CANBERRA, Oct. 20 (Xinhua) -- Tropical inland waters emit far less greenhouse gases than previously estimated, according to an international study led by Australia's Charles Darwin University (CDU).
The study aimed to better understand greenhouse gas emissions in tropical rivers, lakes and reservoirs by collating the growing number of observations from across the world's tropics, including many systems that were previously less represented in global datasets, a CDU statement said on Monday.
The results, published in Nature Water, found while these waters still produce significant amounts of greenhouse gas emissions, it is 29 to 79 percent less than previously thought.
Greenhouse gases, mainly carbon dioxide, methane, and nitrous oxide, trap heat in the atmosphere and are naturally released from inland waters, but human activities greatly increase these emissions, the statement said.
Tropical flowing waters such as streams and rivers contributed to an estimated 46 percent of emissions from global inland waters, and tropical standing waters such as lakes, reservoirs and ponds, about 8 percent, it said.
"The tropics cannot really be considered as one big emissions hotspot because of its complexity and the mosaic of different ecosystems, landscapes, morphologies and levels of human activity," said study lead author and CDU Senior Research Fellow Clement Duvert.
"Some areas in the tropics such as the Amazon or Congo are pristine, lush rainforests, but others are much drier, less productive, or mountainous, and we found this diversity really shapes the amount of gases that freshwater systems release," Duvert said.
Human activities like agriculture increase organic matter and nutrient inputs into inland waters, boosting greenhouse gas emissions, Duvert said, adding the next frontier of this research could be to better quantify what portions of these emissions are natural and what are due to human activities.
Understanding when and how human activities impact these emissions is important to inform management and conservation, he said, adding the tropics, hosting most of the world's population and agricultural growth, will likely see rising emissions from their waters. ■
