Could pumping oxygen-rich surface water into the depths of lakes, estuaries, and coastal ocean waters help ameliorate dangerous dead zones? New work led by Carnegie’s David Koweek and Ken Caldeira and published open access by Science of the Total Environment says yes, although they caution that further research would be needed to understand any possible side effects before implementing such an approach.
When excessive nutrients from agriculture and other human activities wash into waterways, it can create a dangerous phenomenon called eutrophication. This can lead to low-oxygen dead zones called hypoxia.
“Low-oxygen dead zones are one of the most-pervasive problems plaguing both marine and freshwater systems around the world and a major problem for communities that depend on fishing,” Koweek said.
Efforts to fight hypoxia often focus on reducing agricultural runoff and on preventing nutrients from being overloaded into waterways. But this is a very slow process that involves changing farming practices, upgrading wastewater treatment facilities, and altering home fertilizer usage.
Koweek and Caldeira led a team that investigated a proposed technological remedy, called downwelling, which could complement nutrient-reduction programs. This involves pumping naturally more-oxygenated water from the surface down into the depths of the affected body of water.
“In theory, downwelling would create vertical mixing in the water, distributing oxygen and preventing hypoxic conditions from taking hold,” Koweek explained. “We wanted to test this idea and see if it would really work.”
Read more at Carnegie Institution for Science