The objective of this survey was to collect data on seawater turbidity and other environmental parameters both prior to the start of and during primary marine surveys. The contracting authority is the Estonian Safety Investigation Bureau (hereinafter ‘contracting authority’ or ‘ESIB’). The specific terms of reference were as follows:
1) To measure seawater turbidity from the surface of the water down to, at minimum, four metres from the seabed, taking into account the space required for turning the equipment around. In order to obtain a complete picture of the turbidity of the water, the measurements must be taken at a frequency of 0.5 Hz, i.e. at least once every two seconds. At least two dives must be performed per hour;
2) To measure the oxygen content, temperature, and salinity of the seawater from the surface of the water down to, at minimum, four metres from the seabed at intervals of at least 1 hour;
3) To process, analyse, interpret, and visualise the collected data.
The measurements were conducted from 13 April to 1 June 2022, which also included the preliminary laser scanning survey period (23–27 May 2022).
