Carbon Capture Suggestion

[mistermack]

I've mentioned this idea before, as a way of producing fish, but it could also fix huge quantities of carbon onto the ocean floor if done at scale.

You have a specially designed ship stationed at a very non-productive part of the ocean. ( most of the world oceans are ocean desert )

The ship controls a robotic electrical pump, on the ocean floor. The pump stirrs up sediment, and pumps it to the surface through a thin (but large diameter) polythene tube. 

When the sediment meets the surface, you get a bloom of algae, which naturally happens whenerver water from the depths upwells. The algae are then the bottom of a food chain, that supports vast clouds of plankton. Besides being fish food, the plankton fix CO2 in their bodies which sinks to the ocean floor when they die, fixing CO2 for thousands of years in a natural way, with no possibility of it getting released in the future.  It eventually becomes limestone rock after miliions of years. 

The money for the pumping could eventually come from fishing licences, taxing the catch that results from the proliferation of fish, in an area where previously there were none. So it could be self financing, once running. 

So a win-win situation, with carbon being stored and food being harvested from what used to be ocean desert. 

I realise that this will never happen because of politics and investment problems, but I'm pretty sure it would work. Maybe if the climate really does start giving trouble, it might come into the picture, when the politicians start to panic. 

Edited April 26, 2023 by mistermack

[studiot]

34 minutes ago, mistermack said:

I realise that this will never happen because of politics and investment problems, but I'm pretty sure it would work.

Interesting suggestion +1

 

To see how well it would/could work you would need to develop what amounts to a full business plan.

That explores and answers questions like

How much sediment would need to be pumped up to produce how much plankton which would deposit how much limestone over how many years.

What would be the eco-nomics ( ie the gain over the cost of fuel) of pumping that much material.

 

Nature already does it in the Southern Ocean; some figures are availble as a start here

bg-11-2635-2014.pdf (copernicus.org)

 

[mistermack]

9 hours ago, studiot said:

Nature already does it in the Southern Ocean; some figures are availble as a start here

Thanks. Actually, the effect of upwelling is pretty much accepted as fact. Pretty much all of the fisheries around the world are fed by natural upwelling, usually where the ocean current meets an obstruction like a land-mass, forcing colder nutrient-rich deep water upwards. Island areas like Hawaii stand out, they support a fishery in a vast empty ocean, so the principle can be studied. I remember seeing a chart of the world's productive fisheries, and it was all centered around land-masses, where upwellings occur naturally. Something like this : 

It's quite obvious even from this that there are vast areas of ocean that are desert. It's only lack of nutrient that keeps it that way. Even in the areas that have a fishery, the production is probably way below what it could be, if the nutrient level were to be enhanced. The natural upwellings are not likely to be as rich in nutrient as what a mechanical stirring of the ocean floor could produce. The interesting statistic in the text above is that 99% of the global commercial catch comes from within 200 miles of the coastline, proving that it's upwelling that creates fisheries. 

On the fuel side, you could design a ship that uses solar panels to power the pump, or floating wind turbines, or a combination of the two, designed to match local conditions. 

[swansont]

34 minutes ago, mistermack said:

The interesting statistic in the text above is that 99% of the global commercial catch comes from within 200 miles of the coastline, proving that it's upwelling that creates fisheries. 

Or that boats dock on the coast, and that the EEZ is 200 miles.

[mistermack]

5 minutes ago, swansont said:

Or that boats dock on the coast, and that the EEZ is 200 miles.

Except that scientific studies show that most of the ocean is classed as desert. They don't just rely on catches. And 200 miles is nothing to a modern fishing vessel. See the Cod Wars. (wiki)  " Fishing boats from Britain have been sailing to waters near Iceland in search of their catch since the 14th century."    

The EEZ is probably 200 miles BECAUSE that's usually as far as the worthwhile fishing zone extends.

[TheVat]

How would your proposed system deal with eutrophication?  Seems like red tides, hypoxic zones, cyanobacteria blooms with their toxins, etc could be a problem. Also, what's the phosphorous content of these mid-ocean sediments that are being stirred up?  

[mistermack]

5 minutes ago, TheVat said:

How would your proposed system deal with eutrophication?  Seems like red tides, hypoxic zones, cyanobacteria blooms with their toxins, etc could be a problem. Also, what's the phosphorous content of these mid-ocean sediments that are being stirred up?  

Those are relevant questions, but if you look at natural upwellings around the globe, then those things can happen, but are not game changers. The natural upwelling are just the same thing via a different method. If you look at the Hawaii example, you have deep ocean all around, with forced upwellings around the underwater land mass. The fishing around Hawaii is pretty good, or so I've heard. 

With this sort of pumping, you can obviously control how much you pump, and measure the surface concentrations, so there should be no need for blooms at a harmful level. You would learn as you go along, like everything else. 

