The Atlantic Meridional Transect Programme (1995-2012)

The aims of the Atlantic Meridional Transect (AMT) Programme [www.amt-uk.org] are to quantify the nature and causes of ecological and biogeochemical variability in the planktonic ecosystems of the Atlantic Ocean, and to assess the effects of this variability on biological carbon cycling and air–sea exchange of radiatively active gases and aerosols (Fig. 1). Since 1995, marine and atmospheric data have been collected twice a year along a 13,500 km transect between 50°N and 52°S in the Atlantic Ocean. This transect encompasses a range of biogeographical provinces including the subtropical gyres and the equatorial and coastal upwellings. The sampling strategy is described in Robinson et al. (2006a), and for the last six cruises has involved continuous surface seawater and atmospheric sampling, and twice daily deployment of the CTD, bio-optical sensor rig and mesozooplankton nets. Up to 70 determinands were measured on each cruise (see Table 2 in Robinson et al., 2006a). The programme has included 18 research cruises, involving 180 scientists from 11 countries (Fig. 2), contributing to 170 refereed publications and 70 Ph.D. theses. This unique, spatially extensive, decadal dataset continues to be made available to the wider community through the British Oceanographic Data Centre (BODC) (www.bodc.ac.uk).