Seeding oceans with iron could help limit global warming
A team of German researchers believe stimulating the growth of algae in our oceans may offer a viable method of removing excess carbon dioxide from the atmosphere. Indeed, despite alternative studies suggesting the above-mentioned approach is ineffective, a recent analysis of an ocean-fertilization experiment conducted 8 years ago in the Southern Ocean indicates that encouraging algae blooms to grow can soak up carbon - which is then deposited in the deep ocean as the algae dies.
Way back in February 2004, researchers involved in the European Iron Fertilization Experiment (EIFEX) fertilized 167 square kilometers of the Southern Ocean with several tons of iron sulphate. For 37 days, the team on board the German research vessel Polarstern monitored the bloom and demise of single-cell algae (phytoplankton) in the iron-limited but otherwise nutrient-rich ocean region. Interestingly enough, each atom of added iron pulled at least 13,000 atoms of carbon out of the atmosphere by encouraging algal growth which, through photosynthesis, captures carbon. As noted above, much of the captured carbon was transported to the deep ocean, where it will remain sequestered for centuries - essentially acting as a "carbon sink." "At least half of the bloom was exported to depths greater than 1,000 metres," explains Victor Smetacek, a marine biologist at the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven, Germany, who led the study. The team used a turbidity meter - a device that measures the degree to which water becomes less transparent owing to the presence of suspended particles - to establish the amount of biomass, such as dead algae, that rained down the water column towards the sea floor. Samples collected outside the experimental area showed substantially less carbon being deposited in the deep ocean Seeding oceans with iron could help limit global warming Well, old rocks should we cover the entire ocean with this?