Energy from seaweed

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Energy from seaweed
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Cathryn

Joined: 16 Jul 2005
Posts: 19856
Location: Ceredigion

Posted: Mon Mar 16, 15 10:22 pm Post subject:

Not sure about the shading itself to death but brief reading that I've done suggests that one reason for overproducing is because of excessive nitrogen levels which are apparently run off from the land? Wonder how sea weed farms would encourage growth. (Does a cynical tone come through on the forum?)

The article was expounding this as an eco friendly bio mass crop and I cannot see how it could be.

jamanda
Downsizer Moderator

Joined: 22 Oct 2006
Posts: 35056
Location: Devon

Posted: Mon Mar 16, 15 10:26 pm Post subject:
Lanildut in Brittany is big on seaweed. It's kelp that they harvest. They have contraptions on the back of the boats that work like giant pasta forks. I think it needs a more sheltered bay than yours Cathryn.

Cathryn

Joined: 16 Jul 2005
Posts: 19856
Location: Ceredigion

Posted: Mon Mar 16, 15 10:28 pm Post subject:
The beach is SSSI so it wouldn't happen in any case.

Hairyloon

Joined: 20 Nov 2008
Posts: 15425
Location: Today I are mostly being in Yorkshire.

Posted: Mon Mar 16, 15 10:41 pm Post subject:

Cathryn wrote:

Not sure about the shading itself to death...

It is algae, it is not like proper plants which send food down from the leaves.

Quote:

but brief reading that I've done suggests that one reason for overproducing is because of excessive nitrogen levels which are apparently run off from the land?

Yes, very often. But before you asked when it is overproduction, not why.

Tavascarow

Joined: 06 Aug 2006
Posts: 8407
Location: South Cornwall

Posted: Tue Mar 17, 15 7:44 am Post subject:

Cathryn wrote:

You have answered your question already. It is growing excessively in some places because of nitrate run off so why not harvest it? Personally I wouldn't use it as a bio-fuel but as a fertilizer on the very land that has had the excess fertilizer.

Mistress Rose

Joined: 21 Jul 2011
Posts: 15598

Posted: Tue Mar 17, 15 8:00 am Post subject:
It has been used as a fertilizer for years. It has also been harvested for burning for glass making and other uses that need potassium chloride or nitrate.

Ty Gwyn

Joined: 22 Sep 2010
Posts: 4563
Location: Lampeter

Posted: Tue Mar 17, 15 9:39 am Post subject:

Mistress Rose wrote:

It has been used as a fertilizer for years. It has also been harvested for burning for glass making and other uses that need potassium chloride or nitrate.

Calcified Seaweed is the one that comes to mind,

Did`nt know about the Glass making,interesting.

Hairyloon

Joined: 20 Nov 2008
Posts: 15425
Location: Today I are mostly being in Yorkshire.

Posted: Tue Mar 17, 15 9:50 am Post subject:

Tavascarow wrote:

Personally I wouldn't use it as a bio-fuel but as a fertilizer on the very land that has had the excess fertilizer.

Run it through an anaerobic digester and you can do both.

Tavascarow

Joined: 06 Aug 2006
Posts: 8407
Location: South Cornwall

Posted: Tue Mar 17, 15 10:05 am Post subject:

Hairyloon wrote:

Tavascarow wrote:

Personally I wouldn't use it as a bio-fuel but as a fertilizer on the very land that has had the excess fertilizer.

Run it through an anaerobic digester and you can do both.

True.
& anaerobic digestion makes the fertilizer more stable. If used to replace some or all of the artificial nitrates & animal slurry there would be very little run off.
Plant a belt of short rotation coppice on the lower slopes to mop up any excess & I think (with the aid of the article) we have just designed a bioremediation system.
Of course the likes of Monsanto will say it would never work, & if there was any chance they would patent, & bury it.

Tavascarow

Joined: 06 Aug 2006
Posts: 8407
Location: South Cornwall

Posted: Tue Mar 17, 15 10:45 am Post subject:

Ty Gwyn wrote:

Mistress Rose wrote:

It has been used as a fertilizer for years. It has also been harvested for burning for glass making and other uses that need potassium chloride or nitrate.

Calcified Seaweed is the one that comes to mind,

Did`nt know about the Glass making,interesting.

Calcified seaweed beds are a threatened habitat & not a sustainable source at current rates of exploitation.
There's a huge difference between harvesting kelp washed ashore & dredging the sea bed.
Also a huge difference in chemical composition. Calcified seaweed is more suited for raising the pH of acid soils than as a fertilizer substitute.
It's 50% CaCO3 10% Mg CO3 & if I remember correctly only about 1% NO3.
I know they have stopped dredging it in the Fal estuary years ago, because of over exploitation.

Cathryn

Joined: 16 Jul 2005
Posts: 19856
Location: Ceredigion

Posted: Tue Mar 17, 15 2:29 pm Post subject:

Tavascarow wrote:

Cathryn wrote:

But that isn't what the article says. One project collects the excess that grows but the main plan (because that's not realistic in the longer term is it) seems to be large farms where they grow the seaweed themselves.

Ty Gwyn

Joined: 22 Sep 2010
Posts: 4563
Location: Lampeter

Posted: Tue Mar 17, 15 3:03 pm Post subject:

Tavascarow wrote:

Ty Gwyn wrote:

Mistress Rose wrote:

It has been used as a fertilizer for years. It has also been harvested for burning for glass making and other uses that need potassium chloride or nitrate.

Calcified Seaweed is the one that comes to mind,

Did`nt know about the Glass making,interesting.

Swings and roundabouts Tav,
Usually raising the pH encourages clover,hence increases the nitrogen,so in-fact is a substitute to chemical fertilizer.

The 50% calcium is made up of the crushed sea shells.
I really don`t know how much seaweed it contains.

Tavascarow

Joined: 06 Aug 2006
Posts: 8407
Location: South Cornwall

Posted: Tue Mar 17, 15 4:35 pm Post subject:

Ty Gwyn wrote:

Tavascarow wrote:

Ty Gwyn wrote:

Mistress Rose wrote:

It has been used as a fertilizer for years. It has also been harvested for burning for glass making and other uses that need potassium chloride or nitrate.

Calcified Seaweed is the one that comes to mind,

Did`nt know about the Glass making,interesting.

The clue is in the name my friend. Yes there is a small proportion of shell but the majority is the 'calcified' remains of a specific species of seaweed. It's more like crushed coral than a plant but that is what it is, & the habitat is quite rare, valuable & easily destroyed.

Quote:

3.2.2 MAERL
Divers have reported seeing maerl, calcified seaweed, on the seabe
d at the mouth of the estuary,
particularly in the vicinity of the wreck of the ‘Rock Island Br
idge’. Maerl beds are a sub feature of
the Fal & Helford SAC. The larger maerl beds, within the Rose
land VMCA in the adjacent Fal
estuary have been dated as approximately 7,000 years old and are we
ll known for their marine
wildlife as the interstices of the very slow growing maerl pr
ovide shelter and security for a wide
range of invertebrates and fish. Dead maerl which has accumulat
ed in substantial quantities in
various parts of Falmouth Bay not far from the Helford River also pr
ovides an interesting although
more mobile habitat.

from this document.

jamanda
Downsizer Moderator

Joined: 22 Oct 2006
Posts: 35056
Location: Devon

Posted: Tue Mar 17, 15 11:46 pm Post subject:
It's also used for making agar, for growing bacteria, making jelly and various creams and potions in the cosmetics industry.

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