[swansont]

1 hour ago, mistermack said:

Except that scientific studies show that most of the ocean is classed as desert.

Links? Citations?

Pretend this is a scientific discussion.

 

1 hour ago, mistermack said:

They don't just rely on catches. And 200 miles is nothing to a modern fishing vessel. See the Cod Wars. (wiki)  " Fishing boats from Britain have been sailing to waters near Iceland in search of their catch since the 14th century."    

The EEZ is probably 200 miles BECAUSE that's usually as far as the worthwhile fishing zone extends.

No mention of Iceland in your link.

[mistermack]

8 minutes ago, swansont said:

No mention of Iceland in your link.

That's not my link. I just pasted the wiki sentence from cod wars. https://en.wikipedia.org/wiki/Cod_Wars 

And I quoted cod wars and wiki. Anyone can check wiki.  

Your suggestion that fishing catches are influenced by the distance from port is comically off the mark. Norway, Korea, China, and Chile are the biggest krill fishing nations in the Antarctic. http://www.antarcticfund.org/fisheries#:~:text=Norway%2C Korea%2C China%2C and,sectors) where krill fishing occurs. 

Check the mileage from Norway and China to the Antarctic. 

[Ken Fabian]

Um... no.

21 hours ago, mistermack said:

Besides being fish food, the plankton fix CO2 in their bodies which sinks to the ocean floor when they die, fixing CO2 for thousands of years in a natural way, with no possibility of it getting released in the future.

To give some perspective - ocean carbon sedimentation is not much to start with, a bit under 1/1000th of fossil fuel emissions (see lower right vs upper left) -

 

And there are the scales involved; flow rates involved in natural ocean upwelling/overturning are staggeringly huge - around Antarctica alone (according to National Geographic)  -

Quote

"An estimated 35 million to 45 million cubic meters (between 1.2 billion and 1.6 billion cubic feet) of water per second are continually moved from the ocean bottom to the surface."

And Antarctica's is a fraction of that small amount. All for so little carbon sequestration.

 

If we have the clean energy to do enough ocean overturning to matter we could displace fossil fuel burning with it directly.

Or if we could bring so much cold water to the surface easily we could have Stirling engine power stations using the temperature differences - more clean energy for the same purpose.

 

[Sensei]

11 hours ago, swansont said:

Or that boats dock on the coast, and that the EEZ is 200 miles.

It is 200 nautical miles (230 miles, 370 km).

[studiot]

11 hours ago, mistermack said:

Thanks. Actually, the effect of upwelling is pretty much accepted as fact.

That it works is not in doubt.

But the thrust of my comments relates to the sheer scale of the pumping required. I note Ken Fabian has also picked this point up.

I had hoped that some of our Chem Eng members might have useful information to add here ?

 

But some further thoughts.

Most of the waterculturally useful sediment is generated close to the continental shelves.
In the last few years the effect of submarine landslides off the ends of the shelves down the continental slopes has been studied and it's extreme significance realised.
The University of Otago leads in this.
These landslides stir up  and distribute the waters and sediments over wide areas, with noticeable increase in marine life activity.

But this lead on to a comparison with the land.

According to United Nations Sources, only 38% of the land surface is agriculturally productive, but worse this 38% is being annually degraded 

Quote

• World Atlas of Desertification - Rethinking land degradation and sustainable management - World | ReliefWeb
• Over 75% of the Earth's land area is already degraded, and over 90% could become degraded by 2050.
• Globally, a total area half of the size of the European Union (4.18 million km²) is degraded annually, with Africa and Asia being the most affected.

 

We also know from examples around the world that this process can (and should) be reversed.

We also know the difficulties of farming in 'poor soil'  and of improving that soil.

So cost and effort comparisons need to be made between your pumping requirements and recovering and extending current agricultural land.

 

Finally watching Attenborough's latest offerings bring out just how transitory these large schoals of fish are.
How would you stop the fish just swimming away ?

 

[geordief]

Just an interesting aside  but underwater farming seems to be a "thing" if only of local benefit

 

https://edition.cnn.com/travel/article/nemos-garden-underwater-farm-italy-spc-intl/index.html

 

"Nemo’s Garden is the world’s first underwater cultivation system of terrestrial plants. Located off the coast of Noli, Italy, southwest of Genoa, the farm consists of an array of suspended, transparent, dome-shaped greenhouses called biospheres, anchored to the bottom of the ocean."

[mistermack]

1 hour ago, Ken Fabian said:

To give some perspective - ocean carbon sedimentation is not much to start with, a bit under 1/1000th of fossil fuel emissions (see lower right vs upper left) -

 

" The ocean acts as a “carbon sink” and absorbs about 31% of the CO2 emissions released into the atmosphere according to a study published by NOAA and international partners in Science. "     https://www.ncei.noaa.gov/news/quantifying-ocean-carbon-sink#:~:text=The ocean acts as a,and international partners in Science.   

