RRS James Clark Ross JR20061206 (JR155, JR163, JR164)
Cruise summary report
| Cruise Info. | |||||||||||||||||
| Ship name (ship code) | RRS James Clark Ross (74JC) | ||||||||||||||||
| Cruise identifier | JR20061206 (JR155, JR163, JR164) | ||||||||||||||||
| Cruise period | 2006-12-06 — 2006-12-17 | ||||||||||||||||
| Status | Completed | ||||||||||||||||
| Port of departure | Stanley, Falkland Islands (Malvinas) | ||||||||||||||||
| Port of return | Rothera, Antarctica | ||||||||||||||||
| Purpose | Research | ||||||||||||||||
| Objectives | Twelfth occupation of the Drake Passage section, established during the World Ocean Circulation Experiment as repeat section SR1b, first occupied by Southampton Oceanography Centre (now the National Oceanography Centre) in collaboration with the British Antarctic Survey in 1993, and re-occupied most years since then.
The main objectives are: (i) to determine the interannual variability of the position, structure and transport of the Antarctic Circumpolar Current (ACC) in Drake Passage; (ii) to examine the fronts associated with the ACC, and to determine their positions and strengths; (iii) by comparing geostrophic velocities with those measured directly (by the lowered ADCP), to determine the size of ageostrophic motions, and to attempt to estimate the barotropic components; (iv) to examine the temperature and salinity structure of the water flowing through Drake Passage, and to identify thereby the significant water masses; (v) to calculate the total flux of water through Drake Passage by combining all available measurements. ACCLAIM Bottom Pressure Recorders have been used for making measurements of the Antarctic Circumpolar Current (ACC) since 1988, initially in the Scotia Sea and then later across the Drake Passage between the Falkland Islands and the Antarctic peninsula. Some of the Bottom Pressure Recorders (BPRs) are combined with Inverted Echo Sounders (IES). During this cruise, one BPR and one BPR/IES were recovered and re-deployed in the Drake Passage. The Sea Level Recorders at Stanley, Falkland Islands, Vernadsky and Rothera Research Stations in Antarctica, were also serviced. JR155 was part of a continuing series as part of an AFI project (NERC NER/G/S/2002/00024 Biogeochemical Particle Flux Study in Marguerite Bay Antarctic Peninsula AFI4/13 PIs Jickells, Clarke, Brandon and Meredith) to study the physical and chemical properties, primary productivity processes and sedimentation processes in Marguerite Bay. The work is designed to augment the ongoing BAS Rothera Biogeochemical Times Series (RaTS) programme in Ryder Bay in northern Marguerite Bay, and to extend the programme into the open waters of Marguerite Bay. The sampling is therefore undertaken at two sites, the RaTS station in Ryder Bay and in the deeper water within Marguerite Bay itself. The cruise also contributed to another AFI project (NERC AFI4/02) PIs Elderfield, Ganeshram, Rickerby and de la Rocha "Behaviour of trace elements and isotope ratios of sea-ice brine and microaalgae: reconstructing the Antarctic sea-ice environment." In this second season (2006/7), moorings deployed earlier in the project were continued through a further full season and additional sediment sampling was undertaken. Hence the aims of JR155 were: 1. recover, service and redeploy the moorings previously deployed on JR136/7 in 2006, 2. conduct CTD casts to describe the physical structure of the water column and to provide water samples for nutrient and particulate matter analyses, 3. take box cores at both sites. The locations were, as on previous cruises for this project, one 'deep' mooring 22 miles from Rothera research station with a ~840m water column depth and one 'shallow' mooring at the Ryder Bay site (RaTS) 2 miles from Rothera with a ~500 m water column depth. | ||||||||||||||||
| Chief scientist | Adam P Williams (National Oceanography Centre, Southampton), Rachel Hadfield (National Oceanography Centre, Southampton), Tim Jickells (University of East Anglia School of Environmental Sciences) | ||||||||||||||||
| Project | Drake Passage repeats | ||||||||||||||||
| Cruise report |  (1.02 MB) (1.57 MB) (0.19 MB) | ||||||||||||||||
| Ocean/sea areas | |||||||||||||||||
| General | South West Atlantic Ocean (limit 20W) Southern Ocean | ||||||||||||||||
| Specific | Drake Passage. Marguerite Bay. | ||||||||||||||||
| Track charts | (0.12 MB) | ||||||||||||||||
| Measurements | |||||||||||||||||
| Physical oceanography | |||||||||||||||||
