Phytoplankton Are Causing a 'Significant Regime Shift' in the Arctic Ocean

The Arctic Ocean has had several obstacles this year such as the recent oil spill from Russia's nuclear powerplant and recent reports of acidification due to climate change. Moreover, researchers discovered a 'significant regime shift' due to phytoplankton activity.

Global warming is causing the polar ice caps to melt at alarming rates, affecting wildlife ranging from polar bears to microscopic phytoplankton. An earlier study predicted that The Arctic Ocean may absorb 20% more carbon dioxide by the end of the century, drastically changing phytoplankton uptake.

Phytoplankton are microalgae ranging from good microbes to protists and single-celled plants. Their role in the ecosystem is to convert sunlight and carbon dioxide into sugars that sea creatures can eat.

However, when too many nutrients are available in the water, the phytoplankton goes into overdrive and form harmful algal blooms. The blooms produce toxic compounds that poison fish, shellfish, birds, and even humans.

'Significant Regime Shift'

A team from Stanford University recently published a report in the Science journal about the phytoplankton in the Arctic Ocean causing a 'significant regime shift.' Professor Kevin Arrigo from Stanford's School of Earth, Energy & Environmental Sciences (Stanford Earth), said, 'the rates are really important in terms of how much food there is for the rest of the ecosystem. It's also important because this is one of the main ways that CO2 is pulled out of the atmosphere and into the ocean.'

Between 1998 and 2018, the team measured a 57% increase in the ocean's net primary production (NPP), or the rate which algae and plants photosynthesize to create food for other creatures. Furthermore, while NPP increased alongside the rate of sea ice melting, productivity still grew even when melting slowed down in 2009.

'The increase in NPP over the past decade is due almost exclusively to a recent increase in phytoplankton biomass," Arrigo said. As phytoplankton thrives in warmer temperatures, since they grew northward in melted waters, they've continued to grow in more concentrated populations, creating a thick 'algae soup.'

'In a given volume of water, more phytoplankton were able to grow each year,' said Kate Lewis, a researcher at Stanford's Department of Earth System Science. 'This is the first time this has been reported in the Arctic Ocean.'

Phytoplankton Blooms

Currently, scientists are debating over the rate of phytoplankton blooms continuing to grow, contemplating if and when the growth will stop and how big their population can become. Because of this, the Stanford team built a new algorithm to estimate microalgae concentration in the Arctic Ocean. Arrigo said that 'It's still early days, but it looks like now there is a shift to greater nutrient supply.'

Lewis said, 'We knew the Arctic had increased production in the last few years, but it seemed possible the system was just recycling the same store of nutrients,' responding to the hypothesis that the ocean is receiving a new influx of nutrients. She explained that the phytoplankton is absorbing more carbon each year with significant ecological consequences.

'There's going to be winners and losers,' Arrigo explained. 'A more productive Arctic means more food for lots of animals. But many animals that have adapted to live in a polar environment are finding life more difficult as the ice retreats.'