Investigating the relationship between measured brightness and length of ice cores
Tiny organisms – phytoplankton/microalgae – are the primary producers of food webs in the Antarctic. Microalgae photosynthesise, just like plants on land do. During the warmer months, when the sea ice melts, microalgae communities float freely. Other times of the year, these communities live in and under the sea ice.
Sea ice core for measuring available light
Ice cores provide a wealth of information. The thickness of ice impacts how much light gets through to phytoplankton. Some species require high levels of light while others thrive with less.
Snow and ice impact the amount of visible light that gets through to the microalgae. Scientists working in Antarctica study these impacts and their effects on the different types of algae. One method is to collect ice cores to measure how much usable light (photosynthetically active radiation) organisms receive. This activity uses ice cores – water frozen in Pringles® tubes – to model aspects of this research.
In this activity, students investigate the relationship between the length of an ice core and the brightness of light transmitted through it, simulating experiments performed by scientists on photosynthetically active radiation (PAR).
By the end of this activity, students should be able to:
explore the absorption and transmission of light
measure light intensity at various lengths of ice cores
graph data and analyse the results
discuss photosynthetically active radiation and its role in photosynthesis
consider the availability of light and implications for microalgae and Antarctic food webs.
Download the PDF file (see link below).
Related content
Learn more about the Antarctic marine ecosystem.
The Voice of the Sea Ice series has background information about the Antarctic sea ice cycles and research on microalgae and ice thicknesses.
Antarctic life – microalgae – podcast explores the effects of ice cover and light on microalgae. The podcast has a transcript – making it easy to locate pertinent information.
Information about scientists working with ice can be found in the Hub article Trapped in ice, which includes videos on transporting, analysing and dating ice cores.
Light and sight – introduction curates Hub resources on the basics of light and how it behaves.
Useful links
This activity uses the free phyphox app to use the built-in light meter in most cell phones.
Watch these YouTube videos to learn more about photosynthetically active radiation and microalgae/plankton.
Learn more about algal communities under the ice in the Conversation article Antarctica’s sea ice is changing, and so is a vital part of the marine food web that lives within it.
Acknowledgement
This activity was written by Douglas Walker, Head of Science at St Patrick’s College, Wellington. Doug conducted field work in the McMurdo Sounds as part of the K892 expeditions, with an additional focus on educational outreach.
