Characterization of soil microflora on a successional glacier foreland in the high Arctic on Ellesmere Island, Nunavut, Canada using phospholipid fatty acid analysis

We investigated soil microbial biomass and community structure along a primary successional gradient after deglaciation in the high Arctic, at Ellesmere Island, Nunavut, Canada (80° 50′N, 82° 45′W). Soil samples were collected from five glacial moraines (M1 to M5) with different developmental periods. Time since the recession of glaciers at M1, M3, and M5 was estimated to be 300, 9000, and over 17000 years, respectively. Soil samples from five points in each moraine were subjected to phospholipid fatty acid (PLFA) analysis. Total PLFA content (an index of microbial biomass) in M1 was significantly lower than those in older moraines (M2-M5), whereas the content remained at an almost constant level from M2 to M5. Significant differences in PLFA composition (an index of microbial community structure) were also observed between M1 and older moraines (M2-M5); the proportion of straight chain saturated fatty acids in M1 was higher than those in older moraines (M2-M5), whereas those of branched fatty acids and unsaturated fatty acids in M1 were lower than those in older moraines (M2-M5). These results suggest that changes of microflora occurred in the early phase of succession after deglaciation and became stable thereafter. Microbial biomass had a positive correlation with soil carbon and nitrogen contents over the successional chronosequence, suggesting that development of soil microflora was affected in part by organic matter accumulation.