Marine Wildlife Is Starting to Suffocate

Global warming and agricultural runoff have driven the loss of oxygen in oceans around the world, with looming ecological consequences

Brilliant shades of blue and green explode across the Barents Sea in this natural-colour image showing a massive bloom of phytoplankton that are common in the area each August. Photo: Jeff Schmaltz/NASA Earth Observatory via Wikimedia Commons

By Ramin Skibba

A multitude of marine species, from bottom-dwellers to fish and octopuses, are gasping for air. In swaths of ocean the world over, creatures are being increasingly deprived of oxygen. It’s a hidden consequence of climate change, less obvious than rising seas and mass coral-bleaching events — yet no less dangerous to marine life.

Oxygen levels vary in oceans around the world, but signs of global warming–driven declines have begun to emerge beyond those natural fluctuations, and conditions in coastal areas exposed to agricultural runoff, such as the Gulf of Mexico and the East Coast’s Chesapeake Bay, are worsening. The declines are wreaking ecological change that won’t be reversed for centuries, if at all, climate scientists warn.

The very existence of some species is at stake, according to research led by Lisa Levin, a biological oceanographer at the Scripps Institution of Oceanography in La Jolla, California, who is known for her studies of deep-sea ecosystems and oxygen-deficient ocean waters. “Climate change and warming are making naturally occurring…