Dissolved organic matter: Climate change’s double-edged player in global carbon and pollution cycles

Overview

As global temperatures climb, a critical but often overlooked component of ecosystems is stepping into the spotlight: dissolved organic matter (DOM). Found everywhere from river water to forest soils, DOM moves carbon, nutrients, and pollutants across environments and scales.

Role of DOM in climate and pollution cycles

A new review led by scientists from Kunming University of Science & Technology and international partners finds DOM to be both a buffer and a potential accelerator of climate change, playing a surprisingly complex role in the planet’s environmental balance.

Composition and sources

DOM is a diverse mixture of molecules released from decomposed plants, microorganisms, and even plastics. These sources contribute to its wide range of chemical properties and environmental impacts.

Impact of climate change on DOM

When temperatures rise and rainfall patterns shift, DOM’s molecular structure changes, altering its environmental behavior and biological effects. Climate-driven changes render DOM both a concern and a potential solution in the face of global warming.

“Our work highlights how global warming can push DOM to act as a carbon source, fueling greenhouse gas emissions, or as a carbon sink, capturing carbon for long periods,” says the lead author.

Climate-driven processes

Events such as droughts, floods, wildfires, and permafrost thaw shape how DOM forms, transforms, and interacts with ecosystems. These processes influence whether DOM tends to store carbon or release it to the atmosphere.

Chemical characteristics

Global warming increases the aromaticity and carboxyl content of DOM, resulting in molecules with higher stability or higher reactivity. The fate of these molecules helps determine whether DOM stores carbon or releases it.

Key takeaway

DOM’s response to climate change is dual: it can mitigate or amplify climate effects depending on environmental conditions and DOM’s evolving chemistry.

Author summary

Global warming reshapes DOM chemistry and behavior, making it either a carbon sink or a carbon source, with broader implications for carbon cycling and pollutant dynamics.

EurekAlert! — 2025-11-19