The water chemistry of Northern Patagonian lakes and their nitrogen status in comparison with remote lakes in different regions of the globe

Keywords:

Abstract:

Eighteen small shallow lakes located in the Northern Patagonian Lake District, in southern South America, were sampled in
2001 and analysed for the main chemical variables (pH, conductivity, alkalinity, major ions and nutrients). The study lakes span a
wide geographical and altitudinal range and belong partly to the Pacific and partly to the Atlantic watershed. The main aim of this
study was to investigate the relationships between water chemistry and physical/geographical properties of these lakes. Secondly, the
nitrogen content of the lakes was considered in detail, and results compared to those obtained in previous studies carried out in other
remote areas of the globe (the Central Southern Alps in Italy, the Sierra da Estrela region in Portugal, the Svalbard Islands in the
Arctic, the Khumbu-Himal region in Nepal, and the Terra Nova Bay area in Antarctica). In the Alps, lakes are characterised by
markedly high nitrogen concentrations, manly as nitrate, due to the high inputs of nitrogen compounds from downwind sources like
the Po Plain in Northern Italy. Conversely, lakes at remote locations such as the Andes, Antarctica and Himalaya are characterised
by a low nitrogen content, mainly as organic nitrogen. This status is related to the limited atmospheric inputs of nitrogen affecting
these regions.