Physical environment - In situ data - Chlorophyll a concentration collected during the International Bottom Trawl Survey in 2007

Three environmental parameters were measured in situ during the IBTS in 2007. Temperature and salinity were measured using thermosalinometer 3 to 5 m under sea surface. Sub-surface (3-5 m) chlorophyll a concentration was measured using a fluorometer (measure the fluorescence emitted by the pigment). The IBTS survey, which takes place each year in January, gives a good illustration of winter conditions.