Artificial light during the polar night disrupts Arctic fish and zooplankton behaviour down to 200 m depth

Abstract

For organisms that remain active in one of the last undisturbed and pristine dark environments on the planet-the Arctic Polar Night-the moon, stars and aurora borealis may provide important cues to guide distribution and behaviours, including predator-prey interactions. With a changing climate and increased human activities in the Arctic, such natural light sources will in many places be masked by the much stronger illumination from artificial light. Here we show that normal working-light from a ship may disrupt fish and zooplankton behaviour down to at least 200 m depth across an area of >0.125 km 2 around the ship. Both the quantitative and qualitative nature of the disturbance differed between the examined regions. We conclude that biological surveys in the dark from illuminated ships may introduce biases on biological sampling, bioacoustic surveys, and possibly stock assessments of commercial and non-commercial species.

Into the Deep: New Data on the Lipid and Fatty Acid Profile of Redfish Sebastes mentella Inhabiting Different Depths in the Irminger Sea

“…The contents of TAGs were found to increase with depth, most likely due to the accumulation of high-energy lipids and their FA components as strategic resources, as TAGs comprise a class of molecules with a high energy capacity (generating 2.5-times more energy than carbohydrates) that can be quickly mobilized from adipocytes [19]. The epipelagic zone and upper mesopelagic layers are where the bulk of zoo-and phyto-plankton, which synthesize high-energy FAs, are concentrated [64,65,[71][72][73][74]. The depth range inhabited by beaked redfish in the Irminger Sea extends down to more than 1000 m [42,47,48], where a depth-wise food deficit may develop [64,65].…”

Cloud shadows drive vertical migrations of deep-dwelling marine life

“…Sunlight is the primary cue for this behavior down to depths where organisms can no longer detect it ( 4 , 5 ), with migrators arriving at the sea surface within less than an hour after sunset and departing less than an hour before sunrise globally ( 6 ). Migratory organisms can respond to light from sources other than the sun, such as moonlight ( 7 – 9 ) and anthropogenic light ( 10 , 11 ). Furthermore, zooplankton alter their DVM in response to chemicals produced by fish, called kairomones ( 12 , 13 ), and to internal circadian rhythms that can cue migration during periods of polar midnight sun ( 14 ).…”

Wavelength-dependent effects of artificial light at night on phytoplankton growth and community structure

“…Despite the surge of interest in the ecological effects of ALAN, most of the evidence collected so far comes from terrestrial habitats, while studies on marine populations and communities are currently limited [20][21][22][23][24][25]. Although a small number of studies have investigated the effects of monochromatic ALAN on cyanobacteria and microalgae, these focused on benthos and periphyton [2,[26][27][28][29][30], while no study so far has investigated the effects of polychromatic LEDs on marine phytoplankton.…”