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Controlling Microbes: Key to Reducing Carbon Emissions?

A team of ecologists from San Diego State University reveals the effects of changing weather patterns on soil microbial activity and global carbon emissions.

Changes in weather affect not only humans, but also microbes. As scorching summers cool to chilling winters, we adapt by raising our energy consumption to keep our bodies warm. Likewise, microbes, such as bacteria and fungi, consume more carbon – their source of energy – in response to seasonal changes in soil temperature and moisture. For soil microbes, which are key players in propelling the exchange of carbon between land, ocean and atmosphere, this change brings consequences like elevated soil carbon emissions and altered nutrient cycles.

In a modelling study conducted by San Diego State University (SDSU), a team of ecologists have discovered that microbial seasonality exerts a significant influence on global carbon emissions and is a key regulator of interactions between land and climate, as well as underground soil biogeochemistry. Using microbial modelling framework known as the CLM-Microbe (Community Land Model), the group investigated the effects of climate change on the terrestrial carbon cycle.

The CLM-Microbe model is capable of simulating the underlying forces of bacterial and fungal mechanics in order to enhance our understanding on how the microbial ecology of soil affects the carbon cycle. The team also employed the model to mimic carbon fluxes in 9 natural biomes including the tropical/subtropical forest, temperate coniferous forest, temperate broadleaf forest, boreal forest, shrubland, grassland, desert, tundra, and wetland.

Xiaofeng Xu, global change ecologist and lead author, elaborated, “When microbial colonies in the soil are in a productive phase, increasing in numbers and size, they will need more carbon to fuel their growth. When we manipulated the quantities and activities of soil microbes in simulations and observed the reciprocal changes in soil carbon, we found that when seasonal variation was removed, microbial respiratory rates went down.”

Their investigation revealed that preserving microbial populations at a constant level, by reducing tillage and management particles, can help to reduce carbon emission. Besides minimising the effluence of carbon, stabilising microbial populace presents agricultural benefits such as maintaining soil fertility. The model has also demonstrated how various groups of soil microbes contribute to the carbon cycle and the substantial role of these microbes to precipitate carbon flux which refers to the level of carbon exchanged between the planet’s carbon pools – land, oceans, and atmosphere.

“The model’s ability to simulate bacterial and fungal dynamics improves our understanding of the soil microbial community’s impact on the carbon cycle,” said Liyuan He, first author and doctoral student at SDSU.

In the light of climate change, this study emphasises the need to factor in microbial seasonality when modelling earth systems to better understand the rapidly changing soil carbon storage, and forecast interactions between carbon and weather patterns. Investigators are also keen on taking a closer look on how microbial seasonality can help to maintain global carbon balance, all while taking into consideration the dynamics of global changes in land usage. [APBN]