Assessing the use of sediment organic, carbonate and biogenic silica content as indicators of environmental conditions in Arctic lakes

摘要

The objective of this paper is to examine three sediment parameters used in paleolimnological studies, sediment organic, carbonate and biogenic silica (BSi) content, and to quantify the relationship among these parameters and modem environmental conditions for a series of Canadian Arctic lakes. Sediment samples from 63 lakes were analysed for organic, carbonate and BSi content. The environmental and physical parameters of these lakes were recorded. Bedrock composition exerted a very strong influence on sediment organic, BSi and carbonate content, and differences in lake production accounted for much of the remaining variance. The strongest relationships existed among sediment carbonate content, BSi content and water pH. A statistical model developed for predicting water pH provides a new tool for reconstructing past environmental conditions for Arctic aquatic ecosystems. A positive relationship between mean July air temperature and sediment organic and BSi content was detected, but was confounded by effects of bedrock on these parameters. However, the relationship between mean July air temperature and sediment organic and BSi could be even more significant in the context of constant bedrock composition, as is the case in paleolimnological studies.