Cruise inventory

RRS James Clark Ross JR20120120 (JR255A)

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Clark Ross (74JC)
Cruise identifierJR20120120 (JR255A)
Cruise period2012-01-20 — 2012-02-03
StatusCompleted
Port of departureStanley, Falkland Islands (Malvinas)
Port of returnStanley, Falkland Islands (Malvinas)
PurposeResearch
ObjectivesThe objectives of the GENTOO project are:
(i) to quantify and understand the possible new source of dense water overflow and its variability; to determine the outflow's potential as an early indicator of Antarctic climate change; to assess the impact of changing dense overflows on the locations and strengths of the surface currents and frontal jets; to provide valuable constraints for climate models that describe how changes in ocean circulation feedback on and regulate climate change in polar latitudes.
(ii) to determine the krill biomass distribution and (temporal and spatial) variability to the east of the Antarctic Peninsula and its likely impact on the circumpolar krill ecosystem; to assess the impact of any variations in the location of the frontal jets (from objective i) on the krill biomass distribution; to alleviate a severe regional lack of field data on krill, a key species in the Antarctic food web.
To achieve the two objectives, our technological deliverable is a critical evaluation of our ability to measure (i) current velocity from a glider and (ii) krill biomass from a glider.
The GENTOO fieldwork in the Weddell Sea was accomplished through a SeaGlider campaign in early 2012. A glider deployment cruise (JR255A) was the primary data gathering exercise; as well as deploying three SeaGliders, a hydrographic survey was undertaken together with nets and underway biological, chemical and physical measurements. The recovery of the three gliders was to have taken place on the recovery cruise.
Chief scientistKaren J Heywood (University of East Anglia School of Environmental Sciences)
ProjectGliders: Excellent New Tools for Observing the Ocean (GENTOO)
Coordinating bodyNatural Environment Research Council (NERC)
Cruise reportRRS James Clark Ross JR20120120 (JR255A) cruise report jr255a.pdf — access key 'C' (2.71 MB) 
Ocean/sea areas 
GeneralSouthern Ocean
SpecificDrake Passage, Weddell Sea, Powell Basin
Track chartsRRS James Clark Ross JR20120120 (JR255A) cruise track — jr255atrk.pdf (00 MB) 
Measurements 
Physical oceanography 
Surface measurements underway (T,S)Quantity: activity duration in days = 12
Description: Underway Temperature and Salinity of surface water
BathythermographQuantity: activity duration in days = 12
Description: Underway Temperature and Salinity of surface water
CTD stationsQuantity: number of stations = 41
Description: Vertical profiles of Salinity, Temperature, Dissolved Oxygen, Chlorophyll
Current profiler (eg ADCP)Quantity: activity duration in days = 12
Description: ADCP current velocities
Chemical oceanography 
IsotopesQuantity: number of stations = 9
Description: Nitrous oxide isotopes
Biology and fisheries 
Primary productivityQuantity: number of stations = 37
Description: Chlorophyll and phytoplankton data
CrustaceansQuantity: number of hauls = 5
Description: Krill sample catch
Acoustic reflection on marine organisms.Quantity: activity duration in days = 12
Description: EK60 backscatter data
Moorings, landers, buoys 
Physical oceanography 
Subsurface temperature and salinity measurements63° 22' 17" S  52° 58' 35" W — Seaglider 522 deployment, measuring Chlorophyll fluroescence, Oxygen, Temperature, Salinity
Subsurface temperature and salinity measurements63° 22' 35" S  52° 58' 30" W — Seaglider 539 depoyment measuring dissolved oxygen, Temperature, Salinity, chlorophyll fluorescence
Subsurface temperature and salinity measurements61° 36' 29" S  48° 25' 35" W — Seaglider 546, measuring Temperature, Salinity
Neutrally buoyant floats63° 31' 17" S  51° 7' 11" W — Argo float measuring Temperature and Salinity
Neutrally buoyant floats63° 31' 17" S  51° 7' 11" W — Argo float measuring Temperature and Salinity
Neutrally buoyant floats63° 1' 29" S  51° 30' 0" W — Argo float measuring Temperature and Salinity
Data held at BODC 
Discrete samples 
31  CTD frame plus rosette samplerChlorophyll pigment concentrations in water bodies