More melt water is entering the Artic Ocean from the glaciers due to climbing temperatures. In addition, the rivers are carrying large amounts of sediment from thawing permafrost. By this, for example the nutrient content of the sea water is increasing in the river estuaries and it is getting more turbid. How the Arctic Ocean will react to such changes is a very big question, which is concerning scientists around the world. Because the availability of nutrients, and increasing or decreasing turbidity subsequently affect the biological communities: This could be a factor affecting the micro-algae with the lack of light for photosynthesis, while the bacteria might appreciate the increase of food.
In order to observe the distribution of different water masses and the substances contained therein, measurements are needed locally. Rafael Gonçalves-Araujo and Prof. Dr. Astrid Bracher from the Alfred Wegener Institute, the Helmholtz Centre for Polar and Marine Research, have now published, together with international colleagues, the usage of a new optical method by which it is easier and quicker to identify different water masses. In the scientific journal Nature Scientific Reports, high-resolution spectral fluorescence measurements of dissolved organic compounds are presented. Specifically, they have been used this optical method to distinguish water masses from the Eurasian and Canadian basins, which leave the Arctic Ocean through the Fram and Davis Straits.
In the future, this method should allow a more cost effective and more comprehensive method to investigate the impacts of global-warming in the Arctic region. Scientists will continue to develop their sensors for the FRAM observatory of the AWI. They will then for example be used on gliders or floats and autonomously measure the fluorescence spectra for the determination of the water masses. This allows data, with a higher spatial and temporal resolution, to produce a more complete picture of the oceanographic conditions in the Arctic region, which up until now required the time consuming sampling on-board research vessels and measurements of the oxygen isotopes in the laboratory.
Gonçalves-Araujo R., Granskog M. A., Bracher A., Azetsu-Scott K., Dodd P. A., Stedmon C. A. (2016): Using fluorescent dissolved organic matter to trace and distinguish the origin of Arctic surface waters. Scientific Reports 6: 33978, doi: 10.1038/srep33978