Comparison of organic carbon properties in extracted soil solutions obtained underneath Cryptomeria japonica and Quercus acutissima and its implication on stream dissolved organic carbon

Figures & data

Table 1. Carbon isotope analysis on SOC and soil DOC in forest ecosystems.

References	Collected/ Extracted^a	Location	Extracting method (soil:water mass ratio)	Controlling factors	Depth (cm)	Δ^14C-SOC (‰)	δ^13C-SOC (‰)	Δ^14C-DOC (‰)	δ^13C-DOC (‰)
van der Voort et al. (2019)	Extracted	46–47^oN, 6–10^oE	1:4	Climate, Soil type	soil: 0–40 soil DOC: 0–100	−416 to 211		−164 to 205
Nakanishi et al. (2012)	Extracted	40^o00′N, 140^o56′E	1:5	Depth, OC fraction	0–60	−19.8 to 78.6	−28.3 to −25.8	6–102	−27.5 to −24.7
Nakanishi et al. (2014)	Extracted	40^o00′N, 140^o56′E	1:5	Depth, Climate	0–15	−19.8 to 78.6	−28.3 to −25.8	0–120	−28 to −24.5
Sanderman et al. (2008)	Extracted		1:50	Depth, LULC	0–∼70	−442 to 107	−28 to −23	−488 to 111	−28 to −23
Tegen & Dörr (1996)	Collected	51.6°N, 7.4°E 49.2°N, 8.4°E	lysimeter	Tree species, Climate	soil: 0–13 soil DOC: 0–50	40–275	−30.5 to −24.2	29–105	−29.9 to −27.6
Dutta et al. (2006)	Extracted	69°31′N, 161°52′E 69°39′N, 162°31′E	1:10	Temperature, Depth	surface: 0–10 mineral soil: 200–1300	−993 to −421	−26 to −22	−938 to −20	−26.5 to −24.6
Trumbore et al. (1992)	Collected/ Extracted	45°23′N, 79°08′W	from 1:10 to ∼ 1:2 lysimeter (only high flow period)	Depth, Acidity	detrital layers, 0–40	175 (litter)	−30 to −28 (litter), < −150 (10–40 cm)	175^b (litter), 10^b (10–25 cm)	−27^b
Fröberg et al. (2007)	Collected	35°58′N, 84°16′W	lysimeter	Soil type, Litter addition, Depth	15, 70			42–399
Fröberg et al. (2009)	Collected	35°58′N, 84°16′W	drain (the day after a major rainfall)	Litter addition, Depth	10 (O and A horizon)	123–167 (A horizon)		112–453 (A horizon)
Michalzik et al. (2003)	Collected	58°22′N, 08°13′E 50°08′N, 11°52′E	lysimeter	Depth	9–45	99–126		101–120
Karltun et al. (2005)^c	Collected		lysimeter	LULC, Stand age	soil: 5–15 soil DOC: 15–35	−50 to 100		−10 to 110
Hensgens et al. (2021)	Extracted	64°14′N, 19°46′E	from 1:40 to ∼1:4	Depth	up to ∼75	−130 to 126		493–195

^aCollected: DOC collected in situ from soils using lysimeter, sampling probe, or glass bottle. Extracted: DOC extracted from soil samples with deionized water in laboratory. Only van der Voort et al. (2019) used 0.5% NaCl solution to extract DOC from soils.

^bArithmetic mean.

^cΔ¹⁴C-SOC or Δ¹⁴C-DOC was calculated from ¹⁴C enrichment of % absolute modern provided by the reference.

Figure 1. The location (red circle) and the boundary of the forested watersheds (red line) of this study. Soil samples were collected at orange triangle (Cryptomeria japonica stand) and circle (Quercus acutissima stand) points. The blue lines are streams. Stream samples were collected at green circles in the Bukmoongol (BM) and Baramgol (BR) watersheds.

Figure 2. The relationships between SOC concentration and [WEOC] by (a) EC1, (b) EC2, and (c) EC3. Black triangles and dashed line are for Cryptomeria japonica and red circles and dashed line are for Quercus acutissima. Dashed lines are linear regression lines.

Table 2. Arithmetic mean and SE (standard error of the mean, n = 3) of the [WEOC] and cations.

