Diatom data from north Baffin Island

• Main Authors: Finkelstein, Sarah, Devlin, Jane
• Format: Dataset
• Language: English
• Published: Canadian Cryospheric Information Network 2011
• Subjects: Baffin Island; Bylot Island; Climate change; Diatoms; Paleoclimate; Paleolimnology; International Polar Year-Dynamic Inuit social strategies in changing environments a long term perspective; Arctic; Baffin; International Polar Year; inuit; Sirmilik National Park
• Online Access: https://dx.doi.org/10.5443/10905; https://www.polardata.ca/pdcsearch/?doi_id=10905

Surface sediments from 20 lakes and ponds in Sirmilik National Park were collected using a gravity corer or an Ekman dredge. Water samples were taken for detailed chemical analysis of nutrient status and major ions. Diatom assemblages were also analyzed from short sediment cores (<50 cm) collected from two lakes. The lakes were chosen to span the major physiographic sectors of the park. Modern diatom assemblages differed significantly between the two sectors of SNP, indicating strong relationships between species composition and water chemistry. Fossil diatom assemblages also differed considerably between the two lakes. Coupled with the modern diatom data, the study showed that diatom assemblages began to change around 1900 AD at both lake sites, but the sites differed in their responses as a function of lake morphology and pre-existing limnological conditions. : Purpose: Diatoms are unicellular algae found in aquatic environments. Since diatom species vary in their responses to limnological conditions, diatom assemblages are used as bio-indicators. Diatom assemblages in surface sediments were analyzed from twenty lakes and ponds in Sirmilik National Park (SNP), along with limnological data for each site, with the goal of quantitatively relating diatom assemblages to particular physico-chemical conditions. Lake sediment cores spanning at least 2 centuries were also collected from two sites for detailed analysis with the goal of measuring the impact of recent environmental change in the context of pre-industrial lake conditions. : Summary: Arctic lakes cannot be easily monitored due to their remoteness. Thus, bioindicators for rapid assessment of lake status are an important area of research. Diatoms are a group of algae that are very effective bioindicators since they have a siliceous outer shell which is resistant to decay, they are present in all aquatic environments, and species differ in their responses to key environmental variables such as nutrient status, pH or duration of the ice-free season. Diatom assemblages were studied for 20 lakes in Sirmilik National Park (Bylot Island and northern Baffin Island) and compared statistically to data on the physical and chemical characteristics of the lakes. This analysis showed that some diatom species change in their abundance based on the chemistry of the water. Sediment cores were also collected for the purpose of examining past changes in the lake environment. Since diatoms preserve well in sediment cores, these cores can be used to track changes over decades or centuries into the past. The study of two lake cores confirmed that these lakes have undergone considerable ecological change in response to warming, beginning around 1900 AD. The type of change that each lake site undergoes is a function of its pre-existing morphology and chemical environment.