A ‘regime shift’ in the Arctic Ocean

Scientists have found out that the growth of phytoplankton has increased 57% over the two decades. This phenomenon have drastically changed the Arctic’s ability to transform atmospheric carbon into living matter. Over the past decade, exploding blooms of phytoplankton have enhanced its ability to soak up carbon dioxide. Scientists at Stanford University while once linked to melting sea ice, the increase is now ‘propelled by rising concentrations of tiny algae’.

The study has been published on Stanford News website, which looks at the growth of phytoplankton in the Arctic Ocean and its ability to soak up carbon dioxide. The Arctic’s ability to transform atmospheric carbon into living matter has drastically changed. Kevin Arrigo, a professor in Stanford’s School of Earth, Energy & Environmental Sciences, said that the influence of phytoplankton biomass can be representing ‘significant regime shift’ for the Arctic.

Arctic has been described as a region that is warming faster than anywhere else on Earth. The report called “Changes in phytoplankton concentration now drive increased Arctic Ocean primary production”, that appeared on ScienceMag website, states that majority of warming is centered over the Arctic Ocean and summer sea ice is predicted to disappear completely by mid-century.

The ocean colour algorithm has been used to show the increase in primary production by 57% between 1998 and 2018. This has allowed to discover that Artic Ocean in the future can support ‘higher trophic-level production and additional carbon export’, as the subsequent rise in primary production has been said to be driven primarily by increased phytoplankton biomass.

Scientists measured the ongoing changes in Arctic climate using satellite-derived estimates of chlorophyll a, sea surface temperature, and sea ice concentration. A modified version of the standard empirical NASA-Chl an algorithm has also been used, which was needed to ‘better account for the distinct bio-optical properties of the AO’ – as they differ from the global ocean, because of higher pigment packaging.

Figures included in the report show regions of interest and changes in phytoplankton biomass – with many subregions showing significant increase. Scientists have eliminated few causes for the observed increase in phytoplankton Chl a over the past decade saying: 

“Earlier phytoplankton blooms could intensify the mismatch between grazing and phytoplankton growth, resulting in higher Chl a concentrations in recent years. However, this possibility is diminished by annual changes in Chl a being the same in spring (April through June) as they were in summer (July through September), when grazing rates would be expected to be highest.”

Stanford News describes phytoplankton need for light and nutrients to grow, however the availability of those throughout the water column are said to depend on complex factors. This is the reason why researchers have debated on how long the bloom may last or how high it may climb. The website sums it up saying:

“Arctic waters open up, and the fact that the Arctic is simply too small to take much of a bite out of the world’s greenhouse gas emissions. “It’s taking in a lot more carbon than it used to take in,” Arrigo said, “but it’s not something we’re doing to be able to rely on to help us out of our climate problem.”

By Julita Waleskiewicz

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