快猫短视频

MICHAEL MARKELS plans to feed the world, and reduce global warming into the
bargain. His idea is not modest, but it is beguilingly simple. He believes he
can make fish multiply in the open oceans by adding nutrients such as phosphorus
and iron to the water, in much the same way as a farmer fertilises a field.

Markels, a chemical engineer from Virginia, points out that 60 per cent of
all marine life occurs in just 2 per cent of the oceans鈥� surface area. In the
Pacific Ocean off Peru, for example, deep nutrient-rich waters rush to the
surface, feeding huge populations of plankton which underpin a vast anchovy
fishery. Markels鈥檚 dream is to create similar conditions in the Gulf Stream off
the US鈥檚 east coast鈥攁nd turn what is now a fishery open to all into a
privately owned farm. He says that with 25 000 tonnes of his fertiliser he would
increase fish production by 50 million tonnes. What鈥檚 more, he claims, if ocean
farming really took off it could offset all of the US鈥檚 carbon dioxide
production from burning fossil fuels.

Sounds too good to be true? That鈥檚 just what some oceanographers are saying.
鈥淲e spend our entire careers working on keeping nutrients out of aquatic
ecosystems,鈥� says Sallie Chisholm of the Massachusetts Institute of Technology.
It is the overload of nutrients from agriculture and sewage that creates
thick鈥攁nd sometimes toxic鈥攂looms of algae in lakes and coastal
waters. Chisholm, the most outspoken critic of Markels鈥檚 scheme, believes that
his plan could trigger the world鈥檚 worst ever toxic tide and risks making global
warming worse, not better. 鈥淎t best,鈥� she says, 鈥渋t might marginally increase
production, while destroying the entire ecosystem.鈥� Life in the upwelling waters
off Peru has been evolving for hundreds of millions of years, she says. 鈥淵ou
can鈥檛 just expect to duplicate that by pouring nutrients into the water.鈥�

Ironically, Chisholm was involved in research that has spurred Markels on.
She was a member of the team that tested the idea that the iron in dust blowing
off continents determines which parts of the ocean are deserts and which are
gardens. In 1993, the first IronEx ship dribbled a solution of dissolved iron on
a 64-kilometre-square patch of the equatorial Pacific Ocean near the
Gal谩pagos Islands. A second IronEx cruise in 1995 fertilised a
72-kilometre-square patch. Both experiments created plankton blooms, turning the
waters from their typical blue to milky green. The populations of some species
increased as much as 15 times.

When Markels heard about IronEx he was already working on the idea of ocean
farming, and the findings seemed to validate his radical plan. Here was evidence
that fertilisers really could encourage the growth of photosynthesising
phytoplankton that bob around in the oceans鈥� surface waters. These diatoms,
dinoflagellates, green algae and cyanobacteria provide a floating pasture where
zooplankton such as shrimp-like copepods and krill can graze. These in turn
provide food for larger, roaming carnivores such as squid and plankton-eating
fish.

The main problem with IronEx, as far as Markels was concerned, was that the
algal blooms lasted less than a week after the last infusion of iron. Within
hours, 95 per cent of the added iron clumped together and sank below the sunlit
surface waters where plankton grow. So Markels set about developing a
longer-acting fertiliser, and he now holds patents in 15 countries on a floating
fertiliser pellet the size of a fingernail that releases iron and phosphorus
over a period of days.

Using his own money plus funds from investors, Markels aims to commercialise
the idea. He has established a new company, Ocean Farming, and enlisted the help
of biological oceanographer Richard Barber from Duke University, North Carolina,
and environmental scientist Doug Burton from Baylor University in Texas. In the
first pilot tests, held in the Gulf of Mexico in January 1998, Markels added 3.3
tonnes of his iron and phosphorus pellets to three plots measuring 23 square
kilometres each. After 32 hours, levels of plankton in these plots had risen to
between five and seven times the normal.

And when Markels returned four months later, when the seas were calmer than
in winter, he found that adding 3 tonnes of pellets increased phytoplankton
almost sevenfold to 600 tonnes. 鈥淥cean farming of the Gulf Stream along the
Atlantic coast could increase that area鈥檚 phytoplankton by a factor of about one
thousand,鈥� says Markels. And that, he estimates, could increase the fish catch
by as much as 400-fold鈥攆rom 125 000 to 50 million tonnes per year.

