Gaping activity of oysters (O. edulis) deployed in the Voordelta (North Sea) during spring (A) (from 17th of May until the 3rd of June 2021) (oyster 1, 2 and 5) and autumn (B) period (from 27th October to 13th November 2020) (oyster 6, 7 and 8). The x-axis denotes time (days). The left y-axis and black solid line denote the relative valve gape (0 indicates closed and 1 indicates maximally opened). On the right y-axis temperature (30 min average) is indicated (red dotted line) in °C in Figure 8A. In Figure 8B turbidity is indicated (red dotted line) in FTU on the right y-axis