Talk:Iron Hypothesis

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It seems that there is a article about iron fertilization that was created sometime ago. My entry (Iron Hypothesis) is not a plagiarism. It came about because I noticed there was nothing discussing John Martin's discovery of the Iron Hypothesis AND more importantly, because the Virgin Earth Challenge was announced the day before and I thought I should put my tuppence in! I am interested to hear any criticism of the work and try to improve it.

Whilst I accept that there are some major problems to overcome, whilst some of the studies indicate that the majority of the POC stays in the euphotic zone, it is my firm belief that by 'harvesting' the phytoplankton and then storing it where it can do no harm - in depleted oil wells, it can be removed somewhere that methanogenesis is not a problem and might actually be a fringe benefit!

A lot of the research work that is being done, suggests that iron hypothesis is correct, but that the consequences of creation of such a large amount of POC suddenly - over a very short period of time - to counter and sequester anthropogenic CO₂ - may result in the production of increased biomas in surface waters and/or the production of un-welcome imbalances, such as the production of methane, or the depletion of surface O₂, or even increased DMS and CCN - and what that might do to rainfall.

Despite the grave concerns over the amount of anthropogenic CO₂ being pumped into the system, it must be considered where that carbon came from? Fossil fuels were once free atmospheric CO₂ that was sequestered by photosynthesis - on land or sea. So what I am getting at is that the carbon being released - was itself free in the atmosphere at one time and after each pre-historic deposition period, more and more was locked up.

I am even suggesting that the ice ages are periods when the CO₂ are 'laid down', as one would lay down a good claret, whilst the inter-glazial periods are actually when the PCO₂ becomes more prevalent due to lack of iron fertilisation. As we are only 10,000 years out of the last ice age and just warming up (artificially as well as glacially), then we should be expecting increasing levels of CO₂. The Earth's systems must have created a balance with these PCO₂ levels in the past. Despite the acidification effect on the coral reefs, they have been in existence since periods when the PCO₂ should have been quite acidic. In my view, it is possible that it is not the quantity of CO₂ that is a problem, but merely the speed with which it is appearing. The systems cannot re-balance fast enough and that's why farming the blooms might be a better way of ensuring that the CO₂ cannot damage or overload nature.

What do you think? Nigelpwsmith 03:00, 15 February 2007 (UTC)

[edit] Additional Discussion

In the past few days, I have become aware of several other interesting points that might bear some discussion.

First of these is the possibility that sequestration of the POC is a lot easier if the fertilisation takes place in subduction zones. The Thermohaline Circulation 'starts' in the North Atlantic, near the Arctic Circle. Quite apart from the 'desolate' zones, it would be interesting to see the extent of sequestration, if the blooms are created in zones where the water undergoes a downward shift and could forceably move the POC below the thermocline. There are other areas where this sort of subduction occurs, but as the Thermohaline Circulation has a 4,000 year cycle, before the water emerges at the other end, it would seem that there is plenty of opportunity for the marine snow to be buried, without being re-minerlised and thereby be effectively permanently removed from the cycle.

The second was that there are areas of the oceans where iron is not such a limiting factor, but nitrogen is. It has been postulated that artificial seeding by urea could initiate phytoplankton blooms in these (non-desolate zone) areas and thereby lead to carbon sequestration. Sadly, the production of Urea to be used in this initiative is being considered by artificial chemical means. This would be energy intensive. Any method of carbon sequestration that requires fossil fuel energy production to operate, would be self-defeating. There are methods of fixing nitrogen by natural means - including seeding by nitrogen fixing bacteria. So whilst iron fertilisation might be the method of choice in HNLC zones, seeding by nitrogen fixing bacteria might help elsewhere.

The third that came to light was that dead zones have appeared off the coast of California. In these areas, large blooms of phytoplankton have reached their limiting factor and stopped growing. The blooms have then started to remineralise by bacteria and used up all the oxygen in the euphotic zone. Whilst fish swim away, slower animals such as crabs, die from asphyxiation. In these dead zones, nothing living remains until the water mixes with the oxygenated waters around them. It is almost as if someone had carried out a seeding experiment in shallow waters and did not consider the consequences of destabilising the ecological balance. Natural blooms do occur around river estuaries. However, there is a 'motive force' to encourage the mixing of the bloom waters, which prevents oxygen starvation. This maybe a reminder that seeding should only be carried out where there is sufficient turbulence to allow waters to mix and that the bloom size should carefully controlled, to prevent the aquatic ecosystem from being unable to 'consume' the results.

The fourth and last point was that other scientists have been working on cloud condensation to increase the albedo of the sky and reflect sunlight back to space. These experts have been working on solar-powered yachts that use a Bernoulli sail and a water current powered sea water-atomiser to spray water particles into the sky. Small particles of salt (in the spray) act as CCN (nucleation particles) to create the clouds. This would reduce the ambient sunlight to the sea surface, but used in conjunction with iron fertilisation, the clouds could limit the light reaching the phytoplankton, so that it is not an uncontrolled production at maximum speed. The analogy is that of altering the light in the greenhouse, so that the plants are not forced to grow out of control, but carefully controlled at all times.

Nigelpwsmith 13:31, 21 February 2007 (UTC)