Limnological characteristics of lakes located across arctic treeline in northern Russia

Limnological data (e.g., water chemistry, lakewater temperature, vegetation zone and degree of human impact) were collected from lakes spanning the Ru ssian arctic treeline in three regions: on the Taimyr Peninsula and near th e mouth of the Lena River, both in central arctic Siberia, and near the mou th of the Pechora River, western arctic Russia. Pearson correlation and can onical variates analyses revealed similar environmental gradients in all th ree regions. Variables expressing ionic composition of the water (i.e., cat ions, anions, dissolved inorganic carbon and conductivity) were highly inte rcorrelated, as were nutrients, chlorophyll a, particulate organic matter a nd metal (i.e., Fe and Mn) concentrations. Lakewater transparency was relat ed to water colour (i.e., Fe, Mn and dissolved organic carbon) and producti vity. Regional differences among the lakes were strong and appeared to refl ect differences in geology, hydrology and human impact. For example, Na and Cl concentrations were related to proximity to the ocean in the Lena and P echora River regions but not in the more inland Taimyr region. Extensive mi ning and smelting at Norilsk, on the Taimyr Peninsula, has apparently resul ted in elevated major ion and metal concentrations in lakes closer to the c ity. Surface water temperatures, nutrients, and related variables were part icularly useful for distinguishing lakes in different vegetation biomes. Fo rest lakes were typically warmer, with slightly elevated concentrations of dissolved organic carbon (DOC). Lakes in the forest-tundra zone often had h igher concentrations of particulate organic matter, Fe and Mn. Tundra lakes were characterized by low nutrient and DOC concentrations. These data will facilitate the development of models that predict the outcome of future cl imatic change on arctic and subarctic aquatic ecosystems, as well as provid e baseline data for future limnological studies in these remote regions.