Typical deep-sea water masses have been isolated from the surface for long periods of time and have limited supplies of dissolved oxygen that are replenished at extremely slow rates.

Multiple strata separate these deep waters from the surface waters and from the atmosphere, so that O2 equilibria in these deep water layers are (a) slow to replenish, and (b) likely to be highly-sensitive to disruption.

Given what we already know about nutrient-induced eutrophication in aquatic systems and the catastrophic effects of the anoxia that results (classic textbook subject-matter), we should be quite skeptical of schemes that imagine wide-scale fertilization of the ocean’s surface layers. First, of course, on a century-to-century time scale, deep-sea organisms are adapted to one of the most stable, unchanging environments on earth.

Secondly, while fertilization of the sea’s surface waters (with a dusting of iron, for example) may enhance phytoplankton growth, the increased biomass will not be confined to surface waters, but will result in export of tons of additional organics to the deep-water layers.

Heterotrophic microbes in the deep-sea can be expected to respond to an increased import of such organics with a burst of exuberant growth – quickly depleting already limited supplies of dissolved oxygen, and producing a cataclysmic deep-sea anoxia.

Since the ocean covers approximately 70% of earth’s surface, advocates of wide-scale fertilization, if successful in their campaign, may unwittingly trigger an ecosystem disruption and an extinction event on an unimagined scale.

Even our brightest, most well-meaning, and most ingenious suggestions need to be measured against the human propensity to error, blunder, and trigger unintended consequences.

Although we are an inventive species, we are also brash and display a reckless lack of humility. Current projects that envision re-engineering the operation of 70% of earth’s biosphere** constitute a clear example.
** and apparently without so much as a vote or a ballot initiative

Footnote

Humanity’s central problems today are: (a) the impending arrival of a 7th, 8th, and 9th billion by mid-century, along with (b) the extreme levels of overpopulation / environmental impacts that we already exhibit.

With additional billions on track to join us by mid-century and many other millions rapidly industrializing, the combined effects of today’s planet-wide demographic tidal wave constitute the single greatest risk that our species has ever undertaken.*

Yet, the biospheric and civilizational implications of these numbers are essentially absent. For instance, can biosystem functioning even survive a continuation of the impacts that we are already exerting today, even without the avalanche of new arrivals who are arriving at a rate of 800,000 additional persons every four days?

The economic premise of ocean-fertilization is that the phytoplankton would help combat or offset global warming by removing CO2 from the atmosphere – and private companies could then sell “carbon credits” to polluters for a profit by simply sailing out to sea and dusting the oceans with untold tons of powdered iron. While assorted policymakers (and industries) are attracted to such adventures, the passage above suggests that the results of any such large-scale projects could trigger a deep-sea extinction event of unimaginable proportions.

NYU needs to re-think its apparent support of these particular schemes.

Rocky

I think using phytoplankton as a carbon offset is a great idea. Form my limited knowledge on the carbon offsets I think that a phytoplankton carbon offset is the most efficient type of carbon offset. I would really like to see the option to purchase a phytoplankton offset whenever I pay for something that will produce a green house gas: air travel, gasoline purchase, payment of my electric bill and so on. I’m guessing that this phytoplankton offset would be very affordable. Also, I think before this happens we need to get a grasp on global dimming as explain in the next paragraph.

Have you heard of global dimming? Just in case you haven’t it is the idea that the some pollutants are allowing less light into the earths atmosphere. Now we also have global warming, which is essentially that some pollutants make the earth hold in more heat. Recent research shows that global dimming may have prolonged our discover of global warming. Now, from what I understand most of the current approaches to combating global warming will actually mostly combat global dimming and therefor in the worst case could potentially make the earth heat up more quickly as in more heat would be allowed into the atmosphere and less heat would be allowed out. (Sorry for the above over simplifications global warming and global dimming) We need to find a way to combat global dimming and global warming equally at the same time. We also need more information and more accurate models.
Here is a bit of info on global dimming:
http://www.pbs.org/wgbh/nova/sun/

Thanks,

Ronald Charles Price
http://ronald.charles.price.googlepages.com/ronprice