Microzooplankton abundance and biomass from CTD bottle samples during the Atlantic Meridional Transect AMT12 cruise in May-June 2003

This dataset contains microzooplankton abundance and biomass data from CTD bottle samples collected during the AMT12 cruise in the Atlantic between Port Stanley, Falkland Islands, and Grimsby, United Kingdom, in May-June 2003. Seawater samples were collected from the CTD Niskin bottles at the pre-dawn cast from up to 4 depths equivalent to 55%, 33%, 14% and 1% surface irradiance. Water samples were fixed with Lugol's solution and formalin directly from the CTD rosette bottles. Slides were prepared for analysis after the cruise. The slides 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 contribute to the AMT project and were collected by scientists from the Plymouth Marine Laboratory.