The influence of Coriolis force driven water circulation on the palaeoenvironment of Hornsund (S Spitsbergen) over the last century

Abstract

The influence of the Coriolis force on the Hornsund fjord environment (southern Spitsbergen) was investigated in the marine sedimentary record from the last century. Due to the influence of the rotational effects, Atlantic and Arctic Water enter the fjord along the southern shore and exit along the northern shore. Thus, the sedimentary record from the southern part reflects the large‐scale hydrological processes associated with these oceanic water‐masses, whereas the northern portion is affected by a combination of regional and local waters (including glacial meltwater). To assess the significance of the Coriolis force driven circulation in this environment over the last century, two short sediment cores were sampled from the southern and northern parts of the fjord. The cores were dated with 210Pb and 137Cs and analysed for grain size, ice‐rafted debris, benthic foraminifera and stable isotopes (δ18O and δ13C). The influence of the Coriolis force was most apparent in the benthic foraminiferal record. The foraminiferal assemblage of the southern part of the fjord is characterized by markedly higher species diversity and a high percentage of Atlantic water species compared to the northern part. This pattern probably resulted from the lower level of environmental disturbance and the constant introduction of propagules and juveniles from offshore pools. The northern part of the fjord is characterized by more unstable environmental conditions due to the variable delivery of turbid meltwater, which is reflected in the low‐diversity foraminiferal assemblage dominated by glaciomarine taxa and bottom current indicators. The influence of the Coriolis force on the sedimentary regime is less clear. As the geometry of many of the European Arctic fjords allows the rotational dynamics of water‐masses, our results may serve as a reference for further studies on the influence of the Coriolis force‐driven rotational dynamics on modern and past environments.