First Discrete Analyser to be Taken on Polar Missions to Analyse Nutrients in Arctic Deep Water

The Department of Chemistry at the University of Göteborg in Sweden is equipped with two Smartchem 200 discrete analysers from AMS (France) for its research projects on the concentration of nutrients in the waters of the polar sea. The first is used in the university laboratory for research and teaching purposes. The second is taken onboard the icebreakers that cut across the North Pole and Antarctica during polar missions.

The Marine Section of the Chemistry Department at the University of Gothenburg specialises in analysing the biogeochemical complexity of seawater. The analytical chemistry applied to this sector consists of separating, identifying and quantifying the elements present in seawater and sedimentary interstitial water. Advances in the marine chemistry sector will help give a better understanding of major environmental issues (climate change, pollution, eutrophication, coastal management, etc.), and will contribute to the development of future solutions.

Each Smartchem is used in the same way, irrespective of whether it is in the laboratory, the university or on board the boat: intensive series of analyses conducted over short time periods, but spaced out over long intervals to allow for data processing and research. The Smartchem 200, with its discrete technology and completely automatic operating principle, responded perfectly to the requirements of the scientists. “We already used a system with reagent tubes but it became essential to find an appliance that would be operational more rapidly, as soon as the first sample was prepared, whilst still maintaining a high level of reliability and performance,” explained Professor Stefan Hulth. Prof. Hulth and Prof. Leif Anderson are principal investigators for investigations on carbon and nitrogen cycling in marine environments at the department.

“In order to analyse the deep water of the polar seas, we have installed a Smartchem on ice breakers used to cut channels in the Arctic Ocean between June and August, when the climatic conditions are most favorable”, said Stefan Hulth. A polar cruise is normally organised once every second year within extensive international collaboration between the University and various partner institutions. An expedition generally lasts several months during which water samples are taken using a set of often 12 plastic mini containers, each with a capacity of 20 liters. For water sampling, these bottles are mounted on a rosette (or carousel), and triggered individually at pre-set depths. “During our missions, we take samples from depths up to 4,000 or 5,000 meters!”

The parameters analysed are the main nutrients present in seawater: nitrate, nitrite, silicate, phosphate and ammonium. In sea water, concentrations of nutrients are normally very small. “The Smartchem enables research in small concentrations (a few μM) which is particularly indispensable for ammonium and phosphate. Given the extent of its possibilities, we are aiming to use the analyser in the near future to detect conservative elements such as bromide and chloride”, explained Professor Hulth.

Sample analysis is carried out directly onboard the boat. If the mission had to bring water samples back to Göteborg, the composition of the stored samples would undergo changes resulting from possible bacterial or biological modifications. “Freezing presents potential risks of alterations – even minor ones – in the composition,” explained Professor Hulth. “In addition, it is imperative to ensure continuous processing of the very large quantity of samples, which is in the region of several hundreds to about a thousand.”