And the important quality of absorbtion by shelled animals in the ocean is that the carbon is out of circulation for a very long time. Growing forests etc on land just achieves a very temporary dip, as the carbon is constantly being re-emitted. These are known as volatile carbon sinks, and are pretty worthless long-term. And on the question of fuel, this is not being discussed in a vacuum.

There are real suggestions and plans for mechanically removing CO2 from the atmosphere as an industrial process, and storing it. I haven't gone into the detail of that, but I'm pretty sure that it would be far more costly than pumping sediment. The only processes I've come across that would genuinely store carbon long term are very energy hungry. 

At first sight the energy input needed to pump sediment would be mainly in overcoming friction in the pipes. The water itself is effectively weightless. Maybe someone can correct me on that. 

 

[swansont]

11 hours ago, mistermack said:

Your suggestion that fishing catches are influenced by the distance from port is comically off the mark.

The main point was that you did not substantiate your claim - a long-standing pattern - and stated a conclusion without actual evidence or eliminating other possible explanations. IOW, not providing any proof and yet claiming that something was proven. No links, not even to the infographic you pisted.

[TheVat]

Still needs evidence that this would absorb more than a miniscule fraction of CO2 emission.  The overwhelming proportion of ocean absorption is just the gas dissolving in water.  And waters are warming, which would decrease their capacity to hold dissolved gas.  

2 hours ago, mistermack said:

At first sight the energy input needed to pump sediment would be mainly in overcoming friction in the pipes... 

And pump sediment, which has mass and is heavier than water, so you would be doing some lifting, too.

[Genady]

12 minutes ago, TheVat said:

And pump sediment, which has mass and is heavier than water, so you would be doing some lifting, too.

I got the idea. You freeze the sediment on the bottom. Being lighter than water, the chunks of ice with the sediment will float up by themselves. 🤩

[mistermack]

This is a nicely written article from the University of New Hampshire about a research team, studying "ocean deserts". Their estimate is that 40% of the planet's surface is ocean desert which is a lot. That's out of 71% total ocean coverage. https://www.unh.edu/unhtoday/2022/07/nourishing-ocean-deserts#:~:text=Ocean deserts typically exist in,more biologically productive coastal regions.   

A quote from it "nutrients in the open sea tend to sink to the bottom and get trapped there because the ocean doesn’t mix vertically very well, thus leading to the term “ocean deserts,” Letscher explains."                                      

As far as pumping up solid matter goes, I wouldn't have thought that that would be desirable, but that sort of thing would have to come with experience and study. My own initial inclination would be to have one propeller stirring up the bottom, and another sucking up the cloudy water that results. You could easily postion the second one so that it's not getting much in the way of solids. 

The energy input would be just overcoming the friction in the pipe, and the more you scale it up, the less that would be, per gallon pumped, because of the ratio of the circumference of a circle to its diameter. You could easily design the pipe material to be neutrally bouyant, or slightly bouyant, whichever worked best. 

From what I've read, there are only two natural ways that carbon gets sequestered long-term. The other way is through natural weathering of rocks. You could theoretically design a program of accelerated weathering, by grinding up rock, and spreading it on land surfaces, but it would be hugely expensive, and could cause immense damage to waterways and natural habitats. And the other suggested means of carbon storage sound very expensive.

With a system like this, there is at least the prospect of it becoming self-financing through fishing, and in any case, the extra fish production would be a good thing, taking pressure off the depleting wild fish stocks that we have at the moment, and providing food for the extra billions of humans that are likely to inhabit the planet in this century.

 

 

[studiot]

12 minutes ago, mistermack said:

This is a nicely written article from the University of New Hampshire about a research team, studying "ocean deserts". Their estimate is that 40% of the planet's surface is ocean desert which is a lot. That's out of 71% total ocean coverage. https://www.unh.edu/unhtoday/2022/07/nourishing-ocean-deserts#:~:text=Ocean deserts typically exist in,more biologically productive coastal regions.   

A quote from it "nutrients in the open sea tend to sink to the bottom and get trapped there because the ocean doesn’t mix vertically very well, thus leading to the term “ocean deserts,” Letscher explains."                                      

As far as pumping up solid matter goes, I wouldn't have thought that that would be desirable, but that sort of thing would have to come with experience and study. My own initial inclination would be to have one propeller stirring up the bottom, and another sucking up the cloudy water that results. You could easily postion the second one so that it's not getting much in the way of solids. 

The energy input would be just overcoming the friction in the pipe, and the more you scale it up, the less that would be, per gallon pumped, because of the ratio of the circumference of a circle to its diameter. You could easily design the pipe material to be neutrally bouyant, or slightly bouyant, whichever worked best. 

