Iron: a solution to climate change?
because they soak up CO2. But suggests that we may be wasting our time trying to force the oceans to store the extra carbon humans produce by burning fossil fuels.
But first, some basic biology. Tiny organisms that teem in our seas reduce climate change because they extract CO2 from the atmosphere as they grow. When these organisms die they sink to the sea floor, taking the carbon with them. The more of these organisms (phytoplankton), the cooler our climate.
So if we encourage phytoplankton to flourish (say, by bombarding anaemic waters with iron, which is crucial for phytoplankton growth) then we can cool the climate, right?
Wrong. All that time scientists spent sprinkling eddies with iron in the notoriously stormy Southern Ocean (a doughnut of water circling Antarctica) didn't make a blind bit of difference to the amount of carbon that was eventually removed from the atmosphere, according to new findings.
A joint expedition of the Alfred Wegener Institute and the found that this was because predators scoffed the phytoplankton, dead or alive, before they had time to sink.
Dr Wajih Navi, co-chief scientist of the expedition said: 'To our surprise, the iron-fertilised patch attracted large numbers of ... predators belonging to the crustacean group known as amphipods ... the increasing grazing pressure ... prevented further growth of the phytoplankton bloom.'
Is that it, then? Is it the end of the line for this particular climate fix? Not necessarily. The technique could work with the right species of phytoplankton. Some species come encased in a snazzy sort of armour made from silica (basically glass, to you or I). These warriors of the phytoplankton world are less likely to be ambushed by predators, and so they're more likely to sink to the sea floor, where the carbon stays. The trick is to find them. Note: They don't hang out in the Southern Ocean.
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