How to get rid of CO2 and Save our Oceans at the same time

Our oceans are losing oxygen. This is because they are warming up, and warmer water can contain less gasses. Nitrogen, CO2 and O2 are dissolved (along with other gasses like methane) and will gas out as our oceans warm. The warming is hard to prevent as only a small percentage of sunlight that hits our oceans is reflected. Large parts of our oceans are already anoxic, and fish can’t live without oxygen, even if they only need very little.

Oceanic oxygen is high near the surface and deeper down, but can be to low for fish to live

We have to do something about our oceans, because gradual acidification due to absorbtion of CO2 from the atmosphere is a problem for its oxygen generating plantlife, as well as all other life. Acidification inhibits growth, especially in cell processes during procreation, in other words, acidification makes it harder for many species to procreate.

Ocean acidification is a problem we need to address

Any CO2 that is turned into O2 and sugars through the well known photosynthetic process is a win against acidification. We have written that to achieve more photosynthesis we can pump nutrients from deeper water to the surface, to fix the nitrogen shortage. Another limiting factor is iron. Many people have looked into this and its actually a viable way to increase oxygen production and stimulate life in the oceans. Sadly companies involved in this have been obstructed or have failed.

A paper considering deep ocean fertilization was against it on the grounds that it would help (in several ways) but if we stopped we would have warmed the water more. Of course there is only one thing our oceans are going with current CO2 levels and emissions : Warmer! Due to above described problems from acidification there actually is a window in which we can try, of about 30 years some estimate.

This is the Pacific, covered in pumice from a vulcanic eruption

So what can we do? We could start growing seaweed near the surface on a gigantic scale, fertilized by deep ocean water we pump to the surface using wave pumps. That’s an idea. We could increase ocean albedo in some way, by creating something reflective that floats well. We have seen enormous pumice islands, these have prevented warming of the ocean below it. We could create something artificial with the same effect. We have written about floating islands of biomass, grown at sea for instance. We could use plastic as well, that would still be a good tradeoff against boiling oceans.

Generatnig power to split water down below

So what would it take to actually capture carbon at sea and adding oxygen to the deeper oceans so fish an trhive (and capture carbon as well). It would in fact be a matter of generating electricity, then using that to split water down below, then burning the hydrogen (or using it as fuel) at the surface, while leaving the oxygen dissolved in the deep water.

Then you would have to have a CO2 reactor at the surface, the availability of water would be a plus. You use the H2 in the following reaction

CO2 + 2 H+ + 2 e → CO + H2O

Then you are left with highly reactive CO, which you can turn into C and O2. Of course the available Hydrogen can also be used to make hydrocarbons, methan and even oils, which can then be sunk to the ocean floor and stay there. This process, which removes Carbon and H2 from oils and gas from our atmosphere have gotten a lot of attention.

Even though its kind of the premise of this post, using oceanic real estate to fight climate change makes a lot of sense, because it is much easier to traverse, is extremely vast so there is plenty of room. Here are a few more methods we found :

Recently more direct methods of turning CO2 into Carbon have been developed using liquid metal as a cathalyst. This method works at room temperature.

” Cerium-containing LM were utilised as an electrocatalytic system, successfully converting CO2 to carbonaceous and graphitic products at room temperature. “

Another way is to use Magnetite, which can be primed using H2 to cause the decomposition of CO2 into Carbon.

” The oxygen-deficient magnetite, which is obtained by flowing H2 gas through the powder magnetite at 300°C for 2h, efficiently decomposes CO2 into C at 300°C.  “

Methods using lower cost metals have been developed, using Copper and Tin. Of course we should not be surprised about the possibility of splitting CO2 back into its constituents or even making methane with it, after all plants do it all the time. The metals available to them are mainly Iron, Zinc, Copper and Manganese. As rust can be photoactivated oxygen evolution may even have occured without life. Once life harnessed the water splitting ability of iron, binding CO2 into cellulose and sugars became an option that provided much needed and lighter protection than Calcium.

Of course the easiest way to return CO2 back to the deep ocean would be to use a floating plant that can stand the acidification and spread long enough. According to geologists this happened when an ancient version of Duckweed covered an enormous sweet water lake close the the North Pole (can’t find source). There is no salt water version but we can certainly create sweetwater basins to grow duckweed in our oceans!

When sequestering CO2 we should really look at the option of also providing more O2 to our oceans. Oceans are a better source of CO2 than our atmosphere because the CO2 dissolve to higher concentrations. This may make the ocean the best place to capture and sequester carbon and return hydrocarbons back into our Earths crust.