Glob. Change Biol. http://doi.org/xhk (2014)

Credit: MINT IMAGES LIMITED / ALAMY

Reductions in lake area in some regions of the Arctic and subarctic have occurred in recent years. These changes raise concerns about the fate of stored carbon and could also have serious consequences for the health of the lake ecosystems themselves. The mechanisms of lake reduction are thought to relate primarily to increased evaporation and decreased inflow, and lake drainage due to permafrost degradation. These climate-sensitive mechanisms are also likely to impact lake water chemistry.

To investigate possible effects of shrinkage on lake ecosystems, Tyler Lewis from the University of Alaska Fairbanks, USA, and co-workers, examined changes in lake water nutrients in several Alaskan lakes, including examples that were shrinking, stable and expanding. They found that the concentrations of the six nutrient solutes measured (total nitrogen, total phosphorus, and ions of calcium, chloride, magnesium, and sodium) increased in shrinking lakes over the 25-year study period, but changed little in stable or expanding lakes. These changes were most likely the result of shifts in the evaporation-to-inflow ratio and indicate that shrinking lakes may suffer from high-nutrient or saline conditions.