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Experiments to date (2003)
From 1993-2002, 7 major scientific expeditions were performed in the major HNLC areas of the world - the Equatorial Pacific, the East and West Southern Ocean, and the sub-Arctic.
The following map indicates sites of iron-fertilisation experiments to date (late 2003)
The Sites marked above indicate the sites of iron fertilisation experiments, as follows:
- A: IronEx I
- B: IronEx II
- D: SOIREE
- E: EisenEx
- G: SEEDS
- H: SOFeX
- J: Planktos
- K: SERIES
SoFex (H) and SEEDS (G) both seeded 2 separate areas in the same expedition, while the Planktos (J) experiment was a private venture for which no results are publicly available. Although promised via private e-mail, none appeared.)
The first 2 experiments were simplest, but gave stunning results - largely because the clearly-visible reaction was seen for the first time. The clear blue oceans turned into "pea-soup" for miles, and experimenters could smell the change.
Later expeditions included international teams of 100's of scientists, all concentrating on different aspects of biogeochemistry. 100's of papers have since been written, detailing these results.
What has been found is that:
- Iron is indeed a limiting nutrient in HNLC areas, with chlorophyll increasing by up to 40-fold (SEEDS)
- Additional carbon dioxide is drawdown from the atmosphere by resultant phytoplankton blooms
- Other gases are produced (eg DMS), and other limiting nutrients (nitrates and phosphorous) are used up.
- Marine communities change, with micro-zooplankton altering. In the South, diatoms are favoured over flagellates, and in the north, centric diatoms over pennate.
What has *not* been found is any proof that any additional carbon sinks to the ocean floor and gets buried, thus entering long-term storage.
Future Plans
The Alfred Wegener Institute plan a follow-up project to the EisenEx project.
This is EIFEX - for European Iron Fertilsation EXperiment.
It will be carried out from January 20th to March 26 2004, in approximately the same area as EisenEx.
Summary
The following 'summary of open-ocean iron enrichment experiments to date' is taken from the US JGOFS (Joint Global Ocean Flux Study) newsletter, October 2002, vol 12, 1.
| experiment | location | date | observations |
|---|---|---|---|
| IronExI | equatorial Pacific | 1993 | 3-fold increase in chlorophyll patch subducted 4 days into experiment |
| IronExII | equatorial Pacific | 1996 | 10-fold increase in chlorophyll patch subducted 4 days into experiment 90µatm drawdown in CO2 5µM drawdown in NO3 |
| SOIREE | Southern Ocean Pacific Sector | 1999 | South of APFZ 6-fold increase in chlorophyll 25µatm drawdown in CO2 2µM drawdown in NO3 |
| EisenEx | Southern Ocean Atlantic Sector | 2000 | dispersion in eddy 4-fold increase in chlorophyll |
| SEEDS | western subarctic Pacific Ocean | 2001 | 40-fold increase in chlorophyll 13µM drawdown in NO3 |
| SOFeX North | Southern Ocean Pacific Sector | 2002 | North of APFZ Greater than 10-fold increase in chlorophyll Greater than 40µatm drawdown in CO2 |
| SOFeX South | Southern Ocean Pacific Sector | 2002 | South of APFZ Greater than 10-fold increase in chlorophyll Greater than 40µatm drawdown in CO2 |
| SERIES | eastern subarctic Pacific Ocean | 2002 | Greater than 10-fold increase in chlorophyll More than 5µM drawdown in NO3 |
Used with permission of U.S. JGOFS
http://usjgofs.whoi.edu/general_info/newsletter.html -->
http://usjgofs.whoi.edu/general_info/vol121.pdf