Meltwater flowing from the Greenland ice sheet is stirring up nutrients from the ocean depths, fueling algal blooms. A new study reveals the extent to which melting is driving the growth of algae.
As Greenland melts, water is trickling down through the ice and flowing out to the sea. Fresh water tumbles down hundreds of feet, and then, being lighter than saltwater, returns to the surface, drawing up iron and nitrate from the depths. These nutrients fuel blooms of algae, which form the base of the Arctic food chain. Prior research has shown that halibut are more abundant in fjords fed by meltwater.
The biggest outlet for meltwater lies beneath Jakobshavn Glacier, which dispenses more than 300,000 gallons a second at the height of summer. For the new study, scientists modeled the flow of fresh water from Jakobshavn Glacier using more than three decades of data on temperature, pressure, and salinity. They found that melting is boosting the summertime growth of algae by between 15 and 40 percent. The research was published in Nature Communications: Earth & Environment.
The study also showed that melting is diluting ocean water, making it less able to take up carbon dioxide. But the loss is more than canceled out by larger algal blooms, which are soaking up even more CO2.
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