| Surface measurements underway (T,S) | Quantity: activity duration in days = 9 Description: Oceanlogger: SBE45 Conductivity, temperature, depth. Turner Designs 10-AU Fluorometer. Continuous sampling. Intake ~ 6-m depth. | ||||||||||||||||
| Water bottle stations | Quantity: number of stations = 2 Description: 2 CTD stations with water samples collected for nutrient analysis | ||||||||||||||||
| Water bottle stations | Quantity: number of samples = 368 Description: Water samples for salinometer salinity determinations at the 30 CTD stations | ||||||||||||||||
| CTD stations | Quantity: number of samples = 368 Description: SBE35 High Precision Thermometer. 11 seconds of data recorded every time a water sample was collected | ||||||||||||||||
| CTD stations | Quantity: number of stations = 2 Description: 2 CTD stations with water samples collected for nutrient analysis | ||||||||||||||||
| CTD stations | Quantity: number of stations = 31 Description: Vertical profiles, continuous recording. Temperature, conductivity, pressure, oxygen, transmissivity, fluorescence. | ||||||||||||||||
| Current profiler (eg ADCP) | Quantity: activity duration in days = 9 Description: Velocity profiles. Vessel-mounted Acoustic Doppler Current Profiler (VM-ADCP) 75 kHz RD Instruments Ocean Surveyor (OS75) | ||||||||||||||||
| Chemical oceanography | |||||||||||||||||
| Silicate | Quantity: number of samples = 56 Description: Biogenic Silica | ||||||||||||||||
| Other chemical oceanographic measurements | Quantity: number of samples = 56 Description: Particulate Inorganic Matter | ||||||||||||||||
| Biology and fisheries | |||||||||||||||||
| Phytoplankton pigs (eg chlorophyll, fluorescence) | Quantity: number of samples = 131 Description: Chlorophyll | ||||||||||||||||
| Particulate organic matter (inc POC, PON) | Quantity: number of samples = 53 Description: Particulate Organic Matter | ||||||||||||||||
| Meteorology | |||||||||||||||||
| Routine standard measurements | Quantity: activity duration in days = 9 Description: Standard meterological measurements by automated sensor package on JCR | ||||||||||||||||
| Geology and geophysics | |||||||||||||||||
| Core - soft bottom | Quantity: number of stations = 2 Description: 2 box core stations | ||||||||||||||||
| Moorings, landers, buoys | |||||||||||||||||
| Physical oceanography | |||||||||||||||||
| Current meters | 67° 56' 35" S 68° 22' 51" W — Sediment traps and current meters recovered and deployed | ||||||||||||||||
| Sea level (inc. bot. press., inverted echosounder) | 60° 51' 1" S 54° 42' 47" W — | ||||||||||||||||
| Sea level (inc. bot. press., inverted echosounder) | 54° 56' 35" S 58° 21' 24" W — Bottom pressure recorder deployed 2005, recovered Dec 2006. Drake North | ||||||||||||||||
| Sea level (inc. bot. press., inverted echosounder) | 60° 51' 0" S 54° 42' 46" W — bottom pressure recorder and inverted echo sounder. Deployed Dec 2005, recovered Dec 2006. Drake South. | ||||||||||||||||
| Sea level (inc. bot. press., inverted echosounder) | 54° 56' 35" S 58° 21' 18" W — bottom pressure recorder deployed Dec 2006. Drake North | ||||||||||||||||
| Biology and fisheries | |||||||||||||||||
| Sediment traps | 67° 56' 35" S 68° 22' 51" W — Sediment traps and current meters recovered and deployed | ||||||||||||||||
| Data held at BODC | Get data | ||||||||||||||||
| Series/Profiles | |||||||||||||||||
| 1 Acoustic doppler current profiler | Reference numbers Date and time Vertical spatial coordinates Platform or instrument orientation Horizontal velocity of the water column (currents) Metadata parameters Acoustic backscatter in the water column Reference numbers Date and time Vertical spatial coordinates Platform or instrument orientation Horizontal velocity of the water column (currents) Metadata parameters Acoustic backscatter in the water column
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| 3 Moored CTD | Moored instrument depth Reference numbers Date and time Salinity of the water column Temperature of the water column Density of the water column Electrical conductivity of the water column Moored instrument depth Reference numbers Date and time Salinity of the water column Temperature of the water column Density of the water column Electrical conductivity of the water column
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| 2 Water temperature and/or salinity monitor | Reference numbers Date and time Temperature of the water column Sea level
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| Discrete samples | |||||||||||||||||
| 1 Instrument mooring |
