The Upper Mekong's Secret Weathering Story

The Lancang River, which is the starting point of the Mekong River, is super important for understanding how land and water interact. This river carries a lot of dissolved elements, and one key player in this mix is strontium, or Sr for short. Scientists have been looking at how Sr moves through the river system, especially during the rainy season. They used a fancy statistical model to figure out where all this Sr is coming from. Turns out, most of it comes from the breakdown of carbonate rocks, with smaller amounts from salt, silicate rocks, and groundwater. This breakdown process, known as chemical weathering, is happening pretty fast in the Lancang River. In fact, the amount of carbon dioxide being used up by this process has doubled in just 10 years. This could be a sign of bigger changes happening in the region's climate. The river carries about 42. 9 tons of a specific type of Sr, called 87Sr, into the Mekong River every year. A big chunk of this, about 38%, comes from the breakdown of silicate rocks. This can have a noticeable effect on the ocean's Sr levels.So, what's driving all this weathering? Well, there are a few suspects. Dams being built along the river could be one factor. Another is the warming climate, which is causing more snow to melt and more rain to fall. All this extra water could be speeding up the weathering process. But to really understand what's going on, more research is needed. This could help in managing the river basin better and getting a handle on the bigger picture of climate change in the region. The study of the river's chemistry is not just about understanding the past. It's also about predicting the future. As the climate continues to change, the way the river behaves could change too. This could have big impacts on the people and ecosystems that depend on it. So, keeping an eye on the river's chemistry is more important than ever. It's a complex puzzle, but every piece of data brings us one step closer to solving it.