http://blog.wired.com/wiredscience/2009/04/antarcticdrake.html
Report From Antarctica: Geoengineering the High Seas
By Wired Science EmailApril 14, 2009 | 7:18:25 PMCategories: Climate,
Oceans, Reports From Antarctica
Drake_passage_map3_copy_2
ABOARD THE AKADEMIK IOFFE, Drake Passage — Located at the southern
confluence of the Atlantic and Pacific oceans, the Drake Passage is
infamous for its gargantuan waves, powerful winds and intense storms,
as well as its place in history. But perhaps equally intriguing is its
potential as a venue for a massive geoengineering experiment.
The Southern Ocean, which includes the majority of the Drake, is high
in nutrients, but low in chlorophyll — an indicator of biological
activity. While there are plenty of nutrients like nitrogen and
phosphorous in the water column, a relative lack of other nutrients is
likely limiting planktonic growth. The primary suspect for the missing
ingredient is iron, which makes the area a tempting place to
experiment with iron-seeding to stimulate biological activity that
would soak up atmospheric carbon dioxide, and potentially help
mitigate climate change.
But there are also clear dangers in tinkering with poorly understood
global systems. There is no control experiment for a large scale
perturbation of the Earth, said MIT engineer Janelle Thompson. At
what point does a scientific experiment become geoengineering?
The Drake passage is a 500-mile stretch of water that separates the
Antarctic Peninsula from the rest of the world's land, named for Sir
Francis Drake, who hunted for an easy route to the Pacific to pillage
the treasure of unprotected ships in the 16th century. Of course, the
Drake Passage turned out to be far from easy, and hundreds of ships
over the centuries have been impaled on the craggy shores of Tierra
del Fuego.
On our voyage south from Ushuaia, Argentina, our Russian research
vessel encountered the strongest storm of the season, complete with 40-
foot swells, near-hurricane-force winds, and seas so rough we had to
admit defeat and halt all forward movement. The Drake's ferocity stems
from the cold air flowing down from frigid Antarctica, the world's
highest continent, and its unusual geographical position, surrounded
by vast stretches of ocean over which strong winds and big waves build
and then crash on the southern tip of South America.
The reason for the region's low biological activity relative to the
high levels of some nutrients is a little harder to pin down.
Oceanographer John Martin first proposed the iron hypothesis in the
late 1980s. He believed that the addition of iron into high-nutrient,
low-chlorophyll regions would stimulate enormous plankton blooms, and
he set out to prove it. Indeed, by sprinkling a relatively small
amount of iron over parts of the Pacific Ocean, Martin and his team
showed that significant biomass growth could be artificially and
effectively induced.
This exercise would be little more than an academic curiosity if it
weren't for the fact that plankton blooms suck vast quantities of
carbon dioxide out of the atmosphere. The idea is that these plankton
are then either consumed or left to accumulate on the ocean floor,
effectively creating a path for long-term carbon storage.
Martin's experiments left a controversial question on the table:
Should we attempt to lower atmospheric carbon dioxide levels by
seeding ocean areas like the Drake with iron? A number of subsequent
experiments have proven the iron hypothesis over increasingly large
swaths of ocean, but several issues remain unresolved. MIT's Thompson
points out that localized tests fail to capture ecosystem-wide
consequences. And as these experiments grow they get closer to being
considered geoengineering, which has become something of a dirty word.
It is increasingly difficult for scientists to get permission to do
this work, she said. The entire ocean need not be seeded, Thompson
argues, but scientists should seek to understand the full consequences
of this potentially disruptive procedure.
Stalled academic investigations leave private sector companies as the
main actors in oceanic iron seeding. Planktos Science, for instance,
has run a number of eco-restoration projects, most recently in the
Indian Ocean. Its operations generally introduce around 50 tons of
iron over 4,000 square miles, a level of dilution that is far below
natural iron-seeding events such as continental dust being blown out
to sea.
NASA has detected a 25 percent decrease in ocean iron deposition over
the last 30 years, and Planktos believes it's only helping to make up
for this decline. Both Planktos and Climos, another iron-seeding
company, have extensive scientific oversight, and they appear to be
moving deliberately but cautiously toward more extensive
demonstrations.
On our way back to civilization, heading north across the Drake
Passage once again, we were blessed with Drake Lake conditions, and
a gentle rocking motion prevails. Up on deck, the
