Ancient marine DNA discovered in Antarctic sediments holds clues to ocean ecosystem shifts to come

Scientists have discovered 1-million-year-old marine DNA in deep-sea sediments of the Scotia Sea, north of the Antarctic continent, which gives insights into past ocean ecosystem-wide changes and will help predict how marine life will respond to climate change now and into the future.

The Institute for Marine and Antarctic Studies (IMAS) led an international team that found the marine ‘sedimentary ancient DNA’ (sedaDNA) in sediment samples collected up to 178 metres below the seafloor. The fragments are the oldest authenticated marine sedaDNA discovered to date. To analyse these fragments, the researchers used a new technique called sedaDNA analysis, which can identify what species were present in the ocean at what time, across multiple ice-age cycles

The study demonstrates that marine sedaDNA analyses can be expanded to hundreds of thousands of years, opening the pathway to investigating ecosystem-wide ocean shifts and paleo-productivity phases throughout multiple glacial-interglacial cycles. This research can help to better predict how marine life around Antarctica will respond to ongoing climate change.

Among the organisms detected in the sediment were diatoms, a type of phytoplankton. Dated back to around 540,000 years ago, the diatom sedaDNA data showed they were consistently abundant during warm climatic periods.

The study was published in Nature Communications. Read more about the study here.