RV Lough Foyle LFnov91
Cruise summary report
| Cruise Info. | |
| Ship name (ship code) | RV Lough Foyle (74LG) |
| Cruise identifier | LFnov91 |
| Cruise period | 1991-11-19 — 1991-11-21 |
| Status | Completed |
| Port of departure | Belfast, United Kingdom |
| Port of return | Belfast, United Kingdom |
| Purpose | Research |
| Objectives | 1. 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 technique. 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 scientist | Richard Gowen (Department of Agriculture for Northern Ireland) |
| Cruise report |  (0.15 MB) |
| Ocean/sea areas | |
| General | Irish Sea and St. George's Channel |
| Specific | The Irish Sea, Solway Firth |
| Track charts | (0.03 MB) |
| Measurements | |
| Physical oceanography | |
| Water bottle stations | Quantity: number of stations = 12 Description: Water samples from 5, 10, 20, 45m |
| CTD stations | Quantity: 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 productivity | Quantity: number of stations = 2 Description: Sample taken from stations' 43 and 46 to determine productivity |
| Primary productivity | Quantity: 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 productivity | Quantity: 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 | |
| Contamination | |
| Bottom deposits | 54° 10' 59" N 5° 18' 17" W — Samples collected of bottom sediment and associated benthic fauna |
