Recently we mentioned that drowned trees along the Uatumã River a likely the cause for enhanced methane emissions measured at ATTO. Now Angélica Resende and her co-authors investigated how changes in flooding regimes impact tree mortality in floodplains. They compared two sites in the Amazon basin. Along the Jaú River, the floodplain environment is still largely undisturbed. Along the Uatumã near ATTO, on the other hand, the flooding regime has been altered by the implementation of the Balbina hydroelectric plant further upstream.
Santiago Botía and his co-authors analyzed methane in the atmosphere at ATTO. Over the course of five years, they measured methane along with other properties, such as wind speed, wind direction and the stratification of the atmosphere. They noticed frequent pulses of methane emissions during the night, but only under certain conditions. Surprisingly, these nighttime events mostly occurred in the months of July to September – the dry season in the Amazon. Botía et al published the study Open Access in Atmospheric Chemistry and Physics, Issue 20: Understanding nighttime methane signals at the Amazon Tall Tower Observatory (ATTO).