Amazonian lakes have been found to sequester carbon dioxide (CO2) at a rate 39% higher than the rainforest itself, according to a 2022 study by researchers from multiple countries. These lakes store 113.5 grams of carbon per square meter per year in their sediment, compared to the rainforest’s average of 81.72 grams per square meter per year.
The research revealed that preserved tropical rainforest lakes in the region sequester 10% of the carbon present. Tropical lakes absorb three times more carbon than temperate ones and ten times more than subpolar lakes.
The study analyzed sediment at the bottom of the lakes, rich in organic matter that acts as a carbon reservoir. Forests sequester carbon and transfer it to the lakes through sediment, preventing its emission as gas into the atmosphere. By analyzing these sediment layers, researchers could trace environmental changes over time, including deforestation’s impact on carbon sequestration.
The researchers first compiled earlier studies on tropical rainforest lakes worldwide, doubling the representation of these lakes in tropical forests. They then conducted fieldwork in the Brazilian Amazon, studying 13 lakes over a period of 50 to 100 years. By drilling sediment cores, they collected layers representing changes in carbon accumulation due to various factors, including deforestation. The research provides insights into the significance of lakes in the carbon cycle, with tropical lakes playing a pivotal role due to higher forest productivity.
While the world’s natural lakes cover a small fraction of the Earth’s surface, they play a vital role in carbon sequestration. The study highlights the need to preserve both forests and lakes to mitigate carbon emissions effectively. Further research is required to explore temperature’s role in sediment burial rates and potential carbon release from lakes in the future.
www.news.mongabay.com/2023/08/tropical-lakes-are-carbon-super-sinks-even-more-than-forests-study-shows/