BODC Cruise Metadata Report for RRS James Clark Ross (74JC) cruise JR20110715 (JR253)
Introduction
This report collates information from the BODC cruise inventory and oceanographic databases. It presents
- Cruise Inventory Information
- A summary of BODC data holdings for the cruise from the
- References - including cruise tracks and cruise reports
Cruise Inventory Information
| Long name | RRS James Clark Ross (74JC) cruise JR20110715 (JR253) |
|---|---|
| Short name | JR20110715 (JR253) |
| Objectives and Narrative |
All global climate change scenarios (with CO2 concentration increasing to at least 500 ppm), forecast large and irreversible change in the Arctic Ocean. Coupled ocean - atmosphere modelling predict warming of shallow Arctic seas by +5C and +14C for surface-waters by the year 2100. Indeed, direct observations of upper-waters (at 250 m water-depth) in the western Fram Strait, record a ~+1C increase between 1998 and 2006. Recent marine geophysical research has identified methane hydrate in the Arctic Ocean (including west of Svalbard) and determined some bounds of their thermodynamic stability. Recent discoveries show the Svalbard site to be venting methane as free gas (into at least the lower water-column) where the hydrate outcrops at the seafloor at a water-depth of 350-400 m. A crucial unknown science question is to determine whether there is a causative effect of warming shallow Arctic seas that will perturb the stability of sub-seabed gas hydrates leading to different / faster dissociation fluxes and / or processes?
The critical unknowns in methane dissociation processes in shallow Arctic seas are: (1) what is the volume / inventory of sub-seabed methane hydrate of Arctic continental shelf and slopes? (2) what is the volume / inventory of free methane gas beneath the hydrate? (3) what are the mechanisms, and physical - chemical processes that releases free gas from hydrate? (4) what is the flux, physical state, and chemical fate of methane vented from the seafloor? (5) what is the flux of free methane venting to the atmosphere? Within the Arctic, the western Svalbard shelf and slope is sited at a critical location. The site is bathed by a northward flowing filament of the North Atlantic Current that is a crucial "barometer" of global ocean warming, which shows evidence of warming (and localised cooling) over time scales of years, and is an area of known methane venting with over 250 individual gas bubble plumes ascending through the water-column (with the pre-dominant majority located at the immediate landward edge of the gas hydrate stability zone at ~396 m water depth). The main JCR253 cruise objectives were to: (1) service the AOEM / MASOX seafloor lander with data downloading and installation of replacement batteries and subsequent redeployment at the site (2) undertake acoustic mapping of ascending gas plumes along the western Svalbard slope (3) undertake seafloor ROV and side-scan mapping of seafloor "vent" sites along the western Svalbard slope (4) undertake CTD survey and biogeochemical analysis of water-column around AOEM site and along the western Svalbard slope (5) undertake sediment coring and biogeochemical analysis of sediments and pore-water around AOEM site and along the western Svalbard slope (6) undertake ship-board meteorological and air-sampling measurements during the cruise. The cruise completed all objectives with the recovery and redeployment of the AOEM / MASOX lander, deployment and recovery of the BOB lander for a 17 day experiment, integrated seafloor and water-column sampling along three transects that cross the known gas - hydrate stability zone boundary at the 400 m water-depth, and extensive hydro-acoustic mapping of new methane gas flares where acoustic bubble plumes ascend to the sea-surface - with this newly discovered shallow venting extensively sampled with water-column sampling, sea-surface air sampling, and HyBIS video imaging of the seafloor venting. |
| Ship | RRS James Clark Ross |
| Departure Port | Glasgow, United Kingdom |
| Departure Date | 2011-07-26 |
| Arrival Port | Longyearbyen, Svalbard and Jan Mayen |
| Arrival Date | 2011-08-25 |
| Principal Scientist(s) | Ian Wright (National Oceanography Centre, Southampton) |
| Responsible Organisation | National Oceanography Centre, Southampton |
| Associated Project(s) | Oceans2025 and ESONET |
