Can Controversial Ocean Iron Fertilization Save Salmon?
Source: David Biello, Scientific American
In a bid to restore lost fish abundance, the Haida Salmon Restoration Corp. (HSRC) undertook to mimic the effects of a volcanic eruption by fertilizing the ocean with iron. The idea was to provide the missing nutrient for a plankton bloom that would then trickle up the food web and restore salmon—with the ancillary effects of gathering data on the ocean food web and, potentially, removing carbon dioxide from the atmosphere.
"What if this is a means by which ocean pastures can be stewarded and brought back to health?" asks Russ George, chief scientist of the expedition as well as a controversial businessman with a history of attempting to start CO2-removal schemes ranging from reforestation to ocean fertilization. "This is a tiny village of people trying to take care of their backyard."
Old Masset village on the Haida Gwaii Islands off the British Columbia coast did this by contracting George and others to initiate the largest such intentional ocean fertilization effort to date. It authorized the release of roughly 110 metric tons of iron dust, 91 metric tons of the iron sulfate fertilizer commonly used as a lawn treatment and employed in other scientific experiments, and nearly 20 metric tons of the iron oxide found in soils around the world. "It's micronutrient enrichment," Jason McNamee, operations officer and corporate director for the HSRC, told a press conference on October 19. "We took a bag of iron, and we slapped it over one square kilometer [of ocean]."
To do that, this past July the HSRC team motored more than 300 kilometers west from the Haida Gwaii Islands to an ocean eddy in the fishing vessel Ocean Pearl. The area had previously been scouted by collecting water samples since January and lies outside Canadian territorial waters. The team also used more than 20 autonomous oceangoing robots, including two bright yellow gliders and 20 Argo drifter robots on loan from the U.S. National Oceanic and Atmospheric Administration, to survey the scene—work that is ongoing. Over the course of several days the researchers then released the 110 metric tons into the fishing boat's wake in an attempt to raise the levels of iron in the water from one or two parts per trillion up to five to 10, although both concentrations are estimates.
Satellite images as well as maps of chlorophyll abundance appear to show that the iron did indeed fuel a plankton bloom in August. But questions remain: Was it the right kind of bloom to bury carbon? Will it have any effect on the salmon?
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