereno significant differences (Mann–Whitney U-test, a = 0.05)between reference and grave pits or between shallow and deepgraves. There were no clear seasonal trends in reference pits orgraves.

Mean N2O flux ranged from close to zero at the reference pits(R2 and R4, 0.10 and �0.24 mg m�2 d�1) to emissions at theshallow graves (S1 and S3, 10.2 and 28.2 mg m�2 d�1, Table 1).Shallow graves showed significantly higher N2O fluxes (Mann–Whitney U-test, a = 0.05) than deep graves. Graves containing barecarcasses had significantly higher N2O fluxes than graves withbagged carcasses. Seasonal trends in N2O flux were observed at S1,G1 and Gb1 with the highest fluxes in spring and summer, but therest did not show clear seasonal trends.

Fluxes of CO2 were generally higher during the spring andsummer months of 2013. Mean CO2 fluxes were 5.16 g m�2 d�1 atthe reference grave (R4) and ranged from 3.95 g m�2 d�1 at thebagged, deep grave (Db1) to 14.04 g m�2 d�1 at the unbaggedsurface surface remains (G1) following skeletonization. MedianCO2 fluxes from shallow graves were significantly larger than thosefrom deep graves, which were not significantly different from R4.

3.2. Soil pore air concentration of CH4, N2O and CO2

Methane concentrations decreased with depth in the soilprofiles of graves and reference pits, ranging from means of1.5 ppm at 10 cm to 0.5 ppm at 100 cm (Fig. 3). There were nostatistically significant differences between graves and referencepits, between shallow and deep graves or between gravescontaining bagged and bare carcasses. There were no distinctseasonal trends in CH4 concentration although concentrations>9 ppm were occasionally encountered.

Soil pore air N2O concentration showed little vertical variationin the reference pits, averaging 0.3 to 0.4 ppm, but increased withdepth at the graves reaching a mean of 17.5 ppm at a depth of50 cm in the shallow graves with bare carcasses (Fig. 3). Shallowgraves showed significantly larger N2O concentrations than deepgraves and shallow graves with bare carcasses had significantlylarger N2O concentrations than those with bagged cadavers

plots. S.D. = standard deviation, n = number of measurements, n.d. = not determined.

CO2

. Min. Max. n Mean Median S.D. Min. Max. n

.46 �1.37 0.53 12 n.d. n.d. n.d. n.d. n.d. n.d.

.69 �2.3 1.14 23 5.16 4.25 4.32 0.18 11.85 8

.31 4.43 47.14 24 9.93 10.85 4.62 1.58 14.65 10

.63 1.16 19.22 12 8.91 9.75 3.87 2.75 14.76 9

.76 5.88 46.5 25 8.23 8.07 3.88 2.44 14.95 9

.37 0.09 5.53 25 3.96 3.69 2.31 0.68 7.52 10

.15 0.05 11.34 25 4.86 4.90 1.80 0.66 6.79 10

.06 0.6 5.03 23 8.28 4.45 9.30 0.77 28.67 9

.87 �0.01 3.42 17 3.95 3.46 3.47 0.11 11.19 9

.48 �0.08 1.73 24 7.19 4.52 5.79 1.86 16.95 8

.2 �0.62 26.85 21 14.04 13.12 10.07 0.29 33.05 9

.51 �0.18 5.74 21 12.46 14.52 8.27 0.72 24.52 10

Fig. 3. Mean (and standard deviation) concentrations of (A) CH4, (B) N2O and (C) CO2 in soil pore air at various depths in the grave and reference pits. Numbers beside each bar

represent the number of samples. Spatial locations for the samples are illustrated in Fig. 1.

M. Dalva et al. / Forensic Science International 247 (2015) 41–4744

(Mann–Whitney U-test, a = 0.05). There were no significantdifferences in N2O concentration between deep bagged and barecarcasses graves except at the 20 cm depth where the lattershowed slightly higher concentrations than bagged graves. Meanand median N2O concentrations were significantly larger in2013 than in either 2012 or 2011 at deep and shallow graves(Related samples Wilcoxon signed rank test, a = 0.05), with theexceptions of the reference and a site in-between graves (P17)(Supplementary Table A1).

