Burying global warming at the bottom of the ocean

A team of German researchers claim that fertilising algae found at the bottom of the ocean with iron could lock away carbon dioxide, helping combat the effects of climate change.

The method has been looked into many times over the years, and it was thought that it wasn’t a realistic form of geo-engineering. However, in February 2004 a team of scientists fertilised 167 square kilometres of the Southern Ocean with several tonnes of iron sulphate.

Eight years later and the results have started to show that algae absorbs carbon dioxide, and even when they die the carbon remains at the bottom of the ocean for centuries.

The research was carried out as part of the European Iron Fertilisation Experiment (EIFEX), which is one of many studies look at technical ways to reverse the effects of climate change. The initial theory behind this research stems from the late oceanographer John Martin, who suggested in 1988 that iron deficiency limits phytoplankton growth in parts of the ocean.

Announcing the research in the Nature Journal, marine biologist Victor Smetacek said that further experiments needed to be carried out to see what effects adding iron to the sea would have on other organisms: “We just don’t know what might happen to species composition and so forth if you were to continuously add iron to the sea. These issues can only be addressed by more experiments including longer-term studies of natural blooms that occur around some Antarctic islands.”

There are some sceptics, however. The University of Essex’s Dr Michael Steinke told the BBC that it was unlikely that this new research would be a guaranteed tool in the battle against global warming.

He added: “Of the twelve fertilisation experiments of this kind, this group’s experiment is the only example to date that demonstrates the all-important carbon burial in the deep sea sediments, away from the atmosphere.”