The great thing is that a small amount of fertilisation gives you a big bang
for your buck, he says. 鈥淓very pound of fertiliser potentially produces 4000
pounds of increased plankton. By the time it works its way up the food chain,鈥�
Markels estimates, 鈥渇ertilising a square mile of ocean with 5 tonnes of
fertiliser over a year could generate 300 to 500 tonnes of harvestable fish.鈥� He
makes the comparison with farming livestock on land, where producing a pound of
beef takes 10 pounds of feed. 鈥淲e look forward to some very happy fish,鈥� he
says.

As Markels sees it, there is just one major hitch. Even if he can make the
Gulf Stream bloom, how will he reap the benefit? There are no fences on the high
seas, and the strip of ocean 370 kilometres from American shores, a region known
as the Exclusive Economic Zone, is a publicly held commons. In 1995, after
getting nowhere in his efforts to acquire proprietary rights to part of the
American EEZ, Markels decided to look elsewhere for a testing ground, and
successfully negotiated an agreement with the Republic of the Marshall Islands.
For a fee, this collection of South Pacific islands gave Markels property rights
to the 2.7 million square kilometres of its EEZ. For just over a dollar per
square kilometre or 7 per cent of the value of the catch鈥攚hichever is
larger鈥攈e can fertilise the ocean around the islands to his heart鈥檚
content and claim the fish as his own.

Markels will begin by fertilising about 1300 square kilometres to measure any
resulting increase in growth rates of fish. At the moment, the waters around the
Marshalls don鈥檛 even have a starter stock of fish to fatten up. It is pretty
barren now, he admits. 鈥淭here aren鈥檛 any fish there to eat this stuff.鈥� So he
plans to add bait fish such as anchovy that eat plankton in the hope that they
will entice larger predators such as tuna and swordfish. 鈥淥ceanic fish such as
tuna tend to be mobile and move long distances because their food is dispersed,鈥�
says Barber. 鈥淪o I think that fish might find the patches.鈥�

The right mix

Chisholm is sceptical. 鈥淵ou can鈥檛 extrapolate the results of the IronEx
experiments to the Marshall Islands,鈥� she says. She points out that in the
equatorial Pacific, where IronEx was conducted, and in the Gulf where Markels
has run his initial experiments, there is excess nitrogen and phosphorus in the
water, so when you add iron you get a bloom. But the Marshalls are low in
nitrogen and phosphorus. Markels will have to add a lot of extra phosphorus as
well as iron, and hope that the nitrogen-fixing plankton will pull in enough
nitrogen from the atmosphere.

Even if he gets the right mix of nutrients into the water to cause plankton
to bloom, it doesn鈥檛 necessarily follow that he will be rewarded with more fish.
鈥淚n a way it鈥檚 a crazy idea,鈥� says Andy Solow, director of the Marine Policy
Center at the Woods Hole Oceanographic Institution. 鈥淧eople who like it compare
it to agriculture. But the problem with that is that farmers don鈥檛 throw just
fertiliser, they also seed. You know what seeds will grow into. What species you
get in the ocean may not be valuable or even edible.鈥�

Chisholm agrees. 鈥淵ou can鈥檛 fertilise the oceans without dramatically
changing the structure of the food web,鈥� she says. In the open ocean the
dominant plankton are usually tiny cyanobacteria called Prochlorococcus.
But in a recent study in the equatorial Pacific, Chisholm found that when iron
was added, the number of Prochlorococcus actually decreased while the
number of diatoms surged. Within a week Chisholm and her colleagues saw a
dramatic change in the phytoplankton community, from one ruled by tiny
picoplankton to one dominated by large diatoms, which increased 85-fold in total
biomass. 鈥淲e didn鈥檛 expect that at all,鈥� she says.

Will this lead to more food for the kind of fish Markels wants? Nobody can
say for sure. But some studies have shown that diatoms are an inferior food
source for certain plankton feeders. Copepods, for example, have been found to
produce fewer eggs when fed on diatoms. This, says Chisholm, weakens a link in
the food chain and could result in fewer commercial fish. Instead, noncommercial
species such as jellyfish might compete with the commercial fish. 鈥淵ou might
find that the area will become overrun with lots of things you don鈥檛 want, and
that you didn鈥檛 even know were there,鈥� says Chisholm.