Soil pore air CO2 increased with depth at both grave andreference pits, with graves (bagged and bare carcasses) showingsignificantly larger (related samples Wilcoxon signed rank test,a = 0.05) concentrations than the reference pits, by two to threetimes (Fig. 3). There were no significant differences in CO2

concentration between shallow and deep graves and in all cases,graves with bare carcasses showed significantly larger CO2

concentrations than those with bagged carcasses. Concentrationsof CO2 decreased slightly through the 3 years in the reference pits;graves with bare carcasses, shallow and deep, increased from2011 to 2013, while those with bagged carcasses decreasedalthough still at significantly greater concentrations than referencepits (Supplementary Table A1).

Pore air concentrations of N2O rose in the summer and fall of2012 and showed lags with mean daily air temperature at thedepth of the carcass (Fig. 4). N2O concentrations from shallowgrave S1 showed a stronger variation with mean daily air

Julian Date

340320300280260240220200180160140120

N2O

ppm

0

10

20

30

40

50

60

70

o

-20

-10

0

10

20

30

40S1

Fig. 4. Seasonal variation during 2012 in soil pore air N2O concentration at a sha

temperature than that at deep grave D1, where temperaturevariations were smaller at the burial depth. There were significant(p < 0.0001), positive relationships between N2O fluxes and soilpore air N2O concentrations at the shallow and deep graves.Shallow and deep grave sites with bare carcasses, showed higherN2O concentrations in 2013, while bagged graves showed a slightdrop in concentrations from 2011. Both N2O and CO2 pore airconcentrations tended to be higher at mid points of the graves thanat the edges.

There were strong positive correlations between soil pore airN2O and CO2 concentrations at both shallow and deep graves, withlog10-transformed regressions yielding r2 values of 0.42 and 0.65,respectively (Fig. 5). Soil pore air CH4 and CO2 concentrations werenot significantly correlated.

4. Discussion

Our study has demonstrated how burial depth and pig carcasscondition (bagged versus bare) may affect the concentration andemission of greenhouse gases. Burial density was high at the site:82 kg of pig carcass over �2 m2. In well-drained, sandy and stonysoils such as those found at our site, remains have been shown todecompose more rapidly in shallow than deep graves, with O2

diffusion dropping markedly beneath 1 m [28,29]. The absence ofhigh concentrations of N2O and CO2 from sites between graves andtheir overall similarity to the reference sites suggests that there

Mea

n da

ily te

mpe

ratu

re C

Julian Date

340320300280260240220200180160140120

N2O

ppm

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5

10

15

20

25

30

35

Mea

n da

ily te

mpe

ratu

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o C

-20

-10

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D1

llow (S1) and a deep (D1) graves and mean daily temperature at S1 and D1.

Soil pore air log10CO2 (ppm)

5.04.54.03.53.02.5

Soi

l por

e ai

r log

10N

2O (p

pm)

-0.5

0.0

0.5

1.0

1.5

2.0

A

Soil pore air log10CH4 (pp m)

0.80.60.40.20.0-0.2-0.4-0.6-0.8-1.0

Soi

l por

e ai

r log

10N

2O (p

pm)

-0.5

0.0

0.5

1.0

1.5

2.0

B

Fig. 5. Relationships between soil pore air (A) CO2 and N2O concentrations and (B)

CH4 and N2O concentrations. Open and black circles are shallow and deep graves

(bagged and bare carcasses), respectively.

M. Dalva et al. / Forensic Science International 247 (2015) 41–47 45

is little, if any, lateral diffusion of the gases produced by thecarcasses.

4.1. CH4

In contrast to our work on the zoo burial field in southernQuebec [25], we found no effect of burial on CH4 concentration oremission. We propose several reasons for this:

(1) To meet provincial regulations, the pig digestive tracts had tobe removed prior to burial. This removal may have affected theprocess of decomposition and the generation of gases; themajority of decomposition can be initiated by the gut floraactivity.

(2) The sandy texture of the well-drained soils at this pigexperimental burial site facilitates CH4 oxidation, resultingin sub-ambient (<1.8 ppm) pore air concentrations of CH4,compared to the clay-loam texture, poorly drained soils at thezoo site. In addition, mice burrows seen at some of the gravesmay provide additional channels of oxygen diffusion for CH4

oxidation. The result is an overall uptake of atmospheric CH4 bythe soils at the reference and burial sites. Anaerobic incuba-tions of grave soil taken above the carcass (S1) did not show anypotential for CH4 production.

