In July of 2012, the Haida Salmon Restoration Corporation in conjunction with American businessman Russ George, carried out an audacious and completely unauthorized ocean fertilization experiment. Approximately 100 tonnes of iron sulfate were spread across the surface of an ocean eddy, some 300 kilometers off the west coast of Canada’s Queen Charlotte Islands. When details of this experiment emerged it was widely condemned by scientists, and environmentalists. The reasons for this reaction are not hard to see; the effects of such large-scale attempts at ocean fertilization are completely unknown, the experiment was not sanctioned by the scientific community, it was not possible to accurately quantify the results, and many scientists considered the dangers of unforeseen side effects to be too high to justify this approach. The Guardian called it the largest experiment in geoengineering ever attempted, and many commentators noted that it violated a number of international laws and UN covenants.
And yet, here’s the thing; it appears that this rogue experiment may have worked, and worked much more dramatically than anyone could have foreseen. To see why, it is necessary to look at the bigger picture. In recent years fish stocks have been in serious decline, with significantly reduced catches being reported from most of the world’s major fisheries. The classic example was the collapse of the Newfoundland cod fishery, a resource which had been fished for over 500 years, and which many had believed to be inexhaustible. The collapse of this fishery in 1992 lead to a moratorium on cod fishing, which caused widespread hardship in coastal communities throughout Newfoundland. More than 20 years later stocks of cod on the Grand Banks have yet to show a significant recovery.
It is tempting to blame declining catches on overfishing. After all the world’s fishing fleet is capable of extracting many more fish than is ecologically sustainable. Modern fishing trawlers are equipped with sophisticated fish finders, and are capable of scooping up vast numbers of fish in a single day. Industrial fishing is clearly unsustainable, and there needs to be significant reform of fisheries policy worldwide if ocean fishing is to have a long-term future. However, blaming the decline of fisheries solely on over-fishing is an oversimplification. There is a rapidly growing body of evidence which suggests that a number of other factors may also be affecting global fish stocks.
Increasing levels of CO2 in the Earth’s atmosphere in recent years have resulted in warmer ocean temperatures. If this extra heat were to be absorbed evenly by all the water in the oceans, then its effect would be insignificant. However when water is warmed it tends to stratify, with a layer of warmer water forming on top of the cooler deep ocean water. Stratification of the ocean prevents mixing of surface and deep ocean waters, which results in surface waters becoming largely sterile. This is the reason why warm tropical seas are often crystal clear, since there is little mixing with deep ocean waters, depriving the surface layer of essential nutrients. In order to support a healthy marine life, it is necessary for cooler waters from the ocean depths to mix with the warmer surface waters.
Healthy oceans contain abundant concentrations of phytoplankton, which form the basis of the marine food chain. Phytoplankton are simple photosynthesizing organisms, and are the food source for more complex zooplankton. In turn, zooplankton are the primary source of food for many marine organisms, including most species of fish. Where nutrient availability is high, phytoplankton will often flourish in astonishingly high concentrations. This abundance can impact the entire food chain, leading to abundant fish stocks in the months and years following a phytoplankton bloom.
One of the most critical nutrients required by phytoplankton is iron. Where ocean waters have stratified, this mineral tends to be in short supply. Areas where upwelling occurs from the deep ocean are mineral rich, and these have traditionally been associated with the world’s most productive fisheries. However, even parts of the ocean that are rich in most nutrients, but are short of iron tend to have low levels of productivity. For this reason, it has been suggested by a number scientists that adding iron to the ocean could have a beneficial effect on marine life. However the scientists who suggested this approach urged caution, since the effects of ocean fertilization on a large-scale are largely unknown.
Another potential benefit of ocean fertilization is that it could offer a way of sequestering atmospheric carbon. As phytoplankton multiply they use carbon in the process of photosynthesis, just as land-based vegetation does. The theory is that eventually the phytoplankton die and sink to the bottom of the ocean, where the carbon becomes locked up in sediments on the sea floor. Though not yet scientifically verified, there is reason to believe that large-scale ocean fertilization could sequester significant amounts of atmospheric carbon.
In 2009 a German experiment was carried out in which six tonnes of iron sulfate were deposited over an area of 300 square kilometers of the Southern Ocean. This experiment was called off by the German Federal Environment Ministry after environmentalists expressed concerns over the potential for unforeseen consequences. By way of contrast, the 2012 experiment conducted by the Haida Salmon Restoration Corporation released more than 16 times the quantity of iron sulfate, over an area of 5,000 square kilometers. What the Haida Salmon Restoration Corporation did was to throw caution to the wind by carrying out an unauthorized experiment on an unprecedented scale, and without adequate scientific oversight. But what were the reasons for carrying out such a large-scale ocean fertilization project in this area in the first place? To answer this question it is necessary to look at the migration patterns of the pacific salmon, and to look at what has happened to their numbers in recent years.
