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Most of the ocean is desert lacking the limiting nutrients of nitrogen, phosphorous and iron. If we can cheaply fertilize large swathes of the ocean with these
by rjtc 3y ago
Most of the ocean is desert lacking the limiting nutrients of nitrogen, phosphorous and iron. If we can cheaply fertilize large swathes of the ocean with these limiting nutrients in a controlled manner, then this could trigger massive algae blooms that on sinking sequester massive amounts of carbon.
- analog31 3y agoUnfortunately, fertilizer presently has a large carbon footprint
- fosk 3y agoCan’t fertilizer production emission be compartimentalized?
- sacnoradhq 3y agoFertilizer isn't a singular thing or a hivemind. Terrestrial ag fertilizers don't have to be produced by fossil fuels. The Haber–Bosch process used to make ammonium nitrate can be solar powered instead of using methane. Phosphate rock processing could greenified for a green "green" phosphoric acid wet process. Potassium from potash is mostly a passive solar evap process. For seaweed aquaculture, iron sulfate is used because iron availability is the most frequent limiting factor. It's frequently a byproduct of steel production, in much need of greening itself, and produced in large quantities. Volcanic ash is another abundant source.
- canadianfella 3y ago[dead]
- ben_w 3y agoMany crop fertilisers have that issue, but fertiliser is not only one thing. One hypothesis is that algae are limited by some single resource which could be gradually dropped out the back of cargo ships as they cross oceans, seeding carbon-absorbing algal blooms as they go. (I heard about this nearly 20 years ago, so I assume that has either been tested or banned since then…)
- analog31 3y agoI'm thinking mainly about the Haber-Bosch process, which runs on methane, and feeds more than half of the world's animal population. As mentioned in a sibling comment, it could run on some other heat source, but that hasn't been demonstrated yet on the scale of agriculture.
- ben_w 3y agoIndeed, that's one of the main possibilities I guessed you were thinking of; for triggering algal blooms, one of the things suggested was iron. (And given it was immediately going into salt water, ore would presumably have been fine… if the hypothesis was correct).
- rjtc 3y agoit depends on the final balance. As mentioned above the ratio for iron is 13k Carbon atoms sequestered for atom of iron. Keep in mind the vast majority of agricultural yield growth the last century is giving these limiting nutrients as fertilizer for plants, so it is successful and worthwhile for land based farming atleast.
- ravenstine 3y agoWould we have to continually fertilize the ocean? And at whose expense? It'd be great if such an operation could be profitable, but it there's only so much seaweed people can eat.
- rickydroll 3y agoneed more whale poop to keep the fertilization cycle going. https://www.newscientist.com/article/2309262-scientists-want-to-restore-the-oceans-with-artificial-whale-poo/ https://www.newscientist.com/article/2309262-scientists-want... https://www.dw.com/en/artificial-whale-poop-could-save-the-planet-heres-how/a-61247529 https://www.dw.com/en/artificial-whale-poop-could-save-the-p... and burning Australia is a proven way to generate more plankton. https://nicholas.duke.edu/news/australian-wildfires-triggered-massive-algal-blooms-southern-ocean https://nicholas.duke.edu/news/australian-wildfires-triggere....
- sacnoradhq 3y agoIt doesn't take an unreasonable amount of iron and the sequestering efficiency is 13k:1 C:Fe on a molar basis. https://en.wikipedia.org/wiki/Iron_fertilization https://en.wikipedia.org/wiki/Iron_fertilization
- euroderf 3y agoDo you mean rather: 1:13k Fe:C From that Wikipedia item, "Each iron atom converted at least 13,000 carbon atoms into algae."
- sacnoradhq 3y agoYes, of course.
- mcguire 3y agoAlgae blooms result in de-oxygenated water, no? (Among other consequences.) https://www.cdc.gov/habs/environment.html https://www.cdc.gov/habs/environment.html
- pvaldes 3y agoit depends on the context