A fundamental shift occurred around 2009: the Arctic has flipped from being limited by light to being limited by nitrogen. As sea ice retreats, increased plant growth on shallow Arctic shelves is driving far greater loss of nitrate from the water, reshaping the base of the food web.
The Arctic Ocean may have crossed a dangerous tipping point. Scientists say the rapid disappearance of sea ice is triggering a hidden chemical shift that is stripping the ocean of nitrate — a nutrient...
