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Sohom Roy
Application Scientist at Picarro
Picarro Spotlight is a blog series showcasing important scientific work from our customers around the world. Each blog is selected and summarized by our team. Enjoy!
Pristine tropical peatlands are among the most efficient long-term carbon stores on Earth, locking away organic carbon over thousands of years under waterlogged conditions. When these systems are drained and converted into plantations, they shift from long-term carbon sinks to active sources of carbon loss—but not always through the pathways we typically measure. Much of the previous research has been on studying carbon emissions to the atmosphere. But a growing body of work shows that a still unknown fraction of carbon loss may instead be quietly transported to other places through water, with drainage networks acting as hidden conduits.
Dr. Pierre Taillardat, now at Nanyang Technological University, together with co-authors from the National University of Singapore, Nanyang Technological University, James Cook University (Australia), the UK Centre for Ecology & Hydrology, and Indonesian institutions including IPB University and Asia Pacific Resources International Ltd., set out to investigate how methane (CH₄) and carbon dioxide (CO₂) are produced, transformed, and transported in a drained tropical peatland plantation in Sumatra. Their study, published in Geophysical Research Letters as “Methane and Carbon Dioxide Production and Emission Pathways in the Belowground and Draining Water Bodies of a Tropical Peatland Plantation Forest,” provides one of the most detailed views to date of carbon cycling across soil, porewater, and drainage networks in these systems.
The work was carried out in an industrial, short-rotation fiberwood (Acacia crassicarpa) plantation located on a large ombrotrophic peatland complex on Sumatra’s Kampar Peninsula. The peat underlying the site is thousands of years old, and the plantation is managed through a network of ditches and canals designed to regulate the water table for plantation productivity.
Across multiple field campaigns, the team measured dissolved carbon forms in both peat porewater (belowground) and surface waters (ditches/canals), then used stable isotopes and radiocarbon to determine carbon sources, ages, and dominant production pathways.
Figure 1: A typical undisturbed peatland in Sumatra. One like this was turned into a tree plantation for making paper and the NUS led study investigates carbon production, transformation and transport process in a managed peatland plantation system, including the role of canals in lateral carbon movement. Credit: Pierre Taillardat
Not Just Emissions — Carbon on the Move
The study was motivated by the need to better understand carbon pathways beyond vertical emissions, particularly the processes by which carbon is produced, transformed, and transported within drained peatland systems. It aimed to investigate the processes by which carbon is mobilized belowground and transported laterally through water before it is ever released.
Measurements across porewaters and drainage canals revealed exceptionally high concentrations of dissolved organic carbon, CO₂, and CH₄, identifying plantation drainage systems as conduits of carbon loss. Much of this carbon was not recently fixed but originated from older peat deposits—often centuries old—indicating the release of long-stored carbon reservoirs.
From Soil to Stream: Linking the Full Carbon Pathway
Capturing these dynamics required tracking carbon across multiple phases. The team combined dissolved gas measurements with isotopic and radiocarbon analyses to separate newly released carbon from deeper, legacy peat carbon. The result is a system where fresh inputs and old carbon are tightly coupled.
High-precision measurements of CO₂ and CH₄ concentrations and isotopic signatures using Picarro G2201-i analyzers were central to this effort. These instruments allowed the researchers to assess the linkages of subsurface carbon production with surface and aquatic transport pathways, through the development of mass-balance models. This moved the study beyond simple flux measurements to a mechanistic understanding of where carbon comes from and how it moves.
The results contribute to the changing the paradigm on carbon cycling in peatlands. Carbon is not only emitted from soils. It also dissolves within porewaters, moves through drainage networks, and is then released downstream to the atmosphere or the ocean. This lateral pathway is rarely captured in conventional measurements, yet it represents a potentially important and often underrepresented component of total carbon loss.
Figure 2: Conceptual model of biogeochemical processes in peat porewater and surface water. Adapted from Taillardat et al. (2025), Geophysical Research Letters, CC BY 4.0.
A Trade-Off That Isn’t What It Seems
Drainage also reshapes the balance between methane and carbon dioxide. Methane concentrations in plantation waters are often lower than in natural peatland streams. This reflects increased oxygen availability and enhanced methane oxidation. At first glance, this might seem like a benefit.
It isn’t.
Aerobic conditions accelerate decomposition, increasing CO₂ production while enhancing the concentration of dissolved carbon. The system shifts from storing carbon to re-mobilizing it. Even if methane decreases, overall climate impact does not. The landscape becomes both productive and leaky—generating new carbon while releasing older, stored carbon. Understanding this carbon re-mobilisation dynamic is essential for accounting for the climate costs of peatland drainage and for designing management strategies that consider net long-term carbon stability.
Rethinking How We Measure Impact
These findings matter at scale. Approximately 41% of Southeast Asia’s peatlands have already been altered by land-use change, with plantation conversion among the most widespread outcomes. Yet most carbon accounting still focuses on direct gaseous emissions.
This study demonstrates that that carbon is produced, transformed, and transported through multiple oxic and anoxic pathway, including lateral pathway, as well as through lateral transfers that are often overlooked in traditional net ecosystem carbon accounting.
By resolving carbon production and transport across soil and water simultaneously, this work calls for a more complete view of peatland emissions. One that captures both vertical fluxes and lateral transfers. Technologies like Picarro’s CRDS analyzers make this possible—enabling high-resolution, system-level insights that ensure critical carbon pathways are not overlooked in climate assessments and mitigation strategies.
Figure 3: Dr. Taillardat's Lab
For More Information
Read the Paper - Taillardat et al, Geophysical Research Letters, 2025
Explore the Picarro Research Center