The Iron Hypothesis

[hehe299792458]

I desperately need help on the iron hypothesis and related facts:

Where are HNLC waters found and why? (a map would be nice)

What is the fate of the organic carbon fixed by photosynthesis in the deep ocean?

How does iron enter the ocean eco-system?

What is role of silicic acid in the iron hypothesis?

According to the proponents of the iron hypothesis, are there any expected benefits of fertilizing the ocean with iron other than the removal of carbon dioxide?

Where are the least productive areas in the ocean (ocean deserts) found? What makes them unproductive?

Where are the most productive areas in the ocean found? What makes them productive?


The one about silicic acid is especially hard to understand for me since I couldn't find an explanation that isn't PhD paper or 125 page long research document. I really hope you guys can help me out. Thanks in advance!

[kotoreru]

Normally I wouldn't answer any of your questions as you're clearly just posting homework, and I'd scorn you for doing so. However, since I am genuinely interested in this area...

HNLC waters are simply shouldn't exist. If I remember right, the Southern Ocean and waters off the west and north west of the US i.e. parts of the Pacific are HNLC.

The fate of fixed carbon in the world's oceans is uncertain, at least in the long term. That's the whole point of the debate over iron fertilisation on a big scale.

Iron enters the oceans eco systems in a number of ways, but I often hear it blows in as dust from the land... look at some nice feedback system theories based on this.

Fertilising the oceans with iron on a large scale should actually cool the planet directly, in addition to increasing C drawdown, because all those liddle phytos release DMS (dimethyl suphide) which is a water nucleator i.e. a rainmaker.

Unproductive areas are far from land (see above) and the most productive ones are where you have a coupling of light and nutrients from upwellings and shelves etc.

The acid bit I have no idea about...

I imagine some of that is wrong, but it's very late and Im pulling it all from memory.

[mith]

Iron is also present in lava.

There's actually a company trying to sell carbon offset credits by promising to dump an amount of iron that supposedly will get the CO2 levels down, but most people think it'll probably cause a (un)natural disaster.

[AstusAleator]

I'm against the idea (philosophy) of it. Carbon credits are just a way for the wealthy (read: corporations) to continue their unsustainable practices. Carbon pollution tends to be focused in certain areas, which become defacto low-rent slum areas. By "creating" carbon credits, rather than diminishing carbon outputs, we come no closer to justice for the people living in these slums.

[hehe299792458]

never mind, I solved most of the questions list above. The question I can't seem to find any articles, essays, encyclopedic entries, etc on is: HOW DOES THE IRON LEAVE THE ECO-SYSTEM???

[AstusAleator]

without looking it up and doing your research for you:

I'd say iron leaves the ecosystem when it becomes bound up in organic matter and then stored in geologic layers on the ocean floor.

[hehe299792458]

that's not technically "leaving" the eco-system is it? It's just trapped on the sea floor decaying or being eaten by some animal or bacteria.

[AstusAleator]

Well, the idea is that it gets buried, and over time, becomes folded into geologic layers and trapped therein (until an oil company drills it back out)

"out of the ecosystem" would imply to me that either
a) it's left the biotic realm entirely, and exists in an abiotic environment, or
b) it's left the ecosystem it was in, and entered a seperate, different one.

[kotoreru]

'leaving' probably means, in this context, that the iron is no longer cycling in the oceans in any way.

iron -> phyto (die) -> sink -> buried?
-or-
iron -> phyto -> fish -> man

Also: 'never mind' is hardly the most grateful response I could have hoped for after typing out that lot...