Ocean Fertilization Promotes Toxic Algae in Haida Gwaii

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One hundred tons of an iron-rich dirt-like material was dumped into the ocean near Haida Gwaii, an island off the shores of British Columbia and Alaska, in an effort to enhance the growth of phytoplankton and improve fishery [1]. It was done without permits as part of a $2-million project, initiated by the Haida Salmon Restoration Corporation in the hope of obtaining carbon credits, and has sparked considerable controversy.

Previous open ocean geoengineering experiments hoping to stimulate photosynthesis and carbon fixation have shown that iron additions stimulated growth of the toxigenic diatom genus Pseudonitzschia. The sparse oceanic Pseudonitzschia community at the high-nitrate, low-chlorophyll Ocean Station PAPA (50 degrees N, 145 degrees W) produced approximately 200 pg/L of the neurotoxic domoic acid (DA) in response to iron addition. This finding raised serious concern over the net benefit and sustainability of large-scale iron fertilizations [2].

The Haida Gwaii iron-dumping [1] was done in the face of clear evidence that the procedure is likely to lead to toxic algal blooms. Even if the salmon crop survives the toxic bloom, the fish may be unfit for consumption. The killer whales and grey whales living off Haida Gwaii may not survive the dumping and the people of the Islands may become ill from shell fish and salmon carrying the toxic algae. The dumpers of iron do not appear to have been required to monitor the toxic bloom.

DA naturally produced by marine phytoplankton presents a significant threat to the health of marine mammals, seabirds and humans via transfer of the toxin through the food web. In humans, acute exposure causes a neurotoxic illness known as amnesic shellfish poisoning characterized by seizures, memory loss, coma and death. Regular monitoring for high DA levels in edible shellfish tissues has been effective in protecting human consumers from acute DA exposure. However, chronic low-level DA exposure is a concern, particularly in coastal and tribal communities that harvest shellfish. DA exposure via consumption of planktivorous fish also has a profound health impact on California sea lions (Zalophus californianus), affecting hundreds of animals yearly [3].

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