Climate change makes the octopus blind

The amount of oxygen in the ocean decreases due to the great impact of climate change, causing many marine animals to lose their eyesight, greatly affecting their viability. Long term is a heavy loss to the marine ecosystem.

To understand more about the effects of oxygen on sight of invertebrates, researcher Lillian McCormick, of Scripps Institution of Oceanography in La Jolla (California, USA) and her colleagues conducted experiments on ink. , crab, octopus.

These are species that dive deep into the water during the day and swim upstairs at night to hunt. When these organisms move up and down, the amount of oxygen they absorb will also vary significantly between water levels.

The ability to receive and interpret information from the light entering the eyes of both humans and animals depends heavily on oxygen.For invertebrates and crustaceans like squid, crab, octopus, oxygen is even more important - (Photo: Fracademic).

They attach tiny electrodes to the eyes of each species to record electrical activity in their eyes when the retina reacts to light. After that, each animal is placed in a water tank with extra light while the oxygen level of the water decreases.

The results showed that retinal activity of these species decreased significantly when placed in a low oxygen environment for at least 30 minutes. Even octopus loses eyesight almost immediately, completely blind before oxygen is adjusted again.

These results are the first evidence that visibility in marine invertebrates is very sensitive to oxygen levels and thresholds that allow visual impairment due to hypoxia to be specific to each species. Decreased retinal function due to lack of oxygen can alter important visual behaviors for their survival.

Lillian McCormick said that in the marine environment, oxygen varies with the daily, seasonal, and yearly time scales . Vision is related to survival in many marine animals, especially crustaceans, mollusks and fish.

The first phase of these species relies on a vision to catch prey and detect predators. As ocean oxygen levels continue to decline due to climate change effects, their vision will decline and risks will increase.

"We are afraid that this will come very soon and get worse. Many animals lose sight, marine ecosystems are also severely affected," McCormick said.

According to a 2017 study in Nature, the total amount of oxygen in the ocean has decreased by 2% globally in the past 50 years and is expected to decrease by 7% by 2100. Climate change is a key factor. Important to this.