Lost World of Doggerland: Ancient DNA Reveals Ice Age Refuge

A lost world beneath the North Sea wasn’t the frozen wasteland previously imagined. Fresh research reveals that Doggerland, a landmass connecting Britain to mainland Europe during the last ice age, supported temperate forests and a surprising range of animal life as early as 16,000 years ago. This discovery, based on ancient DNA extracted from sediments, challenges previous assumptions about the environment and potential human habitation of this now-submerged region.

Doggerland’s Unexpectedly Lush Past

For decades, archaeologists have known of Doggerland’s existence, a vast area repeatedly exposed by lower sea levels during glacial periods. Named after the Dogger Bank, a sandbank in the North Sea and, historically, the Dutch fishing boats that worked those waters, the region was fully inundated by rising sea levels between 10,000 and 7,000 years ago – though recent findings suggest the final submergence may have occurred closer to 6,000 years ago. Although the idea of a land bridge between Britain and Europe wasn’t new, the nature of that land remained largely speculative. Previous theories posited a cold, tundra-like environment. This new study, published in the journal Proceedings of the National Academy of Sciences, paints a extremely different picture.

Researchers, led by Professor Robin Allaby at the University of Warwick, analyzed 252 sediment samples from 41 cores drilled from the Southern River area of Doggerland. They focused on ancient sedimentary DNA – genetic material preserved in the mud and sand for millennia. This technique allowed them to reconstruct the plant and animal life that thrived in the region, offering a far more detailed understanding than previous methods relying on pollen records. The team specifically targeted fine silts and clays, as these sediments are more likely to preserve DNA intact, unlike coarser sands which can contain mixed and unreliable genetic material.

A Genetic Snapshot of a Lost Ecosystem

The analysis revealed a thriving ecosystem of oak, elm, and hazel trees, establishing themselves in Doggerland around 16,000 years ago. This is significantly earlier than the recolonization of similar forests in Britain following the end of the last glacial period approximately 11,700 years ago. The presence of these trees suggests a milder climate than previously thought, and the discovery of a walnut relative (Pterocarya) – previously believed to have gone extinct in the region 400,000 years ago – is particularly noteworthy. Warmth-loving lime trees (Tilia) further support the idea of a surprisingly temperate environment.

But the forests weren’t the only sign of life. The ancient DNA too revealed evidence of a diverse fauna, including boars, deer, bears, and aurochs – the extinct wild ancestors of domestic cattle. “We got evidence of boars, deer, bears, aurochs,” explained Professor Allaby to Live Science. “To my knowledge, it’s the largest sedimentary DNA study that’s been done.” This suggests Doggerland could have provided a substantial habitat for these animals, and potentially, for early human communities.

What the DNA Tells Us About the Past – and the Present

The study’s findings have implications for understanding how plant and animal life dispersed across Europe after the last ice age. The presence of established forests in Doggerland could explain how trees recolonized Britain and northwestern Europe more quickly than previously thought. The region may have acted as a “microrefuge,” allowing species to survive and then spread northward as conditions improved. This challenges the long-held assumption that recolonization occurred primarily from southern refugia, such as the Iberian Peninsula.

The research also sheds light on a phenomenon known as Reid’s paradox, which concerns the discrepancy between the rate at which trees disperse their seeds and the speed with which forests re-established themselves after the ice age. Doggerland, or similar regions like northern France, may have provided stepping stones for forest expansion, facilitating faster dispersal than previously estimated.

Limitations and Future Research

While the study provides compelling evidence for a forested Doggerland, it’s important to acknowledge its limitations. The analysis focused on a specific area – the Southern River – and may not be representative of the entire landmass. The interpretation of ancient DNA data can be complex, and researchers must carefully distinguish between local and non-local DNA sources. The team addressed this by categorizing sediments as “secure” (containing local DNA) and “insecure” (containing DNA from distant sources), ensuring the reliability of their findings. As Professor Allaby notes, “It’s another highlight of the imprecision of what our knowledge is of this landscape. It really is a frontier.”

Future research will likely focus on expanding the geographic scope of the study, analyzing sediment cores from other areas of Doggerland to create a more comprehensive picture of the region’s environment. Further investigation into the potential presence and activities of early human communities in Doggerland is also warranted. The archaeological potential of the area was first identified in the early 20th century, with finds including a barbed antler point dating back to when the area was tundra, and later discoveries of mammoth and lion remains. Doggerland, as detailed by Wikipedia, continues to yield clues about its past.

What’s Next for Doggerland Research?

The study of Doggerland is an ongoing process. Researchers are continually refining their understanding of this lost world through new technologies and analytical techniques. Expect to see further studies utilizing ancient DNA, alongside traditional archaeological methods, to reconstruct the region’s environment, and history. The findings will also inform models of post-glacial landscape evolution and species dispersal, providing valuable insights into the long-term impacts of climate change. Ongoing marine surveys and potential future excavations may also uncover further evidence of human presence in Doggerland, offering a glimpse into the lives of those who once inhabited this now-submerged realm. The team plans to continue refining the timeline of Doggerland’s inundation, aiming for a more precise understanding of when this crucial land bridge finally disappeared beneath the waves.