[CARBONIUM CONFERENCE] September 2025

• Fransesco Ulloa Cedamanos (Post doc fellow) / Research Institute for the Environment and Livelihoods, Charles Darwin University
• Clément Duvert (senior research fellow) / Research Institute for the Environment and Livelihoods, Charles Darwin University

These two researchers will give two seminars during their visit to France, which can be followed via video link. We hope to see many of you there!

PROGRAMME BELOW

Monday 15 September 2pm (Osug B) Lecture in English

From source to ocean: river carbon dynamics across Australia

Abstract: Rivers and streams play a key role in the global carbon (C) cycle, but their role in carbon storage, transformation and export remains poorly understood in Australia. In this presentation, I bring together three complementary studies from my postdoctoral research that fill this gap at different spatial and temporal scales. First, I present OzRiCa, the first national database of carbon concentrations, gas fluxes and isotopes in Australian watercourses. Compiling nearly 55,000 observations from 2,900 sites over six decades, OzRiCa highlights significant knowledge gaps, particularly in tropical and semi-arid regions, and provides a robust platform for assessing riverine carbon processes. On this basis, I present continent-wide estimates of riverine carbon exports to the ocean, showing that tropical rivers dominate national carbon fluxes, with wet season pulses leading to up to 420-fold increases in exports compared to dry periods. Finally, I focus on headwater streams in contrasting Australian biomes, where intensive field campaigns and geochemical/isotopic modelling reveal that dissolved inorganic carbon is largely biogenic in origin and that CO2 leakage far exceeds downstream transport. Together, these studies demonstrate the central role of Australian rivers, particularly tropical rivers and headwater streams, as dynamic hotspots for carbon cycling, emissions and exports. They also provide an empirical and conceptual framework for integrating river processes into regional and global carbon budgets, while identifying monitoring priorities in a context of rapid environmental change.

Join via Zoom: https://grenoble-inp.zoom.us/j/92031623167

Meeting ID: 920 3162 3167 / Passcode: 610273

Friday, 19 September, 1:30 p.m.: Lecture in English

Greenhouse gas emissions from inland waters: perspectives from tropical regions and Australia

Clément Duvert (principal investigator): Institute for Environmental and Livelihood Research, Charles Darwin University

Abstract: Tropical rivers, lakes and wetlands receive large amounts of terrestrial carbon and nitrogen, which they process and release as greenhouse gases (GHGs). However, our understanding of tropical inland waters has been dominated by data from a few systems (particularly the Amazon), leading to a simplistic view of the tropics as a homogeneous region. In this presentation, I will provide an overview of work conducted in the tropics and Australia over the past decade. I will begin by describing the role of hydrological connectivity in linking terrestrial and aquatic environments, then discuss the challenges of identifying carbon sources in watersheds. I will then present the results of a new database of GHG observations in tropical inland waters, highlighting the extreme spatial heterogeneity of fluxes, the role of small streams and wetlands as emission hotspots, and the importance of seasonal pulsations in triggering emissions. Finally, I will address remaining uncertainties, including the contribution of methane boiling, one of the least constrained components of inland water GHG budgets.

Join via Zoom: https://univ-grenoble-alpes-fr.zoom.us/j/94970127128

pwd=OuyBnFiuE9oaD1F4uPTsPYkWEM2cfR.1

Join the Zoom meeting: https://grenoble-inp.zoom.us/j/92031623167

Meeting ID: 920 3162 3167 / Passcode: 610273