Cruise inventory

RRS Discovery D306

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD306
Cruise period2006-06-23 — 2006-07-09
StatusCompleted
Port of departureFalmouth, United Kingdom
Port of returnCork, Ireland
PurposeResearch
ObjectivesThe aim of this cruise was to develop a better understanding of carbon cycling in the pelagic waters of the Porcupine Abyssal Plain (PAP). There were three objectives:
1) Turnaround moorings at the PAP Observatory;
2) Conduct a 1-D time series on the central station of a wide range of biogeochmical processes and to back this up with a mesoscale survey of key variables;
3) To trial the use of Autosub for mesoscale surveys in conjuction with the ship.
All objectives were met, although the tops of the moorings were found to be missing probably due to fishing activity and the Autosub trials were incomplete due to vehicle failure. A full mesoscale survey was carried out using the ship and an eleven day time series at the central station was achieved.

Friday 23 June [JD174]
Scientific party met at 13:00 to agree work plans. The Master gave welcome & safety talk at 15:00. We sailed at 18:00 after a series of delays. The Chief Officer was discharged off sick and a replacement was travelling from Lincolnshire. On reaching Plymouth, the railway shut due to a suicide on the track. The replacement mate required taxi from Plymouth to Falmouth. One of the ship's cranes broken, compromising our ability to handling moorings. The ship's engineers worked flat out yesterday and today and managed to cannibalise parts from other cranes. On sailing we moved into the lee of Falmouth Bay to carry out ship's compass check and then deployed Autosub briefly to check its sensors were working. The sea-state was surprisingly benevolent considering how hard the wind had been blowing for previous 3 days. The skies were still very cloudy.

Saturday 24 June [JD175]
We made an easy passage with winds BF 3-4. The scientists were finding their sea-legs, with no major problems. An Emergency muster & life boat drill was run at 10:30. We had a discussion about Autosub mission and decide to work the central box at PAP for the first deployment.
Chief scientistPeter H Burkill (National Oceanography Centre, Southampton)
ProjectBICEP
Coordinating bodyGDD, NOCS
Cruise reportRRS Discovery D306 cruise report d306.pdf — access key 'C' (1.81 MB) 
Ocean/sea areas 
GeneralNorth East Atlantic Ocean (limit 40W)
SpecificNorth Atlantic Ocean
Measurements 
Physical oceanography 
Surface measurements underway (T,S)Quantity: activity duration in days = 17
Description: On-line TSG: conductivity, temperature, fluorescence
CTD stationsQuantity: number of profiles = 50
Description: CTD varying in depth from 200-4000m. 23 of 50 at PAP site. C,T,D,fluor, oxygen and for some ISUS NO3 and FRRF plus 24 bottles at every station
Current profiler (eg ADCP)Quantity: activity duration in days = 17
Description: Ship mounted ADCP operated throughout cruise
Other physical oceanographic measurementsQuantity: activity duration in days = 4
Description: Moving Vessel Profiler: towed for 4 days, 18 hours per day, punctuated by CTD casts
Other physical oceanographic measurementsQuantity: number of samples = 334
Description: Salinometry from CTD bottle samples and on-line non-toxic
Other physical oceanographic measurementsQuantity: number of stations = 18
Description: Measurements of turbulent dissipation using freefall profiler. Typically 6-10 proilfes to 200+m per station
Other physical oceanographic measurementsQuantity: track kilometres = 532
Description: CTD measurements by Autosub on 4 missions
Chemical oceanography 
OxygenQuantity: number of profiles = 50
Description: Samples from CTD bottles
PhosphateQuantity: number of profiles = 50
Description: Samples from CTD bottles
NitrateQuantity: number of profiles = 50
Description: Samples from CTD bottles
SilicateQuantity: number of profiles = 50
Description: Samples from CTD bottles
Biology and fisheries 
Primary productivityQuantity: activity duration in days = 12
Description: Prim Prod from 13C and 14C plus nitrate uptake from 15N using incubations from dawn cast
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of profiles = 41
Description: FRRF measurements of physiology both continuous and from discreete CTD bottle samples
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of profiles = 40
Description: HPLC analysis from range of depths from CTD bottles. Samples also taken from 3 SAPS and 2 sediment traps
Particulate organic matter (inc POC, PON)Quantity: activity duration in days = 4
Description: Flow cytometric analysis of pico and anaoplankton underway at 12min intervals
Particulate organic matter (inc POC, PON)Quantity: track kilometres = 532
Description: Flow cytometric analysis of pico and anaoplankton underway from Cytometer on Autosub
Particulate organic matter (inc POC, PON)Quantity: activity duration in days = 12
Description: POC, PON from 12 depths to 200m at dawn every day
Particulate organic matter (inc POC, PON)Quantity: number of profiles = 22
Description: Molecular diversity of photosynthetic picoeukaryotes
Particulate organic matter (inc POC, PON)Quantity: number of profiles = 13
Description: Flow cytometric analysis of pico and anaoplankton
Particulate organic matter (inc POC, PON)Quantity: number of profiles = 11
Description: Micro-organisms role in uptake of CO2 and amino acids using stable isotopes
Particulate organic matter (inc POC, PON)Quantity: number of profiles = 5
Description: Microbial activity from uptake of isotopically labelled precursors
Sediment trapsQuantity: number of deployments = 9
Description: Deployments of PELAGRA drifting sediment traps
Sediment trapsQuantity: number of profiles = 7
Description: Carbon export from 234Th and 238U disequilibria using CTD bottle stations from between 8-10 depths to a max of 1000m
PhytoplanktonQuantity: activity duration in days = 12
Description: Size-fractionated phytoplankton biomass from 12 depths to 200m at dawn every day
PhytoplanktonQuantity: number of stations = 11
Description: WP2 200micron nets for zooplankton from between 1 and 5 haul depths
ZooplanktonQuantity: number of profiles = 8
Description: Microzooplankton grazing
ZooplanktonQuantity: number of stations = 11
Description: 20micron Apstein nets for phytoplankton from between 1 and 5 haul depths
Meteorology 
Routine standard measurementsQuantity: activity duration in days = 17
Description: Standard met measurements
Moorings, landers, buoys 
Biology and fisheries 
Sediment traps48° 59' 8" N  16° 25' 39" W — Sediment traps deployed: 2 at 3000m; 1 at 4700m (100mab)
Data held at BODC 
Discrete samples 
1  Instrument mooringSedimentation flux quantification in the water column