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  • Aquatic processing enhances the loss of aged carbon from drained and burned peatlands. Global change biology Bowen, J. C., Hoyt, A. M., Xu, X., Nuriman, M., Anshari, G. Z., Wahyudio, P. J., Aluwihare, L. I. 2024; 30 (7): e17394

    Abstract

    Water-logged peatlands store tremendous amounts of soil carbon (C) globally, accumulating C over millennia. As peatlands become disturbed by human activity, these long-term C stores are getting destabilized and ultimately released as greenhouse gases that may exacerbate climate change. Oxidation of the dissolved organic carbon (DOC) mobilized from disturbed soils to streams and canals may be one avenue for the transfer of previously stored, millennia-aged C to the atmosphere. However, it remains unknown whether aged peat-derived DOC undergoes oxidation to carbon dioxide (CO2) following disturbance. Here, we use a new approach to measure the radiocarbon content of CO2 produced from the oxidation of DOC in canals overlying peatland soils that have undergone widespread disturbance in Indonesia. This work shows for the first time that aged DOC mobilized from drained and burned peatland soils is susceptible to oxidation by both microbial respiration and photomineralization over aquatic travel times for DOC. The bulk radiocarbon age of CO2 produced during canal oxidation ranged from modern to ~1300 years before present. These ages for CO2 were most strongly influenced by canal water depth, which was proportional to the water table level where DOC is mobilized from disturbed soils to canals. Canal microbes preferentially respired older or younger organic C pools to CO2, and this may have been facilitated by the use of a small particulate organic C pool over the dissolved pool. Given that high densities of canals are generally associated with lower water tables and higher fire risk, our findings suggest that peatland areas with high canal density may be a hotspot for the loss of aged C on the landscape. Taken together, the results of this study show how and why aquatic processing of organic C on the landscape can enhance the transfer of long-term peat C stores to the atmosphere following disturbance.

    View details for DOI 10.1111/gcb.17394

    View details for PubMedID 38988095

  • Quantifying the fluxes of carbon loss from an undrained tropical peatland ecosystem in Indonesia. Scientific reports Asyhari, A., Gangga, A., Putra, C. A., Ritonga, R. P., Candra, R. A., Anshari, G. Z., Bowen, J. C., Perryman, C. R., Novita, N. 2024; 14 (1): 11459

    Abstract

    Conservation of undrained tropical peatland ecosystems is critical for climate change mitigation as they store a tremendous amount of soil carbon that is preserved under anoxic water-logged conditions. Unfortunately, there are too few measurements of carbon fluxes from these ecosystems to estimate the climate change mitigation potential from such conservation efforts. Here, we measured carbon dioxide (CO2) and methane (CH4) fluxes as well as fluvial organic carbon export over the peat swamp forest within an undrained tropical peatland landscape in East Kalimantan, Indonesia. Our measurements throughout one year (Oct 2022-Sep 2023) showed that despite its water-logged condition, peat and water overlying the swamp forest on average emits 11.02 ± 0.49 MgCO2 ha-1 yr-1 of CO2 and 0.58 ± 0.04 MgCO2e ha-1 yr-1 of CH4. Further, the fluvial organic carbon export contributes to additional carbon loss of 1.68 ± 0.06 MgCO2e ha-1 yr-1. Our results help improve the accuracy of carbon accounting from undrained tropical peatlands, where we estimated a total carbon loss of 13.28 ± 0.50 MgCO2e ha-1 yr-1. Nevertheless, the total carbon loss reported from our sites is about half than what is reported from the drained peatland landscapes in the region and resulted in a larger onsite carbon sink potential estimate compared to other undrained peat swamp forests. Together, these findings indicate that conserving the remaining undrained peatland ecosystems in Indonesia from drainage and degradation is a promising natural climate solution strategy that avoids significant carbon emissions.

    View details for DOI 10.1038/s41598-024-62233-6

    View details for PubMedID 38769331

    View details for PubMedCentralID 5495247

  • Canal networks regulate aquatic losses of carbon from degraded tropical peatlands NATURE GEOSCIENCE Bowen, J. C., Wahyudio, P. J., Anshari, G. Z., Aluwihare, L. I., Hoyt, A. M. 2024