More than 30 years ago John Martin unravelled the vital role of iron, that arrives with dust in the wind, has on ocean plankton blooms.
His lifelong studies had convinced him that preceding the Ice Ages, dusty times produced vast plankton blooms. The blooms converted CO2 into ocean life, and that reduced the CO2 in the Earth’s atmosphere.
In those ancient times there was so little “extra” CO2 in the atmosphere that it formed not a “greenhouse blanket” as we say it does today, ancient CO2 made for the flimsiest of warm covering for the planet, more like a mosquito net than duvet. When those Pre-Pleistocene dusty winds blew they brushed that thin coverlet away from Mother Earth and she fell into a deathly cold chill we now call the ice age.
The findings, published in Science, 21 March 2014, confirm Martin’s longstanding theory that wind-borne dust carried iron to this region of the Antarctic. This iron bearing dust drove plankton growth and eventually led to the removal of carbon dioxide from the atmosphere. The great work of the authors also disprove the skeptics arm-chair “political science hypothesis” that some unknown nitrogen related phenomenon was driving those blooms.
Here’s a great video showing the circulation of dust and other aerosols around the world.
As plankton grows, it removes carbon dioxide (CO2) from the atmosphere. As their remains sink to the bottom, the CO2 is transferred to the deep ocean. Scientists have previously suggested iron fertilization as a possible cause of the lower CO2 levels that occur during ice ages. These decreases are, in turn, believed to have amplified the ice ages by making them much colder. Some researchers think that there would have been no ice ages at all without the CO2 depletion.
Martin’s and others research has also suggested that iron fertilization could be one way to draw down the rising levels of CO2 associated with the burning of fossil fuels. Having a better understanding of the driving factors of ocean carbon storage could help scientists to make better predictions about how the rise in manmade carbon dioxide will affect climate in the coming years.
Daniel Sigman, Princeton’s Dusenbury Professor of Geological and Geophysical Sciences, an author of the new study says the results confirm Martin’s theory. “I was an undergraduate when Martin published his ‘ice age iron hypothesis,” he told Princeton’s Catherine Zandonella.
“I remember being captivated by it, as was everyone else at the time. But I also remember thinking that Martin would have to be the luckiest person in the world to pose such a simple, beautiful explanation for the ice age CO2 paradox and then turn out to be right about it.”
A strong correlation of cold climate, high dust and productivity in the Subantarctic region — a band of ocean encircling the globe between roughly 40 and 50 degrees south latitude that lies in the path of the winds that blow off South America, South Africa and Australia — was established by prior efforts to test Martin’s theory. These studies, however, did not make it clear whether the productivity was due to iron fertilization or the northward shift of a zone of naturally occurring productivity that today lies to the south of the Subantarctic. The uncertainty over productivity was made more acute by the finding that ice age productivity was lower in the Antarctic Ocean, which lies south of the Subantarctic region.
Sigman’s research team collaborated with Gerald Haug and Tim Eglinton at ETH Zurich to settle the matter using a new method developed at Princeton. Fossils found in deep sea sediment — deposited during the last ice age in the Subantarctic region — were analyzed with the goal of reconstructing past changes in the nitrogen concentration of surface waters. The results were combined with side-by-side measurements of dust-borne iron and productivity. The nitrogen should have been completely consumed by the plankton, leading to lower residual nitrogen concentrations in the surface waters, if the dust-borne iron fertilization theory was correct. On the other hand, if the productivity increases were the result of a northward shift in ocean conditions, then the concentration of nitrogen would have risen.
The teams findings proved Martin was right about it!
Note: The terrible state of climate change today is unlikely to find a solution in any single solution. Surely replenishing and restoring dust we deny the oceans is one solution that can remove billions of tonnes of CO2 from the air and ocean at incredibly low-cost while restoring ocean pastures and fish populations. That CO2 is certain death for ocean life as it becomes carbonic acid. The better choice is to help ocean plankton covert that deadly CO2 into life itself.
IT JUST WORKS!
Read everywhere on this blog how our work has brought a large ocean pasture back to life and how that pasture has sent back to us hundreds of millions of additional wild salmon. http://russgeorge.net/2013/10/28/fish-came-back-next-day/.
Read more from the Princeton web:
Dust in the wind drove iron fertilization during ice age