Regarding my comments on:
The Coming Green Wave: Ocean Farming to Fight Climate Change
by Brendan Smith
November 23, 2011
http://www.theatlantic.com/life/archive/2011/11/the-coming-green-wave-ocean-farming-to-fight-climate-change/248750/
Mike G. wrote:
> Okay Mike so you don't think too much of what was said or the guy
> who said it... We get that but what exactly is wrong with what was
> written.
Um, well, I though Pete went into considerable detail on exactly what
was written.
+ Confusing nitrogen with nitrate & nitrite in water
+ Confusing nitrogen with nitrogen oxides in air
Yes, in agriculture, in the lab and perhaps elsewhere, referring to
the nitrogen (or phosphorus or potash -- aka potassium -- or other
elemental) content of fertilizer and other materials is accepted
shorthand in the same way that measuring propane in BTUs (instead of
units of mass or volume) is HVAC engineering shorthand.
But it's not good expository science writing, sufficiently not good
that I suspect the writer of not understanding what he's writing about.
But suppose we overlook that. Say the author means well and is
striving to pass on a Big Idea. Lets look at a couple of paragraphs:
Seaweed farms alone have the capacity to grow massive
amounts of nutrient-rich food. Professor Ronald Osinga
at Wageningen University in the Netherlands has
calculated[6] that a global network of "sea-vegetable"
farms totaling 180,000 square kilometers - roughly the
size of Washington state - could provide enough protein
for the entire world population.
The goal, according to chef Dan Barber[10] -- named one
of the world's most influential people by Time and a
hero of the organic food movement -- is to create a
world where "farms restore instead of deplete" and allow
"every community to feed itself."
The second paragraph is, very roughly, about the now much maligned
"back to the land" impulse of the 60s, of which I am to some degree an
exemplar. This is intrinsically a small-scale concept, one requiring
a lot of work otherwise eliminated by the mechanization of megafood
agribusiness and promising either expensive food of the acceptance of
minimal incomes by the producer. Nice, doable with dedication but
presently being regulated out of existence here in Nova Scotia.
The first paragraph, though, that talks about feeding the *whole
world*, is talking about Soylent Yellow, krill and seaweed protein. A
staple of a whole genre of not-with-a-bang-but-a-whimper apocalyptic
science fiction. Kelp burgers, krill-mush.
If these two paragraphs in sequence don't engender a frisson of
cognitive dissonance, you're reading too fast.
Lets take another:
But rather than monolithic factory fish farms, they see
the oceans as the home of small-scale farms where
complementary species are cultivated to provide food and
fuel....
Small scale? Fuel? How many homes can you heat, megawatts can you
generate from anything "small scale"? The notion of turning corn and
other non-byproduct food into fuel alcohol is already messing with
food prices. That project is not even slightly small scale and it
isn't coming close to supplanting other fuel sources. If it's pursued
to the point where it does, we will be in the position of feeding the
boilers with the ship's deck and planking to save on coal. There's no
mention of the energy audit -- units of energy resource invested to
produce a unit of energy product. I gather from (perhaps inadequate)
reading that the audit for fuel alcohol from corn, taking into account
the coal-generated electricity, diesel and gasoline, fertilizer
manufacture etc. to plant, raise and process it, comes so close to
breaking even that it's an even bet that it will run in the energy red
in the long term, after the "externalized diseconomies" are
recognized for what they are. And corn farming is sooo much easier and
more developed tech than seaweed.
Another:
Seaweed is one of the fastest growing plants in the
world; kelp, for example, grows up to 9-12 feet long in
a mere three months. This turbo-charged growth cycle
enables farmers to scale up their carbon sinks quickly.
Of course, the seaweed grown to mitigate emissions would
need to be harvested to produce carbon-neutral biofuels
to ensure that the carbon is not simply recycled back
into the air as it would be if the seaweed is eaten.
Um, say what? If we eat the carbohydrates (and maybe a bit of
protein) in seaweed, some goes into the sewer as solids and some into
the air as exhaled CO2. Right. But if we use it for fuel it just
goes, well, *away*? What? If we burn it, *all* the carbon goes back
into the air.
