Arctic Ocean passed a tipping point and scientists say it may never recover

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 essential for the tiny plankton that support Arctic life. As nitrate levels plunge, the entire food web could feel the impact, from fish and seabirds to whales and polar ecosystems.