But did it bury any carbon? Previous studies suggested that most of it will end up back in the atmosphere.
We don't know that yet. I don't agree with you that most of it will end up back in the atmosphere. Look at the [Victor] Smetacek paper [this year in Nature]. A significant amount of carbon ended up on the seafloor. Diatoms [a type of shelled algae] are big carbon sinkers because of their stony shells and powered buoyancy. When they run out of power they sink.
Tell me about the 120 metric tons of iron you dumped.
We didn't choose the simplest form of iron and dump it in the ocean. We did a carefully thought through, planned process that asked, "What forms of iron does the ocean use today and historically? How might we determine what's the right form or composition or method of preparation or method of distribution of the forms of iron that we know are effective?" So we had an experimental matrix that we believe will answer that and we have the data now.
Mother Nature blows dust in the wind, which carries fully reduced iron oxides. That's the form of iron in dust in the wind. Upstart scientists, humans, say, "We can do better than Mother Nature. We won't use that natural source of iron that nature uses; we'll use commercial fertilizer. We'll use iron sulfate because iron sulfate has greater solubility and greater biological availability."
We tested both. Our data will tell us. Do you get a different plankton bloom if you exactly mimic Mother Nature than if you exactly mimic some supplier of agricultural chemicals?
Where did you get the iron?
It's an extremely commonly available material. Iron ore dust is in use everywhere. Australia sells 600 million tons of it to China [to make steel]. The amount of sweepings, the fugitive dust from the 600 million tons shipped from Australia to China is infinitely more than we used.
We're not at liberty to divulge precise details of suppliers and such. Anybody associated with this project is viciously attacked.
Why did you pick the location you did?
Where could you do a more perfect experiment than in between a normal, natural similar phenomenon and an enormous unnatural absence? The best experimental design is to go in between two natural controls, which is where our bloom was placed. That's why [the late marine biologist] John Martin picked west of the Galápagos, because those islands are a massive source of iron. Here's a massive iron stimulated bloom that goes off to the west of the Galápagos for hundreds of miles and here's the most iron-depleted ocean in the southeast Pacific.
The best place to do science on this and get knowledge is to put the bloom in between. See what natural iron-stimulated blooms produce and what the non-blooming ocean has. Test whether or not the characteristics of what you've created [are] different in any way to a natural system.
So what did you observe at sea?
Life appeared. The nightly migration of zooplankton from the thermocline [a layer of water in the ocean that marks the transition from warmer surface waters to colder deep waters] to the surface, we saw that. Copepods, salps, all the little fish. We have thousands and thousands of biological samples now going under microscopes around the world to be identified and quantified. We didn't have a ship with 58 scientists. We didn't have a lab on board, and it's not a great big ship with the stability to do microscopy on board. What we could do is work 24/7 and the Haida crew on the ship worked literally 24/7. Their job was to collect an unimaginably vast collection of samples.