h a l f b a k e r yContrary to popular belief
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Vast oceanic areas are biotically unproductive, despite being sunlit, and replete with most nutrients, because the low levels of trace iron limit nitrogen fixation there, which is key to plankton growth when and where all else is present, as in these areas.
Iron, in even trace amounts, acts as a co-factor
for marine cyanobacteria's nitrogenase, which fixes dissolved atmopheric dinitrogen, making it accessible to plankton, which can then grow and sequester dissolved atmospheric carbon dioxide. This reduces atmospheric CO2, ameliorating the greenhouse effect.
Supplementing iron is possible, but must be continually done, as most iron soon forms precipitates which settle out of the sunit surface areas.
Proposal: Step 1) Design a nitrogenase which uses strontium as a co-factor, instead of iron. Strontium is rare in seawater, but more concentrated than iron in these specific oceanic areas. Check that the new nitrogenase can be eaten safely by sealife.
Step 2) put the DNA sequence coding for the new nitrogenase into marine cyanobacteria, and release them into these areas of the oceans, to thrive.
Goal: Vastly increase marine photosynthesis especially in those relatively unproductive oceanic areas. In this way reverse the ongoing increase in Earth's atmospheric CO2, and thus stabilize the global climate.
Beneficial side effect: increase deep ocean fisheries, like tuna. Expand the amount of sunlight energy entering the biosphere, increasing life on earth.
Arsenic substituting for phosphorus
http://www.astrobio...-the-periodic-table
[bungston, Feb 17 2011]
Johnny Alpha
http://en.wikipedia..._Alpha#Johnny_Alpha
Strontium Dog [DrBob, Feb 18 2011]
Vanadium
http://pubs.acs.org.../80th/vanadium.html
" V is the second most abundant transition-metal ion in surface seawater after molybdenum" [bungston, Feb 18 2011]
Designing Strontium Binding Proteins
http://www.ncbi.nlm...gov/pubmed/15473703
[briancady413, Feb 27 2011]
Flame test
http://en.wikipedia.org/wiki/Flame_test
Metal is pretty. [bungston, Mar 04 2011]
Iron enrichment
http://www.sciencem...5/5812/612.abstract
[bungston, Jan 10 2014]
[link]
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The account has been around since '03 - probably not [beanangel]. |
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I think it would not work. Strontium can sub in for calcium in biologic systems, which is why strontium generated in the nuclear tests accumulated in peoples bones. Strontium is in the same column of the periodic table as calcium. Linked is another instance: arsenic substituing for phosphorus, which was in the news recently. |
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For something like this to work you would need to sub in something which was plausibly close to iron in the period table, I think. |
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That said I like the idea of tinkering with nitrogenase. I think nitrogenases are very highly conserved, but this may be because screwing with them is lethal. It might be possible to engineer a nitrogenase using a different metal which was better than naturally occurring ones. |
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If we don't like how increased levels of nitrogenous compounds are impacting ocean life the simplest thing to do would be to control their ingress into the watershed. It is a waste of energy and damages natural ecosystems and valued resources. As to the factors involved in Red Tide type events it is clear that cyanobactor are relatively uncompetitive in areas of undisturbed ocean. If we reduce the levels of human sourced digestables in effluent waters the problem will largely disappear. In areas where population growth and industrialization cause this to be impractical seeding with iron is simply cheaper and more efficient than trying to propagate a new and (hypothetically) dramatically more aggressive species that utilizes a novel enzyme the implications of which are unforeseeable. Given natures ingenuity if such an enzyme/niche were "easy" it would already be "done". More likely than not the redox activity of strontium peroxide/dioxide puts it outside the biological pail so to speak. |
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large areas of open ocean that are currently low in any nutrients cannot be made fertile by nitrogen fixation and photosynthesis. It takes more than nitrogenous compounds to make a cell. The low fertility open ocean water has almost nothing it it due to the natural diffusion of nutrients and the tendency for organisms to sink when they die. Your premise is that these areas would be fertile if we sprinkled them with iron? I don't see any basis for this. |
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Coastal zones: Excessively aggressive microbial growth: Anerobic conditions=dead zones. |
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Open ocean: Nutrients are diffuse. Occasional pockets of fertility can exist briefly but cannot be sustained due to diffusion and the tendency of plankton to aggregate nutrients, die, and drag them to the bottom of the ocean. A massive bloom of any organism in the open ocean would be brief and leave a wasteland devoid of any nutrition. |
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This flaw lies at the heart of every "make the oceans more productive" idea. The productivity of the open ocean is limited by gravity. |
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it can.
