There is a 1,000 km stretch of coastline in Northern Australia that is covered with dead mangrove forests. The research found that these mangrove trees have been emitting methane that is 8 times more than live trees.
A group of scientists from Southern Cross University has used the site to collect methane emissions from mangrove tree stems. It was the first time that a sample from the area is collected. The forest along the coastline died because they have been exposed to extreme heat with very little to no rainfall and low sea levels during the months of 2015 to 2016.
This mass mortality of trees has been one of the worst things that were ever recorded. What's even worse is that it happened around the same time the mass coral bleaching happened in the Great Barrier Reef. In August, the team of researchers traveled to the area in the Gulf of Carpentaria to take measurements of the methane emissions where the mangrove trees were still alive. The data they extracted was compared to the methane emissions of dead mangrove that's about two kilometers away.
They found out that the emissions released by dead mangroves are eight times higher than those produced by healthy living trees. According to the lead author of the study, Luke Jeffrey, they intend to find out how several climate stressors including heat waves cause the ultimate mortality of these forests. The results of their study was published in the journal New Phytologist.
The team found out that the death of mangroves has significant implications for greenhouse emissions along coastal areas. Given the current condition of the world's atmosphere that makes it warm, these catastrophic diebacks would only make the living conditions much worse. These deaths will become more often in the future. Methane is more potent as a type of gas that traps heat.
"Because Methane is a potent greenhouse gas. This means that for every molecule of methane released, about 34 molecules of carbon dioxide has to be consumed by mangroves to even things out," Jeffrey said. "When people consider the mangrove system that is now dead and how it does not help bring down the levels of carbon dioxide present in the atmosphere, then this practice shows a significance in the imbalance.
Therefore, it is important to know if these numbers add up and how they increase impacts on the ecosystem. Underestimating the capacity of the tree to capture carbon and how methane is emitted as a byproduct could bring about huge changes not only in its immediate environment but it the world in general.