The main nitrogen polluter is agricultural fertilizer
runoff. All told, the production of synthetic
fertilizers and pesticides contributes more than one
trillion pounds of greenhouse gas emissions to the
atmosphere globally each year. That's the same amount of
emissions that are generated by 88 million passenger
cars each year.
Much of this nitrogen from fertilizers ends up in our
oceans, where nitrogen is now 50 percent above normal
levels. According to the journal Science, excess
nitrogen "depletes essential oxygen levels in the water
and has significant effects on climate, food production,
and ecosystems all over the world."
Eutrification due to fertilizer runoff has been a problem for fresh
water lakes, especially smaller ones, for decades. There's a lake
near me where I used to swim in 1970 that is half its former size now.
But that figure about the oceans is, IMHO, meaningless. There may be
significant nitrogenous pollution in parts of the ocean but even
present agriculture hasn't made it uniform enough to make that 50%
number tell me anything. I suspect the author of having patched
together notes about the ocean and about fresh water for the sake of
rhetoric.
Oysters to the rescue. One oyster filters 30-50 gallons
of water a day -- and in the process filters nitrogen
out of the water column. Recent work done by Roger
Newell of the University of Maryland shows that[13] a
healthy oyster habitat can reduce total added nitrogen
by up to 20 percent. A three-acre oyster farm filters
out the equivalent nitrogen load produced by 35 coastal
inhabitants[14].
Leaving aside, as we agreed, the misleading use of "nitrogen", 35
coastal inhabitants don't produce that much nitrogenous effluent.
Assuming a mix of processed and un- or poorly-processed sewage, we're
talking about the amount of nitrogen, in the form mostly of fecal
bacterial proteins or ammonia, in the protein eaten by 35 people. The
massive effluent nitrogen comes from the tonnage of 10-10-10 dumped
onto 10s of thousand of acres of corn, soybean, sugarcane, wheat,
barley and all the other megacrop varieties. How many acres of oyster
bed does it take to compensate for, say, 1000 acres of cornfield? Can
they do phosphorus, too?
Well, enough of addressing what "exactly is wrong with what was
written." In general, I think I have two thoughts:
+ Anything in the way of aquaculture that actually works will quickly
be spun up into or taken over by giant agribusiness with the sort
of unhappy results that the article quite rightly points to in
former corporate fish farming.
+ Our overfishing and (probably) our pollution have already seriously
disturbed the marine biome. No cod for dinner or swordfish gets
expensive? That's nothing beside the possible disruption of the
global marine ecosystem. AFAIK, we (collectively) have only
hopeful surmises about the dynamics of the global marine biome.
As with complex systems in general, there exists the potential for
catastrophic change when enough variables and/or the right
variables exceed limits that we have no way assessing.
So good, lets do some small scale fish or seaweed farming farming. I
haul home something like 5 tons (wet weight) of seaweed every year. I
spread it on sod and plant potatoes under it but on top of the sod.
The potatoes come up nearly clean (a little beach sand sometimes), the
sod rots and, after using that patch for potatoes for 3 to 5 years, I
till it and plant something else there. Potatoes move to a new place.
And some seaweed, a couple of truckloads, goes to mulch cabbages and
tomatoes. The seaweed contains negligible amounts of N-P-K but
replenishes trace elements in our heavily leached soils. Either the
salt or the marine-type carbohydrates in the seaweed seems to deter
creepy-crawlie herbivore pests that live happily under hay mulch. And
the accumulated seaweed, year after year, improves the tilth of the
otherwise heavy soil.
All small scale. It's a lot of work with a dung fork. Good for the
soil, local food production and all that. If someone tries to
commercialize this use of seaweed that I and some neighbors enjoy, it
will suppress rather than support an environment-friendly practice.
> Okay Mike so you don't think too much of what was said or the guy
> who said it.
I don't think anything I wrote was an ad hominem attack. Don't know
anything about him other than what he wrote.
> So, dropping the (Sci Guy) attitude(s)...
Gee, and I'm the guy who claimed to subscribe to Naive Realism with
Sprinkles. :-)
Jeez, I thought Pete's bit got me off the hook for writing this. Guess
not.
- Mike
--
Michael Spencer Nova Scotia, Canada .~.
/V\
[email protected] /( )\
http://home.tallships.ca/mspencer/ ^^-^^
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