Isfjorden in West Spitsbergen; a High-Arctic Model System for Studying Hydrographical and Ecological Changes

Isfjorden at 78 °N represents a unique model system for studying the influence of hydrographic processes on biological systems, and for ground truthing observations made from remote sensing platforms. The open, high-Arctic Isfjorden is influenced by the warm and saline West Spitsbergen Current which periodically enters the system. In this large fjord, sympagic communities develop in its innermost, seasonally ice-covered parts while the outer parts have largely been ice-free the last decade. Two time series stations in the fjord are frequently sampled; the winter sea ice covered BAB station (Billefjorden, since 2008) and the usually ice free IsA station (Adventfjorden, since 2009). Standard biological parameters including chl a biomass, nutrients, phytoplankton and zooplankton community composition along with CTD profiles are collected regularly at these two stations allowing comparison with observations from satellites and moored observatories. Available data on fluorescence, sea surface temperature and sea ice distribution from satellites and fluorescence data from moored ocean observatories are here compared to data collected at our Isfjorden time series stations. We will discuss ecological trends along the continuum from seasonal ice-cover to year-round open water in warm vs cold scenarios to identify the range of variability on weekely, seasonal to annual scale. To predict potential impacts of climate change on Arctic marine systems, short term physical and biological interactions and variability in these strongly seasonal systems must be better identified.