(3) The small size (2 m2) of the individual graves at this currentsite may not have been conducive to the development ofanaerobic conditions necessary for CH4 production, incontrast to the much larger area (13 m2 average size of thecomingled graves) and denser carcass occurrence at the zoosite.

(4) There may have been CH4 production within the cadavers,but our sampling interval and the CH4 consumption ofthe sandy soil prevented its detection. Furthermore,garbage bags used in covering some of the carcasses mayhave provided a further barrier to CH4 diffusion and hencedetection.

4.2. N2O

Nitrous oxide in soils is produced during the microbialprocesses of nitrification and denitrification. Nitrification involvesthe stepwise oxidation of ammonia and its subsequent breakdownto nitrite (NO2

�) and nitrate (NO3�) under aerobic conditions,

while denitrification involves the reduction of NO3� to N2O and N2

under generally anaerobic conditions. In grave soils, the processesof nitrification and denitrification may occur simultaneouslywhere ammonia is sequentially oxidised in the upper soil profilewhile denitrification and reduction processes may take place inthe anaerobic pockets deeper down the soil profile or within theremains.

Fluxes of N2O from the grave soils are at least an order ofmagnitude greater than those reported from forest soils in thesame region: for example 0.3 and 1.2 mg N2O m�2 d�1 for forestedupland and wetland soils [30]. The experimental burial of 3 pigs ina forensic investigation revealed greater N mineralization and CO2

respiration rates from grave soils than reference pits, as well asrates that increased with depth [31], a pattern consistent with ourresults.

Assuming each pig weighing �85 kg contains 1.8 kg of N [32]and an average N2O flux of about 30 mg m�2 d�1 at S1 from May toNovember, then approximately 0.0045 kg (0.25%) of the cadaver Nhas been lost as N2O. Precluding losses of N2O as N2 duringdenitrification, N2O could be a long-term indicator of graves inthese types of soils where NO2

� and NO3� from cadaver

decomposition is not limiting. This is supported by the increasesin pore air N2O concentrations observed in grave soils through3 years of measurements (Supplementary Table A1).

4.3. CO2

Carbon dioxide in soils is produced from plant respirationwithin the rhizosphere, decomposition of organic matter andduring cadaver decomposition. Although soil CO2 sources maybe difficult to partition, the significantly higher pore airconcentrations observed in the graves than the reference pitssuggest that CO2 from cadaver decomposition accounts for asignificant portion of the total soil CO2. The strong correlationbetween soil air CO2 and N2O concentrations and increasingconcentrations with depth support this and CO2 may also be agood long term indicator. The initially higher concentrations atthe reference site may be caused by the disturbance of diggingand subsequent organic matter turnover. The nutrients generat-ed from cadaver decomposition may also contribute towardsplant growth and root respiration resulting in distinct cadaverdecomposition islands [33] and higher soil CO2 concentrations.Flux of CO2 from the soil surface in the third year (2013)showed a more muted effect of cadaver presence, though thesurface and shallow buried cadaver sites emitted substantiallymore CO2 than the reference pits and those with deeply buriedcadavers.

In conclusion, determination of soil gas concentrations andfluxes may have utility in grave detection, but this will depend onfactors such as soil properties, the occurrence of aerobic andanaerobic regimes, hydrologic status, and mass and areal extentof the remains.

M. Dalva et al. / Forensic Science International 247 (2015) 41–4746

Appendix A. Appendix A

Table A1.

Table A1Mean and median (in parentheses) N2O and CO2 and pore air concentrations, 2011–2013.

Site Depth (cm) N2O (ppm) CO2 (ppm)

2011 2012 2013 2011 2012 2013

R4 10 0.5 (0.5) 0.4 (0.4) 0.6 (0.6) 1695 (1686) 1353 (1343) 1078 (719)

20 0.5 (0.5) 0.4 (0.4) 0.6 (0.6) 2014 (1876) 1748 (1757) 1749 (1379)

30 0.5 (0.5) 0.4 (0.4) 0.6 (0.6) 2577 (2279) 2290 (2659) 2391 (1944)

50 0.5 (0.5) 0.4 (0.4) 0.6 (0.6) 3739 (3011) 2803 (2812) 1994 (1925)

P17 10 0.4 (0.4) 0.4 (0.5) 0.6 (0.6) 2092 (2003) 1639 (1835) 1298 (979)