More worrying than mere failure is the possibility that fertilising the ocean
on a large scale could actually do harm. Markels hopes to stimulate
cyanobacteria, which will fix nitrogen, but Chisholm points out that some
cyanobacteria are toxic. And certain diatoms can suffocate fish by clogging up
their gills with a slimy secretion. Even 鈥済ood鈥� plankton can be bad news. In
high enough concentrations, plankton blooms kill fish by depleting the oxygen in
the water, says Daniel Pauly, a fisheries scientist at the University of British
Columbia鈥檚 Fisheries Centre. What鈥檚 more, as dying blooms decay they can produce
ammonia, sulphides and other chemicals that are harmful to marine life.

Toxic blooms happen only in coastal waters, replies Markels, a defence that
Barber backs. 鈥淏looms require strong stratification and very high nutrients,鈥�
Barber says. 鈥淢ixing in the open ocean is much stronger.鈥�

But Chisholm sees it differently. She says that toxic blooms occur in coastal
waters because that鈥檚 where fertilisation is taking place. 鈥淭he open ocean has
never experienced heavy nutrient fertilisation in unnatural proportions,鈥� she
notes. Pauly is equally pessimistic, and predicts that the waters around the
Marshall Islands face the same fate as a lake next to a pig farm, where plankton
bloom but fish perish. 鈥淲hat happens to the lake?鈥� he asks. 鈥淵ou get a lake full
of beautiful rotting fish.鈥� If Markels goes ahead, says Pauly, the Marshallese
will have to pay the bill for this pollution.

Markels dismisses such dire warnings. He and Barber say that the effects of
their fertiliser will be short-lived, and if they stop applying it conditions
will return to normal in about 20 days. They point out that when El Ni帽o
blocks the normal, nutrient-rich currents from forming in the waters off Peru,
it decimates the existing plankton community in a matter of weeks. He assures
the critics that he will monitor his experiment and stop adding pellets if
problems arise.

Chisholm fears that by that time irreparable damage might already have been
done. Overfertilisation could create a thick soup of plankton that shades,
smothers and kills a nonrenewable resource鈥攃oral reefs, the 鈥渞ainforests
of the sea鈥�. Coral reefs provide shelter and food for a whole range of marine
creatures. When the reefs go, so do their inhabitants, she points out.

Because plankton absorb carbon dioxide from the atmosphere as they grow and
sink to the seafloor when they die, Markels believe that they could make a
significant contribution to reducing global warming. He calculates that 1.5
million tonnes of fertiliser, spread over a patch 550 by 1850 kilometres, could
produce enough biomass to lock up a year鈥檚 worth of the US鈥檚 carbon dioxide
emissions. But here, too, Chisholm sees dangers. 鈥淎ny significant carbon dioxide
reduction might just be negated by the production of other greenhouse gases,鈥�
she says. Fertilising can create local zones that are low in oxygen, in which
anaerobic bacteria pump out methane and nitrous oxide. These gases have
respectively 21 times and 2000 times the global warming potential of carbon
dioxide.

Even if Markels鈥檚 plan works, his critics fear they will do the same sort of
damage that farming has done on land. 鈥淲e鈥檝e already run rampant across the
terrestrial biosphere and seriously overfished much of the marine realm. Do we
want to despoil the seas with the equivalent of overgrazing and high-yield
factory farming?鈥� asks Chisholm. For Markels鈥檚 project is not the only one. At
the University of Sydney, the Ocean Technology Group is planning a pilot project
off Indonesia. And in Norway, researchers from two companies, Norsk Hydro and
Maricult, are investigating ways to maximise fish harvests. Chisholm see this as
a very worrying trend.

Markels, however, is encouraged by these schemes, citing them as confirmation
that his own plans are not as wacky as some would make out. And he continues to
push for the privatisation of the oceans, which he believes is the only way that
he can make a commercial success of ocean farming in the Gulf Stream.

Meanwhile, if pilot tests around the Marshalls work, a commercial operation
could begin there by 2002. It could be the start of a new industry. 鈥淭he
potential is absolutely staggering,鈥� says Burton. 鈥淭here are many steps and a
lot of research that needs to be done. But we need to be thinking about this the
same way we thought about the development of agriculture.鈥� Markels remains
unashamedly entrepreneurial. 鈥淚f one coral reef gets impacted, but millions of
people who are starving get food, then I鈥檒l do it. And I hope to make a return
for the investors as well.鈥