They measure with tea bags how wetlands lose CO2 retention

Dec. 3 () –

A global study using tea bags as a measuring device shows that rising temperatures can reduce the amount of carbon stored in wetlands.

The international team of scientists buried 19,000 green tea and rooibos bags in 180 wetlands in 28 countries to measure the ability of wetlands to retain carbon in their soil, known as wetland carbon sequestration.

Although the tea bags may seem like an unusual instrument To measure this phenomenon, it is a proven indirect method to measure the release of carbon from soil to the atmosphere. However, this is the first time that tea bags have been used for a large-scale, long-term study, and tea leaves have revealed which types of wetlands are filtering the most carbon.

Dr. Stacey Trevathan-Tackett of RMIT University, Australia, led the study published in Environmental Science and Technology, which involved 110 co-authors, along with many others who helped, such as university students and citizen scientists.

“This is the first long-term study of its kind, using this tea bag method, which will help guide how we can maximize carbon storage in wetlands and help reduce emissions globally,” he said. in a statement Trevathan-Tackett, who is now at RMIT’s School of Science.

“Changes in carbon sinks can significantly influence global warming: “The less carbon is broken down, the more carbon is stored and the less carbon in the atmosphere.”

Tea bags provide a simple, standardized way to identify how climate, habitat type, and soil type influence carbon decomposition rates in wetlands.

BETWEEN 40 AND 80 BAGS AT 15 CM. IN DEPTH FOR THREE YEARS

At each site, the scientists buried between 40 and 80 tea bags about 15 cm underground and collected them at various time intervals over three years, tagging their GPS location. They then measured the remaining organic mass to assess how much carbon had been preserved in the wetlands.

The project used the two types of tea bags (green and rooibos) as measurements for the different types of organic matter found in soils. Green tea consists of organic matter that decomposes easily, while rooibos decomposes more slowly. Using both types of tea bags in this project allowed the researchers to get a more complete picture of the wetlands’ ability to store carbon.

“These data show us how we can maximize carbon storage in wetlands globally,” Trevathan-Tackett said.

The team studied the effect of temperature in two ways: using data from local weather stations for each site and comparing differences in climate regions.

“Overall, warmer temperatures led to greater decomposition of organic matter, which translates to less carbon conservation in the soil,” Trevathan-Tackett said.

The two types of tea acted differently with increasing temperature. “In the case of rooibos tea, which is harder to degrade, it doesn’t matter where it is found: higher temperatures always cause more decomposition, indicating that the types of carbon that we would normally expect to last longer in the soil are vulnerable to higher temperatures“Trevathan-Tackett said.

“With rising temperatures, green tea bags disintegrated at a different rate depending on the type of wetland: it was faster in freshwater wetlands, but slower in mangroves and seagrass wetlands.

“Rising temperatures may also help increase carbon production and storage in plants, which could help offset carbon losses in wetlands due to warmer climate, but this warrants further investigation with future studies.” “.

Freshwater wetlands and tidal marshes had the largest remaining tea mass, indicating greater carbon storage potential in these ecosystems.

The study’s findings are helping to piece together the puzzle of carbon sequestration in wetlands on a global scale. Within the land-based TeaComposition initiative led by Djukic, information on garbage decomposition has been collected at about 500 sites around the world, which led to several peer-reviewed publications.

“Applying the common metric across aquatic, wetland, marine, and terrestrial ecosystems allows for conceptual comparison and understanding of the key drivers involved in controlling global trash carbon turnover,” Djukic said.

“Now that we are starting to better understand which environments store more carbon than others, “We can use this information to ensure we protect these areas from environmental or land use changes.”