These data were collected under NSF Grant # ARC-0722448 ("BEST: Impacts of Sea-ice on the Hydrographic Structure, Nutrients, and Mesozooplankton over the Eastern Bering Sea Shelf") to Dr. G.L. Hunt, Jr., University of Washington. The eastern Bering Sea shelf supports productive marine ecosystems with extraordinarily valuable fisheries and subsistence resources, but sub-arctic seas are predicted to be one of the regions most sensitive to future warming of the world oceans. Some of the most direct effects of changing climate will be on the extent, duration and timing of sea-ice over the Bering Sea shelf. Sea-ice controls the timing of the spring phytoplankton bloom, the fate of primary production, water column temperature and salinity, and provides a haul out and molting platform for marine mammals. Thus, the most urgent priority of the Bering Sea Ecosystem Study (BEST) is to examine the role of changing sea-ice conditions on the chemical, physical, and biological characteristics of the ecosystem. The first BEST cruise was scheduled on the USCG Healy in April-May 2007, however, physical observations, water column nutrient chemistry, and zooplankton distribution/abundance were not among the ecosystem components funded in the first call for proposals. Project ARC-0722448 funded by NSF after the first call for BEST proposals filled this gap in chlorophyll collections until the remainder of BEST projects could be assembled in 2008.