Iron fertilization in the Southern Ocean doesn’t sequester carbon

March 24, 2009
I can haz ur carbon sequestration? NOM NOM NOM.

I can haz carbon sequestration? NOM NOM NOM.

The results of the latest iron fertilization experiment in the Southern Ocean are in – and it doesn’t look good as a solution for climate change. The Lohafex project, a collaboration between Indian and German scientists, found that merely stimulating a plankton bloom with iron did not lead to carbon sequestration.

What they were hoping would happen was this:

  1. Iron input
  2. Diatom bloom – diatoms have fast-sinking silica shells
  3. Diatoms die & sink to bottom
  4. Silica shells buried for all eternity
  5. Carbon sequestration WIN!

What actually happened was this:

  1. Iron input
  2. Yummy Phaeocystis algae bloom – no silica shells
  3. Copepods (tiny crustaceans) eat delicious soft algae.
  4. Amphipods (small crustaceans) eat delicious crunchy copepods.
  5. Copepods and amphipods respire, turning the algae right back into carbon dioxide.
  6. Carbon sequestration LOSE.

Previous studies have shown that only 1-2% of sinking carbon (and that’s a generous estimate)  gets sequestered. There’s life in the deep midwater and life in the deep sea and all life is HUNGRY. (Personally, I blame the deep-sea sea cucumbers – those gluttons are major consumers of what little detritus makes it down there.)

Though the iron fertilization part of this cruise didn’t work out as desired, understanding nutrient cycling and plankton dynamics in the Southern Ocean is really important. As the polar ice melts it could cause nutrients to fluctuate, affecting the whales and squid and birds that all depend on Antarctic food sources. So please count me in for any future collaborations with Indian scientists! From the press release:

Spicy Indian curries were prepared at each meal by a Goan cook specially engaged for this cruise and contributed to the good atmosphere.

Will dumping cornstalks into the ocean sequester carbon?

February 11, 2009

There a new ocean carbon sequestration scheme in town – dumping crop waste. A study published in Environmental Science and Technology last month proposes baling up corn husks and wheat stalks, weighting them with rocks, and tossing them into the deep sea. (Here’s the NYT blurb.)

The authors claim that marine creatures will be unable to digest chewy terrestrial plants chock-full of lignin and cellulose, so the sea will keep that carbon down for thousands of years. If this worked, they calculate it would reduce carbon accumulation in the atmosphere by 15%.

Unfortunately, their entire premise might be wrong. The deep sea is not a lifeless cold dark empty place – it is filled with animals that are evolved to take advantage of whatever food drifts down from above, terrestrial or not. For example, wood that falls into the deep sea gets eaten. There’s even a deep-sea bivalve that specializes in drilling into wood.

Since wood is a lot harder on the digestion than grass stems, I doubt that all that crop waste would just sit there bereft and alone for thousands of years. It’s going to get munched upon and decomposed, and the carbon will go back into global circulation. I wish that controlling climate change were as simple as dumping some stuff nobody wants anyway into the ocean, but I just don’t think it’s going to be that easy.

Stuart E. Strand, Gregory Benford (2009). Ocean Sequestration of Crop Residue Carbon: Recycling Fossil Fuel Carbon Back to Deep Sediments. Environmental Science & Technology, 43 (4), 1000-1007.

The risks & benefits of geoengineering

January 9, 2009

ResearchBlogging.orgGeoengineering – the deliberate manipulation of the earth’s atmosphere in order to mitigate global warming – seems to be gaining more credibility worldwide. Just today, Wired reports that an iron fertilization experiment is being conducted in the Southern Ocean by Indian and German scientists.

Though iron fertilization is the best-known geoengineering proposal (thanks to Planktos’ shenanigans), there are several other serious methods under discussion. In a commentary published in Nature Geoscience in November, Philip Boyd summarized current geoengineering proposals and ranked them based on effectiveness, cost, risk, and time.

Here are the proposals Boyd ranked:

  • Iron fertilization. Deliberately stimulating plant growth in the ocean with the aim that the excess material will be permanently sequestered in the deep sea. This would remove carbon from the atmosphere.
  • Stratospheric aerosols. Injecting sulfer particles into the upper atmosphere to mimic a volcanic explosion and physically deflect sunlight. This would not remove carbon from the atmosphere, but would lower the overall amount of  heat reaching Earth.
  • Cloud whitening. Spraying seawater droplets into marine clouds in order to increase their reflectance of sunlight. Like the stratospheric aerosols, this would not remove carbon from the atmosphere, but would lower the overall amount of  heat reaching Earth.
  • Atmospheric carbon capture. Removing carbon from the atmosphere with a chemical absorbent (“scrubbers”) and then sequestering it.
  • Geochemical carbon capture. Removing carbon from the atmosphere by using brine pools to transform it to a dissolved or solid state.

