Results cast doubt on potential ‘climate fix’ - March 24, 2009
A controversial experiment which poured iron into the Southern Ocean has also poured cold water on the idea that such ‘ocean fertilization’ can mitigate against climate change.
The Lohafex project was investigating suggestions that carbon dioxide can be removed from the atmosphere by promoting algal blooms with iron. Despite protests from some groups, researchers aboard the Polarstern research vessel carried out their experiment this month.
However, the Alfred-Wegener institute, which was backing Lohafex, says “only a modest amount of carbon sank out of the surface layer by the end of the experiment. Hence, the transfer of CO2 from the atmosphere to the ocean to compensate the deficit caused by the LOHAFEX bloom was minor compared to earlier ocean iron fertilization experiments.”
Although the iron did initially stimulate plankton production, predation from small copepods prevented further growth. In addition, previous experiments have led to increases in diatom algae, which form silica shells that sink after the algal blooms, trapping the carbon.
The institute says previous, natural blooms had extracted all the silicic acid, preventing diatom growth. It adds:
Hence a major finding was that other algal groups, although stimulated by iron fertilization, are unable to make blooms equivalent to those of diatoms. Since the silicic acid content in the northern half of the Southern Ocean is low, iron fertilization in this vast region will not result in removal of significant amounts of CO2 from the atmosphere.

Kenneth Coale, director of Moss Landing Marine Laboratories in California, was more upbeat.
He told the BBC, “To date we’ve conducted experiments in what amounts to 0.04% of the ocean’s surface. All have indicated that iron is the key factor controlling phytoplankton growth, and most have indicated that there is carbon flux (towards the sea floor) - this is one that didn’t.”
Image top: Polarstern in the open sea. / Alfred-Wegener-Institut
Image lower: copepod / G. Mazzochi, SZN / Alfred Wegener Institute

Comments
I must disagree with the inference on the 'cast doubt tagging' of the LohaFex experiment. What this experiment showed is that iron replenishment and ocean ecorestoration is indeed very possible. That the bloom created was quickly converted from living plant biomass into living animal biomass is the natural scheme of ocean ecology.
There can be no question that the few tonnes of replenished iron restored ocean plant life at the same levels of efficiency shown by decades of research, that being each tonne of iron yields the plant biomass equivalence of 367,000 tonnes of CO2. Given that this vast amount of biomass is now in the web of ocean life means it is restoring vital ocean fertility.
Recall that the Southern Ocean has suffered decimatng loss of plant life, due to iron depletion effects of high CO2, more than 10% of ocean plants are missng from what was seen less than 30 years ago. So while those few tonnes of iron may not have sent the CO2 to the bottom it has taken that amount of CO2 out of the ocean acidification pathway and repositioned it in the standing living biomass of the Southern Ocean. Had those few millions of tonnes of CO2 not become Southern Ocean plant life it would surely now be Southern Ocean acidifying death.
This work showed that there is an absolute need to carefully pick the ocean ecosystem that one aims to replenish and restore to achieve the greatest benefit. It also shows that one must design the work to meet minimal ecosystem demands in terms of scale, timing, location, and ecological implications. What LohaFex did was to replenish a very small amount of iron into a very small patch of ocean that was surrounding the new bloom and already enjoying abundant blooming.
It was surely clear from the first water samples taken that the state of depleted silica meant the ocean had bloomed and consumed other vital mineral nutrients thus limiting the beneficial effect of the iron replenishment. Thus it was known this would redirect the ecologicl effect toward species that are less dependent on silica. This led quite predictably to less sinking of large diatom carbonate rocks and instead favoured other species. However it also means that the iron, as observed at the end of the project, remains replenshed in the surface ocean continuing to benefit the ecosystem for months to come. It is the same as what is happening in that same region of ocean as the observed iron rich icebergs randomly support and sustain a more robust and varied ecosystem. In fact iron leaves the surface ocean primarily fixed to the biomass it stimulates growth of, as it recycles thus no iron goes to waste.
A key feature of the LohaFex blooms is that the very small size of the patch, and the fact that the region was blooming and preloaded with grazers, led to those grazers enjoying the free lunch and dispatching the new bloom in relatively short order. It is as if you decided to plant a tiny patch of lettuce in a vast field of rabbits, the rabbits would graze the emerging lettuce in a flash leaving little to grow to maturity. If had planted a large patch of lettuce some considerable distance from any large populations of rabbits before the rabbits discovered the lettuce patch it would have grown to maturity and be sustaining itself. Lettuce and rabbits would fall into synch along with the rest of the ecosystem and all would flourish.
However even so the LohaFex rabbits(copepods and amphipods)continue to recycle the iron and other nutrients as they eat and defecate and are eaten and converted into healthy whales and other marine life.
What LohaFex does NOT show is that the replenishment of iron to achieve ocean restoration does not work as your report tends to suggest. This politically charged sentiment is nonsense that panders to the distortions of those who would make the guise of science into an excuse for non-critical thinking?
How is it that a forest on land which never leaves the living biosphere to be buried in abysmal sediments is recognized as being of enormous value to the envirnment and society and its carbon content as standing biomass is allowed to be monetized in emerging carbon markets to provided an economic stimulus to the planting, restoration, and protection of forests.
So most certainly LohaFex is another,albeit small, step along the path to understanding how we must proceed to becoming active stewards of our oceans. Those oceans are by all accounts in the most dire of straits as reports are showing. Only this year the Southern Ocean was reported to be doomed to tip over the proverbial deadly tipping point of ocean CO2 acidification by 2030, a mere 21 years away. That tipping point is certain based on the preloaded carbon bomb of hundreds of gigatonnes of CO2 already in the air and destined to dissolve into the surface ocean. It will occur regardless of whether we slow additional emissions, as the first carbon bomb is more than sufficient to produce the deadly acidification. The only means to counter that first carbon bomb is by replenishing the oceans mineral micronutrients and accomplishing ocean ecorestoration. The restored ocean plants will fix and convert deadly CO2 into ocean life, the phyto-plankton, copepods, amphipods and whales of PolarStern's voyage.
My own company Planktos Science is well known in this field and in fact we worked hard some few years ago to convince the German Institute and Prof. Smetacek to engage in a much larger more ideally situated, longer term, and better suited iron replenishment experiment. Sadly the attacks on this topic by means of lies and subterfuge of the likes of Greenpeace scared the Germans and their Indian partners into this minimalist effort which is now most useful in proving How Not To engage in meaningful ocean restoration.
Your casting this important work into the mere context of the fight story over potential CO2 sequestration results does a grave disservice to this important field of ecorestoration science and to the planet.
For more info read www.planktos-science.com
Posted by: Russ | March 24, 2009 05:16 PM