Extended ozone layer over Antarctica hole endangers marine life by UV radiation

The ozone hole that occurs over Antarctica every spring has begun to recede over the last 25 years. However, throughout the last four years, the hole has continued for an exceptionally lengthy period of time despite shrinking. According to our most recent data, it has continued to operate well into December rather than ceasing in November. Early summer is when most new plants in coastal Antarctica sprout, and it’s also when seals and penguins reproduce to the fullest.

That is cause for concern. Greater amounts of UV radiation may pass through the atmosphere as the ozone hole occurs. Furthermore, while seals and penguins have protective coverings, their young can be more exposed.

Why is ozone important?

We have harmed the earth’s ozone layer during the last fifty years by utilizing chemicals similar to chlorofluorocarbons (CFCs). These substances are now prohibited as a result of a concerted international effort.

The lengthy half-lives of CFCs mean that decades will pass before they are totally eliminated from the environment. Consequently, the ozone hole continues to develop every year. The majority of ozone depletion occurs over Antarctica. The UV index doubles and reaches severe levels as the hole appears. In Australia or California, we may anticipate seeing more than 14 UV days throughout the summer, but not in the arctic areas.

Fortunately, when the ozone hole forms in early spring, most species on land are dormant and shielded by snow (September to November). Sea ice protects marine life, while snow covers Antarctica’s moss forests. Up until recently, the majority of Antarctic life has been shielded from ozone depletion by these insulating ice blankets.

abnormally extended ozone holes

In 2020 and 2023, a sequence of anomalous occurrences caused the ozone hole to last until December. Three years of La Niña, the massive undersea volcanic eruption off Tonga, and the record-breaking Australian bushfires in 2019 and 2020. Ash and smoke may be sent into the stratosphere by volcanoes and bushfires. Ozone may be destroyed by chemical processes that take place on the surface of these minuscule particles. Significant sea ice loss occurred at the same time as these longer-lasting ozone holes, which would have reduced the number of hiding places for many animals and plants.

Increased UV exposure is very dangerous.

Animals that spawn in the summer along Antarctica’s extensive coastline will be subjected to high amounts of reflected UV radiation if ozone holes persist longer. Since ice and snow are extremely reflective, more ultraviolet light may pass through and bounce off of them. High UV exposure raises the risk of cataracts and skin cancer in humans. However, we are fur- and feather-free. Seals and penguins are protected by their skin, but not by their eyes. Is it causing harm? We cannot be certain. The effects of UV light on animals in Antarctica are seldom documented in research. The majority are carried out at zoos, where scientists investigate the effects of keeping animals under artificial light.

It’s still a cause for worry. Early summer UV radiation may be especially harmful to young animals, including late-spring-hatching or born seal pups and penguin chicks. Plants that get maximal UV exposure in late spring include those like Antarctic hairgrass (Deschampsia antarctica), cushion plants (Colobanthus quitensis), and mosses in abundance.

In order to shield themselves from UV rays, Antarctic mosses really make their own sunscreen, although doing so slows down their development. Under the sea ice, billions of microscopic phytoplankton reside. Additionally, these tiny floating algae produce microsporine amino acids, which are chemicals used in sunscreens.

What about aquatic life? Though not all fish life stages are as well shielded, fish eggs often contain melanin, the same defensive chemical as humans. Krill will dive deeper into the water column if the UV radiation is too severe. Sea ice extent has decreased in four of the last five years, which is directly related to climate change.

Because more UV radiation may reach the water with less sea ice, Antarctic phytoplankton and krill have a tougher time surviving. These microscopic organisms, which are the foundation of the food chain, are vital. Up the food chain, hunger will spread if they have a tougher time surviving. Climate change is also causing the seas around Antarctica to grow warmer and more acidic.

An unclear future for Antarctica

It is only fitting that we celebrate the triumph of the CFCS ban, which is an uncommon instance of an environmental issue being resolved. However, that might be too soon. The regeneration of our ozone layer may be hampered by climate change if, for example, bushfires become more frequent and intense.

Proposals for geoengineering that include pouring sulphates into the atmosphere to reflect sunlight and more frequent rocket launches might potentially have a negative impact on ozone. More harm to plants and animals is likely, especially if the current trend persists and the ozone hole lasts into the summer, in addition to other dangers.

The longer-lasting ozone hole’s potential continuation is unknown. However, we are aware that the atmosphere is acting in previously unheard-of ways due to climate change. We must move quickly to cut down on the amount of carbon we release into the atmosphere in order to maintain the ozone layer’s recovery.

(This article was written by Rachele Ossola, a postdoctoral fellow at Colorado State University; Laura Revell, an associate professor of environmental physics at the University of Canterbury; and Sharon Robinson, a distinguished professor and deputy director of ARC Securing Antarctica’s Environmental Future (SAEF) at the University of Wollongong; https://theconversation.com/)