Root oxygen mitigates methane fluxes in tropical peatlands

Girkin, Nicholas T.; Vane, Christopher H.; Turner, Benjamín L.; Ostle, Nicholas J.; Sjögersten, Sofie

doi:10.1088/1748-9326/ab8495

Cited by 24 publications

(15 citation statements)

References 45 publications

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“…This may be because of the influence of oil palm rhizosphere, as plant rhizosphere and their nitrogen uptake mechanisms have been shown to increase the pH in rhizosphere (Nye, 1981). Similar increases in pH closer to tree and plant stems were also observed in Panamanian peatlands (Girkin et al, 2019) and associated with differences in the concentration and composition of root exudates (Girkin et al, 2018a,b) and oxygen (Girkin et al, 2020b).…”

Section: Discussionsupporting

confidence: 55%

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

Dhandapani

Girkin

Evers

2021

Soil Use and Management

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The expansion of oil palm monocultures into globally important Southeast Asian tropical peatlands has caused severe environmental damage. Despite much of the current focus of environmental impacts being directed at industrial scale plantations, over half of oil palm land‐use cover in Southeast Asia is from smallholder plantations. We differentiated a first generation smallholder oil palm monoculture into 8 different sampling zones, and further divided the 8 sampling zones into oil palm root influenced (Proximal) and reduced root influence (Distal) areas, to assess how peat properties regulate in situ carbon dioxide (CO2) and methane (CH4) fluxes. We found that all the physico‐chemical properties and nutrient concentrations except sulphur varied significantly among sampling zones. All physico‐chemical properties except electrical conductivity, and all nutrient content except nitrogen and potassium varied significantly between Proximal and Distal areas. Mean CO2 fluxes (ranged between 382 and 1191 mg m−2 h−1) varied significantly among sampling zones, and between Proximal and Distal areas, with notably high emissions in Dead Wood and Path zones, and consistently higher emissions in Proximal areas compared to Distal areas within almost all the zones. CH4 fluxes (ranged between −32 and 243 µg m−2 h−1) did not significantly vary between Proximal and Distal areas, however significantly varied amongst sampling zones. CH4 flux was notably high in Canal Edge and Understorey Ferns zones, and negative in Dead Wood zone. The results demonstrate the high heterogeneity of peat properties within oil palm monoculture, strengthening the need for intensive sampling to characterize a land use in the tropical peatlands.

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Section: Discussionsupporting

confidence: 55%

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

Dhandapani

Girkin

Evers

2021

Soil Use and Management

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“…In non-oil palm peat with fern vegetation, the lignin might has not been decomposed compared to oil palm which has deeper roots. Girkin et al (2020) reported that roots exclude oxygen that affect the decomposition activities. Lignin is a material that is quite resistant to decomposition.…”

Section: Discussionmentioning

confidence: 99%

“…Differences between species are significant. Root oxygen mitigates methane fluxes in tropical peatlands (Girkin et al 2020).…”

Section: Discussionmentioning

confidence: 99%

Exploration of Lignocellulolytic Microbes in Oil Palm Rhizosphere on Peat Soils and Their Respiration Activities

Widiastuti¹,

SISWANTO²,

Taniwiryono³

et al. 2021

Microbiol Indones

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Microbial respiration in peatlands plays a role in contributing CO emissions. Studies of microbial exploration 2 and respiration on peat soils in oil palm plantations have not been widely reported. This study was aimed to explore lignocellulolytic microbes found in peat soils (planted with 12-year-old oil palm, and fern vegetation peat), and compared with that found in mineral soils. Exploration was done by growing the samples on specific medium for each group of microbial functions. Respiration activity of the obtained culture was then analyzed based on the oxidation of peroxidase catalysis using a chromogen substrate (tetramethylbenzidine) and measured using spectrophotometry at a wavelength of 450 nm. The results showed that both in mineral (MS) and peat 2 planted with oil palm (GS) in a depths of 0-20 cm, lignolytic fungi were found with a population of 17 x 10 . Similar results were also found in peatland with fern vegetation (GNS) but at a depth of 20-40 cm. Lignolytic bacteria (related to methylene blue degradation) can be found on peat soils planted with oil palm at a depth of 0-60 cm and the population increases with increasing depth. This lignolytic bacteria was also found on peat soils with fern vegetation and mineral soils planted with oil palm. At a depth of 0-20 cm the population of lignolytic bacteria in non-oil palm peat is highest. Cellulolytic bacteria were isolated at a depth of 0-60 cm. Cellulolytic bacterial populations were highest in oil palm peat at all depths compared to other samples. Respiration analysis of several dominant isolates showed fairly high variation between microbial function groups and within the same function group. The lignolytic microbial group degrading methylene blue showed high respiration activity and varies greatly (0.19-1.85 MER). While the respiration activity of cellulolytic bacteria ranged from 0.45 to 0.62 MER.

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“…Despite its large spatial extent, relatively little is known about greenhouse gas (GHG) emissions from the Cuvette Centrale. Although pristine tropical peatlands are significant sources of methane (CH 4 ) emissions (Girkin et al, 2020) they are usually net carbon sinks (i.e. they accumulate more carbon than the amount of carbon released through decomposition).…”

Section: Peatland Carbon Stocks and Cyclingmentioning

confidence: 99%

“…Second through species-specific adaptations found in flood-tolerant plants in tropical peat swamp forest that increase gas exchange under waterlogged conditions, such as enlarged lenticels (stem pores), the presence of aerenchyma (spongy, porous tissue) and pneumatophores (aerial roots specialised for gas exchange; Pangala et al, 2017). These adaptations can affect fluxes by either increasing oxygenation in the rooting zone, potentially increasing CO 2 production or decreasing CH 4 production, or by providing a physical pathway through which CH 4 , produced belowground, can travel to the atmosphere (Girkin et al, 2020).…”

Section: Studymentioning

confidence: 99%

Current knowledge on the Cuvette Centrale peatland complex and future research directions

et al. 2022

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The Cuvette Centrale is the largest tropical peatland complex in the world, covering approximately 145,000 km2 across the Republic of Congo and the Democratic Republic of Congo. It stores ca. 30.6 Pg C, the equivalent of three years of global carbon dioxide emissions and is now the first trans-national Ramsar site. Despite its size and importance as a global carbon store, relatively little is known about key aspects of its ecology and history, including its formation, the scale of greenhouse gas flows, its biodiversity and its history of human activity. Here, we synthesise available knowledge on the Cuvette Centrale, identifying key areas for further research. Finally, we review the potential of mathematical models to assess future trajectories for the peatlands in terms of the potential impacts of resource extraction or climate change.

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Root oxygen mitigates methane fluxes in tropical peatlands

Cited by 24 publications

References 45 publications

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

Spatial variability of surface peat properties and carbon emissions in a tropical peatland oil palm monoculture during a dry season

Exploration of Lignocellulolytic Microbes in Oil Palm Rhizosphere on Peat Soils and Their Respiration Activities

Current knowledge on the Cuvette Centrale peatland complex and future research directions

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