Antarctic waters warming, impacting plankton community

Scott Base - Warming water and receding sea ice in the Western Antarctic Peninsula is changing the plankton community with potential consequences for climate change, a new study has found.

The five-year Western Antarctic Peninsula study found water temperature and sea ice cover to be dominant factors affecting the makeup of microscopic sea life, according to research scientists from Duke University in the US and Duke Kunshan University in China.

The tiny sea life declined in species richness, with those changes leading to less ocean absorption of carbon dioxide, a greenhouse gas associated with global warming.

The future of the Antarctic’s frozen integrity is critical to rising sea levels impacting New Zealand.

Scott Base, New Zealand's only Antarctic research station, is just 3800km south of Christchurch and 1350km from the South Pole.

Study researchers said the plankton forest in the ocean sucks up carbon dioxide from the atmosphere, so changes to it are incredibly important.

Published in the scientific journal Nature Communications this week, the study, is the longest ever time-series research on DNA-based plankton community structure and carbon export in the Antarctic region.

The research team and collaborators, which included scientists from Columbia University in the US. The British Antarctic Survey made annual trips to the Western Antarctic Peninsula, spent primarily aboard a research vessel, with short spells at the US Antarctic base Palmer Station and the British Antarctic Survey station Rothera.

They collected DNA samples of microbial sea life, including algae and microzooplankton, as well as employing a mass spectrometer to monitor carbon sequestration levels.

Following each trip, researchers spent months at Duke University and at the University of Nantes in France analysing the samples using a high-throughput DNA sequencing technology, which allowed them to measure species numbers, community composition, carbon levels and other features in the samples, despite their microscopic size.

They found significant changes in the community of microscopic sea life as some organisms better adapted the to a warmer environment with less ice survived and others perished.

This shift may have an impact on climate change, as analysis of the changing community showed a reduction in the amount of carbon dioxide it absorbed from the atmosphere, said Lin.

Coastal regions of Antarctica are especially vulnerable to climatic change, and some of them are showing rapid losses of ice.

The new research shows that as this progresses and spreads, it could result in substantial declines in plankton diversity.

This could have knock-on consequences for the Antarctic ecosystem and also affect the Southern Ocean's ability to mitigate carbon emissions.

The findings are particularly timely and relevant, in the wake of the recent report published by the UN Intergovernmental Panel on Climate Change.

The findings also come ahead of the 2021 United National Climate Change Conference (COP26) in November and the UN Convention on Biological Diversity, scheduled for October.