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Jeffrey LC, Johnston SG, Tait DR, Dittmann J, Maher DT. Rapid bark-mediated tree stem methane transport occurs independently of the transpiration stream in Melaleuca quinquenervia. THE NEW PHYTOLOGIST 2024; 242:49-60. [PMID: 37984803 DOI: 10.1111/nph.19404] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 10/27/2023] [Indexed: 11/22/2023]
Abstract
Tree stem methane emissions are important components of lowland forest methane budgets. The potential for species-specific behaviour among co-occurring lowland trees with contrasting bark characteristics has not been investigated. We compare bark-mediated methane transport in two common lowland species of contrasting bark characteristics (Melaleuca quinquenervia featuring spongy/layered bark with longitudinally continuous airspaces and Casuarina glauca featuring hard/dense common bark) through several manipulative experiments. First, the progressive cutting through M. quinquenervia bark layers caused exponential increases in methane fluxes (c. 3 orders of magnitude); however, sapwood-only fluxes were lower, suggesting that upward/axial methane transport occurs between bark layers. Second, concentrated methane pulse-injections into exposed M. quinquenervia bark, revealed rapid axial methane transport rates (1.42 mm s-1 ), which were further supported through laboratory-simulated experiments (1.41 mm s-1 ). Laboratory-simulated radial CH4 diffusion rates (through bark) were c. 20-times slower. Finally, girdling M. quinquenervia stems caused a near-instantaneous decrease in methane flux immediately above the cut. By contrast, girdling C. glauca displayed persistent, though diminished, methane fluxes. Overall, the experiments revealed evidence for rapid 'between-bark' methane transport independent from the transpiration stream in M. quinquenervia, which facilitates diffusive axial transport from the rhizosphere and/or sapwood sources. This contrasts with the slower, radial 'through-bark' diffusive-dominated gas transportation in C. glauca.
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Affiliation(s)
- Luke C Jeffrey
- School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Scott G Johnston
- School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Douglas R Tait
- School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Johannes Dittmann
- School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Damien T Maher
- School of Environment, Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
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Kajiura M, Tokida T. Diurnal variation in methane emission from a rice paddy due to ebullition. JOURNAL OF ENVIRONMENTAL QUALITY 2024; 53:265-273. [PMID: 38418922 DOI: 10.1002/jeq2.20553] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Accepted: 01/30/2024] [Indexed: 03/02/2024]
Abstract
Diurnal fluctuations in methane (CH4 ) emission are frequently observed in rice paddy fields, yet the driving mechanisms behind these variations are not fully understood. We posited that the observed diurnal patterns are predominantly due to temperature-dependent bubbling emissions (ebullition). To investigate this hypothesis, we conducted measurements of CH4 emission in a Japanese rice paddy using static chambers coupled with a high-time-resolution CH4 analyzer that allowed us to partition the total flux into its two principal components: plant-mediated transport and ebullition. Diurnal variation in the total flux was minimal during the early parts of reproductive growth (panicle formation and booting stages), when plant-mediated emission was dominant. At a later stage (heading period), ebullition accounted for 43%-70% of the total emission, and CH4 emission via both pathways varied diurnally; however, the diurnal range was much greater for bubbling emission (ratio of maximum to minimum = 3.5) than for plant-mediated emission (ratio of maximum to minimum = 1.4). The magnitude of emissions due to ebullition depended on the temperature, but was greater during the flux-increasing phase in the morning than the flux-decreasing phase in the afternoon even at the same temperature, forming a hysteresis in the flux versus temperature relationship. These findings support our hypothesis and indicate that abiotic processes, such as a change in the solubility of gases and the temperature dependence of the gas-phase volume (Charles's law), may play a central role in shaping the diurnal pattern of the CH4 ebullition.
