Origin and age of riverine carbon across a land use gradient in tropical Australia

Funding source
Australian Institute of Nuclear Science and Engineering

Background
Streams and rivers in the wet tropics tend to export considerable amounts of terrestrial carbon to the ocean. This is important because some of the carbon thought to be stored by ecosystems is in fact lost via this aquatic pathway. But there are many unknowns related to the amount, origin and age of the carbon that leaks out of tropical soils. Also unknown is the effect of land use change, such as the conversion of pristine rainforest to agriculture, on the riverine export of terrestrial carbon.
Recent work suggests that deforested areas in the tropics can export ancient carbon into waterways, a process that may compromise ecosystem health and further fuel the greenhouse effect. But to date, no such research has been conducted in the fragile ecosystems of the wet tropics of northern Australia. These major unknowns are likely to cause errors in estimates of the Australian net carbon soil storage, and may result in poorly informed policy and erroneous predictions about climate and land use change impacts.

Expected outcomes
This project will make a contribution to understanding the movement of carbon from soils to rivers, and the impact of current and future land use change on soil carbon storage in the wet tropics of Australia. Utilising unique radioisotope technology, we will examine the nature and age of riverine carbon across a land use continuum, from native rainforest to land converted for agriculture. For each land use we will determine the contributions of recently produced carbon versus older carbon to the riverine export flux.

Team
Dr Clément Duvert, CDU
Dr Dioni Cendón, Australian Nuclear Science and Technology Organisation
A/Prof David Butman, University of Washington
A/Prof Robert Spencer, Florida State University
Prof Lindsay Hutley, CDU