Cruise inventory

RRS Discovery D211

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74E3)
Cruise identifierD211
Cruise period1994-10-09 — 1994-11-11
StatusCompleted
Port of departureMuscat, Oman
Port of returnMuscat, Oman
PurposeResearch
ObjectivesThe cruise formed part of a suite of four cruises (209-212) on RRS Discovery during her 1994 Indian Ocean Campaign. The overall objectives of RRS Discovery cruise 211 were the following:
1. To test the hypothesis that the Oxygen Minimum Zone (OMZ) has a profound effect on community composition, abundance, diversity, size structure, reproductive mode and lifestyle of benthic biota by a comprehensive sampling strategy across areas where the OMZ impinges on the bottom.
2. To see what role the OMZ, and other related physical gradients, play in determining depth-related changes in the benthic community compared to data sets available from the northern Atlantic.
3. To test whether the upper and lower OMZ boundary is a zone of enhanced biological activity with respect to the benthos in the Arabian Sea.
4. To measure size-related biomass, particulate organic carbon fluxes and total benthic metabolism in the sediment at sites within and below the OMZ in order to examine the roles of different food-web components in the benthos, particularly in the context of carbon, nitrate and sulphate fluxes and the relative importance of aerobic and anaerobic metabolism in the sediment.
5. To investigate the benthic response in terms of biogenic reworking, bioturbation, redox conditions and burial rates along oxygen gradients through the OMZ and in response to seasonal carbon input in relation to benthic fluxes and activity, and to determine how organism interactions affect the recycling and/or burial of organic matter.
Chief scientistJohn D Gage (Dunstaffnage Marine Laboratory)
Cruise reportRRS Discovery D211 cruise report d211.pdf — access key 'C' (7.74 MB) 
Ocean/sea areas 
GeneralArabian Sea
SpecificArabian Sea, Continental margin of Southern Oman
Track chartsRRS Discovery D211 cruise track — trk4009.html RRS Discovery D211 cruise track — trk4009a.html RRS Discovery D211 cruise track — trk4009b.html
Measurements 
Physical oceanography 
CTD stationsQuantity: number of stations = 22
Description: CTDs, one station analysed for nutrients, chlorophyll, phyto/microzooplankton
Chemical oceanography 
OxygenQuantity: number of cores = 2
Description: O2 above and below sediment/water interface
OxygenDescription: diss. oxygen (Winkler), salinity, sulphate, carbon, nitrogen
Carbon dioxideQuantity: number of cores = 4
Description: bacteria/organic geochemistry/worms
Carbon dioxideQuantity: number of cores = 4
Description: organic geochemistry
Total - NQuantity: number of cores = 27
Description: organic geochemistry
Total - NQuantity: number of cores = 4
Description: organic geochemistry
Total - NQuantity: number of cores = 4
Description: bacteria/organic geochemistry/worms
pHQuantity: number of cores = 17
Description: bioturbation estimates, redox conditions, sediment strength
IsotopesQuantity: number of cores = 70
Description: isotope incubations for mass spectrometry (15N), GC (N20) analysis
IsotopesQuantity: number of cores = 27
Description: organic geochemistry
IsotopesQuantity: number of samples = 180
Description: sediments sectioned at 1cm intervals for Pb-210 analysis; 6 cores/station
IsotopesQuantity: number of cores = 1
Description: Kasten corer, deep frozen for later C14 analysis
Other chemical oceanographic measurementsQuantity: number of cores = 17
Description: bioturbation estimates, redox conditions, sediment strength
Other chemical oceanographic measurementsQuantity: number of cores = 27
Description: organic geochemistry
Contamination 
Trace metalsQuantity: number of cores = 27
Description: organic geochemistry
Biology and fisheries 
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of samples = 180
Description: for HPLC analysis of pigments
Dissolved organic matter (inc DOC)Quantity: number of cores = 4
Description: organic geochemistry
Dissolved organic matter (inc DOC)Quantity: number of cores = 4
Description: bacteria/organic geochemistry/worms
Biochemical measurements (eg lipids, amino acids)Quantity: number of cores = 27
Description: organic geochemistry
Biochemical measurements (eg lipids, amino acids)Quantity: number of cores = 9
Description: foram lipid biochemistry
ZooplanktonQuantity: number of hauls = 2
Description: vertical net hauls in 200m
Benthic bacteria/micro-organismsQuantity: number of cores = 10
Description: bacteria/geochemistry/nematodes
Benthic bacteria/micro-organismsQuantity: number of cores = 4
Description: organic geochemistry
Benthic bacteria/micro-organismsQuantity: number of cores = 4
Description: bacteria/organic geochemistry/worms
ZoobenthosQuantity: number of cores = 4
Description: organic geochemistry
ZoobenthosQuantity: number of cores = 4
Description: bacteria/organic geochemistry/worms
ZoobenthosQuantity: number of deployments = 2
Description: Epibenthic sledges, megabenthos
ZoobenthosQuantity: number of hauls = 5
Description: Tjarno dredges for megabenthos
ZoobenthosQuantity: number of deployments = 44
Description: Multiple corer;12 cores/deployment;meiofauna/foraminifera abundance
ZoobenthosQuantity: number of hauls = 9
Description: Agassiz trawls, megabenthos
ZoobenthosQuantity: number of cores = 49
Description: USNEL box core samples
MolluscsQuantity: number of deployments = 44
Description: Multiple corer;12 cores/deployment;meiofauna/foraminifera abundance
MolluscsQuantity: number of hauls = 9
Description: Agassiz trawls, megabenthos
MolluscsQuantity: number of hauls = 5
Description: Tjarno dredges for megabenthos
MolluscsQuantity: number of deployments = 2
Description: Epibenthic sledges, megabenthos
CrustaceansQuantity: number of deployments = 2
Description: Epibenthic sledges, megabenthos
CrustaceansQuantity: number of hauls = 9
Description: Agassiz trawls, megabenthos
CrustaceansQuantity: number of hauls = 5
Description: Tjarno dredges for megabenthos
CrustaceansQuantity: number of deployments = 44
Description: Multiple corer;12 cores/deployment;meiofauna/foraminifera abundance
Other biological/fisheries measurementQuantity: number of images = 100
Description: x-ray radiographs of sediment slabs for biogenic structure analysis
Other biological/fisheries measurementQuantity: number of cores = 17
Description: bioturbation estimates, redox conditions, sediment strength
Geology and geophysics 
Bottom photographyQuantity: number of images = 40
Description: bottom photographs; 2-4 at each station
Bottom photographyQuantity: number of deployments = 5
Description: epibenthic camera sled, transects for megabenthos, densities, biomass
Other geological/geophysical measurementsQuantity: number of cores = 17
Description: bioturbation estimates, redox conditions, sediment strength
Moorings, landers, buoys 
Biology and fisheries 
Zoobenthos19° 49' 0" N  58° 23' 59" E — 3hr video benthic lander mechanism/sea bed activity
Pelagic fish19° 49' 0" N  58° 23' 59" E — 3hr video benthic lander mechanism/sea bed activity
Pelagic fish19° 22' 0" N  58° 10' 59" E — loss of lander and equipment
Geology and geophysics 
Bottom photography19° 49' 0" N  58° 23' 59" E — 3hr video benthic lander mechanism/sea bed activity
Data held at BODC 
Discrete samples 
22  CTD frame plus rosette samplerDensity of the water column
Transmittance and attenuance of the water column
Visible waveband radiance and irradiance measurements in the water column
Raw fluorometer output
Salinity of the water column
Raw light meter output
Temperature of the water column
Dissolved oxygen parameters in the water column