Fe-eding the Ocean

This satellite image shows a large phytoplankton bloom, about 150 miles in diameter, that occurred in the Northwest Pacific Ocean off the coast of Hokkaido, Japan in May 2009. Credit: Photo by Norman Kuring, MODIS Ocean Color Team/NASA

The political hot topic of climate change has brought about an idea which has been kicking around the oceanography community for a while: supplementing the oceans with iron (Fe) to improve the health of the ocean by promoting the growth of carbon-dioxide consuming organisms.  This idea was based off a theory that a short lived biological productivity boom after the last ice age (≈14,000 years ago) was caused by  run off from an emerging continental shelf which they assume was rich in iron because iron has been known to cause blooms in today’s oceans.  This theory, however, was recently debunked by a team of scientists from the US, UK and Norway who discovered through the analysis of sediment cores that the level of iron actually decreases during deglatiation (i.e. the melting of the ice which would have been the source of that run off).  Past sediment core studies had looked at the mineral content confirming the productivity boom (increased opal and calcium from shells) but had never looked specifically at iron.  Pheobe Lam of the Woods Hole Oceanographic Institution (WHOI) and co-author of the study said:

"We saw the flux of iron was really high during glacial times, and that it dropped during deglaciation.  We didn't see any evidence of a pulse of iron right before this productivity peak."

They’re re-hypothesis suggests what they are calling a “transient perfect storm of nutrients and light” which produced ideal conditions for optimal growth which could be sustained for only a few hundred years.  They believe that the changing climate produced mixing in the Northern Pacific which pushed nutrients from the deep oceans up and pushed photosynthesizing surface organisms, such as plankton, down.  Then, the freshwater from melting ice stopped the mixing leaving the organisms in a thin, bright, nutrient-rich top layer of ocean allowing the organisms to flourish for a few hundred years until their life producing nutrients ran out.

Some scientists were already skeptical about adding iron to the oceans due to the unknown impact the process could have on the ocean and the thought that it may only decrease carbon-dioxide levels temporarily.  In 2007, another chemist at WHOI said, “While there is still no agreement on the efficiency of [carbon-dioxide] reduction or its environmental impacts, some scientists are willing to consider further experiments to address these remaining uncertainties, given that future policies and carbon-offset markets may emerge with or without a sound scientific basis,” and this recent study did just that.

Now I am going to stand on my soap box.  I think we as humans have a responsibility to interfere when we are deliberately hurting the environment but it can be prevented (such as poaching, overfishing, deforestation, etc.); however, sometimes I think we need to just let nature do its thing.  The earth has an ebb and flow of heating and cooling, productivity and sterility, a series of highs and lows trying to create a balance.  For some reason humans think we can affect the balance for our benefit but what says by pumping the oceans full of iron to reduce something bad we don’t actually end up producing something worse when nature tries to compensate for our actions.  Humans don’t think in an earthly timescale, they think in a humanly timescale.  The productivity boom after the ice age was produced over hundreds of years.  I’m sure the people who want to pump the oceans with iron aren’t thinking of that kind of a timeline.  They are thinking they will see results they’ll see immediately, which there may be A result immediately but THE result may not be for another hundred or thousand years.  The statement by the WHOI chemist saying “future policies and carbon-offset markets may emerge with or without a sound scientific basis” is a perfect example of how politics are manipulating people who want to do good for the planet into doing things that may not be.  If only we could just keep politics out of it.

The planet has gone through phases like this before.  Humans are going to produce carbon-dioxide.  The only way to really prevent the carbon-dioxide levels we make is to stop industry and that ain’t gunna happen.  Yes, there are probably things we can do to keep it from accelerating, yes, we should take better care of our planet, yes, it is better to be “green”, but don’t do it because you want to see climate change stop because it’s not going to (the Quaternary glaciation has seen 8 glacial cycles and we are still technically in it!).  Do it because you don’t want to be destructive and you want to aide in the recovery, not add to the strain.

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• Phoebe J. Lam, Laura F. Robinson, Jerzy Blusztajn, Camille Li, Mea S. Cook, Jerry F. McManus, Lloyd D. Keigwin.Transient stratification as the cause of the North Pacific productivity spike during deglaciation. Nature Geoscience, 2013
  

Glacial and interglacial cycles of the late Pleistocene epoch represented by atmospheric carbon-dioxide measured from ice core samples going back 650,000 years