Natural experiments prove phytoplankton carbon removal works | Hacker News Reader

Natural experiments prove phytoplankton carbon removal works

onepercentbrighter.com

76 pointsgetnormality29 comments

This article shows that we can reliably cause phytoplankton blooms, but doesn't link it with actual "carbon removal". I suppose CO2 is temporarily removed in the form of the bloom, but I believe historically these blooms have a low efficiency for "permanent capture" because the plankton decay or are consumed. The only way to effectively capture would be to somehow create the bloom, then sink the phytoplankton en masse deep within the ocean where the would be neither eaten or decayed. Maybe possible with the right setup, but hard to scale.

I've heard of capture technologies that literally pump organic matter down far enough that it sinks to the seabed (high enough pressure collapses air bubbles and results negative buoyancy). The problem is that your pumps need to operate using less carbon than you capture (easy with solar?) and that they need to be durable enough to pump billions of gallons of seawater with low maintenance (much harder, salt is terrible for machines).

Why can't we make pumps that withstand salt, dammit. It seems pathetic.

How about like a medical pump? Have a flexible polyurethane tube that's squidged by cams to pump the seawater through it. The cams stay in the dry.

It has to handle solids. Something more like a sewage pump.

Couldn't they front a pump with a macerator?

Just because we wants something doesn't mean we can have it, or at least not at a price we will accept.

Even if you get it to the seabed, the majority will be remineralised there. And if you pump enough down there to bury significant amounts of organic carbon, the bottom waters will likely become hypoxic as a result.

This scenario is pretty similar to the Azolla event:

https://en.wikipedia.org/wiki/Azolla_event

Where "event" in this case is something that happened over an 800 000 years interval.

> the resulting draw-down of carbon dioxide has been speculated to have helped reverse the planet from the "greenhouse Earth" state of the Paleocene-Eocene Thermal Maximum, when the planet was hot enough for turtles and palm trees to prosper at the poles, to the current icehouse Earth known as the Late Cenozoic Ice Age.

Time to buy a condo in the Greater McMurdo area?

There are water bodies (Black Sea?) that are very poor at depths, so matter decays very slowly. Bogs aka peatlands are also like that, you can literally preserve meat and other organics, and let it sediment.

How much of the carbon stays in the animal eating the bloom? I would think while it's tricky to calculate assuming them being eaten is bad might not be true. Of course we might end up making farting whales and adding loads of methane to the atmosphere knowing our luck...

Whenever we try playing god it seems we generally mess things up a few times so we'd need to monitor the actual outcomes in reduced CO2 in the atmosphere over several decades. It seems extremely high risk to assume there won't be unintended consequences...

I am curious of what happens to all the other nutrients in the bloom. There is more than just carbon-oxygen-hydrogen in those corpses that are then tied up when they are removed from the carbon cycle. Does anyone here know how that works?

Sequestering algae is how petroleum is produced. Does petroleum contain only hydrogen and carbon?

Hydrocarbons straight from the ground definitely contain a bunch of other crap, somewhat famously sulfur. I don't know what happens to the N and O, though.

So how it works is, you grow the bloom in a massive pond. Wait for it to fully fill up, skim half the pond, add more nutrients and then agitate. With the algae you skimmed off you dry it out then compress it into a brick and burry it. In a 100K years we can the burn it for coal power again. And then repeat that until you've grown enough biomass to match the amount of Carbon put in the atmosphere since the industrial revolution.

Does this expend less carbon than you captured? Skimming, gathering, transport, drying, compression, burying. I assume to reach "gigatons captured per year" this would require heavy machinery and industrial buildout. Not that its impossible, I'm just not sure its a net-negative in CO2.

Diatoms sink when dead and we have decent ideas about the rate at which this happens.

https://www.csiro.au/en/news/all/articles/2022/august/sinkin...

"phytoplankton are estimated to capture 10-20 billion tons of carbon dioxide each year."

also, https://en.wikipedia.org/wiki/Biological_pump

Don't know if it's off topic, ad hominem, or whatnot : but this substack is an almost comical example of a "one-post-poney".

The author is VERY much a fan of phytoplankton fertilization. He does not cite many other people talking about it, but he is very very very convinced.

Maybe he's right, but the tone and the "once you have a hammer, everything look like deep ocean fertilization" bit does not help.

most progress comes from one-post-ponies who love stuff, perhaps unreasonably, and champion it.

most of the time it's BS, but not all the time, and sometimes it takes a nutter to make it visible and effective

see also: the nobel prize winner who was convinced ulcers are bacterial, and was so convinced he gave himself one, and cured it.

> [People think we] couldn’t possibly know what the consequences would be.

> It’s not true, though. We have quite a precise understanding of what happens

Ah, man, the hubris to see a long history of human interventions with unexpected knock on consequences, and think, “but this time we know.” It’s comical, even. We’re talking about an intervention large enough to reverse decades of climate change, of course there will be unintended consequences.

In the end, however, we will likely have to do something, and this might be the solution with the best-mapped consequences (and thus fewest unforeseen consequences).

I look forward to the time when we do something, because it will change the psychological landscape from a quagmire of guilt, hopelessness, and discouragement, into a wide open tundra of shapeless fear and tension, where anything seems possible.

Yep at this point we just have to do whatever seems least risky. It's not like we have a pristine planet. We have to balance the unknown consequences of phytoplankton (and other mitigations) against the known and unknown consequences of a >50% higher CO2 level and >1.4C higher global temperature.

There are other solutions that require mass coordination and possible violence that would be a lot easier than gambling on phytoplankton

BREAKING NEWS: New study shows that plants consume carbon dioxide, emit oxygen. Implications for greenhouse gas reduction unknown but promising.

I had a nightmare where we bred some super plankton to capture CO2 and it quickly colonized and killed the entire ocean and we doomed the world. On the bright side, if this were possible, plankton would have already done it right?

Yup. I'm sure they tried at some point and got beaten into equilibrium by other slimy things that were also trying to proliferate.

Not without first filling the oceans and atmosphere with toxic amounts of oxygen, driving all slimy things that couldn't adapt fast enough into extinction: https://en.wikipedia.org/wiki/Great_Oxidation_Event

On the plus side, since we descend from slimy things that survived the carnage, we have fairly good oxygen tolerance and completely removing all CO₂ might not even hurt all that much.

Provided that the things that used up all the CO₂ were close enough to eat, anyway. Otherwise we'd be left without any agriculture, which would be bad.

Phytoplankton produce about half the oxygen produced on the planet.

So, unlikely.

Reply on news.ycombinator.com