Light intensity time series from 16 locations in Løgstør Bredning, Limfjorden, Denmark, at 3 m above seabed, 9-March-2017

Field studies were conducted in two different areas of the Limfjorden, in Lovns Bredning (26th February to 4th March 2017) and in Løgstør Bredning (6-10th March 2017). In each sampling area, 16 fixed-position moorings were deployed in two circular sensor arrays around a mussel dredging area to investigate possible effects of dredging related sediment plumes (Pastor et al, 2020). The inner array (stations 1 - 8) had a diameter of 200 m and the outer array (stations 9 - 16) was set up with a diameter of 600 m. Integrated temperature and light loggers (HOBO Pendant Temperature/Light 64K Data Logger) were mounted on each mooring in the two circular arrays at three different water depths (0.5, 1.5 and 3.0 m above seabed). The 48 loggers (3 depths and 16 stations) were deployed in each area over a period of four days and light intensity time series were collected with a sampling interval of 30 seconds. Five loggers in the Lovns area did not provide any data due to technical problems (two near-surface loggers and three loggers at 1.5 m above the seabed). However, only one bottom logger at Løgstør Bredning failed to provide data. Each time series was filtered using a 3-minute moving average for removing the largest outliers, but retaining sharp changes in light intensity associated with short-lived sediment plumes caused by experimental mussel dredging.