RV Lough Foyle LFjul92

Cruise summary report

Cruise Info. 
Ship name (ship code)RV Lough Foyle (74LG)
Cruise identifierLFjul92
Cruise period1992-07-13 — 1992-07-16
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 structure of the water column.
2) To estimate phytoplankton production at selected locations and carry out a comparison between in situ and ship-board, incubator estimates of primary production.

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 LFjul92 cruise report lf_jul92.pdf (0.12 MB) 
Ocean/sea areas 
GeneralIrish Sea and St. George's Channel
SpecificThe Irish Sea
Physical oceanography 
CTD stationsQuantity: number of stations = 26
Description: Vertical profiles of temperature and conductivity measured with the Hydrobios CTD and Chelsea Instruments fluorometer
Transparency (eg transmissometer)Quantity: number of stations = 26
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 technique
Chemical oceanography 
OxygenQuantity: number of stations = 2
Description: Samples of near bottom water were collected from seleced stations for the estimation of dissolved oxygen
Biology and fisheries 
Primary productivityQuantity: number of stations = 9
Description: Productivity experiments carried out
Phytoplankton pigs (eg chlorophyll, fluorescence)Quantity: number of stations = 26
Description: Vertical profiles of fluorescence measured with the Hydrobios CTD and Chelsea Instruments fluorometer
ZooplanktonQuantity: number of stations = 26
Description: 2 vertical zooplankton hauls were made at each station using one of the Bongo nets fitted with a 300 micrometer mesh net. One sample was preserved with formalin for later analysis and the second sample was filtered