Amino acids in Antarctic lakes as proxies of primary production

Amino acids represent an important fraction of organic matter in freshwater ecosystems. To our knowledge, this is the first study to characterise amino acids in lacustrine water collected in Terra Nova Bay (Antarctica)in order to define its distributions and to individuate a relationship with primary production. Antarctica represents an excellent natural laboratory to estimate the natural presence, concentration, and variability of compounds, due to its distance from anthropogenic emissions. We improved an enantiomeric separation of forty underivatised amino acids using HPLC-MS/MS method, performing the most sensitive method to determine L-and D-amino acids in environmental samples at trace levels. Our analytical method was validated through the estimation of accuracy, repeatability, and linear range. The method was applied to samples collected in four different lakes.Lake 14 located at Edmonson Point presented the highest concentration of amino acids in comparison with the other samples considered in this study. Climate changes drastically reduced the lake's area in the last decade and probably this have carried out to a concentration of nutrients with a primary growth. We demonstrated that the influence of the sea on lake 10 at Inexpressible Island produced a small increase in amino acid concentrations. We can conclude that amino acids can be used as markers of primary production. However, it will be necessary to monitor these compounds during the next sampling periods to control the influence of climate change on biological production.