Download AEBR 347 Continuous Plankton Recorder sampling of zooplankton and microplastic in the Southern Ocean 2002 to 2023 with special focus on the Ross Sea sector

This report summarises data collected in the third phase of the 15-year project to sample zooplankton and microplastic between New Zealand and the Ross Sea, Antarctica. We also analyse the full international dataset (1991–2023). Samples were collected in the project by towing the Continuous Plankton Recorder (CPR) behind the fishing vessel San Aotea II, during transits between Lyttelton and the Ross Sea.



Key findings:

1. The Ross Sea region is unusual: Consistent with previous work, this project has showed that zooplankton are more abundant in the Ross Sea sector than generally in the rest of the Southern Ocean.



2. Zooplankton are changing: Overall, we found a decreasing trend in total zooplankton abundance in the Ross Sea sector between 2008 and 2023. There are many different species of zooplankton and these did not all change in the same way over time, and some increased in abundance over the last 15 years.



3. Plastics are increasing: Our analysis has shown that average plastic abundance has increased 11-fold in the Ross Sea sector between 2009 and 2023, with 99% of the samples from the last 5 years containing at least one microplastic. Most of the plastics were microfibres.