Antarctica

Antarctica’s Thwaites Glacier got its nickname the “Doomsday Glacier” for its potential to flood coastlines around the world if it collapsed. It is already contributing about 4% of annual sea-level rise as it loses ice, and one theory suggests the glacier could soon begin to collapse into the ocean like a row of dominoes. But is that kind of rapid collapse really as likely as feared? A new study of Thwaites Glacier’s susceptibility to what’s known as marine ice cliff instability offers some hope. But the findings don’t mean Thwaites is stable. Polar scientist Mathieu Morlighem, who led the study, explains the results. Why is the Thwaites Glacier so important? Thwaites Glacier drains a huge area of Antarctica’s ice sheet – about 74,000 square miles (192,000 square kilometers), an expanse bigger than Florida. If a snowflake falls within that drainage system, it will eventually end up as part of an iceberg in the ocean off Thwaites....

The Southern Ocean encircling Antarctica is the world’s largest feeding ground for baleen whales – species like humpbacks that filter tiny organisms from seawater for food. In the 20th century, whalers killed roughly 2 million large whales in the Southern Ocean. Some populations, like the Antarctic blue whale, were reduced by more than 99% and have been struggling to recover, even though most nations ended commercial whaling in the mid-1980s. Today a new threat is emerging: industrial fishing for Antarctic krill – tiny swimming crustaceans, roughly 2 inches (60 millimeters) long. In a newly published study, colleagues and I found that competition with this burgeoning fishery may impede whales’ recovery. I first learned about this issue in early 2022, when a colleague working aboard a cruise ship told me that he had seen approximately 1,000 fin whales feeding on krill near the South Orkney Islands, just north of Antarctica. This was probably the largest a...

Looking out across the Southern Ocean near Antarctica, I can see whales and seabirds diving in and out of the water as they feed on sea life in the lower levels of the food web. At the base of this food web are tiny phytoplankton – algae that grow at the ocean surface, taking up carbon from the atmosphere through photosynthesis, just as plants on land do. Because of their small size, phytoplankton are at the mercy of the ocean’s swirling motions. They are also so abundant that the green swirls are often visible from space. Typically, phytoplankton remain near the surface of the ocean. Some may slowly sink to depth because of gravity. But in the turbulent Drake Passage, a 520-mile-wide (850 km) bottleneck between Antarctica and South America, something unusual is happening, and it has an impact on how the ocean takes carbon dioxide – the main driver of global warming – out of the atmosphere. A satellite image capt...

Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. Subglacial environments on Earth offer important analogs to Ocean World targets in our solar system. These unique microbial ecosystems remain understudied due to the challenges of access through thick glacial ice (tens to hundreds of meters). Additionally, sub-ice collections must be conducted in a clean manner to ensure sample integrity for downstream microbiological and geochemical analyses. We describe the field-based cleaning of a melt probe that was used to collect brine samples from within a glacier conduit at Blood Falls, Antarctica, for geomicrobiological s...

Emperor penguins thrive on Antarctica’s coastlines in icy conditions any human would find extreme. Yet, like Goldilocks, they have a narrow comfort zone: If there’s too much sea ice, trips to bring food from the ocean become long and arduous, and their chicks may starve. With too little sea ice, the chicks are at risk of drowning. Climate change is now putting that delicate balance and potentially the entire species at risk. In a recent study, my colleagues and I showed that if current global warming trends and government policies continue, Antarctica’s sea ice will decline at a rate that would dramatically reduce emperor penguin numbers to the point that almost all colonies would become quasi-extinct by 2100, with little chance of recovering. That’s why the U.S. Fish and Wildlife Service finalized a rule on Oct. 26, 2022, listing the emperor penguin as “threatened” under the Endangered Species Act, effective Nov. 25, 2022. The director of th...