Cruise inventory

RRS James Clark Ross JR20120708 (JR269B)

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS James Clark Ross (74JC)
Cruise identifierJR20120708 (JR269B)
Cruise period2012-07-07 — 2012-07-24
StatusCompleted
Port of departureReykjavík, Iceland
Port of returnReykjavík, Iceland
PurposeResearch
ObjectivesCruise JR269B was the second leg (the first being JR269A in late summer 2011) of a programme to investigate methane hydrate accumulation beneath, and methane venting from, the sea bed in an area on the western margin of the Svalbard archipelago. This area is being studied by a number of laboratories and programmes in order to gain better understanding of the relationships between sea floor temperature changes, the methane hydrate stability zone beneath the sea floor, the presence, formation and dissociation of methane hydrate, the nature and distribution of fluid escape features at and beneath the sea floor, and the resulting fluxes of methane into the water column and atmosphere.

The specific objective of this project is to improve estimates of the total amounts of methane and hydrate involved in this process by quantifying the porosity, and the saturation of that porosity with either methane gas or methane hydrate, in the upper few hundred metres beneath the sea floor. To this end, effort during JR269B focused on acquiring controlled source electromagnetic (CSEM) geophysical survey data from two locations - one to the west of Prins Karl Forland, and one on the Vestnesa Ridge. Analysis of the data will aim to combine constraints on the electrical resistivity structure of the sea floor from this study with seismic constraints from previous studies through constrained and joint inversion methods.
Chief scientistMartin C Sinha (National Oceanography Centre, Southampton)
ProjectArctic hydrate dissociation as a consequence of climate change:
Coordinating bodyNatural Environment Research Council (NERC)
Cruise reportRRS James Clark Ross JR20120708 (JR269B) cruise report jr269b.pdf — access key 'C' (9.07 MB) 
Ocean/sea areas 
GeneralArctic Ocean
SpecificWest Spitzbergen continental margin
Track chartsRRS James Clark Ross JR20120708 (JR269B) cruise track — jr269btrk.pdf (00 MB) 
Measurements 
Physical oceanography 
Surface measurements underway (T,S)Quantity: activity duration in days = 18
Description: Standard meteorology and sea surface measurements underway
BathythermographQuantity: number of profiles = 3
Description: XBT casts
CTD stationsQuantity: number of profiles = 4
Description: CTD casts
Current profiler (eg ADCP)Quantity: track kilometres = 8
Description: ADCP measurements
Other physical oceanographic measurementsQuantity: track kilometres = 130
Description: Water column acoustic measurements for detecting bubble plumes
Meteorology 
Routine standard measurementsQuantity: activity duration in days = 18
Description: Standard meteorology and sea surface measurements underway
Atmospheric chemistryQuantity: activity duration in days = 18
Description: Continuous air chemistry measurements for methane using PICARRO system
Atmospheric chemistryQuantity: activity duration in days = 18
Description: Daily air samples
Geology and geophysics 
Bottom photographyQuantity: number of dives = 27
Description: HYBIS remotely operated vehicle dives
Geophysical measurements made at depthQuantity: track kilometres = 60
Description: Controlled source electromagnetic survey
Multi-beam echosoundingQuantity: track kilometres = 130
Description: Swath bathymetry survey
Multichannel seismic reflectionQuantity: track kilometres = 115
Description: Multi-channel seismic reflection profiling
Other geological/geophysical measurementsQuantity: track kilometres = 60
Description: Controlled source electromagnetic survey