From what I've read, there are only two natural ways that carbon gets sequestered long-term. The other way is through natural weathering of rocks. You could theoretically design a program of accelerated weathering, by grinding up rock, and spreading it on land surfaces, but it would be hugely expensive, and could cause immense damage to waterways and natural habitats. And the other suggested means of carbon storage sound very expensive.

With a system like this, there is at least the prospect of it becoming self-financing through fishing, and in any case, the extra fish production would be a good thing, taking pressure off the depleting wild fish stocks that we have at the moment, and providing food for the extra billions of humans that are likely to inhabit the planet in this century.

 

 

 

I have been looking at some hard fact and figures.

Most importantly there is only one type of pump that would move material (either liquid or sludge) from the bottom of the (shallow part of) ocean to the top.
That is called a 'positive displacement pump'.

The only such pumps of any size that I have any experience of are pumps for placing fresh concrete.

Putzmeister say their pumps require 10 - 40 kg of fuel per hour to place 30 to 120 cubic metres of concrete.

10 kg of diesel releases about 24 kg of carbon dioxide in the process."

 

So I ask again, "How much sediment needs to be lifted and what are the financial and economic costs of doing so  ?"

[StringJunky]

47 minutes ago, studiot said:

 

I have been looking at some hard fact and figures.

Most importantly there is only one type of pump that would move material (either liquid or sludge) from the bottom of the (shallow part of) ocean to the top.
That is called a 'positive displacement pump'.

The only such pumps of any size that I have any experience of are pumps for placing fresh concrete.

Putzmeister say their pumps require 10 - 40 kg of fuel per hour to place 30 to 120 cubic metres of concrete.

10 kg of diesel releases about 24 kg of carbon dioxide in the process."

 

So I ask again, "How much sediment needs to be lifted and what are the financial and economic costs of doing so  ?"

Why does it need to be uplifted  at the energy-intensive density of fresh concrete? The obvious first thing to would be to find an area of upwelling where a desirable natural system exists for reference and emulation. See what the data is for the upwelling deposition and then model systems that replicates the features required. You've made starting assumptions that may not reflect the constraints.

e2a Natural systems of upwelling are intermittent. Engineered system can be more continuous, or even reactive, so the load rate requirements of the system  can be less than natural systems produce.

Edited April 27, 2023 by StringJunky

[mistermack]

I don't think we are on the same wavelength here. I don't think it would be necessary to pump up heavy sediment. I'm pretty sure that the places that have natural upwellings don't have upwellings of heavy sediment. I'm picturing pumping up cloudy water, the sort of stuff that rises like a cloud when you disturb it, and takes hours or days to settle back down. I'm pretty sure that that's all you would get in natural upwellings. That sort of cloudy water would be hugely more productive than the crystal clear ocean water that exists at the surface of these ocean deserts. The waters around Britain are pretty productive, but they still have reasonable visibility for diving.  The sort of cloudy water that I'm talking about wouldn't resemble concrete in the slightest. In fact, heavy sediment would be undesirable, as it would sink faster.

It might even be possible to use the ocean current in some places instead of a pump. You could lower a huge funnel onto the ocean floor, and attach your pipe to the thin end. Point the mouth of the funnel into the current, (it's up to 2 or 3 knots in places), and let the ocean do the work.  Another technique might be to use natural upwellings instead of a pipe. Just have a robotic stirrer, working in the ocean current, upstream of a natural obstacle, and massively increase the nutrient levels of the natural upwellings. That way you might hugely increase the quality and extent of an existing fishery without the need for a pump at all, as well as increasing CO2 uptake. 

[studiot]

8 minutes ago, mistermack said:

I don't think we are on the same wavelength here.

Perhaps not.

You haven't responded to my comment about a positive displacement pump, (amongst others).

Do you understand the significance of this ?

[mistermack]

1 minute ago, studiot said:

Perhaps not.

You haven't responded to my comment about a positive displacement pump, (amongst others).

Do you understand the significance of this ?

Well, I wasn't picturing anything of the sort. My own first thought would be for something like a ships propeller. 

[studiot]

13 minutes ago, mistermack said:

Well, I wasn't picturing anything of the sort. My own first thought would be for something like a ships propeller. 

Well the average continental shelf depth is just 60m

The bottom of the continental slop varies between 3000 - 4000m

 

This affect your previous descriptions and arguments. Both of these depths require somn sort of positive displacement mechanism.

 

It's  your thread and idea, not mine.

But it does require more than guesswork and wishful thinking to make it into a realistic preposition.

You have far to many 'mights' in your words sir.

 

 

Edited April 27, 2023 by studiot

[mistermack]

7 minutes ago, studiot said:

Both of these depths require somn sort of positive displacement mechanism.

I don't get what you mean there. Could you elaborate a bit?