Thursday, July 19, 2012

Nature - EIFEX report

Discussion on Geoengineering google group

Bhaskar M V  
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 Hide options Jul 19, 1:13 pm
From: Bhaskar M V>
Date: Thu, 19 Jul 2012 13:43:22 +0530
Local: Thurs, Jul 19 2012 1:13 pm
Subject: Re: [geo] Nature eifex report
You are right to a certain extent when you say -
"So, to some extent, iron fertilization concentrates productivity in space
and in time."
However the facts are as follows -
Human action has increased the amount of N and P in water.
The Nitrogen (and Phosphorus) cycles have been both speeded up and
increased in volume.
About 100 million tons of urea is manufactured and used as fertilizer in
agriculture, most of this is made by the Haber-Bosch process of capturing
Nitrogen from atmosphere and converting it into ammonia and then into urea.
Thus we are adding more N into water.
Phosphate fertilizer is made by mining rock phosphate and converting this
into phosphoric acid and then into super phosphate, etc.
Thus insoluble rock phosphate and N2 gas in atmosphere are being converted
into soluble N and P in water.
Another way to calculate the increase in N and P due to human action is to
compute the average food intake of people and the N and P content of this
and multiply with the population.
If we consume about 1 kg of food (wet weight) per day, this may contain say
50 mg of N and 10 mg of P. Multiply with the population of 1 billion 200
year ago, 7 billion today and projected population of 9 billion by 2050 and
you can get the total increase in N and P in food and sewage input into
lakes, rivers and oceans. I am not attempting to quantify the actual
numbers, since there are too many variables and averages, the concept is
adequate for the present.
What is the consequence of this?
1000s of eutrophic lakes and 500+ dead zones in the coastal waters.
This is the N and P that will be used up to sequester carbon when oceans
are fertilized with iron.
So there is no need to worry about depletion of macro nutrients in oceans.
:) Once we run out of oil, we can use the defunct Oil tankers to transport
sewage to Southern Ocean to provide the macro nutrients required. Prof John
Martin's recommended dose of half a tanker load of iron can be matched with
a 100 tanker loads of sewage. :)
I guess physicists always get lost in space and time.
On Thu, Jul 19, 2012 at 1:04 PM, Ken Caldeira 

> wrote:
> Recall that this fertilization is using up macronutrients such as N and P
> that may have been used elsewhere at a later date.
> So, to some extent, iron fertilization concentrates productivity in space
> and in time.
> An important question is: how much of the P that was in the fertilized
> water would have been mixed downward as phosphate and how much of it would
> have been transported downward biologically at a later date somewhere else.
> It is only the fract of P that would not have been used biologically
> somewhere else at a later date that represents the increase in
> biological export.
> On top of this, there are additional questions of how the C/P ratio and
> remineralization depth of this carbon that would have been naturally
> exported differs from the C/P ratio and remineralization depth of the
> carbon that was exported in the experiment.
> So, two difficulties in analyzing these results are
> (1) Determining effects that are distal in space and time associated with
> the local (in space and time) consumption of macronutrients
> (1) establishing the counterfactual baseline that could be subtracted from
> the experimental case to determine the delta, taking into consideration
> effects that are distal in space and time (see previous point)
> On Wed, Jul 18, 2012 at 10:59 PM, Rau, Greg> wrote: 
>> So 1 tone of added Fe captures 2786 tones of C or 10,214 tones of CO2 (?)
>> Then the issue is how much of this stays in the ocean for how long.  I'll
>> have to read the fine print.
>> -Greg
>> From: Mick West>
>> Reply-To: "">
>> To: "">
>> Cc: geoengineering
>> Subject: Re: [geo] Nature eifex report 

>> It says 13,000 atoms, not tonnes:
>> "Each atom of added iron pulled at least 13,000 atoms of carbon out of
>> the atmosphere by encouraging algal growth which, through photosynthesis,
>> captures carbon."
>> On Wed, Jul 18, 2012 at 12:54 PM, Andrew Lockley <
>>> wrote:
>>> Personally I find the claims of 13000 tonnes to 1 atom of iron somewhat
>>> difficult to comprehend!
>>> A
>>> ----- 

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