New knowledge on the sea ice of the polar oceans
Sea ice plays an essential role in the global climate. Physicist Giulia Castellani (Alfred Wegener Institute, Germany) published a new study on the properties of sea ice of both the Southern and the Arctic Oceans in the scientific journal ‘Frontiers in Marine Science’.
Scientific knowledge of sea-ice properties is important for the validation of large-scale sea-ice models, so that a good idea of the amount of sea ice on the planet, and potential changes herein, can be obtained. In addition, this knowledge can be used to map sea-ice habitats that are important for certain animal species. This publication provides a basis for researching potential changes resulting from climate warming.
Sensors measure environmental properties
Studying sea ice and the underlying water is not easy due to the barrier this sea ice forms. For years now, researchers of Wageningen Marine Research and the Alfred Wegener Institute use the “Surface and Under Ice Trawl” (SUIT) to investigate organisms that live in the surface waters – underneath the sea ice- of the polar oceans. During SUIT fishing, sensors are used to measure environmental factors such as temperature, available light and depth. These types of measurements are necessary to be able to relate differences in the distribution of species to specific properties of the environment. The measurements done with SUIT are also important to gain insight in the sea ice itself. How and when was the ice formed? How thick is it? How does it change over time? Additionally, the method can give information on the distribution of algae within the ice. These algae are, in addition to algae in the water, an additional food source for small animals. The availability of this food source for these animals can be quantified with the data collected.
The added value of measurements on a ‘medium’ scale
Scientist often investigate sea ice on a small scale by drilling ice cores with a 10 to 20 cm diameter. This way they obtain information about the properties of the sea ice and the life within, but only a few point measurements on the entire ice sheet can be done. On a large scale (hundreds of square meters), sea-ice research is done using satellites or electromagnetic instruments. This gives information about the distribution and thickness of sea-ice in general, but lack information about details in the structure. Using the measurements collected with the SUIT sensors, information about sea-ice thickness and algal abundance in sea ice is collected on a ‘medium’ scale of kilometres. Thickness and algal distribution on this scale can be very variable, which cannot be seen very well when looking at small of large scale measurements.