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Affiliation(s)
- Masako Kajiura
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
| | - Takeshi Tokida
- Institute for Agro-Environmental Sciences, National Agriculture and Food Research Organization, Tsukuba, Japan
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Jeffrey LC, Maher DT, Tait DR, Reading MJ, Chiri E, Greening C, Johnston SG. Isotopic evidence for axial tree stem methane oxidation within subtropical lowland forests. THE NEW PHYTOLOGIST 2021; 230:2200-2212. [PMID: 33715152 DOI: 10.1111/nph.17343] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/13/2021] [Accepted: 03/08/2021] [Indexed: 06/12/2023]
Abstract
Knowledge regarding mechanisms moderating methane (CH4 ) sink/source behaviour along the soil-tree stem-atmosphere continuum remains incomplete. Here, we applied stable isotope analysis (δ13 C-CH4 ) to gain insights into axial CH4 transport and oxidation in two globally distributed subtropical lowland species (Melaleuca quinquenervia and Casuarina glauca). We found consistent trends in CH4 flux (decreasing with height) and δ13 C-CH4 enrichment (increasing with height) in relation to stem height from ground. The average lower tree stem δ13 C-CH4 (0-40 cm) of Melaleuca and Casuarina (-53.96‰ and -65.89‰) were similar to adjacent flooded soil CH4 ebullition (-52.87‰ and -62.98‰), suggesting that stem CH4 is derived mainly by soil sources. Upper stems (81-200 cm) displayed distinct δ13 C-CH4 enrichment (Melaleuca -44.6‰ and Casuarina -46.5‰, respectively). Coupled 3D-photogrammetry with novel 3D-stem measurements revealed distinct hotspots of CH4 flux and isotopic fractionation on Melaleuca, which were likely due to bark anomalies in which preferential pathways of gas efflux were enhanced. Diel experiments revealed greater δ13 C-CH4 enrichment and higher oxidation rates in the afternoon, compared with the morning. Overall, we estimated that c. 33% of the methane was oxidised between lower and upper stems during axial transport, therefore potentially representing a globally significant, yet previously unaccounted for, methane sink.
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Affiliation(s)
- Luke C Jeffrey
- SCU Geoscience, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
- Faculty of Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Damien T Maher
- SCU Geoscience, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
- Faculty of Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Douglas R Tait
- SCU Geoscience, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
- Faculty of Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Michael J Reading
- SCU Geoscience, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
- Faculty of Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
| | - Eleonora Chiri
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Chris Greening
- Department of Microbiology, Biomedicine Discovery Institute, Monash University, Clayton, VIC, 3800, Australia
| | - Scott G Johnston
- SCU Geoscience, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
- Faculty of Science and Engineering, Southern Cross University, PO Box 157, Lismore, NSW, 2480, Australia
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Gorh D, Baruah KK. Estimation of methane and nitrous oxide emission from wetland rice paddies with reference to global warming potential. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2019; 26:16331-16344. [PMID: 30977006 DOI: 10.1007/s11356-019-05026-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2018] [Accepted: 03/27/2019] [Indexed: 06/09/2023]
Abstract
Methane (CH4) and nitrous oxide (N2O) are two important greenhouse gases (GHG) and contribute largely to global warming and climate change. The impact of physiological characteristics of rice genotypes on global warming potential (GWP) and greenhouse gas intensity (GHGI) is not well documented. A 2-year field experiment was conducted with eight summer rice varieties: Dinanath, Joymoti, Kanaklata, Swarnabh, IR 64, Tapaswami (modern varieties), Number 9, and Jagilee Boro (indigenous varieties) for two successive seasons (December-June, 2015-2016 and December-June, 2016-2017) to estimate their GWP and GHGI. The GWP of the rice varieties ranged from 841.52 to 1288.67 kg CO2-equiv. ha-1 and GHGI from 0.184 to 0.854 kg CO2-equiv. kg-1 grain yield. Significant differences (p < 0.05) in seasonal GHG emission, GWP, GHGI, CEE (carbon equivalent emission), photosynthetic efficiency, stomatal conductance, transpiration rate, and grain productivity among the rice varieties were observed during the investigation. A good correlation of GWP (p < 0.01) was recorded with rate of stomatal conductance and transpiration rate of the varieties. The present study reveals a strong relationship between plant biomass (p < 0.01) with GWP and CEE of the rice varieties. The variety IR 64 and Number 9 are identified as the most suitable variety with lowest GWP (909.85 and 876.68 kg CO2-equiv. ha-1 respectively) and GHGI (0.192 and 0.227 kg CO2-equiv. kg-1 grain yield respectively) accompanied by higher grain productivity (4839 and 3867 kg ha-1 respectively). Observations from the study suggest that agricultural productivity and GHG mitigation can be simultaneously achieved by proper selection of rice genotypes.
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Affiliation(s)
- Dipti Gorh
- Department of Environmental Science, Tezpur University, Napaam, Assam, 784028, India
| | - Kushal Kumar Baruah
- Department of Environmental Science, Tezpur University, Napaam, Assam, 784028, India.
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