The Life Cycle of the Sockeye Salmon
The poster child for pacific salmon is the sockeye salmon, which has a four-year life cycle. After hatching, sockeye salmon typically live their first year as freshwater fish, in the rivers and lakes downstream of the spawning grounds. Following this stage of their lives they head down river to the ocean, with most salmon from British Columbia and Alaska ending up in the Gulf of Alaska. Here they will typically feed for a further three years, before returning to their spawning grounds to breed. After they spawn, every last returning sockeye salmon will die. The fish which return to breed represent only a tiny fraction of those that originally entered the ocean. As many as 99% of young sockeye salmon fall victim to predators, or starve to death during their time in the Pacific.
To witness a major salmon spawning event is to see one of nature’s most amazing spectacles. I had the privilege of visiting the 2010 Adams River sockeye run on several occasions. This was the biggest run witnessed on the Adams River since records began. The sheer abundance of fish was breathtaking, as was the smell of dead and rotting fish. It was estimated that almost four million sockeye salmon returned to the river over the month of October. The Adams River is a tributary of the Fraser River, and the total number of sockeye salmon returning to the Fraser river system in that year was estimated at 34 million.
What made the 2010 sockeye run all the more remarkable is that in the preceding years there had been considerable concern over declining sockeye numbers. The 2009 Fraser sockeye run saw only 1.7 million sockeye salmon return, the lowest number since records began. This was part of a clear trend which had seen the number of returning salmon drop steadily over the years prior to 2010. The concern surrounding the declining returns was so great that the Canadian government established the Cohen Commission to investigate what was happening to the Fraser River sockeye. In its 2012 report, the commission concluded that the collapse in sockeye numbers was likely due to a variety of factors. However commercial salmon farming was singled out as potentially having a detrimental effect on wild stocks; a finding that the pro-industry Canadian Government has thus far done its best to ignore.
However the record numbers of sockeye returning in 2010 were clearly due to something quite different. Every four years on the Fraser River there is a dominant run, where sockeye salmon return in much greater numbers than in the intervening years. It was known that 2010 would be a dominant year, but even so the sheer numbers of salmon caught everyone by surprise. When scientists started looking at all the factors which could potentially have influenced salmon survival rates during their time in the ocean, one factor stood out in particular.
In the summer of 2008, there was an eruption of Kasatoshi volcano in Alaska’s Aleutian Islands, which spread volcanic ash over a large part of the Gulf of Alaska. A few months after this event, a massive bloom of phytoplankton developed in the region affected by the ash cloud. Scientists believe that this occurred because of iron introduced to the ocean from the Kasatoshi ash cloud. Thus nature may actually have arranged a dramatic demonstration of the effects of ocean fertilization. While it can never be proven that the Kasatoshi eruption was directly responsible for the phytoplankton bloom and the subsequent improvement in sockeye salmon survival rates, there is strong circumstantial evidence to suggest that it was a significant contributor to the success of the 2010 Fraser River sockeye run. Additional evidence was provided by sockeye returns to the Fraser River in 2011, which were around six million, and for 2012, which were less than half this amount, suggesting a return to previous conditions.
The 2012 Iron Fertilization Experiment
This is the background against which the Haida Salmon Restoration Corporation and Russ George carried out their controversial ocean fertilization experiment in the summer of 2012. After the experiment became public, it was roundly condemned by environmentalists and scientists alike. However within a few months, satellite imagery showed that a massive 10,000 square kilometer phytoplankton bloom had developed in the Gulf of Alaska, centred around the area which was seeded with iron sulfate. The following year, in 2013, catches of pink salmon from the Pacific Northwest showed a 400% increase over the previous year. The latest estimates for the 2014 Fraser River sockeye run are more than double the numbers for 2010. This would be unprecedented, and would represent by far the biggest ever recorded run of sockeye salmon on the Fraser River.
It is impossible to say definitively whether this bonanza is a direct consequence of the 2012 experiment. Even Jason McNamee, the current director of the Haida Salmon Restoration Corporation does not go so far as to claim that there is a definite causal relationship between the 2012 experiment and the current abundance of Pacific salmon. Nonetheless, the timing of the phytoplankton bloom and its location do provide strong circumstantial evidence that its formation may have been the result of the iron seeding experiment. The abundance of salmon in 2013 and 2014 also suggest that the availability of increased food supplies may have substantially increased salmon survival rates.
