by Russ George
July 21, 2004
One might not think that our North Atlantic cod are taking their marching orders from the ghost of Genghis Khan but indeed they may well be. It is all about the story of dust in the wind. Here at the Planktos Foundation (www.planktos.com) we have been working on this story of on how the oceans are being degraded by rising CO2. The key is the link between the oceans and land and the dependency the oceans have on dust born iron and other micro-nutrients. It seems the grass is a bit greener in Mongolia and way less greener in the oceans as a result. Global ocean productivity is down by over 6% and regional oceans like the North Pacific are down by 10-30% (depending on your expert).
In short there is very strong evidence showing that the most responsive terrestrial plant ecosystems are enormously benefited by the present high CO2 levels. This has begun a powerful feedback loop involving the oceans. The dry land short grass ecosystems are an especially important part of the central Asia steppes including much of Mongolia. That short grass has evolved to be able to survive in a very droughty environment where a tiny bit of extra water makes for bumper crops of grass. Aside from rain the major limiting factor for such steppe grass is water lost by evapo-transpiration when the grasses open their stomata (lungs) to exchange gases with the atmosphere seeking the CO2 they need to grow. They have always paid for CO2 by giving up water to the drying effects of the air. They now benefit enormously by the 40% higher CO2 in the air in terms of water conservation. Thus these steppe grasses are growing just a bit bushier for just a bit longer each spring and this is resulting in a huge benefit to soil conservation and the reduction of dust.
Add to this the very large and effective efforts of the governments of Asia to introduce our western remedy for farming in dry lands, winter and spring wheat. This was the cure our Soil conservation Services introduced to stop the Okalahoma dust bowl. We now see from very good data that the number of events of severe dust storms in Mongolia has dramatically declined to only 26% of what it was in the 1950's and 60's. That Mongolian dust has historically made up 50% of global dust so this decline is a big time change and the effects are showing.
and the impacts of the climate change.
Evidence that this dust from Mongolia drives ocean productivity around the Northern Hemisphere is quite clearly shown in the historical scientific record. We see Mongolian dust in the Greenland Ice cores, even in ice cores from glaciers in the Swiss Alps. Both the North Pacific and the North Atlantic depend on Gobi dust to support their productivity. There is one particularly good record showing the connection. It is the period during the 1960's and 70's known as in the North Atlantic as the Gadoid Outburst. During this time there was observed a major enhancement in plankton stocks and an associated outburst in production of cod and hake, the two principal species of the gadoid fish family.
A key paper on this is:
The authors present outstanding data and interpretation pertaining to the decline in fish and plankton in the North Atlantic though I believe they missed the most powerful underlying cause of this decline. Long term data from China shows that extraordinary dust events occurred in the 1960's and 70"s coinciding with what is known in ocean science as the Gadoid Outburst.
The Gadoid Outburst in the North Atlantic was a period of time when super abundance of ocean plankton brought on similar abundance of Cod stocks. I propose that the evidence is clear that this was a result of the unusual amount of dust born iron that arrived in the North Atlantic spurring that unusual abundance of ocean plankton. The evidence is clear that the North Atlantic like the North Pacific depend on the dust from Asia as their primary source of iron and related nano-nutrients. That the Mongolia dust was extraordinarily abundant during the Gadoid Outburst is no unrelated coincidence rather it is the most likely explanation. It is clear that efforts in China to mitigate dust storms and topsoil loss are along with rising CO2 resulting in dramatic reductions of Asian dust reaching the northern oceans of the world and resulting in dire losses of primary productivity. The dust levels in the 90's were only 25% of those in the 60's!!!
In addition the reduction of primary ocean productivity the attendant loss to the ocean CO2 sink is providing a powerful feedback mechanism to global CO2 levels resulting in more rapidly rising global CO2. We see this clearly in the rising CO2 levels in the oceans recently reported in the Journal Science. Indeed the oceans are soaking up more CO2 as a result of higher concentrations in the air. But at the same time they are very much reduced in their capacity to buffer this higher CO2 through biomass sequestration. High CO2 levels have also broken the top down rapid carbon pump in the ocean! Dissolved CO2 will eventually mix into the deep ocean but this is a process that takes place over the course of centuries if not millenia. So is this just another doomsday story, maybe not.
There are obvious solutions at hand that might economically mitigate this lost productivity in the North Atlantic and North Pacific and that is to restore the iron and other micronutrients that topsoil conservation on land is stealing from our critical ocean ecosystems. We know the dust from Mongolia provides roughly half of the dust globally. it is now reduced to one 1/4 of what it was which means the oceans are suffering an enormous dust / iron deficit. This is not going to change for the better and indeed will only become worse as rising CO2 continue to improve the lot of steppe grasses.
Restoring iron and associate micro-nano-nutrients to the oceans can be done intelligently and effectively. The most recent, largest, and longest iron addition experiment (January 2004) found that Fe:C fixation / response ratio was on the order of 1:100,000 !!! This is just about spot on what John Martin suggested some 15 years ago. We have at our disposal the ability to see where and when forest sized patches of ocean are in need of these nutrients. The amounts needed are completely trivial in comparison to the tonnage of cargo that ply's the oceans on the fleet of some 30,000 large vessels that the world operates at sea. Indeed the late great oceanographer John Martin was nearly correct in his estimate that a mere ship load of iron could change the climate. (see the cartoon below on Martin's Geritol Solution.)
It may be a few ship loads out of those 30,000 ships that make many passages each year can solve the problem. This is environmentally safe as it will only restore lost ocean productivity to recent healthy levels, in the bargain will help mitigate global climate change, and is easily economical. Further information on this can be found on the web site of The Planktos Foundation. www.planktos.com.
Russ George - Chief Scientist
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