Srulise Report, RV ATAIR, Cruise 0671013-1, Bremerhaven - Skagen - Aberdeen, 19 Jul - 11 Aug 2022 | 
5 
Scientific 
Too's 
and 
Meirocds 
11 
5.1 Overviev 
Scientific tools that were in use during the cruise comprised profiling of the entire water column 
using a Conductivity-Temperature-Depth (CTD) unit attached to a carousel water sampler sys- 
tem and equipped with a number of sensors that will be detailed in the following sections. 
Additional sensors attached to the CTD-unit involved a sensor measuring dissolved oxygen, a 
dual-wavelength sensor measuring simultaneously both, fluorescence and turbidity. and an 
altimeter for determining the distance of the underwater unit to the sea bottom in order to avoid 
sontact. 
The carousel water sampler was equipped with a fixed number of 10 litres Niskin bottles to 
allow for taking water samples at discrete depths of the water column. Water sampling activi- 
ties consisted of taking salinity samples for the sake of calibrating the conductivity sensors of 
the CTD unit, water samples for water density and chlorophyll-a for home-based laboratory 
analyses. 
Sampling with respect to radionuclides was mostly limited to the surface layer. At one station 
in the Skagerrak (GN808), water samples were taken at different depths between the sea sur- 
face and the bottom of the Norwegian Trench using large-volume samplers (LVS). 
In total, 95 stations involving the CTDO/water sampler system and excluding a test station 
were carried out. Secchi depth determination and water sampling for chlorophyll-a was con- 
ducted on preselected stations and most of the time happened on daylight stations. 
A vessel-mounted Acoustic Doppler Current Profiler (VMADCP) system operating at 150 kHz 
and mostly in narrow-band mode delivered oceanic velocity data of the upper water column 
during the cruise. Further underway measurements focused on standard meteorological data, 
water depth and near-surface values for water temperature, salinity, fluorescence/chlorophyll 
and turbidity. 
5.2 CTD Sensor Unit and Water Sampler Se. 
During cruise 067/013-1, a profiling conductivity-temperature-depth (pressure) sensor unit 
(CTD) of type Sea-Bird Electronics (SBE) 9plus (“CTD Sonde S1”) was in use. It was operated 
and powered from out of the vessel’s hydrography lab via a deckunit of type SBE11plus. The 
CTD sensor package was mounted horizontally in the lower part of a water sampler frame of 
type SBE32, which can carry up to 12 Niskin bottles of 10 litres volume. Raw data recording 
was performed using the BSH software Seasave_ Start, which internally calls the SBE software 
SeaSave, version 7.26.7.121, and the data conversion software (from binary into ASCII) SBE 
DataProcessing, version 7.26.7.129. 
The CTD sensor package consisted of two pairs of temperature (T) and conductivity (C) sen- 
sors, one primary and one secondary. each of which was connected to a particular pump and