The findings
The team studied the effect of temperature in two ways: using local weather station data for each site and comparing differences in climate regions.
“Generally, warmer temperatures led to increased decay of organic matter, which translates to reduced carbon preservation in soil,” Trevathan-Tackett said.
The two tea types acted differently with increasing temperature.
“For the harder to degrade rooibos tea, it didn’t matter where it was – higher temperature always led to more decay, which indicates that types of carbon we’d typically expect to see last longer in the soil were vulnerable to higher temperatures,” Trevathan-Tackett said.
“With increasing temperatures, the green tea bags decayed at different rates depending on the type of wetland – it was faster in freshwater wetlands but slower in mangrove and seagrass wetlands.
“Increasing temperatures may also help boost carbon production and storage in plants, which could help offset carbon losses in wetlands due to warmer weather, but this warrants further investigation with future studies.”
Freshwater wetlands and tidal marshes had the highest tea mass remaining, indicating a greater potential for carbon storage in these ecosystems.
The study’s findings are helping piece together the puzzle of wetland carbon sequestration on a global scale. Within the terrestrial TeaComposition initiative led by Djukic, information on litter decomposition has been collected at about 500 sites worldwide resulting in several peer-review publications.
”Applying the common metric across aquatic, wetland, marine and terrestrial ecosystems allows for a conceptual comparison and understanding of key drivers involved in the control of global litter carbon turnover,” Djukic said.
“Now that we are starting to get a better understanding of which environments are storing more carbon than others, we can use this information to ensure we protect these areas from environmental or land-use change.”
