Why would anyone endure freezing winds, icy waters, and rough seas to dig mud from the Antarctic seabed? Earlier this year, an international team of adventurous scientists did exactly that along the remote Antarctic Peninsula. Their mission aimed to uncover centuries of secrets about the Southern Ocean.
Researchers will now share and analyse these rare mud samples worldwide. They hope to reveal how human activity, including a century of industrial whaling, affected Antarctica and the global environment. This study contributes to a broader effort to understand the complex relationship between the ocean and climate.
A history of ocean life
Scientists used a special coring drill, similar to a giant apple-corer, attached to a research vessel to reach depths of 500 meters. They retrieved more than 40 long cores of seafloor sediment from multiple sites around the peninsula, one of Antarctica’s richest marine habitats.
This area has long attracted fishing, tourism, and, before the 1980s ban, industrial whaling. Sediment layers hold clues to the past, providing what lead researcher Dr Elisenda Balleste of the University of Barcelona described as “a book of history.” The cores show what species thrived, what vanished, and how humans shaped the environment over centuries.
By preserving and dating each layer, researchers can reconstruct Antarctic marine life history, tracking changes and human impact over time.
From ship to lab
Once onboard, scientists froze the cores for transport to Dr Balleste’s laboratory in Barcelona. Carefully extracted mud samples will be sent to universities and research institutions worldwide. Scientists will scan and date the layers, identify microbial life, measure pollution, and calculate the carbon stored in the seabed.
This research forms part of the Convex Seascape Survey, a global collaboration to explore ocean-climate interactions. Oceanographer Claire Allen of the British Antarctic Survey explained the value of cores like these: “Before 1950, sediment and ice cores provide the only insight into Antarctica’s past climate and environmental conditions.”
The DNA fingerprint from whale hunting
The collected samples, stored at temperatures low enough to stop all biological processes, preserve genetic material for analysis. Dr Balleste briefly showed pieces from industrial-sized freezers kept at minus 80 degrees Celsius.
Scientists will use these samples for environmental DNA analysis, a rapidly advancing method that extracts genetic information from soil, water, or air. This technique acts like a fingerprint of past life in the environment. Dr Carlos Preckler from King Abdullah University in Saudi Arabia leads this work, studying how nearly a century of industrial whaling affected oceans and the atmosphere.
Whales, carbon, and climate
Carbon released as CO₂ warms the planet, making oceans and ecosystems critical in storing carbon. Dr Preckler and his team aim to measure how whale bodies contribute to carbon storage when they die and sink to the seafloor. “Whales hold significant carbon due to their massive size,” he said.
By measuring whale DNA alongside sediment carbon levels, researchers can quantify how much carbon whales removed from the atmosphere before industrial whaling drastically reduced their populations. These findings may reveal how marine life naturally mitigates climate change.