| IHB Sea Areas Visited | Norwegian Sea, Arctic Ocean |
| Marsden Squares Visited | 287/288 |
| Work Area Description | Northern Norwegian Sea and Arctic Ocean |
| Unable to lookup cruise bounds at this time | |
| Work Area Bounding Polygon | |
| Southern Limit | unknown |
| Northern Limit | unknown |
| Western Limit | unknown |
| Eastern Limit | unknown |
Cruise Inventory Datasets
| Physical oceanography | |
|---|---|
| CTD stations |
Quantity:
number of profiles =
58
Description: CTD and water sampling. CTD measures conductivity, temperature and depth. Nature of data: chemical composition of seawater samples. Parameters measured: methane, ammonia and oxygen concentration. Further analysis: nutrient concentrations. |
| Current profiler (eg ADCP) |
Quantity:
activity duration in hours =
250
Description: Broadband ADCP. Frequency: 75kHz. Parameter measured: vertical current profiler, continuous recording. |
| Water bottle stations |
Quantity:
number of profiles =
58
Description: CTD and water sampling. CTD measures conductivity, temperature and depth. Nature of data: chemical composition of seawater samples. Parameters measured: methane, ammonia and oxygen concentration. Further analysis: nutrient concentrations. |
| Meteorology | |
| Atmospheric chemistry |
Quantity:
number of samples =
36
Description: Air sampling. Frequency: daily. Nature of data: methane concentration and carbon isotope composition. Parameters measured: wind speed and direction, air temperature, air pressure. |
| Geology and geophysics | |
| Bottom photography |
Quantity:
number of dives =
24
Description: Tethered HyBIS / ROV dives. One dive has the purpose of checking the system and purging the air from hydraulic system; one dive was meant to look for MASOX lander; 4 dives were for recovering the lander, one to examine BOB site, one to lay the thermistor string from MASOX lander and 13 to perform video mapping discovery dives on plume sites and undertake vent fluid sampling and bubble counting, and 4 dives to undertake video transect mapping and grab sampling. . For 10 of them the video was recording. All dives had one or more HyBIS video cameras recording |
| Core - soft bottom |
Quantity:
number of cores =
20
Description: 6 gravity and 14 piston cores, discrete sampling for chemical composition of sediment and porefluids. Parameters measured: methane, alkalinity, ammonia concentration in porefluid. Further analysis: concentration of anion and cations in porefluid; chemical composition of sediments. Gravity coring was use while piston core was being fixed. |
| Grab |
Quantity:
number of cores =
13
Description: Box coring, discrete sampling for chemical composition of sediment and porefluids. Parameters measured: methane, alkalinity, ammonia concentration in porefluid. Further analysis: concentration of anion and cations in porefluid; chemical composition of sediments. |
| Multi-beam echosounding |
Quantity:
number of profiles =
201
Description: 650 hours. EM122. Frequency: 12 kHz. Parameters measured: multi-beam continuous water column vertical profiler and bathymetry measurement. |
| Single-beam echosounding |
Quantity:
number of profiles =
220
Description: 530 hours. EK60. Frequency: 38, 120 and 200 kHz. Parameter measured: single beam continuous water column vertical profiler. |
| Single-beam echosounding |
Quantity:
number of profiles =
20
Description: 10 hours. TOPAS. Frequency: 3-6 kHz. Parameter measured: continuous sub-bottom vertical acoustic signal profiler. |
Cruise Inventory Mooring/Buoy Operations
| Latitude | Longitude | Data type | Description |
|---|---|---|---|
| 78° 33' N | 9° 28' E | In-situ seafloor measurement/sampling | BOB (Bubble Observatory): Autonomous free lander to monitor bubble sources with an ER60 120kHz echo-sounder. Deployed on August 6th at 17:00 GMT in 387 m water-depth and successfully recovered on August 23th 2011 |
| 78° 33' N | 9° 28' E | Single-beam echosounding | BOB (Bubble Observatory): Autonomous free lander to monitor bubble sources with an ER60 120kHz echo-sounder. Deployed on August 6th at 17:00 GMT in 387 m water-depth and successfully recovered on August 23th 2011 |
Summary of BODC Data Holdings for the Cruise
National Oceanographic Database
No data currently held for this cruise in the BODC National Oceanographic Database
Project Database
No data currently held for this cruise in the BODC Project Database