many organisms have the potential to 1)explode briefly, 2)in the open ocean, 3)when conditions are right. |
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without vulcanism a water world is a dead world. |
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//it can many organisms have the potential to explode
briefly in the open ocean when conditions are right.// |
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//without vulcanism a water world is a dead world.// |
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I think you're confusing two things. Leonard Nimoy wasn't in
that film - it was Kevin Costner. |
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there are a lot of ways to fix atmospheric nitrogen. notably it can be done using compounds that contain molybdenum, but no iron. The biological process is very well refined and appears to waste very little energy. This, in a way, explains why there is a lack of Fe in barren ocean water: organisms snatched it all up so they could make energy efficient tools. Given the low actual concentration of strontium in ocean water it is easy to imagine a scenario where a new population of organisms appeared, snapped up all the strontium, dragged it to the bottom and mineralized it in a brief but joyous metabolism. On the other hand the conditions for that sort of explosive boom and bust are exploited in almost every ecosystem, even in veins of mineral ore deep in the earth and volcanic vents. It has happened in the past, likely many many times. On the other hand, suggesting that such an undiscovered niche exists in the natural environment (so excluding 2-4-D resistant corn for example) and developing the organism to exploit currently exceeds our capabilities. |
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In this case, it exceeds our ability to even see what will happen as a direct consequence of our actions. Any organism living in the open ocean will need a constant re-supply of the nutrients that make up its carcass. This is the absolute limiting factor to ocean fertility. |
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The way the anno box ignores line breaks often trips me up. If I use line breaks as a form of punctuation, and they don't show up, it looks like I just puked the words out in a stream (which is likely the case). |
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I was wondering if nitrogenases use molybdenum because it is available. I was looking at the periodic table. The ones under iron are weird; most are weird. Vanadium maybe not so weird; I know sea squirts accumulate it. Could the fact that it is available mean it could be used for a nitrogenase? Sure enough there are nitrogenases that use vanadium (link). |
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Of course, vanadium substitutes for the molybdenum in nitrogenase, as [bungston] said. The iron is still needed. |
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// Air-drop little iron floaty spheres ? // |
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Brilliant! Deserves it's own page at the halfbakery! these could be nano-sized spherical shells, for better dispersion. Problem: energy costs of manufacture, plus financial costs. |
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Make plastic products doped with iron. When they end up in the trash gyre and slowly break down, they release iron gradually. |
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//Make plastic products doped with iron// |
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Brilliant! Right up there with putting some iron in transoceanic jet fuel. |
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/Air-drop little iron floaty spheres ? / |
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It seems so pointless to schlep a whole plane out and back, spurting out CO2 all the way. Sort of defeats the whole global warming purpose! Really, it would be more efficient to shoot the iron into the open ocean using shore based solar powered railguns. Solar is perfect for railguns - slowly charge the capacitor during the day, then at sundown let fly the iron! Plus it would be pretty for people under the flight path of the iron - shooting stars every evening. |
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Thinking further, one could dope the spheres with various metal coatings to alter the color of their coronas in flight. Linked is the wikipedia page on flame tests to help the synthetic shooting star aesthetes pick their color palates. |
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as i pointed out previously this is the barren ocean, the problem isn't getting the bloom to happen, the problem is that the fertility of the water cannot sustain a permanent population. |
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What form of Iron is most useful to the little beasties? |
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If FE2O3 is okay, just get a couple iron ore carrier ships to be your delivery system. 250, 000 Tonnes of relatively high purity Iron oxide a pop for a cape sized vessel. Some kind of saltwater mixer/wet grinder/sprayer should be able to do the disbursement nicely. |
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Perhaps particularly finely ground ore would not settle out anywhere near as quickly and remain in the bio-zone long enough to be utilised. |
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Iron doped styrofoam! It is so obvious! |
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In the Early Earth, before it had an oxygen
atmosphere, iron in the oceans had a particular
"valence" that was quite soluble in water (+2).
After oxygen waste from blue-green life-forms
began affecting everything, it began affecting the
iron ions dissolved in the waters of the world. Its
valence changed (to +3), much less soluble in
water, and it basically precipitated out, leaving
huge deposits of iron oxide all over the world (like
the Mesabi Range). |
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So, what we need is a way to get iron to do the
EQUIVALENT of being dissolved in water, even
while having a +3 valence. That's because if it has
a +2 valence, oxygen will affect it (so, if you start
with nice soluble iron(II) sulfate, you end up with
iron(III) oxide and iron(III) sulfate, neither very
soluble. |
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The answer may be to design a molecule that
includes iron but is "polar" (highly soluble in
water). In doing a bit of research to write this
anno, I came across one place where they said
that certain "iron complexes" were very soluble.
However, it is obvious to me that the more
"complex" the molecule, the more expensive it
would be to make! And of course we do want to
be able to dump lots of this stuff into the oceans,
to encourage sea life. |
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Obviously we also want this molecule to be
nontoxic so that microorganisms in the water can
extract the iron from it, without being poisoned
in the process. |
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Unfortunately, just because one might happen to
think of a reasonable possibility, that doesn't
mean you can find a lot of useful data about it.
For example, I just wasted maybe an hour trying to
find out if FeOCl (iron oxychloride, sometimes also
called iron chloride oxide or iron oxide chloride) is
decently soluble in water. No luck. Ah, well. |
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//as i pointed out previously this is the barren
ocean, the problem isn't getting the bloom to
happen, the problem is that the fertility of the
water cannot sustain a permanent population.// |
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If iron is the limiting factor then adding iron will
cause an increase in primary productivity while it
is retained. In fact I'm pretty sure this has been
tried experimentally, and did so. |
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If the organisms do die and sink to the seabed
then this is a great way of sequestering carbon. If
they're eaten by progressively larger creatures
then it is instead a great way of increasing
productivity of the area for environmentally
friendly fisheries.
I suspect that you could probably sway the result
one way or the other by the regimen of the
treatment. |
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Iron(III) nitrate is highly soluble; unfortunately,
the iron would precipitate out anyway as iron
chloride, sulphate etc., leaving the nitrate ions in
solution. Chelated (e.g. ETDA) iron is presumably
what is meant by an "iron complexes"; that's the
obvious, but expensive, solution. |
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Which leaves us with burning all the coal, oil, and
forests until the iron is reduced and stays in
solution, and allowing vast amounts of topsoil and
agricultural runoff to reach the sea, supplying the
other nutrients. So, we're right on track. |
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There is plenty of precedent for encouraging plankton by pouring iron into the ocean. I linked a link that I found on my idea "Bomb the Ocean Floor". I got that idea from the Superfriends, in which Aquaman reverses red tide by dragging a rock along the ocean floor, stirring up nutrient rich clouds. I always thought that probably one pass would be inadequate to get enough nutrition up where it was needed. Big bombs would work better - the hot plume of detritus would fertilize everything! |
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