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Author Topic: Seaweed and Seashell Farming  (Read 1906 times)

Ken Feldman

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Seaweed and Seashell Farming
« on: March 09, 2018, 07:06:37 PM »
I read "Atmosphere of Hope" by Tim Flannery recently and came across a topic I didn't know about, seaweed farming.  Apparently it's a way to reduce ocean acidification and draw down CO2 from the atmosphere.  It's been growing exponentially in the past decade and people are making money and producing food from it.

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Globally, around 12 million tonnes of seaweed is grown and harvested annually, about three-quarters of which comes from China. The current market value of the global crop is between US$5 billion and US$5.6 billion, of which US$5 billion comes from sale for human consumption. Production, however, is expanding very rapidly.

Seaweeds can grow very fast – at rates more than 30 times those of land-based plants. Because they de-acidify seawater, making it easier for anything with a shell to grow, they are also the key to shellfish production. And by drawing CO₂ out of the ocean waters (thereby allowing the oceans to absorb more CO₂ from the atmosphere) they help fight climate change.

Here are a couple of links to articles about it:

https://theconversation.com/how-farming-giant-seaweed-can-feed-fish-and-fix-the-climate-81761

https://www.washingtonpost.com/lifestyle/food/seaweed-is-easy-to-grow-sustainable-and-nutritious-but-itll-never-be-kale/2015/10/26/1d1719b8-7750-11e5-b9c1-f03c48c96ac2_story.html?utm_term=.ddbbc9294451

https://e360.yale.edu/features/new_breed_of_ocean_farmer_aims_to_revive_global_seas
« Last Edit: March 09, 2018, 10:43:00 PM by Ken Feldman »

Neven

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Re: Seaweed Farming
« Reply #1 on: March 09, 2018, 09:27:27 PM »
It's super healthy too (not too much, of course), but that also depends on toxin levels in the water.

I didn't know either it was this good for CO2 drawdown and ocean acidification.
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P-maker

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Re: Seaweed Farming
« Reply #2 on: March 09, 2018, 10:10:22 PM »
How about including seashells as well in a new and broader title with even more focus on CO2 drawdown:

Seaweed and seashell farming

Ken Feldman

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Re: Seaweed Farming
« Reply #3 on: March 09, 2018, 10:43:24 PM »
How about including seashells as well in a new and broader title with even more focus on CO2 drawdown:

Seaweed and seashell farming

Good suggestion.  I made the change.

mitch

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Re: Seaweed and Seashell Farming
« Reply #4 on: March 10, 2018, 12:14:35 AM »
I would expect that seaweed farming should draw down pCO2 in the ocean where it grew, which would then raise pH some in the surrounding water. However, unless it is buried on land, it will not affect atmospheric CO2.

Ken Feldman

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Re: Seaweed and Seashell Farming
« Reply #5 on: June 13, 2018, 01:02:54 AM »
Here's an article from last week to give this thread a bump:

https://www.sciencefriday.com/videos/kelp-its-whats-for-dinner/

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In addition to requiring fewer chemicals than land agriculture, kelp farming is also good for our carbon future. Kelp captures five times more carbon than land-based plants. It also absorbs nitrogen, so it can offset algal blooms.

Ken Feldman

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Re: Seaweed and Seashell Farming
« Reply #6 on: June 13, 2018, 01:10:18 AM »
I would expect that seaweed farming should draw down pCO2 in the ocean where it grew, which would then raise pH some in the surrounding water. However, unless it is buried on land, it will not affect atmospheric CO2.

I don't think the chemistry is correct.  If the kelp farms lower the pH in them, why would the pH in other areas increase?  The kelp is absorbing the carbonic acid and using it to build organic material.

As to the atmospheric ghg concentrations, it's at least carbon neutral.  The CO2 is used by the kelp, which could then be used as food (carbon neutral, vs the need for nitrogen fertilizers that are ghg intensive) or as fertilizer on land farms (a slight carbon sink, possibly major if you can offset other fertilizer use).

Most importantly, those areas of lower acidity in and nearby kelp farms will allow carbon shelled animals, such as clams, to continue to survive when other parts of the ocean are too acidic.

