Water chemistry of ponds on Southampton Island, Nunavut, Canada : effects of habitat and ornithogenic inputs

Abstract: We investigated the water chemistry of 32 small lakes and ponds on South-ampton Island, Nunavut, in July 2001 and 2002. The ponds were generally small andshallow and at low elevation, with half < 20m a.s.l. and within 5km of the coast. Allof the ponds were alkaline (pH range 7.2–8.1), and shared similar major ion chemis-tries dominated by Ca and Na for cations, and Cl for anions, although there were somedifferences observed among habitats. Nutrients were relatively high compared to otherArctic islands, particularly for total nitrogen, which suggested that ponds on South-ampton Island are P-limited. One pond was located in an eider colony, and waterchemistry underwent a dramatic increase in nutrients, certain ions, and metals over anine week sampling period, presumably the result of ornithogenic inputs from faeces,as well as resuspension of sediments as eiders moved in the pond. Collectively thewater chemistry of ponds on Southampton Island are somewhat similar to those onVictoria and Banks islands, and appear to represent a transition between conditionsfound in sites on the Arctic mainland, and the spartan characteristics of sites on thehigh arctic islands. However, the recent expansion of goose populations and the asso-ciated degradation of lowland habitats on the island may lead to changes in pond che-mistries.Key words: Southampton Island, ponds, nutrients, geese, guano, water chemistry.