Microzooplankton abundance and biomass from CTD bottle samples during the Atlantic Meridional Transect AMT13 cruise in September-October 2003

This dataset contains microzooplankton abundance and biomass data from CTD bottle samples collected during the AMT13 cruise in the Atlantic between the UK and the Falkland Islands in September-October 2003. Seawater samples were collected from the CTD Niskin bottles at the pre-dawn cast from up to 5 depths equivalent to 97%, 55%, 33%, 14% and 1% surface irradiance. Water samples (500 ml) were fixed with 2% Lugol's solution directly from the CTD rosette bottles. 100 ml of the fixed sample was settled for 48 hours prior to examination. The samples were examined using an inverted microscope at x200 magnification to enumerate microzooplankton taxa (>20 µm) (Gifford and Caron, 2000). Estimations of biomass were made after image analysis to estimate standard geometric shapes (Hillebrand et al. , 1999) and by using carbon to volume conversions: pg C cell -1 = 0.22 x (µm 3 ) 0.939 for ciliates and pg C cell -1 = 0.76 x (µm 3 ) 0.819 for dinoflagellates (Menden-Deuer and Lessard, 2000). The data were collected by scientists from the Plymouth Marine Laboratory and contribute to the AMT project.