Melting glaciers may have a (small) upside
Image: Curioso/Shutterstock

Geoengineers have long suggested that we might be able to capture carbon by increasing the growth of phytoplankton in our oceans.

Now it turns out that melting glaciers may be doing just that for us, research has found.

As they melt, glaciers releasing iron, which then fertilises microscopic single-celled phytoplankton, according to research led by Jon Hawkings at Bristol University in the UK.

The team studied the melted water beneath west Greenland’s glaciers and found that they were rich in iron - so rich in fact that the researchers calculate there will be an average of a million tonnes of iron entering the world’s oceans every  year.

At the moment, iron in its unoxidised form - the kind phytoplankton can snack on - is extremely rare in our oceans. But the new research suggests that because this 'melt water' is trapped underneath glaciers without being exposed to oxygen, it’s actually very rich in this unoxidised iron.

As Phil Dooley explains for Cosmos magazine:

This surge of nutrients enables [phytoplankton] to multiply exponentially, in the process trapping large amounts of carbon dioxide. As the phytoplankton die they carry some of that carbon down to the ocean floor, where it remains.

The research also answers a long held puzzle of where large algal blooms spotted by satellites in the middle of the ocean come from.

The research was published in Nature Communications in May.

So could this be good news for climate change? Hawkings tells Dooley there are still a lot of unknowns. “This is an expanding field. There are a whole host of things that plankton and other micro-organisms need: molybdenum, vanadium, cadmium, manganese, even some vitamins.” 

It’s also unknown how much carbon remains trapped when the phytoplankton dies.

For now it’s probably not unreasonable to assume that the benefits of this iron-rich melt water probably aren’t enough to outweigh the damage that led to the glaciers melting in the first place.

Source: Cosmos