RV Lough Foyle LFnov91

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Lough Foyle (74LG)
Cruise identifierLFnov91
Cruise period1991-11-19 — 1991-11-21
Port of departureBelfast, United Kingdom
Port of returnBelfast, United Kingdom
Objectives1. To determine the spatial distribution of dissolved inorganic nutrients (ammonia,
nitrate, phosphate and silicate) and chlorophyll related phytoplankton biomass
in relation to the hydrography of the western Irish Sea.

2. To undertake primary production experiments using a standard 14C incubation

3. To calibrate the Hydrobios CTD for salinity.

Stations 4 and 6 in the North Channel were not worked due to a north easterly gale. The vertical distribution of temperature and salinity were measured at selected stations using the Hydrobios CTD. At these stations, water samples were collected from selected depths for the measurement of dissolved inorganic nutrients, estimation of phytoplankton biomass (chlorophyll) and salinity calibration. The attenuation of downwelling photosynthetically active irradiance was measured at selected stations using Biospherical Instruments Inc. QSP profiling system fitted with a depth sensor. The trAAks autoanalyser was set up to measure concentrations of dissolved inorganic nutrients in near surface waters at six minute intervals using the ships' clean water supply.
Chief scientistRichard Gowen (Department of Agriculture for Northern Ireland)
Cruise reportRV Lough Foyle LFnov91 cruise report lf_nov91.pdf (0.15 MB) 
Ocean/sea areas 
GeneralIrish Sea and St. George's Channel
SpecificThe Irish Sea, Solway Firth
Track chartsRV Lough Foyle LFnov91 cruise track — lf_nov91track.pdf (0.03 MB) 
Physical oceanography 
Water bottle stationsQuantity: number of stations = 12
Description: Water samples from 5, 10, 20, 45m
CTD stationsQuantity: number of stations = 12
Description: CTD profiles. During the periods when the CTD was not used for vertical profiling, it was used to map near surface sea temperature and salinity
Optics (eg underwater light levels)Quantity: number of stations = 3
Description: Light profiles taken for stations 43, 46 and 50
Biology and fisheries 
Primary productivityQuantity: number of stations = 2
Description: Sample taken from stations' 43 and 46 to determine productivity
Primary productivityQuantity: number of stations = 12
Description: A sub-sample (30ml) of near surface water from each CTD station was preserved with acidic Lugol's Iodine for phytoplankton species identification and enumeration
Primary productivityQuantity: number of stations = 2
Description: At stations 43 and 46, water from the ships' clean water supply was used to estimate carbon fixation by phytoplankton. Water samples were inocuklated, incubated, fixed with formalin, filtered and stored for future analysis
Moorings, landers, buoys 
Bottom deposits54° 10' 59" N  5° 18' 17" W — Samples collected of bottom sediment and associated benthic fauna