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Carbon Science for the [Necro]masses: A Fungal Study in Black and White

Kennedy Lab embarks on a new Norwegian collaboration to study the relationship between rotting fungus and carbon cycling on a global scale.
 
The process of sequestering atmospheric carbon is no simple task. Yet as global warming continues to take center stage in many fields of biological study, it is becoming increasingly important for humans to understand more precisely how carbon moves between land and air. Lurking beneath the soil lies an unsuspecting — and quite dead — carbon emissions candidate. In a new collaboration with the University of Olso (UiO) and the Norwegian University of Life Sciences (NMBU), the Kennedy lab will unearth new knowledge of how fungal necromass affects carbon cycling.
 
Everyone is familiar with fungal fruiting bodies — i.e. mushrooms as they appear above ground. What many do not realize is that these fruiting bodies are only the tip of the iceberg. Fungal networks known as mycelia stretch throughout soils, often spanning hundreds of feet and sometimes many miles to silently connect distant parts of ecosystems. “Based on this growth form, some fungi are among the largest and most long-lived organisms on the planet,” says Peter Kennedy, a fungal expert in the departments of plant biology and ecology, evolution and behavior.
 
Large plants like trees are excellent at capturing greenhouse gases from the atmosphere. New research, however, suggests that the story doesn’t end there. Certain species of fungi enmesh themselves among root systems to feed on the carbon deposited by trees belowground. When these fungi die, they become rotting clumps of dead tissue called necromass, at which point other types of fungi and microbes join in on the subterranean feast.
 
“For years, research focused exclusively on aboveground inputs of plant material as the dominant contributor to organic matter held in soil,” says Christopher Fernandez, a post-doctoral researcher in Kennedy’s lab. “It has become increasingly clear that the input of root and fungal necromass are also major sources in boreal soils, which hold a disproportionate amount of the world’s soil carbon.”
 
Kennedy and Fernandez will work with UiO and NMBU collaborators to compare a suite of fungal species that are among the most common in boreal peatlands and forests. Fungi, like plants and animals, vary tremendously in their physical appearance. These differences have the potential to alter important ecosystem processes. Interestingly, some fungi have mycelium that is white while others are black.
 
“Certain fungi generate a tremendous amount of melanin in their cell walls. In high concentrations, melanin gives fungal mycelia a dark brown to black appearance,” says Fernandez. “Because of its complex chemical structure, melanin is very resistant to decomposition. The melanin content of fungal necromass may determine how much carbon is sequestered in soils.”
 
By comparing local results with those from Norway, Kennedy hopes to paint a broader and more comprehensive picture of soil carbon cycling. “The ‘black box’ paradigm that was used in ecosystem ecology for decades is no longer required,” he argues. “We have both the tools and research teams to tackle important outstanding questions in exciting new ways.” – Colleen Smith
 

“For years, research focused exclusively on aboveground inputs of plant material as the dominant contributor to organic matter held in soil. It has become increasingly clear that the input of root and fungal necromass are also major sources in boreal soils, which hold a disproportionate amount of the world’s soil carbon.”  - Christopher Fernandez

 

Posted 
September, 2016