A remotely operated underwater vehicle is being used to measure algae growth within the ‘fast ice’ (sea ice attached to land) at Davis this Antarctic season.

The ‘ROV’ is operated by a team led by Dr Klaus Meiners, of the Australian Antarctic Division, and uses a range of sensory equipment to measure the under-ice structure, ice thickness, light penetration from above, and the amount and distribution of algae living in the ice.

The ROV will carry out weekly observations of the physical and biological properties of the fast ice sub-surface in 200 square metre areas, over about five weeks during the spring-summer transition period.

A key aim of the joint Australia-New Zealand research is to understand primary productivity (algae growth) in the Antarctic fast-ice zone. Ice algae is an important food source for tiny marine herbivores such as zooplankton. As a result, ice algae growth and distribution may influence the location of suitable foraging habitat for predators, such as penguins and seals.

The ROV measurements are being validated by ‘point measurements’ of ice and snow properties from ice cores and enhanced by physical measurements of fast ice growth and decay from fixed fast-ice ‘observatories’. The team is also compiling historical data of ice algae growth and fast-ice formation and decay from around Antarctica using ice observatories, ice cores and satellites.

Altogether, the data collected during this project will be used to determine the relationship between snow and ice thickness and ice algae growth, and to develop a model of the seasonal development and fate of ice algae in the fast ice, at regional and circumpolar scales.

The work will help scientists assess the impact of climate change on ice algae and the broader marine ecosystem.