『Abstract
We consider the design of an in situ enrichment experiment to
test the hypothesis that Fe deficiency limits primary productivity
in some regions of the ocean. A small-scale (10-100 km2)
experiment would be preferable for logistical reasons, but the
chief practical difficulty is that the patch of enriched water
will fragment or streak severely. This problem is made tractable
by adding a conservative marker such as sulfur hexafluoride (SF6) along with the Fe release, enable rapid detection
of enriched water despite fragmentation. The concentration of
SF6 would indicate the amount of dilution
the original injection of Fe had undergone, and regression of
parameters such as p CO2 and Chl against
SF6 at several times postinjection would
enable the degree of fertilization to be assessed. Due to the
complexity of Fe chemistry in seawater, we cannot be certain that
the added Fe will adequately mimic the input of natural aerosol
Fe to the surface. Thus, a null result from the experiment (i.e.
no observable fertilization) would be less valuable than a positive
result: a positive outcome would be proof that Fe enrichment enhances
productivity, but a null result would not be absolute proof of
the converse.』
（Introduction）
Tracer releases in the North Sea
In situ fertilization experiment
The fate of the added Fe
Conclusion
References