For twenty years, a controversy has engaged many scientists in a debate over the role iron plays in marine food chains and the global carbon cycle. A theory has emerged that evidence of high levels of iron in a water system accelerates the growth patterns of phytoplankton; the plankton then capture carbon, which results in a buffering of the effects of global warming. The debate has often become intense, resulting in some previous experiments that involved dumping large quantities of iron into the water systems to measure the acceleration of plankton growth and the corresponding affect on the carbon measurements.
According to a study published last week in the journal Nature Communications and an article completed by Science Daily to summarize the study, a team from the United Kingdom conducted research to follow up on speculation surrounding the ice sheets from glaciers in both Greenland and Antarctica. The team involved in the study comprised researchers from universities in Bristol, Leeds, Edinburgh and the National Oceanography Centre.
For the study, researchers collected meltwater discharge from the Leverett Glacier in Greenland in the summer of 2012. The collections were then tested for bioavailable iron content. The presence of iron that is bioavailable would mean that, as the ice sheets melt, a source of iron is being leaked back into the ocean, rendering most affect from global warming caused by the excess water null and void, as the iron captures carbon to reintroduce a balance to the environment. Essentially, with the added iron being shed by these melting ice sheets, iron could be fighting a bit of the battle against global warming for us.
The researchers found that samples contained a considerable amount of iron, which indicates that, with summer, comes a seasonal boost to ocean productivity. Jon Hawkings, of the University of Bristol and lead author on the study, acknowledges that scientists have long known that, with the melting of the icebergs, came a certain level of iron back into the oceans. However, his study, he specifies, is the first to acknowledge that the cycle of melting icebergs in the summer allows for a continuous source of iron to the coastal ocean. Specifically, the researchers estimate that the melting sheets in Greenland produce between four hundred thousand and two and a half million tonnes of iron per year; in Antarctica, between sixty thousand and one hundred thousand of tonnes per year are brought back into the ocean. Combined, these two figures are enough to create approximately one hundred and twenty five Eiffel Towers.
In regards to the future, scientist who have examined the findings argue that the flux in iron needs to be quantified and the bioavailability tested and demonstrated directly in an experiment. This would allow other oceanographers to rely on the findings and what they mean in regards to the impact against global warming.
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