GLOBEC LTOP stations in the Northern Gulf of Alaska: Red circles denote CTD-nutrient-phytoplankton-zooplankton stations; blue circles denote CTD-nutrient-phytoplankton stations. Click here for a map with the station names incorporated. ADCP and sea surface data are collected continuously underway and while on station. Acoustic data for zooplankton biomass determinations are collected at all zooplankton stations and between stations on the Seward Line. Over twenty years of historical CTD data exist for stations on the Seward and Cape Fairfield Lines. The GAK1 station CTD time series extends back to 1970. Stations along the Cape Cleare Southeast Line are occupied on the April, May and July cruises in years 2001 and 2003 to provide along-shore coverage for comparisons to the Seward Line transects at these times.