Melting glaciers could be triggering a ‘feedback process’ that causes further climate change, according to new research.
An international research team led by the University has for the first time linked glacier-fed mountain rivers with higher rates of plant material decomposition, a major process in the global carbon cycle.
As mountain glaciers melt, water is channelled into rivers downstream. But with global warming accelerating the loss of glaciers, rivers have warmer water temperatures and are less prone to variable water flow and sediment movement. These conditions are then much more favourable for fungi to establish and grow.
Fungi living in these rivers decompose organic matter such as plant leaves and wood, eventually leading to the release of carbon dioxide into the air. The process – a key part of global river carbon cycling – has now been measured in 57 rivers in six mountain ranges across the world, in Austria, Ecuador, France, New Zealand, Norway and the United States.
The findings, funded mainly by the Natural Environment Research Council, are published in the journal Nature Climate Change.
Lead author Sarah Fell, of Leeds’ School of Geography and [email protected], said similar patterns and processes were discovered worldwide.
“We found increases in the rate of organic matter decomposition in mountain rivers, which can then be expected to lead to more carbon release to the atmosphere.
“This is an unexpected form of climate feedback, whereby warming drives glacier loss, which in turn rapidly recycles carbon in rivers before it is returned to the atmosphere.”
The retreat of mountain glaciers is accelerating at an unprecedented rate in many parts of the world, with climate change predicted to drive continued ice loss throughout the 21st century.
However, the response of river ecosystem processes (such as nutrient and carbon cycling) to decreasing glacier cover, and the role of fungal biodiversity in driving these, remains poorly understood.
The study was published in University of Leeds