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RRS Discovery DY077

Cruise summary report

Cruise Info. 
Ship name (ship code)RRS Discovery (74EQ)
Cruise identifierDY077
Cruise period2017-04-14 — 2017-05-01
StatusCompleted
Port of departureSouthampton, United Kingdom
Port of returnSouthampton, United Kingdom
PurposeResearch
ObjectivesThe oceanic water column and the underlying seabed change on a variety of temporal and spatial scales. The objective of the Porcupine Abyssal Plain Sustained observatory is to provide high temporal resolution (hours) of an increasing number of variables which are relevant from the perspective of the biology, physics and chemistry over a relatively small spatial scale (30km). The site has been under examination for over 20 years and during that time, substantial changes have been observed in the benthic environment. The intention is to sustain and enhance these observations in order that a deeper understanding is obtained into the processes which operate; in particular the responses to the changes which are currently taking place in the global environment. The objective of the cruise was primarily to service the infrastructure required for continuous sustained observation, and to put these into context using observations from the ship which as yet cannot be carried out autonomously. In parallel to maintaining and extending exisiting measurements, the over view was enhanced by parallel research into comparing methods of drifting sediment traps and collection of marine aggregates along with studies of the abundance, distribution of and composition of those aggregates. These investigations were carried out using a multi instrument observational approach combined with direct sampling. In addition the cruise achieved sampling of the abyssal plain seabed and its fauna via coring, trawling, and baited traps, and left in place a time-lapse camera system for extended (1-year) seafloor observation.
Chief scientistRichard Stephen Lampitt (National Oceanography Centre, Southampton)
ProjectPorcupine Abyssal Plain deep ocean observatory
Coordinating bodyNatural Environment Research Council (NERC)
Cruise reportRRS Discovery DY077 cruise report dy077.pdf (11.20 MB) 
Ocean/sea areas 
GeneralNorth East Atlantic Ocean (limit 40W)
SpecificPorcupine Abyssal Plain
Measurements 
Physical oceanography 
CTD stationsQuantity: number of profiles = 23
Description: CTD measurements of pressure, salinity, temperature, oxygen, chlorophyll, plus water samples from some CTDs for chlorophyll, oxygen, salinity, DIC and Ammonia
Biology and fisheries 
Particulate organic matter (inc POC, PON)Quantity: number of stations = 2
Description: In situ in-line Hologram water column profiles, (0-250m); Biogeochemical analysis
Particulate organic matter (inc POC, PON)Quantity: number of stations = 10
Description: Snowcatcher water samples analysed for particle size and sinking speed
Particulate organic matter (inc POC, PON)Quantity: number of stations = 3
Description: SAPS microplastics, ammonium, POC PA
ZooplanktonQuantity: number of stations = 5
Description: WP2, plankton net, 200µm, to 200m, 3 x midnight, 3 x noon
ZoobenthosQuantity: number of stations = 10
Description: Multiple sediment cores for various analyses
ZoobenthosQuantity: number of hauls = 2
Description: Otter trawl samples of megabenthos
Demersal fishQuantity: number of hauls = 2
Description: Otter trawl samples of megabenthos
MolluscsQuantity: number of hauls = 2
Description: Otter trawl samples of megabenthos
CrustaceansQuantity: number of hauls = 2
Description: Otter trawl samples of megabenthos
Other biological/fisheries measurementQuantity: number of stations = 3
Description: SAPS microplastics, ammonium, POC PA
Moorings, landers, buoys 
Physical oceanography 
Optics (eg underwater light levels)49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Optics (eg underwater light levels)49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Current meters49° 0' 18" N  16° 27' 53" W — PAP3 deepwater sediment traps Deployment
Current meters49° 0' 27" N  16° 29' 35" W — PAP3 deepwater sediment traps Recovery
Surface drifters/drifting buoys49° 3' 15" N  16° 20' 22" W — NBST tethered traps
Neutrally buoyant floats48° 58' 0" N  16° 21' 0" W — PELAGRA traps
Neutrally buoyant floats49° 3' 15" N  16° 20' 21" W — Marine Snow Catcher
Chemical oceanography 
Oxygen49° 0' 27" N  16° 29' 35" W — PAP3 deepwater sediment traps Recovery
Oxygen49° 0' 18" N  16° 27' 53" W — PAP3 deepwater sediment traps Deployment
Oxygen49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Oxygen49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Carbon dioxide49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Carbon dioxide49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Nitrate49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Nitrate49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
pH49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
pH49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Biology and fisheries 
Primary productivity49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Primary productivity49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Sediment traps49° 0' 27" N  16° 29' 35" W — PAP3 deepwater sediment traps Recovery
Sediment traps49° 3' 15" N  16° 20' 21" W — Marine Snow Catcher
Sediment traps48° 58' 0" N  16° 21' 0" W — PELAGRA traps
Sediment traps49° 3' 15" N  16° 20' 22" W — NBST tethered traps
Sediment traps49° 0' 18" N  16° 27' 53" W — PAP3 deepwater sediment traps Deployment
Zooplankton49° 2' 9" N  16° 20' 21" W — PAP1 Longterm Observatory Recovery
Zooplankton49° 2' 49" N  16° 18' 4" W — PAP1 Longterm Observatory Deployment
Zoobenthos49° 0' 0" N  16° 25' 10" W — 2 x amphipod trap deployment recovery
Zoobenthos49° 0' 23" N  16° 23' 52" W — Time-lapse camera deployment
Crustaceans49° 0' 0" N  16° 25' 10" W — 2 x amphipod trap deployment recovery
Geology and geophysics 
Bottom photography49° 0' 23" N  16° 23' 52" W — Time-lapse camera deployment
Data held at BODC Get data
Discrete samples 
22  CTD frame plus rosette samplerSalinity of the water column
Dissolved oxygen parameters in the water column
1  Instrument mooring