A ‘regime shift’ is happening in the Arctic Ocean, Stanford scientists say (news.stanford.edu)

I'm not attuned to biology, and the article wasn't clear to me on the implications of this. Could someone comment - what does this mean? On the one hand, it seems as if an increase in phytoplankton can process more carbon into sugars, increasing the food supply at the lowest levels (and taking a small bite out of the global carbon footprint). On the other hand, such production usually comes at a cost, e.g., reducing the free oxygen supply in the waters. Experience tells me that the costs almost always outweigh the benefits. Can someone chime in? Thanks!

Could the title be more descriptive? I first expected this to be about politics.

Perhaps: Changes in phytoplankton concentration now drive increased Arctic Ocean primary production

The title from the original research publication, https://science.sciencemag.org/content/369/6500/198