Human-Made Ponds May Be Net Emitters of Greenhouse Gases, Studies Find

New research conducted by Cornell University reveals that human-made ponds have a significant impact on greenhouse gas emissions. Two related studies conducted by researchers from Cornell begin to quantify the effects of both human-made and natural ponds on the global greenhouse gas budget, providing valuable insights into a topic that is not well understood.

The studies found that when the emissions and carbon storage of human-made ponds are added up, the ponds may be net emitters of greenhouse gases. Previous estimates suggest that ponds, which are defined as bodies of water 5 hectares or less, may contribute 5% of global methane emissions. However, without accurate measurements across many ponds, this percentage could range from half to twice the estimated amount. Additionally, there are limited estimates of carbon burial rates in ponds.

One study conducted by the researchers focused on the amount of carbon sequestered in 22 specifically selected ponds. The researchers examined past management activities and measured sediment thickness and carbon content in the ponds. They found that carbon burial rates in the ponds were influenced by factors such as aquatic plants, fish, and nutrient levels. The study also revealed that both natural and human-made ponds globally sequester a significant amount of carbon, indicating that carbon sequestration in ponds is underestimated.

The second study explored the seasonal emissions of greenhouse gases from specific Cornell Experimental Ponds. Methane, a potent greenhouse gas, accounted for the majority of the emitted gases. The study also highlighted the importance of frequent sampling to accurately account for greenhouse gas emissions from ponds.

Overall, these studies suggest that ponds play a role in greenhouse gas emissions and carbon storage. While ponds may currently be net emitters of greenhouse gases due to methane release, there is potential for them to become net sinks by reducing methane emissions. The findings also propose the use of bubblers or underwater circulators to reduce methane emissions in ponds.

Further research and understanding of the role of ponds in greenhouse gas emissions are crucial for accurate climate modeling and predictions.

– Meredith A. Holgerson et al, High rates of carbon burial linked to autochthonous production in artificial ponds, Limnology and Oceanography Letters (2023). DOI: 10.1002/lol2.10351
– Nicholas E. Ray et al, High Intra-Seasonal Variability in Greenhouse Gas Emissions From Temperate Constructed Ponds, Geophysical Research Letters (2023). DOI: 10.1029/2023GL104235
(Source: Cornell)