Tree species	EC	Soil depth (cm)	[WEOC] (mg L^−1)	WEOC/SOC^a (mg g^−1)	[Na^+] (µmolc L^−1)	[K^+] (µmolc L^−1)	[Mg^2+] (µmolc L^−1)	[Ca^2+] (µmolc L^−1)	[Sum of cations] (µmolc L^−1)	[WEOC]: [Sum of cations] (mmol mmolc^−1)
Cryptomeria japonica	1	0–10	1.1 ± 0.1	0.3 ± 0.1	33.6 ± 5.5	9.1 ± 1.5	10.0 ± 1.0	48.7 ± 5.2	101.3 ± 2.7	0.9 ± 0.1
		10–30	0.4 ± 0.0	0.2 ± 0.0	17.9 ± 4.9	7.0 ± 0.9	7.4 ± 0.9	38.2 ± 7.1	70.5 ± 7.2	0.5 ± 0.0
		30–50	0.3 ± 0.1	0.4 ± 0.2	19.2 ± 5.4	8.0 ± 0.5	9.6 ± 1.7	40.7 ± 8.3	77.5 ± 6.3	0.4 ± 0.1
	2	0–10	6.4 ± 0.9	1.9 ± 0.1	98.4 ± 15.9	29.0 ± 3.1	21.4 ± 2.1	114.8 ± 8.1	263.6 ± 26.8	2.0 ± 0.1
		10–30	1.5 ± 0.3	0.7 ± 0.0	38.4 ± 6.3	25.2 ± 4.6	17.8 ± 2.3	74.7 ± 16.1	156.1 ± 8.1	0.8 ± 0.2
		30–50	0.9 ± 0.4	1.4 ± 1.0	33.3 ± 11.9	15.5 ± 3.7	16.2 ± 2.8	73.8 ± 15.6	138.8 ± 15.0	0.5 ± 0.2
	3	0–10	15.7 ± 3.0	1.4 ± 0.3	157.0 ± 16.0	59.7 ± 2.3	52.9 ± 4.2	221.5 ± 27.8	491.1 ± 39.8	2.7 ± 0.7
		10–30	4.9 ± 1.8	0.7 ± 0.1	105.1 ± 18.5	65.6 ± 10.9	48.1 ± 7.5	123.7 ± 30.5	342.5 ± 8.0	1.2 ± 0.5
		30–50	2.9 ± 1.5	1.4 ± 1.1	104.3 ± 35.5	49.6 ± 16.9	43.8 ± 16.2	107.8 ± 34.2	305.6 ± 17.4	0.8 ± 0.4
Quercus acutissima	1	0–10	1.0 ± 0.2	0.3 ± 0.1	29.2 ± 5.8	16.7 ± 2.4	8.4 ± 3.3	12.1 ± 0.5	66.4 ± 5.5	1.3 ± 0.4
		10–30	0.4 ± 0.0	0.2 ± 0.1	22.0 ± 4.1	11.1 ± 0.3	10.7 ± 2.2	10.4 ± 1.1	54.2 ± 3.1	0.6 ± 0.0
		30–50	0.2 ± 0.0	0.3 ± 0.1	16.2 ± 0.5	7.5 ± 0.5	12.9 ± 1.5	11.6 ± 3.3	48.2 ± 3.8	0.4 ± 0.0
	2	0–10	4.1 ± 1.0	1.4 ± 0.2	53.9 ± 5.1	37.8 ± 2.4	18.5 ± 6.4	18.8 ± 3.3	129.0 ± 10.7	2.6 ± 0.5
		10–30	1.1 ± 0.4	0.5 ± 0.1	30.0 ± 5.4	25.3 ± 1.9	20.7 ± 2.6	13.9 ± 3.5	89.9 ± 8.1	1.0 ± 0.2
		30–50	0.3 ± 0.0	0.4 ± 0.1	25.2 ± 1.6	14.6 ± 2.1	22.2 ± 2.2	9.7 ± 2.7	71.7 ± 3.8	0.3 ± 0.0
	3	0–10	7.8 ± 2.8	0.7 ± 0.1	103.1 ± 7.8	85.8 ± 3.7	46.9 ± 6.6	52.7 ± 10.9	288.5 ± 21.1	2.2 ± 0.6
		10–30	2.0 ± 0.5	0.3 ± 0.0	69.2 ± 6.7	48.7 ± 6.5	43.6 ± 3.3	28.2 ± 7.6	189.8 ± 17.3	0.8 ± 0.1
		30–50	1.6 ± 0.7	0.6 ± 0.2	76.9 ± 8.6	25.8 ± 3.9	33.5 ± 3.3	17.3 ± 1.2	153.5 ± 14.2	0.8 ± 0.3

^a The WEOC/SOC ratio is calculated using Equation (1)(1) $$\text{WEOC}/\text{SOC }({\text{mg g}}^{-1})=\left[\text{WEOC}\right]/\text{extraction ratio}/\left[\text{SOC}\right]$$(1) .

Figure 3. The relationships between (a) δ¹³C-SOC and δ¹³C-WEOC and (b) Δ¹⁴C-SOC and Δ¹⁴C-WEOC. Black triangles are Cryptomeria japonica and red circles are Quercus acutissima. Dashed line is 1:1 line.

Figure 4. The relationships between stream [DOC] of the BM watershed ([DOC]_BM) and stream [DOC] of the BR watershed ([DOC]_BR). Black circles and red squares are weekly collected stream DOC and stream DOC during storm events, respectively. The four white circles are outliers of weekly collected samples (> mean + 3 S.D.) which were excluded in the linear regression. Black and red dashed lines are regression lines of weekly collected samples and storm samples, respectively. Gray solid line is 1:1 line.

