Researchers have investigated how fungi recycle their mycelium when they grow. Using microfluidic chips – units that handle and analyse extremely small volumes of fluid through microscopic channels – the researchers could show that the availability of nutrients among fungi affects how much of the mycelium is recycled.
“The results show that the studied fungi can be divided into groups based on two clear strategies. There is a ‘wasteful’ group that leaves large amounts of inactive mycelium behind, and a ‘frugal’ group that quickly recycles the major part of its mycelium during growth,” says Dimitrios Floudas, researcher in biology at Lund University.
The different strategies reflect the ecology of the fungi. The wasteful species colonise short-lived wood substrates such as twigs and branches and often have short lifecycles. Their “live fast, die young” approach means they do not have time to invest energy in reusing nutrients in the remaining mycelium.
By contract, the frugal species grow on large logs and therefore have longer lifecycles. By recycling mycelium they can preserve nutrients, but also reduce losses to hungry springtails and mites as well as competing microbes. The recycling of mycelium actually reduces the amount of available nutrients for these organisms.
“The most surprising aspect was that species that we perceive as slow on a macro level – fungi that grow on tree trunks for several years without dying out – were fastest at recycling their mycelium at the microscale. At the same time they always left small parts of their network behind, a kind of “stand-by-mycelium” ready to grow again if the resources suddenly increase,” says Kristin Aleklett, researcher in biology at Lund University.
The discovery of fungal ecology and strategies for recycling of mycelium is important for climate research. The new study paves the way for more precise estimations of how different fungi contribute to carbon sequestration. The results provide a unique insight into the hidden life of fungi and show how microscopic organisms can affect large ecosystems and the carbon cycle.
“Fungi play a crucial role in carbon sequestration in our forests. Different species do completely different jobs. It clearly shows why biodiversity is so important,” says Dimitrios Floudas.
