> in places such as fish farms, which tend to acidify the water, so this could be a way of helping to counter that effect.
so basically overeating fish is to be offset by miracle technology. brilliant.
How to pull carbon dioxide out of seawater
11–20 of 31 posts
Re: How to pull carbon dioxide out of seawater
#12Had to read most of the way through to get to what I was most interested in: The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. Sounds like a promising area to explore. I wonder how…
Seawater CO2 reactions are quite complex, because various compounds form from dissolved gaseous CO2 in the water and the molecules interact in ways that are difficult to quantify (I am not a chemist). My layperson understanding is that carbonic acid ("normal" dissolved CO2) can break down into bicarbonate ions, which themselves can further break down into single carbonate ions. Then depending on what other ions are p…
Is or could photosynthesis be more efficient in water because of the higher amount of CO2? Do plants pull it out of the water directly?
I've also wondered about whatever mineralization happens in making sea shells - I understand that's another natural process that fixes CO2, is that something that could be replicated, artificially or through growing a high concentration of little shellfish?
Re: How to pull carbon dioxide out of seawater
#13Had to read most of the way through to get to what I was most interested in: The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. Sounds like a promising area to explore. I wonder how…
> concentration of carbon dioxide in seawater is more than 100 times greater than it is in air This is straight up wrong. Unless they mean alkalinity, which is carbonate, but not dissolved CO2. I keep both reef and freshwater aquariums. I have to inject CO2 into my freshwater aquariums to keep the plants happy, and the maximum I can go without killing off the fish is ~30ppm. Given that the PPM of CO2 in air is 4, are…
"Concentration" could either mean ppm or p/m^2. When they go on to say "the volumes of material that need to be handled are much smaller" they're making it quite explicit that they mean the later.
Re: How to pull carbon dioxide out of seawater
#14This article makes no mention of the power required for a process like this. A few days ago there was a post describing the older seawater method which stated that to remove as much carbon from the ocean as we are putting in would require ~70% of current global electricity production.
Unless the improvements made here are really significant, I don't see how this actually solves anything until we have moved to truly clean energy production.
Re: How to pull carbon dioxide out of seawater
#15Had to read most of the way through to get to what I was most interested in: The process could be more efficient than air-capture systems, Hatton says, because the concentration of carbon dioxide in seawater is more than 100 times greater than it is in air. In direct air-capture systems it is first necessary to capture and concentrate the gas before recovering it. Sounds like a promising area to explore. I wonder how…
> Sounds like a promising area to explore. It's so completely obvious in hindsight. It's amazing how many great ideas share that property.
This isn't a new idea. It's possible it was also obvious in hindsight a few decades ago when it was first proposed.
Re: How to pull carbon dioxide out of seawater
#16Earlier quoted context omitted.
Seawater CO2 reactions are quite complex, because various compounds form from dissolved gaseous CO2 in the water and the molecules interact in ways that are difficult to quantify (I am not a chemist). My layperson understanding is that carbonic acid ("normal" dissolved CO2) can break down into bicarbonate ions, which themselves can further break down into single carbonate ions. Then depending on what other ions are p…
Is or could photosynthesis be more efficient in water because of the higher amount of CO2? Do plants pull it out of the water directly? I've also wondered about whatever mineralization happens in making sea shells - I understand that's another natural process that fixes CO2, is that something that could be replicated, artificially or through growing a high concentration of little shellfish?
> Is or could photosynthesis be more efficient in water because of the higher amount of CO2?
Could be - the limiting factor after CO2 access is sunlight. Microalgae have the tendency to self-shade which limits growth. Again, photosynthesis is also a very complex process and there are many pathways to increasing efficiency. Lots of work is being done on improving photon activation in microalgae, meaning fewer photons are required to trigger individual photosynthesis reactions.
> Do plants pull it out of the water directly?
yes
> I've also wondered about whatever mineralization happens in making sea shells - I understand that's another natural process that fixes CO2, is that something that could be replicated, artificially or through growing a high concentration of little shellfish?
Again possible however I believe shells are limited by the availability of calcium ions, finding an appropriate organism etc. I am sure it is possible to genetically engineer some kind of ultra fast growth oyster hybrid. The question is can it be done in reasonable time, cost of deployment etc etc
Re: How to pull carbon dioxide out of seawater
#17Here is some more context on related technologies:
https://www.american.edu/sis/centers/carbon-removal/fact-she...
The MIT article presents an expensive strawman alternative, but ignores simpler, cheaper technologies that already exist.
In particular, since CO2 acidifies the ocean, dumping alkaline chemicals into sea water converts the CO2 to inert solids, which precipitate out. At least, that's the theory. Caveats in link.
Re: How to pull carbon dioxide out of seawater
#18There is a whole industry springing up around this idea, it's known as "MCDR" (marine CO2 removal). Some startups:
Re: How to pull carbon dioxide out of seawater
#19Earlier quoted context omitted.
Is or could photosynthesis be more efficient in water because of the higher amount of CO2? Do plants pull it out of the water directly? I've also wondered about whatever mineralization happens in making sea shells - I understand that's another natural process that fixes CO2, is that something that could be replicated, artificially or through growing a high concentration of little shellfish?
> Is or could photosynthesis be more efficient in water because of the higher amount of CO2? Could be - the limiting factor after CO2 access is sunlight. Microalgae have the tendency to self-shade which limits growth. Again, photosynthesis is also a very complex process and there are many pathways to increasing efficiency. Lots of work is being done on improving photon activation in microalgae, meaning fewer photons…
Cool, thanks for answering!
Re: How to pull carbon dioxide out of seawater
#20One clam at a time