Could oxygen from electrolysis revive oceanic ‘dead zones’?

Germany is anxious to source green hydrogen for heating, powering fuel cells and green steel-making and aviation. Canada has a plan to provide some of that hydrogen from a big new electrolysis plant set up to split water into H2 and O2 using wind power on Newfoundland’s west coast.  A question arises: what to do with the O2? An oceanographer from nearby Nova Scotia, Brian Wallace, would like to pump it all into the sea to revive the ‘dead zones’ expanding in deep offshore waters as a result of climate change and warming oceans. The dead zone in the Gulf of St Lawrence has expanded sevenfold since 2003 to cover an area more than five times the size of Greater London, the Atlantic reports. There’s another one at the mouth of the Mississippi because of agricultural run-off (although the outflow from the mighty River Congo in the eastern Atlantic has the opposite effect – an 800-kilometre plume of relatively fresh water teeming with life). Wallace thinks ocean currents would carry oxygen from the new plant to a dead zone further up the St Lawrence River in two years, and bring it back to life.