RV Lough Foyle LFjun92

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Lough Foyle (74LG)
Cruise identifierLFjun92
Cruise period1992-06-15 — 1992-06-18
Port of departureBelfast, United Kingdom
Port of returnBelfast, United Kingdom
Objectives1) To investigate the distribution of dissolved inorganic nutrients and phytoplankton biomass in relation to the vertical stucture of the water column.
2) To estimate phytoplankton production at selected locations. Miss D. Faughy participated in the cruise as part of her M.Sc. Project 'the distribution of phytoplankton species in relation to the frontal boundary in the western Irish Sea.'

Water samples were collected from depths selected on the basis of the vertical distribution of temperature and salinity for estimation of phytoplankton chlorophyll and dissolved inorganic nutrients. Water samples were preserved with acidic Lugol's iodine for microscopic analysis of phytoplankton species composition and abundance. The spatial distribution of physical, chemical and biological variables in near surface water were mapped continuously when the ship was steaming between stations.
Chief scientistRichard Gowen (Department of Agriculture for Northern Ireland)
Cruise reportRV Lough Foyle LFjun92 cruise report lf_jun92.pdf (0.09 MB) 
Ocean/sea areas 
GeneralIrish Sea and St. George's Channel
SpecificThe Irish Sea and North Channel
Physical oceanography 
Subsurface temperature and salinity measurementsQuantity: number of stations = 36
Description: At each station a vertical profile of temperature and conductivity was measured with the Hydrobios CTD and Chelsea Instruments Fluorometer
Transparency (eg transmissometer)Quantity: number of stations = 36
Description: Secchi disc used
Optics (eg underwater light levels)Quantity: number of stations = 7
Description: At selected stations, downwelling and upwelling irradiance was measured using Licor 2 Phi sensors. At these stations water samples were collected and used to estimate carbon fixation by phytoplankton using a standard C-14 incubation technique.
Chemical oceanography 
OxygenQuantity: number of stations = 5
Description: Samples of near bottom water were collected from selected stations for the estimation of dissolved oxygen.
Biology and fisheries 
Primary productivityQuantity: number of experiments = 7
Description: Productivity experiments
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of stations = 36
Description: At each station a vertical profile of fluorescence was measured with the Hydrobios CTD and Chelsea Instruments Fluorometer.
ZooplanktonQuantity: number of stations = 36
Description: At each station, 2 vertical zooplankton hauls were made using one of the Bongo nets fitted with a 300 micrometer mesh net. One sample was preserved with formalin and the second sample was filtered