Reducing uncertainties of organic matter transport in the land-ocean continuum of tropical systems

Aquatic environments integrate multiple sources and processes over space and time that influence ecosystem functionality. The complexity of these systems and their multiple interactions with the surrounding environment are conceptualised, but often lack empirical scrutiny that allows further understanding of how inland waters mobilise, and utilise carbon and nutrients during transportation to the ocean. This is particularly evident in tropical waters. To advance or understanding we apply advanced geochemical analyses (liquid chromatography with organic carbon and nitrogen detection and high-resolution mass spectrometry) to investigate the flux and composition of dissolved organic matter (DOM) in conjunction with measurements of surfactant activity and organic biomarkers to explore differences between the main water column and the water’s surface film, known as the surface microlayer. We show that the transition from the dry to the wet season is a likely critical factor in DOM mobilisation and transport, while the enrichment of DOM in the microlayer is dominated by surface-active organics likely of biogenic origin from land to ocean of in tropical ecosystems. We further explore the impacts of organic matter enriched in the surface microlayer on the exchange of climate active gases in natural and perturbed fresh and marine waters.

Presentation Preference: Oral

Primary Presenter: Ryan Pereira, Heriot-Watt University (r.pereira@hw.ac.uk)

Authors:

Ryan Pereira, Heriot-Watt University  (r.pereira@hw.ac.uk)

Sevda Norouzi, Heriot-Watt University  (s.norouzi@hw.ac.uk)

Juliane Bischoff, Heriot-Watt University  (j.bischoff@hw.ac.uk)

Beth Cowling, Heriot-Watt University  (bac2000@hw.ac.uk)

Thomas Wagner, Heriot-Watt University  (t.wagner@hw.ac.uk)

Michel Kaiser, Heriot-Watt University  (m.kaiser@hw.ac.uk)