Less easy to quantify is how much CO2 was sequestrated by the phytoplankton bloom. Estimates vary widely as to how effective ocean fertilization is as a way of removing atmospheric carbon. Some estimates suggest it may be possible to remove the equivalent of half our annual emissions using widespread ocean fertilization, whereas others suggest that very little CO2 will be removed from the atmosphere in the long term. There are also concerns that trapping CO2 at the bottom of the ocean may increase ocean acidification, and that the death of large quantities of phytoplankton could deplete parts of the ocean of oxygen. Unfortunately because of the manner in which the experiment was conducted, it is not possible to come up with any valid estimate of the amount of CO2 which may have been removed.
Should we Repeat this Experiment?
The 2012 experiment was unscientific in its design and implementation, and violated a number of international protocols. That being said, there is strong evidence to suggest that it was highly successful, at least as far as boosting salmon survival rates went. While its potential effectiveness in removing CO2 from the atmosphere remains unproven, many scientists believe that ocean fertilization may be an inexpensive way of countering a significant percentage of anthropogenic CO2 emissions. The question is whether the success of this experiment makes up for the dubious methods employed and justifies its repetition.
I would argue that it does. Previous attempts at ocean fertilization have been carried out on too small a scale to provide conclusive evidence of its potential benefits. What the 2012 experiment appears to have done is to build on the natural ocean fertilization provided by the eruption of Kasatoshi in 2008 by providing abundant food for immature salmon in the Gulf of Alaska in 2012 and 2013. Taken together, these two events have very likely lead to the revitalization of a salmon run which was in trouble.
Repeating this experiment with clearly-defined objectives and properly organised scientific monitoring would help to provide ocean fertilization with scientific legitimacy. While the experiment set a dangerous precedent, the cautious approach advocated by scientists and environmentalists means it is unlikely that a similar ocean fertilization experiment would ever have been undertaken on such a scale. The argument that we should not repeat an experiment which clearly has so much potential benefit is analogous to saying that we should not go to space because rocket technology was originally developed by the Nazis.
While there are potential dangers associated with carrying out large scale ocean fertilization, neither the 2008, or the 2012 phytoplankton blooms appear to have had any serious detrimental effects. Again this is an area where proper scientific monitoring would be of enormous benefit if the experiment were to be repeated. There have also been charges that ocean fertilization constitutes geoengineering. If this is the case, what about fertilization of agricultural crops, and the runoff of fertilizer into the ocean? This is unintentional geoengineering, with largely negative consequences. We have also been geoengineering since the dawn of the industrial age through our emissions of CO2. The evidence to date suggests that, unlike these inadvertent by-products of our civilization, the effect of ocean fertilization is likely to be positive.
Responding to this story in various media, a number of people have commented that removing CO2 from the atmosphere is avoiding the issue and that we should instead focus on stopping carbon emissions at source and changing our economy. I think that this argument misses the point completely. The removal of atmospheric carbon is not about finding an excuse to carry on with business as usual. It needs to be carried out in parallel with decarbonising our economy. Moving to a low carbon economy does nothing about the extra carbon we have already added to the atmosphere. The only way to deal with that is through direct removal of CO2 from the atmosphere, and the take up of CO2 by photosynthesizing phytoplankton is analogous to encouraging forest growth on land, in that natural processes are being used to reduce atmospheric carbon levels. The process of ocean seeding has exactly the same effect as a large dust storm blowing iron-rich dust into the sea, a process which occurs frequently in the natural world.
As we try to find solutions for many of the seemingly intractable environmental problems we have managed to create, we have to avoid being rigid in our opinions and adopt a flexible approach, informed by observation and experience. When I first heard about the 2012 iron fertilization experiment, I too was against it. I have always believed in the precautionary principle, and it seemed that the potential risks were just too great. However the apparent success of this experiment has changed my opinion. We are rapidly running out of time to deal with many environmental challenges, and if we continue to investigate issues such as ocean fertilization at the current glacial pace we may miss out on the opportunity to potentially revitalize endangered fisheries. As things stand, fisheries the world over are in trouble. Without intervention it is likely that our current generation will be the last who will be able to eat wild-caught fish. That surely is as good a reason as any to undertake serious large-scale testing of ocean fertilization.
T. Parsons, & F. Whitney (2012). Did volcanic ash from Mt. Kasatoshi in 2008 contribute to a phenomenal increase in Fraser River sockeye salmon (Oncorhynchus nerka) in 2010? Fisheries Oceanography DOI: 10.1111/j.1365-2419.2012.00630.x