Chemogeography of dissolved organic matter across freshwater and marine ecosystems

Dissolved organic matter (DOM) consists of thousands of molecules whose spatial variation reflects the ecological and biogeochemical processes shaping carbon cycling. We introduce a framework for the chemogeography of DOM and demonstrate its utility across major aquatic domains. In rivers, molecular richness and composition show clear geographic structure driven by watershed characteristics, hydrology, and climatic factors. Moving to the global ocean, chemogeographic turnover reveals systematic horizontal and vertical gradients, with decreasing rates toward deep and high-latitude waters where DOM composition becomes increasingly homogenized. For lakes, we highlight how functional chemogeography, integrating intrinsic molecular traits with extrinsic traits such as environmental responses and transformation pathways, provides explanatory power for DOM persistence, ecosystem processes, and predictive modeling. Together, these examples show that chemogeography and its functional extension offer a scalable framework for linking molecular complexity with environmental drivers across ecosystems such as rivers, lakes, and oceans. This approach advances our ability to interpret and predict DOM dynamics under global environmental change.

Presentation Preference: Standard Oral (12 Minutes)

Primary Presenter: Jianjun WANG, Nanjing Institute of Geography and Limnology Chinese Academy of Sciences (jjwang@niglas.ac.cn)

Authors:

Ang Hu, Nanjing Institute of Geography and Limnology Chinese Academy of Sciences  (anghu@niglas.ac.cn)