This paper aims to highlight the potential of using elemental and stable isotope analyses of aquatic macrophytes in palaeolimnological studies. Potamogeton pectinatus material was collected from modern plants (n=68) and from late glacial and Holocene-aged sediments from Koucha Lake (northeastern Tibetan Plateau; 34.0°N; 97.2°E; 4540m a.s.l.). It was analyzed for δ13CPotamogeton (modern: -23 to 0‰, fossil: -19 to -4‰) and δ15NPotamogeton (modern: -11.0 to +13.8‰, fossil: -9.5 to +6.7‰) in addition to elemental carbon and nitrogen (modern C/NPotamogeton: 7 to 29; fossil: 13 to 68) and sulfur (fossil: 188-899μmol/g dry weight). Fossil data were interpreted in terms of palaeo-nutrient availability and palaeo-productivity based on the modern relationships between various proxies and certain environmental data. Productivity of Potamogeton pectinatus mats at Koucha Lake as indicated by palaeo-e{open}Potamogeton-TIC (i.e. the enrichment of δ13CPotamogeton relative to the δ13CTIC) was reduced during periods of high conductivity, especially between 10.3 and 7.4cal kyr BP. Potamogeton pectinatus material from these periods was also characterized by high SPotamogeton indicating high sulfide concentrations and anoxic conditions within the sediments. However, C/NPotamogeton ratios and δ15NPotamogeton from the lower core section were found to have been altered by decompositional processes. A pronounced shift in the aquatic productivity of Lake Koucha occurred at ∼7.4cal kyr BP when the hydrological conditions shifted towards an open lake system and water depth increased. At this time a strong increase in productivity led to a strong decrease in the water HCO3- concentration as inferred from the application of a e{open}Potamogeton-TIC-lnHCO3- transfer function. A comparison of reconstructed productivity changes from Koucha Lake with further environmental proxies suggests that primary productivity changes are probably a function of internal lake dynamics and were only indirectly triggered by climate change. © 2010 Elsevier Ltd.