Measuring algae in the fast ice: research blog
Klaus Meiners' fast-ice research
My name is Klaus Meiners. I’m a sea ice scientist with the Australian Antarctic Division. My research focus is on understanding ecosystem processes in ice-covered waters and this year I’m going down to Antarctica to lead a project with six team members.
The aim of the project is to better understand physical sea ice processes in the coastal zone of Antarctica and how they impact on the seasonal development of microscopic algae communities that grow at the bottom of the ice. So we are particularly interested in understanding how snow cover and ice thickness affects light levels at the bottom of the ice and how that effects the seasonal development of these communities.
This project really brings together physicists and biologists and looks at larger scales using new technologies. We use a Remotely Operated Vehicle which is a tethered platform which is instrumented with different sensors and you can use this to measure ice thickness. We also have an upward looking camera where we can look at the subsurface of the ice to look for animals grazing on ice algae. Importantly we have optical sensors and we use these to estimate the amount of algae in the ice.
We try to tease out is ice thickness a driver of this biological communities, where they are, how they develop over the season, or is it more snow cover.
Having regional information on fast-ice algal distribution will help us to assess the vulnerability of the ecosystem to changes in climate which will change sea ice conditions and therefore habitat extent of the algae. The other thing is the algae are considered an important food source for crustaceans or for the pelagic food web. We hope to identify ‘hotspots’ where we find a lot of algae which are there early in the season and that might affect the distribution of predators or higher trophic levels like penguins or seals.
Working down on the station its good to be out there on a cold day. You hear the snow crunching under your boots, you often see crystals glittering in the air, which is call diamond dusts, that’s really beautiful.
This time I’m going with six people and I did a calculation last night; we have a combined experience of 88 years of sea ice field research, and it’s just nice to work with these people. So you learn a lot. You think you know a little bit but then you go out with the old guys and they show you some tricks. It’s nice.
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.