PAR measurements at Hansneset, Kongsfjorden, above and below kelp canopies from 2012 to 2013

Calibrated diurnal variation of irradiance in the PAR range (Ed(PAR,Z)) (10 min intervals) (in µmol/m²/s) measured at several depths above and below the kelp forest off Hansneset between 5 to 31 July 2012. The Odyssey loggers were mounted on each of four vertical racks which were fixed at the seafloor at 2.5, 5, 10 and 15 m depth MLW accompanying the study of Bartsch et al. (2016) (Polar Biology; doi:10.1007/s00300-015-1870-1). One logger was installed below the kelp canopy, approx. 20 cm (±10 cm) above the seafloor representing the “below canopy” situation, and another logger was mounted 90 cm (±10 cm) above the first logger, representing the “above canopy” situation. At 15 m depth, there was only one sensor above ground as this was below the kelp forest in the red algal zone. The loggers at the 10 and 15 m depths were left to run until June 2013 however, as the sensors were not cleaned in regular intervals from August 2012 onwards, absolute values have to be considered with care.