Bioluminescence potential dynamics during Polar Night in Arctic.

The common conception has been that polar organisms are dormant during the extended darkness of the Polar Night in the Arctic. However, recent ecosystem studies found evidence of winter reproduction, and demonstrated that the Polar Night can no longer be viewed as a time when most of the Arctic ecosystem is quiescent. Bioluminescence (BL) potential studies along the forming ice edge in the Fram Strait region and the Svalbard Archipelago showed high values of BL potential during the extended period of darkness suggesting a strong energetic output by organisms during the Polar Night (Moline et al. 2012, Berge et al. 2015, Cohen et al. 2014, Cronin et al. 2016). Importantly, surveys have demonstrated a coincidence of high BL potential values (which are almost exclusively due to secondary producers, like copepods) with observed frontal structures. For example, elevated BL potential values were found above the intrusion and upwelling of North Atlantic Water into the Arctic Ocean north of the Svalbard Archipelago. How newly discovered processes affect BL potential is unknown, and there are no attempts to model ecosystem dynamics and BL potential during the extended period of darkness. We will present analysis of existing observations and discuss issues related to BL potential, bio-optical and physical modelling for interpreting the BL potential environment and its relationship to physical features in the Arctic Ocean during the Polar Night.