RRS Discovery DY197
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RRS Discovery (74EQ) |
| Cruise identifier | DY197 |
| Cruise period | 2025-08-11 — 2025-09-09 |
| Status | Completed |
| Port of departure | Southampton, United Kingdom |
| Port of return | Dundee, United Kingdom |
| Purpose | Research |
| Objectives | The cruise is a part of the ESWEETS3 project - Enabling Sustainable Wind Energy Expansion in Seasonally-Stratified Seas. The aim is to determine the oceanographic effects of a floating offshore wind farm. Floating wind farms are deployed in deep regions of the shelf seas, where seasonal stratification controls the timing and productivity of phytoplankton growth. The cruise was entirely focused on the Kincardine floating offshore wind farm, about 8 miles east of Aberdeen in the northwestern North Sea.
High-sampling rate temperature and salinity loggers, with good vertical resolution, were deployed on two moorings, north and south of the wind farm to capture water column stratification through the duration of the cruise. Each mooring included a near-bed CTD sensor with dissolved oxygen and chlorophyll. Numerous CTD profiles were carried out around the windfarm, including several 25-hour fixed stations with repeated CTD profiles. CTDs provided high-resolution data on stratification, chlorophyll and oxygen as well as water samples for analyses for inorganic nutrients, DOC, POC, dissolved oxygen, chlorophyll, HPLC pigments, as well as water for onboard incubations of phytoplankton growth. Zooplankton were collected using a WP2 net. A Scanfish CTD system was used in a set of 25-hour repeat box surveys around the wind farm to detect wakes effects as tidal flows passed the wind farm structures. Two Slocum gliders were deployed, which will remain surveying until recovery from FRV Scotia in October. A Seaglider, operated by UEA, was deployed for the duration of the cruise. Additional work was carried out for a related project Equify – this primarily involved deploying and recovering seabed landers with acoustic (active and passive) sensors on them. |
| Chief scientist | Jonathan Sharples (University of Liverpool Department of Earth, Ocean and Ecological Sciences) |
| Project | ESWEETS3 - Enabling Sustainable Wind Energy Expansion in Seasonally-Stratified Seas |
| Ocean/sea areas | |
| General | North Sea |
| Specific | Northwestern North Sea |
| Track charts |  (0.10 MB) |
| Measurements | |
| Physical oceanography | |
| Surface measurements underway (T,S) | Quantity: activity duration in days = 28 Description: Ship surfmet and ADCP. |
| CTD stations | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| CTD stations | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Current profiler (eg ADCP) | Quantity: activity duration in days = 28 Description: Ship surfmet and ADCP. |
| Current profiler (eg ADCP) | Quantity: activity duration in days = 30 Description: Ship's ADCP |
| Other physical oceanographic measurements | Quantity: activity duration in days = 28 Description: Ship's WAMOS |
| Other physical oceanographic measurements | Quantity: number of surveys = 5 Description: Scanfish undulating CTD. Repeat box surveys over 25 or 13 hours. |
| Chemical oceanography | |
| Oxygen | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| Oxygen | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Phosphate | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Phosphate | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| Nitrate | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Nitrate | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| Nitrite | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Nitrite | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| Silicate | Quantity: number of profiles = 190 Description: Water samples for inorganic nutrients (typically 4 - 10 per profile), DOC (4 - 10 per profile) and dissolved oxygen (1 - 2 per profile, triplicates, for sensor calibration) |
| Silicate | Quantity: number of profiles = 206 Description: Seabird 911 CTD system. Vertical profiles to full depth. |
| Biology and fisheries | |
| Primary productivity | Quantity: number of experiments = 8 Description: Primary production and nutrient uptake incubations. |
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of profiles = 100 Description: HPLC for pigment analyses |
| Zooplankton | Quantity: number of hauls = 24 Description: Bongo net hauls for zooplankton |
| Acoustic reflection on marine organisms. | Quantity: activity duration in days = 28 Description: Ship's EK80 |
| Meteorology | |
| Routine standard measurements | Quantity: activity duration in days = 28 Description: Ship surfmet and ADCP. |
| Geology and geophysics | |
| Multi-beam echosounding | Quantity: activity duration in days = 28 Description: Ship's multi-beam |
| Moorings, landers, buoys | |
| Physical oceanography | |
| Subsurface temperature measurements | 57° 3' 29" N 1° 48' 29" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx 100m. Deployed 14th August 2025, recovered 4th September 2025. |
| Subsurface temperature measurements | 56° 57' 0" N 1° 53' 59" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx. 75m. Deployed 14th August 2025, recovered 4th September 2025. |
| Current profiler (eg ADCP) | 56° 57' 0" N 1° 53' 59" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx. 75m. Deployed 14th August 2025, recovered 4th September 2025. |
| Current profiler (eg ADCP) | 57° 3' 29" N 1° 48' 29" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx 100m. Deployed 14th August 2025, recovered 4th September 2025. |
| Current profiler (eg ADCP) | 56° 59' 23" N 1° 52' 58" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Current profiler (eg ADCP) | 57° 2' 10" N 1° 50' 51" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Current profiler (eg ADCP) | 57° 1' 39" N 1° 51' 6" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Current profiler (eg ADCP) | 57° 1' 5" N 1° 50' 19" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Other physical oceanographic measurements | 56° 58' 59" N 1° 45' 6" W — Slocum glider; CTD+chl+backscatter. Deployed 15th August. Due for recovery Oct. 2025. |
| Other physical oceanographic measurements | 56° 58' 59" N 1° 45' 6" W — Seaglider; CTD+chl+backscatter. Deployed 15th August. Recovered 4th Sept. 2025. |
| Other physical oceanographic measurements | 56° 58' 59" N 1° 45' 6" W — Slocum glider; CTD+chl+backscatter. Deployed 15th August. Due for recovery Oct. 2025. |
| Chemical oceanography | |
| Oxygen | 57° 3' 29" N 1° 48' 29" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx 100m. Deployed 14th August 2025, recovered 4th September 2025. |
| Oxygen | 56° 57' 0" N 1° 53' 59" W — Temperature loggers every 2.5 m near-surface, 5 m deeper, near-surface and near-bed microcat CTDs, RBR Concerto CTD with DO near-bed, RDI 300 kHz ADCP. Water depth approx. 75m. Deployed 14th August 2025, recovered 4th September 2025. |
| Biology and fisheries | |
| Acoustic reflection on marine organisms. | 57° 1' 5" N 1° 50' 19" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Acoustic reflection on marine organisms. | 57° 2' 10" N 1° 50' 51" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Acoustic reflection on marine organisms. | 56° 59' 23" N 1° 52' 58" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Acoustic reflection on marine organisms. | 57° 1' 39" N 1° 51' 6" W — Bed lander with ADCP + fish acoustics. . Deployed 14th August 2025, recovered 3rd September 2025. |
| Data held at BODC | |
| Discrete samples | |
| 208 CTD frame plus rosette sampler | |
| 2 Instrument mooring |
