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It was previously announced in 2022 that NEON would discontinue release of sulfur hexafluoride (SF₆) as part of reaeration experiments at 13 sites based on evaluation of the data quality by the Reaeration Technical Working Group (TWG). The TWG recommended continuing SF₆ experiments at the remaining nine NEON sites, using targeted flow windows to better characterize the relationship between gas exchange and discharge within these sites.

In the intervening three years, we were only able to complete a handful of additional experiments at these sites due to logistical challenges of sampling at the targeted flows. Meanwhile, a new Bayesian method of analyzing the data was developed, which showed that additional experiments were unlikely to change the relationship between gas exchange and discharge. The processed and cleaned NEON data used as inputs and the model outputs are available . The above linked dataset was also the foundation for two manuscripts: a paper describing the data () and an analysis paper ().   

Based on the data analysis, the TWG and NEON Science have concluded that SF₆ releases can be discontinued at all NEON sites. Conservative salt slug experiments to measure stream travel time and calculate mean depth will continue at all sites, four times per year. If these salt experiments indicate that major hydraulic changes that could influence gas exchange have occurred, gas release experiments may resume using an alternative gas such as Argon. 

For additional information use the Contact Us form on the NEON Data Portal and select DP1.20190.001 in the Data Product dropdown list.