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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!
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, their role shifts dramatically—but not always in the ways we expect. Much of the focus has been on emissions to the atmosphere. But a growing body of work shows that a significant fraction of carbon loss may instead be quietly transported away through water, with drainage networks acting as hidden conduits.
Dr. Pierre Taillardat, now at the Nanyang Technological University, together with colleagues from the National University of Singapore, the UK Centre for Ecology & Hydrology, and Indonesian institutions including IPB University and Universitas Gadjah Mada, 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 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 peatland in Sumatra. One like this was turned into a tree plantation for making paper and the NTU-led study suggests that a substantial amount of carbon stored in the peatland leaked through the plantations’ drainage canals. Credit: Pierre Taillardat
Not Just Emissions — Carbon on the Move
The study was motivated by the need to reassess the common assumption that emissions from peatland conversion are primarily vertical fluxes from soil to atmosphere. 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 major 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 produced 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. They allowed the researchers to connect subsurface 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 point to a clear shift. 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 may represent a substantial 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 export of dissolved carbon. The system shifts from storing carbon to 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.
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 carbon losses from belowground pools and water bodies occur through multiple oxic and anoxic pathways, 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 G2201-i 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