Seasonal dynamics of benthic Foraminifera in a glacially fed fjord of Svalbard, European Arctic

Seasonal variations in benthic foraminiferal populations from a sediment-laden fjord were analyzed in order to provide insights into arctic foraminiferal ecology and to improve the interpretation of the late-glacial record, The fjord is 25 km long and 100 m deep with a large tidewater glacier at the fjord head. A pilot transect of eight stations sampled in August 1995 revealed the typical off-glacier sequence of foraminiferal taxa, Unidentified allogromiids were abundant in the vicinity of the Ice front. Further down the fjord Elphidium excavatum f, clavatum and Cassidulina reniforme co-dominated the glacier-proximal fauna. Nonionellina labradorica and Islandiella norcrossi characterized the glacier-distal setting. In 1996 three glacier-proximal stations were then sampled in March, May, July, August, September and November. Compared to the summer of 1995 the summer of 1996 was colder, resulting in weaker glacial meltwater discharge, acid the foraminiferal fauna became less influenced by glaciers. This is portrayed by an increase in glacier-distal N, labradorica and a decrease in glacier-proximal C, reniforme and especially E. excavatum. Taxonomic diversity was higher in winter, possibly reflecting a more stable environment in the absence of the turbid meltwater plume, the source of ecological stress.