Reactivity of terrestrially derived dissolved organic matter in aquatic systems - relation to molecular composition and bacterial community structure (38927)

Aquatic systems play a significant role in transforming, remineralizing and sequestering, terrestrially derived organic matter (tDOM). The prevalence of tDOM in aquatic systems is a forcing factor affecting light climate, species distributions, productivity and biogeochemical cycles in freshwater systems and many coastal and marine systems.

Despite the significance of tDOM for the function of aquatic systems and global biogeochemical C cycling, we are only beginning to understand the quantitative and qualitative aspects of aquatic tDOM processes. A key to a better understanding of the role of tDOM is compound level information on the distribution and reactivity of tDOM.

The objectives with the project were to:
- examine which molecular size fractions of DOM are available to degradation processes such as flocculation/sedimentation, photooxidation and bacterial utilization and hence how reactivity of tDOM connects to molecular composition.
- determine if bacterial community structure in different systems alter the molecular size distribution of tDOM differently.
In essence, the project addressed if and how the molecular composition of tDOM and the structure of bacterial communities determine the fate of tDOM in aquatic systems.

The project was funded by the Swedish Research Council.

Research area: Oceanography