Bruce Steele

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Re: Seaweed and Seashell Farming
« Reply #7 on: June 13, 2018, 02:34:49 AM »
Mitch is correct. Kelp absorbs CO2( pCO2 or carbonic acid ) and reduces the amount of pCO2 in seawater. This results in an increase in pH. This is a good thing and decreases acidification locally but as the kelp dies and is consumed by animals or bacterially reduced the pCO2 is released and seawater pH drops.
 It may seem counterintuitive but the formation of shells results in the release of Hydrogen ions and a drop in seawater pH.  So shell formation adds to acidification .

Bob Wallace

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Re: Seaweed and Seashell Farming
« Reply #8 on: June 13, 2018, 07:01:38 AM »
Here's an interesting article about someone who is making a living vertically farming 40 acres of ocean.

https://cleantechnica.com/2018/06/11/interview-with-bren-smith-the-fisherman-shaping-the-future-of-sustainable-ocean-farming/

One of the commenters suggests

"One possible use of the seaweed is to dump it on the deep ocean floor, where the carbon takes centuries to reenter the part of the biosphere we live in."

Ken Feldman

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Re: Seaweed and Seashell Farming
« Reply #9 on: June 14, 2018, 12:30:20 AM »
Mitch is correct. Kelp absorbs CO2( pCO2 or carbonic acid ) and reduces the amount of pCO2 in seawater. This results in an increase in pH. This is a good thing and decreases acidification locally but as the kelp dies and is consumed by animals or bacterially reduced the pCO2 is released and seawater pH drops.
 It may seem counterintuitive but the formation of shells results in the release of Hydrogen ions and a drop in seawater pH.  So shell formation adds to acidification .

I'm embarrassed! :-[  Of course lower pH is more acidic.  Don't know why I didn't catch that when I posted.  Thanks.

Ken Feldman

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Re: Seaweed and Seashell Farming
« Reply #10 on: July 03, 2018, 01:56:57 AM »
Seaweed in feed could help control methane emissions from cows!

https://e360.yale.edu/features/how-eating-seaweed-can-help-cows-to-belch-less-methane

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Kebreab’s experiments with seaweed additives to cattle feed have now surpassed that 30-percent figure, with one type of seaweed slashing enteric methane by more than 50 percent. In the fight to slow climate change, such reductions are no small matter: In the United States alone, domestic livestock — including cattle, sheep, goats, and buffalo — contribute 36 percent of the methane humans cause to be put into the atmosphere, according to the U.S. Environmental Protection Agency.

morganism

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Re: Seaweed and Seashell Farming
« Reply #11 on: May 11, 2019, 10:25:32 PM »
update:

The race is on to cultivate a seaweed that slashes greenhouse emission from cows, other livestock

"Salwen said that while there's some competition to develop cultivation techniques of Asparagopsis, people are largely working together to share information and best practices. She said that those involved see significant room for many different players in what could be a massive new industry.

"This will be like growing corn or soybeans," she said. "There will be a whole lot of people cultivating and building farms. It's not like anyone believes for a second that they could own the production market, so people are really collaborating."

https://phys.org/news/2019-05-cultivate-seaweed-slashes-greenhouse-emission.html

morganism

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Re: Seaweed and Seashell Farming
« Reply #12 on: May 11, 2019, 10:52:06 PM »
this might be a excellent reason to build the major water pipeline they talked about a few years ago.
they were discussing taking the winter flood waters from the upper midwest, and pipe-lining it down to the farming country above the Oolagalla reservoir, to recharge the groundwater in winter, and water plants in summer.

It would make some sense to have a saltwater pipeline to the upper midwest, to raise the seaweed in, and then use as a fertilizer and nutrient additive, rather than trucking it in. Turns out, a little bit of seawater is a great way to renew the nutrients that are leached from the soil.

"All SeaAgri products are produced from the Sea of Cortez containing 92 minerals and trace elements, plus more than 50,000 organic compounds. Scientific data shows that SEA-90’s minerals and trace elements stimulate, feed and enhance micro flora populations in soil, and as little as one ounce of SEA-90 Essential Elements provide nearly complete mineral nutrition."

https://seaagri.com/?v=7516fd43adaa

https://seaagri.com/research/?v=7516fd43adaa



sidd

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Re: Seaweed and Seashell Farming
« Reply #13 on: May 12, 2019, 12:56:58 AM »
Mmmm.

1)pumping water is very expensive
2)hard to collect upper midwest flood without more massive engneering on the missouri
3)all the farmers i know who irrigate in upper midwest (west of the missouri)  will beat you severely, tar and feather you and run you outta town on a stick if you try to put salt on their land. Salinization is a big problem on irrigated soils.

sidd