The new study found that storm water retention ponds are not a significant source of climate-warming nitrous oxide
A new study by researchers from Duke University found that storm water retention ponds are not a significant source of climate-warming nitrous oxide emissions. The study, published in the journal Ecosphere, analyzed 64 retention ponds in eight different cities and ecoregions.
Lead Researcher Joanna Blaszczak and her team collected sediment samples from storm water ponds in Boston, Baltimore, Miami, Minneapolis, Phoenix, Salt Lake City, Portland, Ore., and Durham, N.C., in summer 2014. The team tested the sediment samples for nitrogen and metal concentrations, as well as microbial genes that regulate the denitrification process. By allowing the samples to mature for six hours, the team was able to test how much nitrous oxide, a greenhouse gas, was released.
Overall, the study found that the nitrous oxide released in storm water ponds was similar to the level released in freshwater bodies. Additionally, the intensity of urban land cover around the ponds made little impact on the nitrous oxide levels. While the research eases concerns that storm water ponds are a major source of greenhouse gas emissions, Blaszczak and her team have further questions.
“Stormwater ponds are essentially black boxes,” Blaszczak said. “We understand what goes into them and what flows out of them, but still have limited understanding of the chemical and biophysical processes that occur within them.”