While cloning dinosaurs from fossilized mosquitoes remains the science fiction of Jurassic Park, reconstructing ancient Antarctic ecosystems from frozen sediments has become a reality.

On March 5, a new study published by BGI-Research, in collaboration with the Center for Evolutionary & Organismal Biology at Zhejiang University, the University of Adelaide, and other research institutions, has revealed 6,000 years of Adélie penguin population and ecological history in Antarctica’s Ross Sea, shedding light on the impact of climate change on marine and terrestrial biodiversity. The study, titled “Sedimentary DNA insights into Holocene Adélie penguin (Pygoscelis adeliae) populations and ecology in the Ross Sea, Antarctica,” was published in Nature Communications. 

The study “Sedimentary DNA insights into Holocene Adélie penguin (Pygoscelis adeliae) populations and ecology in the Ross Sea, Antarctica” was published in Nature Communications.

This marks another milestone in Antarctic ecosystem research, following a study published two years ago that used interdisciplinary techniques to investigate 60 million years of penguin evolution and their adaptations to extreme environments, providing insights into species evolution on a large timescale.

The key to unlocking this frozen history is sedimentary ancient DNA (sedaDNA). The sedaDNA recovered from Holocene Antarctic terrestrial sediments was well-preserved, with low terminal deamination rates comparable to those found in previously studied northern high-latitude regions. “Antarctica acts like a time capsule,” said Dr. Chengran Zhou, co-first author and researcher at BGI-Research. “The cold conditions preserve DNA exceptionally well, allowing us to trace past ecosystems through genetic fragments buried in the sediment.”

6,000 Years of Antarctic Biodiversity. (Artwork by Baijing, Copyright Centre for Evolutionary & Organismal Biology at Zhejiang University)

Researchers analyzed 156 sediment samples from various depths and locations across active and abandoned penguin colonies along the Ross Island and East Victoria Land coastlines. Radiocarbon dating confirmed that these samples span over 6,000 years. Using BGI’s advanced sequencing technology, the team identified more than five million DNA sequences from animals, plants, fungi, and microorganisms through a method known as lowest common ancestor (LCA) analysis.

Adélie penguins, as long-term residents of the Ross Sea coastline, are an iconic Antarctic species, but they do not exist in isolation. “Adélie penguins are part of a complex ecosystem,” explained Professor Guojie Zhang, co-corresponding author of the study and a professor at Zhejiang University.

South Polar skuas, the primary predators of penguin chicks, often nest near penguin colonies and are considered their natural enemies. At the other end of the food chain, penguins primarily feed on krill and fish, with krill being a crucial component of the Antarctic marine ecosystem. Among the fish species in their diet are Antarctic silverfish (Pleuragramma antarcticum) and bald notothen (Pagothenia borchgrevinki).

The proportions of penguin food sources have varied over time and by location. Penguins in the mid-Ross Sea consumed more fish, while those in northern regions favored krill. Over the past 4,000 years, the abundance of shallow-water fish, such as bald notothen, has declined, coinciding with an increase in midwater species like Antarctic silverfish. These findings suggest that climate-driven sea ice changes have reshaped marine habitats and prey availability. “Changes in penguin diet reflect broader shifts in the marine ecosystem,” Zhang added.

Adélie penguins and Weddell seal. (Photo by Jamie Wood)

Another significant finding was evidence of a faunal turnover at Cape Hallett. Around 1,400 years ago, warmer temperatures allowed southern elephant seals to inhabit the area. As the climate cooled and sea ice expanded, the seals retreated, and Adélie penguins took over the habitat. “This turnover shows how sea ice dynamics influence the availability of Antarctic habitats,” said Dr. Jamie Wood, co-corresponding author from the University of Adelaide. “Periods of warming facilitated the expansion of some species, while colder conditions favored others, illustrating the sensitivity of polar ecosystems to climate change.”

With climate and environmental changes posing an increasing threat to Antarctic ecosystems, scientists are urgently seeking new ways to understand historical shifts in biodiversity. By studying past ecological changes, researchers can gain valuable insights into how species have adapted to previous environmental fluctuations. “Understanding the resilience of species to these natural environmental and climatic perturbations gives us a better ability to predict how they might respond to future challenges,” explained Dr. Theresa Cole, co-author from the University of Adelaide.

However, researchers emphasize that their work is far from complete. “The data we have is just the tip of the iceberg,” said Dr. Qiye Li, co-author of the study and researcher at BGI-Research. “Expanding genomic references for Antarctic species through international collaboration will be critical for a more comprehensive understanding of this fragile ecosystem.”

For more details, access the full study here: https://doi.org/10.1038/s41467-025-56925-4