30 0.4 (0.4) 0.4 (0.4) 0.6 (0.6) 1820 (1748) 2177 (2482) 1834 (1397)

50 0.4 (0.4) 0.6 (0.6) 0.7 (0.7) 2160 (1894) 3155 (3386) 3424 (2568)

80 0.4 (0.4) 0.6 (0.6) 0.9 (0.7) 2579 (2456) 3355 (3277) 2281 (2599)

S3 (P18) 10 1.3 (1.1) 3.7 (3.4) 11.1 (10.6) 3166 (3819) 2848 (2549) 4444 (4077)

20 1.1 (1.4) 5.0 (4.3) 12.5 (12.6) 4111 (4954) 4132 (3817) 4954 (5045)

30 2.1 (1.8) 5.7 (5.0) 17.7 (16.9) 5159 (5727) 5157 (5386) 6920 (6646)

50 2.1 (1.8) 6.7 (5.6) 21.9 (23.1) 5818 (6305) 6123 (6305) 8442 (8170)

S3 (P19) 30 2.9 (2.4) 9.5 (8.6) 33.5 (32.9) 9431 (12,538) 6477 (6570) 12,583 (12,845)

50 5.0 (4.7) 15.2 (14.7) 44.1 (41.5) 10,327 (10,312) 10,312 (10,007) 16,749 (14,520)

S3 (P20) 10 1.4 (1.5) 3.3 (2.6) 17.6 (17.4) 5429 (6056) 4633 (3853) 7226 (6056)

20 1.6 (1.6) 3.4 (3.0) 24.2 (22.3) 8337 (8829) 5938 (5491) 10,337 (8829)

30 2.7 (2.7) 8.1 (8.5) 48.0 (45.6) 12,211 (12,036) 11,258 (10,510) 18,180 (17,211)

50 2.8 (2.9) 10.2 (9.5) 52.3 (42.4) 13,395 (11,460) 11,460 (10,094) 21,957 (23,412)

Sb2 10 0.7 (0.7) 0.9 (0.9) 3.7 (3.5) 3114 (3331) 2263 (2296) 2214 (1905)

20 0.8 (0.8) 1.3 (1.3) 5.1 (5.2) 4674 (4680) 3347 (3230) 3016 (2574)

30 0.9 (0.9) 1.9 (1.9) 5.8 (6.2) 6342 (5804) 4400 (4287) 3025 (2599)

50 1.7 (1.5) 4.0 (3.8) 19.0 (20.7) 11,658 (9925) 8505 (8568) 6053 (5730)

D1 10 0.6 (0.5) 2.0 (2.0) 7.2 (6.2) 3523 (3508) 3644 (3499) 3586 (3476)

20 0.9 (0.9) 2.6 (2.3) 9.6 (7.5) 5070 (5571) 5451 (5908) 4633 (4793)

30 1.0 (0.9) 3.5 (3.3) 12.7 (11.0) 7375 (5150) 6459 (6382) 6230 (5495)

50 1.4 (1.3) 5.7 (5.4) 24.3 (19.1) 10,130 (8170) 9365 (9861) 10,130 (8170)

80 2.4 (2.0) 6.5 (6.7) 69.5 (76.4) 16,115 (13,324) 12,231 (13,464) 16,115 (13,324)

100 2.8 (2.1) 15.4 (14.0) 72.6 (65.2) 16,863 (13,943) 18,302 (18,597) 29,803 (28,610)

Db2 10 0.6 (0.5) 1.0 (0.9) 1.4 (1.3) 2064 (2037) 1646 (1780) 1908 (1901)

20 0.6 (0.5) 1.5 (1.3) 1.8 (1.7) 3077 (2641) 2625 (2810) 2472 (2392)

30 0.6 (0.6) 1.9 (2.1) 2.6 (2.4) 5019 (3550) 3622 (3589) 3650 (3607)

50 0.8 (0.8) 2.8 (2.8) 3.9 (4.0) 7461 (5961) 5321 (5281) 5575 (4926)

80 1.0 (0.9) 5.3 (5.3) 6.4 (6.0) 9965 (7257) 7008 (6979) 7038 (6579)

100 1.7 (1.2) 6.3 (5.5) 10.6 (10.5) 12,278 (9594) 9257 (9186) 7374 (6787)

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