Pilots flying at high altitudes need extra oxygen, or they’ll start to lose vision — and eventually pass out.
Similarly, creatures dwelling in the oceans also require oxygen to see. Unfortunately for them, the seas are now gradually losing oxygen, a problematic marine event known as deoxygenation. Recognizing that this loss of oxygen could also cause blindness in sea organisms, scientists at the Scripps Institution for Oceanography tested how reduced oxygen levels impacted the vision of squid, octopus, and crab species. Their results, published in the Journal ofExperimental Biology, showed that these organisms did indeed experience varying degrees of blindness, including near total blindness.
“It’s a pretty significant issue in the oceans because organisms rely on oxygen to survive,” said Lillian McCormick, a marine scientist at Scripps and lead author of the study, emphasizing that oxygen is needed for more than breathing. “Vision is a very demanding sensory process. It uses oxygen molecules.”
It’s not as if sea creatures are now on the brink of blindness, suffocation, or death as they wander the dark seas without vision. But as oxygen levels gradually fall — due to the planet’s accelerating warming — these creatures’ vision may very well deteriorate.
“They might not be dead, but if they can’t see well, they potentially won’t see predators, light changes, or things on the sea floor,” said Karen Wishner, a biological oceanographer at the University of Rhode Island who had no role in the research. “It’s potentially of critical importance.”