Study: Climate Hacking Scheme Could Load the Ocean With Neurotoxins

By Andrew Moseman | March 16, 2010 2:20 pm

IronSeedingsOf all the planet hacking possibilities floated as last-minute ways to stave off a climate catastrophe (building a solar shade for the Earth, injecting the atmosphere with sunlight-reflecting aerosols, etc.), iron seeding seems one of the more practical and feasible ideas. The scheme calls for the fertilization of patches of ocean with iron to spur blooms of plankton, which eventually die, sink, and sequester carbon at the seafloor.

However, worries over the consequences of tinkering with the ocean ecosystem have held up plans to attempt this. And now, in a study in the Proceedings of the National Academy of Sciences, researchers claim that such a plan could risk putting a neurotoxin into the food chain.

Iron seeders have targeted the large swaths of ocean surface with high levels of nitrate and low chlorophyll, where an injection of iron could potentially turn a dearth of plankton into a bloom. But too many phytoplankton can be a bad thing, especially when it comes to members of the genus Pseudonitzschia. This alga produces domoic acid, which it spews into the surrounding seawater to help it ingest iron [ScienceNOW]. Sea lions off California have gotten sick from the toxin. In Canada, three people died in the 1980s from eating shellfish that themselves had eaten Pseudonitzschia.

Seeding experiments—about a dozen have taken place so far—had not shown the production of domoic acid. But oceanographer Charles Trick was not convinced, because those previous tests had harvested the plankton in the ocean but not tested them until the researchers returned to shore. So, for their study, the researchers examined water samples taken from open-ocean tracts in the sub-Arctic North Pacific Ocean where iron-fertilization experiments were conducted [AFP]. The results were not encouraging.

Pseudonitzschia collected in midocean and subjected to shipboard experiments produced plenty of domoic acid. “We found there is a lot of toxin out there,” he said. “If we were to seed with iron, the amount of toxin would go up” [The New York Times]. In fact, Trick says, the concentration of Pseudonitzschia doubled, which increased how much domoic acid was in the water. In turn, the preponderance of the acid allows more Pseudonitzschia to grow, in a sort of feedback circle.

Trick says he doesn’t think the acid would make it all the way up the food chain to people, though birds might ingest it. But, he says, this is another sign that tinkering on the planetary scale can be fraught with unintended consequences.

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80beats: Iron-Dumping Experiment Is a Bust: It Feeds Crustaceans, Doesn’t Trap Carbon
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Image: NASA SeaWiFS Project (the 12 seeding experiments thus far)

  • Wes

    Ah, the law of unintended consequences. With death and taxes the unholy triumvarate of certainty. See Judith Curry’s interivew in Discover Online, March 10. “Are you saying that the scientific community, through the IPCC, is asking the world to restructure its entire mode of producing and consuming energy and yet hasn’t done a scientific uncertainty analysis?” The answer? “Yes.”

    Might I suggest humble readers remember to continually invoke the deity to save us from ourselves?

  • Ernie M. Brewer

    The funny thing is that if we are hearing about it now, it is already going on.

  • Doug Watts

    The most provably effective geo-engineering solution to global warming is for us to stop putting so much CO2 into the atmosphere. This is like your car running out of gas and trying to invent a car engine that runs on water instead of just walking down the street to get some more gas.

  • JMW

    @Doug Watts: “The most provably effective geo-engineering solution to global warming is for us to stop putting so much CO2 into the atmosphere…”

    Agreed, but for two things.

    1) It would take some time for the CO2 and other greenhouse gasses to cycle out of the atmosphere. So even if we cut CO2 production to zero tomorrow, we’d still be living with the current CO2 concentration for years to come. Which means we will still get warmer.

    2) We don’t have time to come up with a plan that everyone will accept. By the time the US gets on board, it’ll be because there’s drought in Mexico, Florida, Texas, southern California, India, etc. It’ll be too late by then.

    This is why I advocate the space-borne adjustable shade, to cut the incoming heat from the sun. It has, to my mind, numerous advantages, the biggest being that it is reversible. Seeding the sky with aerosols, seeding the ocean with ocean, etc., are extremely difficult to reverse if it turns out we’ve made a huge mistake. And, it’ll promote (and indeed, inquire) a massive investment in space technologies.

  • Richard Bruce

    There are unintended consequences to all human action, and failure to act counts as action.

    For example, in the early seventies we took several pollutants out of our auto exhaust. As it turned out these pollutants were cooling the earth. We left carbon dioxide, which is warming the earth in, the result a global cooling trend became a global warming trend. So global warming is an unintended consequence of the late sixties, early seventies ecology movement.

    Humans are a major cause of global warming, after all tree hugging, hippie, ecology nuts are humans, and they played a big role in the ecology movement that created global warming.

  • nick

    I can’t believe people are still talking about this.

    More pollution isn’t the answer.

    Well, this is an answer to someone looking to sell a lot of aqueous iron fertilizer.

  • Matt Tarditti

    @Richard Bruce – “For example, in the early seventies we took several pollutants out of our auto exhaust. As it turned out these pollutants were cooling the earth.”
    I can’t tell if you’re trolling, so here’s a chance to to prove that you’re not: what pollutants? Please enlighten us.

  • YouRang

    Although I agree with the hesitancy of all to put iron in seawater, it isn’t obvious to me that more domoic acid would be secreted. It seems more likely that less domoic acid would be secreted since the protozoa wouldn’t have to work as hard to ingest the higher level of iron.

  • Roger

    I dont believe in the AGW hypothesis, in fact I can prove it is extremely unlikely (see my blog), but what I do know is that the only effective measures that would actually achieve co2 emmission reductions in the scale being proposed, is to limit/decrease human population and standard of living.

    The IPCC are not complete fools, I believe this has to be their hidden agenda.



  • scribbler


    Good luck with that “limit/decrease human population and standard of living” thing…

    Most folks don’t take too kindly to such things.


    Most all of us can plant trees somewhere. As a first step, that is in my opinion the most cost effective. The products are at hand and could be made almost universally available. The Earth had many more trees at one time so we are familiar with the pending effects. Trees take up carbon without further human intervention over a period of decades. Wood is a material that we are very familiar with.

    Seems wholesale reforestation has at least a better starting out than anything else I’ve heard.

    I think the iron dump holds a great potential for disaster. There are way too many unknowns and literaly thousands of variables beyond our control.

  • m


    not this again? CO2 does not retain any more or less energy than normal air.


  • JMW

    @9 Roger.

    Y’know, whenever I hear someone saying that climate scientists in general (or the IPCC in particular) is conspiring to transfer wealth from rich countries to poor countries, or reduce the standard of living or the population, or whatever it is that critics say the IPCC is conspiring to do, there is always one thing missing.


    Why would the IPCC want to reduce population? Or the standard of living? Most of the members of the IPCC live in currently-wealthy countries. Why would they want to lower the standard of living in those countries?

    Really, Roger, if you want to presuppose a conspiracy on the part of climate scientists, you need to be able to explain what this conspiracy is trying to do, and why they’re trying to do it.

    For fun? Because they can? Social justice?

    Sorry, but I can’t think of any reason you can come up with that would make sense.

  • Marleen Stencil

    You completed a few good points there. I did a search on the matter and found most persons will go along with with your blog.


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