Ice Cores

Ice cores provide the main way of investigating all the different physical and biological properties of the ice.

Every time the ship stops at a new Ice Station during SIPEX scientists collect up to 40 ice cores to measure everything from the crystal structure, salinity, and oxygen isotope composition of the ice, to the concentrations of inorganic nutrients, dissolved organic matter, chlorophyll a concentration and abundance and biomass of bacteria, algae and metazoans.

How do you take an ice core in Antarctic sea ice?

1. The first job is to find a suitable piece of ice to sample. Ideally, the ice surface is flat and there are no ridges or layers of broken ice underneath it. Once a site is chosen, the snow is scraped away from the surface of the area that will be cored with a shovel.
2. Next, the ice corer is placed perpendicular to the ice and the person taking the core begins to turn the corer around using a handle. At the bottom of the corer is a sharp blade that grinds into the ice. The person taking the core continues to turn the handle and grinds through the ice until it breaks through to the sea water below. If the ice is thicker than the height of the ice corer (approx 1m), extensions are added to the top of the corer in order to get a complete core. Once the corer breaks through to the water, it is lifted out of the hole and it (hopefully) brings the ice core with it. The person taking the core has to be careful not to let the ice core drop out or let anything touch the bottom of it.
3. The core is then carefully placed on a v-shaped chopping board that allows the scientists to measure the length of the core. At this stage, some of the ice cores will be cut up on the ice, placed into plastic containers and melted on the ship in laboratories kept at +4°C. Other ice cores are analysed in a freezer laboratory at -20°C so that scientists can determine the crystal structure of the ice – telling them about the conditions under which the ice formed. These thin sections are cut with a bandsaw then viewed between cross-polarised filters so that the different orientation of the crystals can be observed. Some cores are kept whole and are taken back on the ship to be studied in laboratories around the world after the voyage.

To see a slide show about ice coring, click here.

Try This

Do you want to learn more about ice cores? Why not try some of our classroom activities about ice cores specially designed for primary school students or secondary school students.