Volcanoes May Help Reduce Mortality From Air Pollution, Study

Volcanoes are among the most powerful and destructive natural phenomena on Earth. They can spew hot, dangerous gases, ash, lava, and rock that can cause disastrous loss of life and property, especially in heavily populated areas.

But they can also create new land surfaces and enrich the soil with nutrients, making them fertile grounds for plant colonization and ecosystem development.

Scientists have long been interested in studying volcanoes, not only to understand their origins and dynamics but also to monitor their activity and predict their eruptions.

However, traditional methods of volcanic monitoring, such as seismology, geodesy, and geochemistry, are often costly, complex, and risky, requiring the installation and maintenance of instruments in hazardous environments.

What if there was a simpler, safer, and cheaper way to monitor volcanoes, using the plants that grow on and around them?

This is the idea behind a new research project led by Dr. Gastón Muñoz, a plant ecologist from the University of Chile, who has been studying the effects of volcanic activity on plants and their associated microorganisms for more than a decade.

Plants as bioindicators of volcanic activity

(Photo : ALFREDO ESTRELLA/AFP via Getty Images)

Plants have a symbiotic relationship with their surrounding environment, being a vital indicator of the overall health of the landscape, as well as significant changes within it.

One such driver of plant response is gas emissions, which are one of the main products of volcanic activity.

Gas emissions from volcanoes can have both positive and negative effects on plants, depending on their type, concentration, and duration.

Some gases, such as carbon dioxide and water vapor, can enhance plant growth and photosynthesis, while others, such as sulfur dioxide and hydrogen sulfide, can cause leaf damage, chlorosis, necrosis, and reduced biomass.

Dr. Muñoz and his team have been measuring the effects of gas emissions on plants in different volcanic areas in Chile, such as the Chaitén, Puyehue-Cordón Caulle, and Villarrica volcanoes.

They have found that plants can show different levels of tolerance and sensitivity to gas emissions, depending on their species, genotype, and phenotypic plasticity.

By analyzing the physiological, biochemical, and molecular responses of plants to gas emissions, the researchers have been able to identify specific biomarkers that can indicate the presence and intensity of volcanic activity.

For example, they have found that the activity of antioxidant enzymes, such as catalase and peroxidase, can increase in plants exposed to high levels of sulfur dioxide, as a way to cope with oxidative stress.

The researchers have also found that the composition and diversity of the microbial communities associated with the plants, such as the bacteria and fungi that live in their roots and leaves, can change in response to gas emissions.

These microorganisms can have beneficial or detrimental effects on plant health, depending on their functions and interactions.

For instance, some microorganisms can help plants acquire nutrients, such as nitrogen and phosphorus, from the volcanic soil, which is often poor in organic matter and mineralization.

Others can protect plants from pathogens, pests, and abiotic stress, such as drought and salinity.

However, some microorganisms can also compete with plants for resources, or produce toxins that can harm them.

By using molecular techniques, such as metagenomics and metabarcoding, the researchers have been able to characterize the diversity and function of the microbial communities in different volcanic scenarios and to identify specific indicators that can reflect the impact of gas emissions on plant health.

A new effective monitoring system for volcanic activity

Based on their findings, Dr. Muñoz and his team have proposed a new effective monitoring system for volcanic activity, based on plant health and their associated microorganisms. The system consists of three main steps:

Selecting suitable plant species and sites for monitoring

The researchers suggest using native plant species that are abundant, widespread, and representative of the local vegetation, and that have different levels of tolerance and sensitivity to gas emissions.

 The sites should be located at different distances and directions from the volcanic source and should have similar environmental conditions, such as soil type, climate, and elevation.

Measuring plant and microbial responses to gas emissions

The researchers suggest using a combination of field and laboratory methods, such as visual inspection, leaf sampling, gas sampling, physiological measurements, biochemical assays, molecular analyses, and statistical modeling, to assess the effects of gas emissions on plant health and their associated microorganisms.

The measurements should be done periodically, preferably before, during, and after volcanic events, and should be compared with control sites that are not affected by gas emissions.

Interpreting and communicating the results

The researchers suggest using a color-coded system, similar to the traffic light system used by some volcanological observatories, to indicate the level of volcanic activity and its potential risk to human and environmental health.

The system would use green, yellow, orange, and red colors, based on the intensity and frequency of gas emissions, and the degree of plant and microbial response to them.

The results should be communicated to the relevant authorities and stakeholders, such as volcanologists, emergency managers, farmers, and tourists, using clear and simple language and graphics.