Provenance, processes and productivity through spatial distribution of the surface sediments from Kongsfjord to Krossfjord system, Svalbard

Abstract

Krossfjord-Kongsfjord is a glacial fjord system in West Spitsbergen (Svalbard archipelago) situated adjacent to the Arctic and Atlantic water mass, a suitable site to study the effect of climate change on the environment. To study the sedimentary characteristics, depositional processes, source and their implications on productivity in the fjord, spatial variations of grain size, organic carbon, nitrogen, phosphorus, biogenic silica and calcium carbonate in the surface sediments were studied. Grain size showed the dominance of fine-grained sediment (silt and clay) suggesting relatively quieter hydrodynamic conditions prevailing in the fjord. The nutrient (C, N, P and BSi) concentrations in surface sediments of both the fjords show a clear spatial gradient with lower values in the glacier-dominated inner fjord and higher values towards the outer fjord as high turbidity towards the fjord head diminishes the expanse of the photic zone leading to low primary productivity close to the glacier fronts. Along Krossfjord, the C: N ratio varied from 1.01 to 26.37 and along the Kongsfjord the C: N ratio varied from 6.67 to 17.00 indicating the mixed source of organic matter derived from terrestrial as well as marine with increasing marine influence towards the fjord mouth. In general, calcium carbonate in this region was low and mainly of detrital origin. Sediment grain size seems to be a dominant controlling factor in the distribution of organic and inorganic matter in Krossfjord-Kongsfjord system.