Boyd provides an handy, color-coded guide to the risks and benefits of each type of geoengineering. The more colored blocks a scheme has, the “better” it is.

Ranking geoengineering schemesBased on Boyd’s work, the highest-ranked proposal is cloud whitening. It has a reasonably solid rationale based on observations of ship tracks, it is reasonably affordable & safe, it would rapidly lower the Earth’s temperature if it worked (“mitigation rate”), and can be quickly stopped if there are unintended side effects (“emergency stop”).

The lowest-ranked proposal is (SHOCK!) iron fertilization. Though it has a relatively solid rationale based on experimental data, it has many unpredictable side effects and cannot easily be stopped in an emergency. Oh, and it probably won’t actually work.

Though Boyd’s ranking is certainly oversimplified – for example, cloud whitening, even if it worked, would do nothing to halt ocean acidification – that’s intentional. Boyd intends his system to be used as a logical starting point to figure out which geoengineering schemes deserve more research, and which should be trashed. He writes:

A transparent assessment should strive to increase public confidence in any selected tools, a prerequisite for tackling the difficult questions and complex issues raised by geopolitical, social and economic risks. Such an assessment of all of the
well-established proposals is urgently needed but so far entirely lacking.

Right now, I don’t feel confident in any of these proposals. I am dubious that we understand the ocean and atmosphere well enough to tinker with them. But since the nasty consequences of climate change are already coming fast and furious, I’m willing to listen to sober assessments of geoengineering risks and rewards. Just hold the pseudo-scientific hubris.

Thanks to Hao for the Wired article and Geoff for the geoengineering paper!

Philip W. Boyd (2008). Ranking geo-engineering schemes Nature Geoscience, 1 (11), 722-724 DOI: 10.1038/ngeo348

Planktos turns to copper mining

January 6, 2009

Planktos, the failed iron fertilization company, is changing its name and turning to copper mining.

Planktos is now negotiating to buy private company Churchill Mining, which owns the rights to acquire and redevelop two copper properties in northeast British Columbia. Planktos then plans to change its name to Lobo Resources and secure $1 million in a private placement.

Perhaps it will be a cutting-edge environmentally responsible mining operation? Or…perhaps not.

Iron fertilization limited to “scientific research”

November 17, 2008

The London Convention Treaty, which limits pollution in international waters, has agreed to limit iron fertilization experiments to “legitimate scientific research.” Commercial operations that sell carbon credits will not be allowed. The delegates will *ahem* iron out the details out in May.

Ah, Planktos. We hardly knew – actually, we knew ye quite well enough.

Sunday linking

July 27, 2008

My invertebrate zoology class is over, and my students have returned to their regular lives in a haze of taxonomic dances. (You should have seen them do the Chaetognath!). I shall soon be back to my regularly scheduled blogular procrastination. In the meantime, enjoy a delicious sampling of internet goodness.

  • Like a zombie risen from the grave, the trashy iron-fertilization company Planktos is ba-ack, and more incoherent than ever.
  • I’m probably the last person on the internet to see the Dancing video, but I was absurdly touched. This guy went and did his stupid dance all around the world – 42 countries in 14 months. He danced with Australian crabs, cosplay girls, and even in the North Korean Demilitarized Zone.

Oceanographers fight crime!

June 3, 2008

Four severed sneaker-clad right feet have washed up in British Columbia just this year, and Dr. Curtis Ebbesmeyer is on the case. He’s an expert in marine debris, most famous for his work with the wandering rubber duckies. But Dr. Ebbesmeyer also knows how bodies come apart! Is the mild mannered scientist really just a cover for the crime fighter within?

Curtis Ebbesmeyer, an oceanographer based in Seattle, Wash., said when a human body submerged in the ocean, the main parts like arms, legs, hands, feet and the head are usually what come off the body.

But he’s still baffled by how the exact same part — a right foot — could wash up repeatedly.

“It’s not unusual for body parts to wash up along the United States or Canada,” he said. “There’s so many accidents, like boating. That’s not unusual. It is unusual to find four bodies over the course of the year and just right feet.”

He said his theory is that the feet came along as a result of an accident that might have happened up along the Fraser River, that washed down and spread out along the Straight of Georgia.

Ebbesmeyer said he would urge the police to trace the shoes back to the store they were purchased.

“There’s a lot you can do with the serial number of a shoe and I’m assuming the RCMP are doing that,” he said.


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