Unveiling the Predictable Transformation of Dissolved Organic Matter: A Global Study
A groundbreaking study has revealed the fascinating and predictable changes in dissolved organic matter (DOM) molecular communities across the Earth's oceans, offering a new perspective on chemogeography.
A team of researchers, led by Prof. Wang Jianjun from the Nanjing Institute of Geography and Limnology of the Chinese Academy of Sciences, has created a global map of DOM distribution and variation. The study, published in Environmental Science & Technology, analyzed over 800 samples from 124 stations across the Atlantic, Pacific, and Southern oceans, providing an unprecedented view of DOM's behavior.
The researchers discovered that DOM molecular 'communities' undergo predictable changes as water masses are separated by greater horizontal or vertical distances. This phenomenon, termed 'chemohomogenization', suggests a convergence towards a shared pool of long-lived molecules in the deep sea. Interestingly, this pattern slows significantly in the deep ocean and at high latitudes, indicating a complex interplay of environmental factors.
The study further reveals that environmental factors shape DOM in the upper 200 meters of the ocean and at mid-latitudes. However, at broader scales, pure spatial effects, consistent with dispersal limitation and unmeasured variables, account for the observed variance. This finding has significant implications for understanding ocean carbon storage and its response to climate change.
"Warming will likely expand horizontal homogenization but weaken vertical mixing, especially at high latitudes," said Prof. Wang. "This could enhance the deep ocean's role as a carbon sink by preserving more organic molecules over time."
The findings establish a new chemogeographical theoretical framework, offering a tool to predict how ocean carbon storage will respond to climate change. This study not only advances our understanding of DOM but also provides a valuable resource for future research in oceanography and climate science.
For more information, see the original research published in Environmental Science & Technology: Jianjun Wang et al, Toward the Chemogeography of Dissolved Organic Matter in the Global Ocean, Environmental Science & Technology (2025). DOI: 10.1021/acs.est.5c02477
