As the world grapples with climate change and its consequences, an often-overlooked aspect of the carbon cycle may hold a key to mitigating some of its effects: soil microbes. Soil stores more carbon than plants and the atmosphere combined, with these microscopic organisms playing a crucial role in the process.
However, the increasing frequency and severity of droughts, such as those impacting California, could disrupt this delicate ecosystem and have far-reaching consequences for soil health and future greenhouse gas levels.
In a perspective published in the journal Trends in Microbiology, microbial ecologist Steven Allison of UC Irvine warns that if soil microbes adapt to drought more rapidly than plants do, we could face significant consequences. To better manage the situation in both agricultural and natural settings, it is crucial to understand how microbes respond to drought.
“Soil microbes are beneficial, and we couldn’t live without their cycling of carbon and nutrients, but climate change and drought can tweak that balance, and we have to be aware of how it’s changing,” says Allison.
Some soil microbes help store carbon from decomposing plants in the soil, while others release plant carbon back into the atmosphere. The carbon-rich soil has numerous benefits, including improved nutrient retention, increased plant productivity, and erosion prevention.
However, the changing weather patterns in California, characterized by more intense droughts followed by heavier rainfall, can lead to erosion, landslides, mudslides, and sedimentation.
“From a climate mitigation standpoint, what we want is for more carbon to be in plants and soils and less carbon to be in the atmosphere,” says Allison. Understanding the balance of incoming and outflowing carbon and how it changes with drought, warming, or other climate factors is crucial for managing climate change.
While plants and microbes are both impacted by drought, Allison believes that microbes are more adaptable and can recover faster. Microbes can change their physiology, abundance, and even evolve, which allows them to resist or bounce back from drought more rapidly than plants.
However, if more carbon-releasing microbes survive than carbon-sequestering ones, the result could be carbon-depleted soils with negative implications for plant productivity and future greenhouse gas levels.
To nudge the balance in the right direction, Allison emphasizes that more research is needed. “Right now, we have data that suggests that when we have drought, something changes that results in carbon loss, but we don’t understand exactly how or why that’s happening,” says Allison.
Identifying the microbes most beneficial to plants and most likely to retain carbon in soil could help us tip the balance in their favor.
There is potential to manage or engineer soil microbes to mitigate the effects of drought. In agricultural systems, soil manipulation or the addition of beneficial microbes could be explored.
In more natural systems, managing plants could indirectly benefit the microbial part of the ecosystem. Furthermore, Allison suggests that more measurements are needed to understand how drought affects soil carbon change in different ecosystems, from the Arctic tundra to deserts.
As climate change continues to threaten ecosystems worldwide, understanding the complex interplay between soil microbes, plants, and carbon could provide valuable insights and solutions for mitigating its impacts.
Natural carbon storage mechanisms, also known as carbon sinks, play a vital role in the Earth’s carbon cycle by capturing and storing carbon dioxide (CO2) from the atmosphere. These mechanisms help maintain a balance of carbon on our planet and mitigate the impacts of increasing greenhouse gas emissions. Here are some of the major natural carbon storage mechanisms on Earth:
These natural carbon storage mechanisms help regulate the Earth’s climate by capturing and storing carbon dioxide. However, human activities, such as deforestation, fossil fuel combustion, and land-use changes, have disrupted the balance of the carbon cycle, leading to increased greenhouse gas concentrations and global warming.