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 drifter robots 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?

Ocean restoration

The HSRC's basic idea is born out of marine biology as well as observations of the aftermath of volcanic eruptions in the region. For example, a lack of iron limits the growth of microscopic plants in the Southern Ocean around Antarctica and elsewhere, a fact that prompted marine biologist John Martin to famously muse: "Give me half a tanker of iron, and I'll give you the next ice age."

In the summer of 2008 Mount Kasatoshi in Alaska's Aleutian Islands blew, sending volcanic minerals, including iron dust, far to sea and prompting plankton blooms across the Gulf of Alaska. At the same time, years and years of decline in returning salmon populations led researchers to expect few of the fry from 2008 to return in later years, only to find a record salmon run in Canada's Fraser River in 2010.

"There are three volcanic events in the last 100 years, and we had record sockeye salmon runs in those three volcanic dust events," George says. "That's pretty good data." In fact, government scientists from Fisheries and Oceans Canada speculated in a paper published this year in Fisheries Oceanography that the Kasatoshi eruption might be linked to the abundance of returning salmon in 2010.

But other scientists argue salmon biology is more complicated than that. "There's not evidence that that region is iron-limited," argues phytoplankton researcher Maite Maldonado of the University of British Columbia, who sailed on one of the first experimental iron fertilization cruise in the Southern Ocean in 1999. "We have a project right now looking at the salmon, and what we see is not that phytoplankton biomass has changed. What has changed is the timing of when the spring bloom occurs."

Much as migrating birds or spawning insects rely on the timing of spring so that there is enough available food when they arrive in a given region, so, too, the salmon rely on the timing of phytoplankton blooms, followed by the zooplankton bloom that then feeds baby salmon. As the Canadian government scientists note in the Fisheries Oceanography paper: "The 2010 phenomenal run…may forever remain an enigma due to the lack of precise ecological and chemical data."

In the case of the HSRC, however, the participants simply point to what they observed at sea: an influx of sea life, from seabirds to tuna. "More marine life was observed," Chief Councilor Ken Rea of the Old Masset Village Council told the press conference on October 19.

Not geoengineering

The project is also unlikely to bury much if any carbon dioxide for one simple reason: metabolism. As other iron fertilization experiments have shown, it is relatively easy to get plankton to bloom, but it is harder for that bloom to sink to the bottom of the ocean, where it takes CO2 with it. Instead, as suggested by the trickle-up theory of salmon restoration, the plankton tends to get eaten by tiny animals, which are then eaten by larger animals until, ultimately, all or most of the CO2 sucked up by the tiny plants during their photosynthetic life spans finds its way back to the atmosphere in relatively short order.

To bury carbon at sea requires promoting particular species in the bloom, such as diatoms—shelled algae. When these minute silicon-shelled photosynthesizers die, their corpses can overwhelm natural systems and sink to the bottom, as proved by a scientific research cruise in 2004. But dictating the species composition of a plankton bloom and its aftermath remains beyond the ken of marine biology, causing one researcher involved in the successful 2004 effort, marine biologist Victor Smetacek of the Alfred Wegener Institute for Polar and Marine Research in Germany, to call it beyond control at this stage. It remains unclear at this point which particular species bloomed as a result of the HSRC iron release but the team is sending out for analysis more than 10,000 water samples, data the HSRC team says it will share as other iron fertilization experiments have done. A preliminary review of the data collected is expected by November and a full analysis within the next nine months.

Other scientists are skeptical. In 2009 a group of ocean scientists explicitly called for abandoning iron fertilization efforts in an editorial in Nature. (Scientific American is part of Nature Publishing Group.) "Determining the local effects of iron fertilization against the background of natural variations is difficult, and impacts on fisheries, ocean biota and carbon cycling harder still," wrote members of the In-Situ Iron Studies Consortium—an international group of scientists studying such ocean fertilization—in a letter to the Guardian newspaper, which first reported on the Haida experiment. "I am disturbed and disappointed as this will make legitimate, transparent [ocean iron fertilization] experiments more difficult," Smetacek says.

HSRC's George has a long history of attempting to commercialize such iron fertilization, most notoriously via the company known as Planktos, which went bankrupt in 2008. The business case is to sell the CO2 declines generated by such plankton blooms via an international or national market for such emissions reductions.

The international community has cautioned against such ocean fertilization both in the 1972 London Convention and Protocol on preventing of marine pollution and in the consensus decision of the Ninth Conference of the Parties to the Convention on Biological Diversity, although those nonbinding agreements apply only to national governments. The Ocean Pearl sailed under the flag of the Old Masset Village Council, a part of the Haida First Nations.

Whereas this experiment might shed light on whether or not iron fertilization can hope to draw down atmospheric levels of CO2, it hardly amounts to a long-term planetary scale change—the definition of geoengineering according to the U.K.'s Royal Society. That is both George's hope and contention, rejecting the term geoengineering as a smear word intended to discredit this ocean restoration experiment. "I don't think we should build artificial forests out of concrete with concentrated lye solutions dribbling over the leaf area to absorb CO2," he argues. "I think we should grow real trees."

Unknown unknowns

Growing microscopic "trees" in the ocean may not be without unintended consequences, however. A plankton bloom can spur a bloom in the bacteria that serve to decompose tiny oceanic corpses. These bacteria can rapidly consume all the available oxygen in a given region of water, giving off carbon dioxide as they do so and creating a temporary dead zone. But such areas are not completely dead. Instead, they provide the ideal conditions for the growth of yet other bacteria that in turn produce more potent greenhouse gases, such as nitrous oxide and methane.

Whether that occurred in this case remains unknown, although the bloom faded by September. Regardless, the international attention does not seem to have slowed the HSRC's interest in releasing more iron. "It's part of our business plan," McNamee said at the press conference on October 19.

It may come down to money. The original experiment was funded with $2.5 million in funds from the Old Masset Village Council, a borrowed sum that represents more than 20 percent of the annual budget for this village of 2,500 people. In the loan approval from February 2011, the bank that provided the cash for the expedition raised concerns about both the legality and legitimacy of the project, including whether any carbon credits would ever be sold as a result of the project to help defray the expense, according to documents released by environmental group Living Oceans Society.

"Ultimately, as far as the people of Old Masset are concerned, there's only one jury that will decide whether or not this experiment was a success," argued lawyer James Straith at the press conference. "That jury's out right now in the North Pacific, and it's going to constitute millions of salmon, and they'll render their verdict in the summer of 2014."

Or as Chief Councillor Rea said at the same press conference: "In recent years something has happened in our oceans. The salmon are gone." It remains to be demonstrated whether dumping iron at sea will be able to affect that loss—or have any impact on the rise of carbon dioxide concentrations in the atmosphere.

With additional reporting by Anne Casselman.