A Novel Geoengineering Idea: Increase the Ocean's Quotient of Whale Poop

By Smriti Rao | April 23, 2010 12:26 pm

800px-Humpback_stellwagen_eThe fight against global warming has a brand new weapon: whale poop.

Scientists from the Australian Antarctic Division have found that whale poop contains huge amounts of iron and when it is released into the waters, the iron-rich feces become food for phytoplankton. Phytoplankton absorbs carbon dioxide from the air, the algae is in turn eaten by Antarctic krill, and baleen whales eat the krill. Through this neat cycle, globe-warming CO2 is kept sequestered in the ocean.

Scientists have long known that iron is necessary to sustain phytoplankton growth in the oceans, which is why one geoengineering scheme calls for adding soluble iron to ocean waters to encourage the growth of carbon-trapping algae blooms. While environmentalists have fretted over the possible consequences of meddling with ocean chemistry that way, this new study on whale poop suggests an all-natural way to get the same carbon-trapping effect: Increase the number of whales in the ocean.

When Stephen Nicol of the Australian Antarctic Division analyzed the feces of baleen whales, he found an astounding amount of iron in it. New Scientist reports:

Nicol’s team analyzed 27 samples of faeces from four species of baleen whales. He found that on average whale faeces had 10 million times as much iron as Antarctic seawater.

This led Nicol to suggest that before commercial whaling began, baleen whales may have been the source of almost 12 percent of all the iron in the Southern Ocean’s surface water. Nicol says that when the Baleen whales started to be hunted and killed over the last century, the Southern Ocean lost a rich source of iron.

“Allowing the great whales to recover will allow the system to slowly reset itself,” he says. And this will ultimately increase the amount of CO2 that the Southern Ocean can sequester.

David Raubenheimer, a marine biologist who wasn’t involved in the current study, told New Scientist that the findings are important.

They highlight a specific ecological role for whales in the oceans “other than their charisma”, he says.

Related Content:
80beats:Will Commercial Whale Hunts Soon Be Authorized?
80beats: Videos Show Collision Between Japanese Whaling Ship & Protesters
80beats: Iron Dumping Experiment Is a Bust: It Feeds Crustaceans, Doesn’t Trap Carbon
80beats: If We Can’t Stop Emitting CO2, What’s Our Plan B?

Image: Wikipedia

  • http://www.younglandis.com Ben Young Landis

    Spock was (will be?) right!

  • http://chl-tx.com/instructorsview TXCHLInstructor

    Come on, surely you can think better than this. Whales are *not* a *source* of iron! They can’t be. They can only get iron from other places, and concentrate it. The number of whales in the ocean can’t possibly have any effect on the net amount of iron in the ocean.

    Get real.

  • Georg

    There has been a famous error in calculating the
    iron content of spinach about hundred years ago.
    Somebody made an error by factor ten then,
    and millions of children were tortured to eat
    spinach for about 60 years.
    That first error was due to use of a slide rule
    presumably, the actual errormaybe came from
    a low battery situaion :=(

  • Woody Tanaka

    “Come on, surely you can think better than this. Whales are *not* a *source* of iron! They can’t be. They can only get iron from other places, and concentrate it.”

    I think that’s what the post was saying (and the New Scientist article is even more explicit); that whale feces is a source of iron in, as the post specifically states, “the Southern Ocean’s surface water.” And, in terms of the mechanism described, it is the local concentration which is important, and not the net amount, disbursed in the ocean as a whole.

  • ToneDeF

    @ Woody Tanaka

    So by their rational, whale poop may be detrimental to plankton in other areas of the ocean, as they remove iron to re-deposit elsewhere?…

  • http://tispaquin.blogspot.com Doug Watts

    Too bad we killed most of the whales and now very few are left.


  • Arty

    What I’m thinking is that the as the whales hunt in deeper water, where the plankton population can’t reach or survive there due to the minimal level of sunlight, or lack thereof, they could concentrate the iron there, as well as else where, and then move it to the surface, where the plankton can use it and thrive.

  • Georg

    “They can only get iron from other places, and concentrate it”

    Oh yes, the whales feed in iron-rich areas of the oceans
    and then migrate thousands of miles to areas
    lacking iron to poop.
    Seriously: one has to exclude that the whale who pooped
    has some problem with his guts.
    Any illnes or parasite causing the guts to bleed, will show
    up in high iron content of the poop.
    Gernerally, one has to relate the iron in a whales poop
    to the iron content in his food! For that
    you have to know amount of food, iron percentage of food
    and the same figures for the poop.
    Nobody knows such numbers! This is plain nonsense.

  • Woody Tanaka


    “So by their rational, whale poop may be detrimental to plankton in other areas of the ocean, as they remove iron to re-deposit elsewhere?…”

    No, read the article. The source of the iron is the krill, which have large vertical migrations daily. As the whales eat deep swimming krill and deposit the iron from the krill in surface waters, plankton can grow. It is not removed from other areas, as much as it is from other depths and deposited on the surface or near the surface sufficient to promote plankton growth.

  • Jockaira

    Gee! It seems that the modern scarcity of whales is contributing to global warming.

    I wonder by how much? “12 percent of all the iron in the Southern Ocean’s surface water” seems to be a significant amount, certainly enough to affect the population of plankton and then krill…and then us.

    Just another adjustment we’re gonna have to make if we don’t want to get evicted from earth…


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