Figure 5. The relationships between the ratio of [DOC] to [sum of cations] and Δ¹⁴C-DOC of extracted soil solution (i.e. WEOC) under the two tree species and stream water. Black triangles are Cryptomeria japonica, and red circles are Quercus acutissima. Light to dark green symbols are stream water samples collected weekly and composited for each season, and during summer storms. Blue dashed line is the linear regression line for stream and extracted soil solution.

Figure 6. The relationships between Δ¹⁴C-SOC and Δ¹⁴C of soil DOC or soil WEOC. Data from nine previous studies are also included (Table 1). Blue triangles, purple circles, green diamonds, and gray stars are for conifers, deciduous trees, mixed forests, and other plants such as shrubs and grasses. Black triangles are for Cryptomeria japonica whereas red circles are for Quercus acutissima in this study. Gray and black dashed lines are linear regression line and 1:1 line, respectively.

van der Voort TS, Mannu U, Hagedorn F, McIntyre C, Walthert L, Schleppi P, Haghipour N, Eglinton TI. 2019. Dynamics of deep soil carbon – insights from 14C time series across a climatic gradient. Biogeosciences. 16(16):3233–3246. doi: 10.5194/bg-16-3233-2019.

 Web of Science ®Google Scholar

Nakanishi T, Atarashi-Andoh M, Koarashi J, Saito-Kokubu Y, Hirai K. 2012. Carbon isotopes of water-extractable organic carbon in a depth profile of forest soil imply a dynamic relationship with soil carbon. Eur J Soil Sci. 63(4):495–500. doi: 10.1111/j.1365-2389.2012.01465.x.

 Web of Science ®Google Scholar

Nakanishi T, Atarashi-Andoh M, Koarashi J, Saito-Kokubu Y, Hirai K. 2014. Seasonal and snowmelt-driven changes in the water-extractable organic carbon dynamics in a cool-temperate Japanese forest soil, estimated using the bomb-14C tracer. J Environ Radioact. 128:27–32. doi: 10.1016/j.jenvrad.2013.10.028.

 PubMed Web of Science ®Google Scholar

Sanderman J, Baldock JA, Amundson R. 2008. Dissolved organic carbon chemistry and dynamics in contrasting forest and grassland soils. Biogeochemistry. 89(2):181–198. doi: 10.1007/s10533-008-9211-x.

 Web of Science ®Google Scholar

Tegen I, Dörr H. 1996. measurements of soil organic matter, soil CO2 and dissolved organic carbon (1987–1992). Radiocarbon. 38(2):247–251. doi: 10.1017/S0033822200017628.

 Web of Science ®Google Scholar

Dutta K, Schuur EAG, Neff JC, Zimov SA. 2006. Potential carbon release from permafrost soils of Northeastern Siberia. Glob Change Biol. 12(12):2336–2351. doi: 10.1111/j.1365-2486.2006.01259.x.

 Web of Science ®Google Scholar

Trumbore SE, Schiff SL, Aravena R, Elgood R. 1992. Sources and transformation of dissolved organic carbon in the Harp Lake forested catchment: the role of soils. Radiocarbon. 34(3):626–635. doi: 10.1017/S0033822200063918.

 Web of Science ®Google Scholar

Fröberg M, Jardine PM, Hanson PJ, Swanston CW, Todd DE, Tarver JR, Garten CT. 2007. Low dissolved organic carbon input from fresh litter to deep mineral soils. Soil Sci Soc Am J. 71(2):347–354. doi: 10.2136/sssaj2006.0188.

 Web of Science ®Google Scholar

Fröberg M, Hanson PJ, Trumbore SE, Swanston CW, Todd DE. 2009. Flux of carbon from 14C-enriched leaf litter throughout a forest soil mesocosm. Geoderma. 149(3-4):181–188. doi: 10.1016/j.geoderma.2008.11.029.

 Web of Science ®Google Scholar

Michalzik B, Tipping E, Mulder J, Lancho JFG, Matzner E, Bryant CL, Clarke N, Lofts S, Esteban MAV. 2003. Modelling the production and transport of dissolved organic carbon in forest soils. Biogeochemistry. 66(3):241–264. doi: 10.1023/B:BIOG.0000005329.68861.27.

 Web of Science ®Google Scholar

Karltun E, Harrison A, Alriksson A, Bryant C, Garnett M, Olsson M. 2005. Old organic carbon in soil solution DOC after afforestation – Evidence from 14C analysis. Geoderma. 127(3–4):188–195. doi: 10.1016/j.geoderma.2004.12.008.

 Web of Science ®Google Scholar

Hensgens G, Laudon H, Johnson MS, Berggren M. 2021. The undetected loss of aged carbon from boreal mineral soils. Sci Rep. 11(1):6202. doi: 10.1038/s41598-021-85506-w.

 PubMed Web of Science ®Google Scholar