Light Into Darkness

The light climate of polar regions is extremely seasonal, with long periods of midnight sun in summer being matched by similarly long periods of polar night in winter. This creates a uniquely challenging environment where biological speies have to specifically adapt to these extreme of light and dark. In this study we plan to extend the range of light conditions that can be accurately measured both on land and below the surface of the ocean. We have developed several new light sensors that are significantly more sensitve than what is currently commercially available. This project will provide the means to do the first full field trials in Arctic conditions. We will extend the depth range for which we are able to measure light signals during the day, and also at night when other natural (e.g. the moon) and artificial light sources can become important. We will also measure the surface light field continuously from September through to early January, covering the period from the equinox to the winter solstice when light levels reach their lowest point in the year. Our aim here is to measure the full spectral distribution across the visible range down ot the lowest light levels found in the annual cycle. Thi work will provide importnt new observations to validate radiative transfer model that predict the light climate in Kongsfjorden and inform our thinking about light availability for photosynthesis and animal behaviour. These processes are subject to change due to the effects of global warming, and it is essential that we better understand how biological systems will repsond to reduced sea-ice cover, increased inputs of sediments and coloured dissolved organics, and increasing amounts of artificial light from human settlements and associated impacts on natural light fields.